Methods and Summary Data for Limnology and (2005-2013)

Methods and Summary Data for Limnology and (2005-2013)
Methods and Summary Data for Limnology and
Food Web Structure in Osoyoos Lake, B.C.
(2005-2013)
K.D. Hyatt, D.J. McQueen, D.P. Rankin, M.M. Stockwell, H. Wright,
S. Lawrence, A. Stevens, C. Mathieu, and L. Weins
Fisheries and Oceans Canada
Salmon & Freshwater Ecosystems Division
Pacific Biological Station
3190 Hammond Bay Road, Nanaimo, BC
V9T 6N7
2015
Canadian Data Report of
Fisheries and Aquatic Sciences 1258
Canadian Data Report of Fisheries and Aquatic Sciences
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Canadian Data Report of
Fisheries and Aquatic Sciences 1258
2015
METHODS AND SUMMARY DATA FOR LIMNOLOGY AND FOOD WEB
STRUCTURE IN OSOYOOS LAKE, B.C. (2005-2013)
by
K.D. Hyatt1, D.J. McQueen2, D.P. Rankin1, M.M. Stockwell1,
H. Wright3, S. Lawrence3, A. Stevens3, C. Mathieu3, and L. Weins3
1
Fisheries and Oceans Canada
Salmon & Freshwater Ecosystems Division,
Pacific Biological Station, 3190 Hammond Bay Road,
Nanaimo, BC V9T 6N7
2
Emeritus Research Professor, York University
Adjunct Professor Simon Fraser University
125 Pirates Lane, Nanaimo, BC V9R 6R1
3
Okanagan Nation Alliance,
#101 3535 Old Okanagan Highway,
Westbank, BC V4T 3L7
ii
© Her Majesty the Queen in Right of Canada, 2015.
Cat. No. Fs 97-13/1258E ISSN 0706-6465 ISBN 978-0-660-02015-0 (print version)
HTML Version: Cat. No. Fs 97-13/1258E-PDF
ISSN 1488-5395
ISBN 978-0-660-02016
Correct citation for this publication:
Hyatt, K.D., McQueen, D.J., Rankin, D.P., Stockwell, M.M., Wright, H., Lawrence, S.,
Stevens, A., Mathieu, C., and Weins, L. 2015. Methods and summary data for
limnology and food web structure in Osoyoos Lake, B.C. (2005-2013). Can. Data
Rep. Fish. Aquat. Sci. 1258: vi + 71 p.
iii
TABLE OF CONTENTS
LIST OF TABLES................................................................................................................. iv
LIST OF FIGURES .............................................................................................................. iv
ABSTRACT ........................................................................................................................... v
RÉSUMÉ .............................................................................................................................. v
ACKNOWLEDGEMENTS .................................................................................................... vi
INTRODUCTION .................................................................................................................. 1
OSOYOOS LAKE SITE DESCRIPTION................................................................................ 2
PHYSICAL DESCRIPTION ............................................................................................... 2
WATER CHEMISTRY ....................................................................................................... 2
OSOYOOS LAKE FISH HISTORY AND METHODS 1997-2005 ....................................... 3
METHODS 2005 - 2013 ........................................................................................................ 4
WATER CHEMISTRY ....................................................................................................... 4
PHYTOPLANKTON ........................................................................................................... 4
ZOOLANKTON.................................................................................................................. 4
Mysis relicta ................................................................................................................... 5
OSOYOOS LAKE SOCKEYE AND KOKANEE ................................................................. 5
In Lake Sampling ........................................................................................................... 5
Laboratory Processing ................................................................................................... 6
Assessment of Age-Specific Fish Densities ................................................................... 6
Fish Density and Echosounder Sampling Errors ............................................................ 7
Densities of Presmolts versus Smolts ............................................................................ 8
RESULTS ........................................................................................................................... 10
OSOYOOS LAKE WATER TEMPERATURES ................................................................ 10
OSOYOOS LAKE OXYGEN CONCENTRATIONS .......................................................... 19
OSOYOOS LAKE WATER CHEMISTRY ........................................................................ 28
OSOYOOS LAKE PHYTOPLANKTON BIOMASS ........................................................... 30
OSOYOOS LAKE ZOOPLANKTON BIOMASS ............................................................... 34
OSOYOOS LAKE ZOOPLANKTON DENSITY ................................................................ 37
OSOYOOS LAKE MYSIS RELICTA BIOMASS ............................................................... 41
OSOYOOS LAKE MYSIS RELICTA DIETS ..................................................................... 44
OSOYOOS LAKE FISH LENGTH, WEIGHT, and DENSITY ........................................... 46
OSOYOOS LAKE FISH STOMACHS .............................................................................. 55
REFERENCES ................................................................................................................... 64
iv
LIST OF TABLES
Table 1.
Osoyoos Lake temperature profiles, 2005 - 2013. …………………………..
10
Table 2.
Osoyoos Lake oxygen profiles, 2005 - 2013. ………………………………...
19
Table 3.
Osoyoos Lake water chemistry summary, 2005 - 2013. ……………………
28
Table 4.
Osoyoos Lake 2005 - 2013, TOTAL algal standing stock. ………………….
30
Table 5.
Osoyoos Lake 2005 - 2013, EDIBLE algal standing stock. ………………...
32
Table 6.
Osoyoos Lake zooplankton biomass 2005 - 2013. ………………………….
34
Table 7.
Osoyoos Lake zooplankton densities 2005 - 2013 ………………………….
37
Table 8.
Osoyoos Lake 2005 - 2013 Mysis relicta biomass. ………………………….
41
Table 9.
Osoyoos Lake 2005 - 2013 Mysis relicta diets as average number of prey
per Mysis. ………………………………………………………………………...
44
Table 10.
Osoyoos Lake 2005 - 2013 fish length, weight, and density. ………………
46
Table 11.
Osoyoos Lake 2005 - 2013 fish stomach summary. ………………………..
55
LIST OF FIGURES
Figure 1.
Location of the Okanagan River, Skaha, and Osoyoos Lakes. ……………
69
Figure 2.
Osoyoos Lake bathymetric contours. …………………………………………
70
Figure 3.
Osoyoos Lake North Basin showing hydro-acoustics survey transects
and water chemistry sampling stations. ………………………………………
71
v
ABSTRACT
Hyatt, K.D., McQueen, D.J., Rankin, D.P., Stockwell, M.M., Wright, H., Lawrence, S.,
Stevens, A., Mathieu, C., and Weins, L. 2015. Methods and summary data for
limnology and food web structure in Osoyoos Lake, B.C. (2005-2013). Can. Data Rep.
Fish. Aquat. Sci. 1258: vi + 71 p.
In 1994, the Okanagan Nation Alliance approached Fisheries and Oceans Canada with a
request for assistance in status and trend assessments to support stock and habitat restoration
work focused on Okanagan sockeye salmon that appeared to have fallen to historic lows of
abundance. In the following years, several collaborative habitat and stock restoration projects
were initiated to facilitate rebuilding of the Okanagan sockeye salmon population to historic
abundance levels. Here we provide a detailed site-description and report on field survey and
sample processing methods used on Osoyoos Lake to assess: (1) limnological conditions
(temperature, oxygen, water transparency, nutrient concentrations, plankton community
structure etc.) in the principal nursery lake, (2) annual to seasonal changes of abundance and
biological traits of juvenile sockeye salmon, and (3) abundance of other limnetic fish species.
Monthly or sub-monthly survey work was especially intensive during the years 2005-2013 when
detailed field observations were required to serve as: (a) critical response variable observations
to determine whether DFO recommended increases in abundance of adult sockeye spawning
in the Okanagan River (Hyatt and Rankin 1999) were accompanied by proportionate increases
in abundance levels of fry recruiting to Osoyoos Lake and subsequent production of both smolts
and returning adults, (b) “control” observations of seasonal to annual patterns of growth and
survival of wild-origin, sockeye fry relative to hatchery-origin fry introduced into either Skaha or
Osoyoos lakes as part of an Okanagan Nation Alliance stock restoration project and (c) “test
interval” observations to monitor annual production of wild fry and smolts following the 2004
deployment of a fish-and-water management tools (FWMT) decision support system to improve
“fish friendly” water management decisions for the Okanagan River and Lake system (Hyatt et
al. 2015). Annual to seasonal observations obtained from Osoyoos Lake are documented in the
current report while comparative observations from Skaha Lake are published in a companion
Data Report (Hyatt et al. 2015).
RÉSUMÉ
Hyatt, K.D., McQueen, D.J., Rankin, D.P., Stockwell, M.M., Wright, H., Lawrence, S., Stevens,
A., Mathieu, C., et Weins, L. 2015. Méthodes et données sommaires relatives à la
limnologie et à la structure du réseau trophique du lac Osoyoos, en ColombieBritannique (2005-2013). Can. Data Rep. Fish. Aquat. Sci. 1258: vi + 71 p.
En 1994, l'Okanagan Nation Alliance a demandé à Pêches et Océans Canada de l'aider à
réaliser des évaluations de l'état et des tendances à l'appui des activités de restauration du
stock et de l'habitat visant le saumon rouge de l'Okanagan, dont l'abondance semblait avoir
atteint ses plus bas niveaux historiques. Au cours des années suivantes, plusieurs projets de
collaboration visant à restaurer l'habitat et le stock de saumon ont été entrepris afin de favoriser
le rétablissement de la population de saumon rouge de l'Okanagan jusqu'aux niveaux
d'abondance historiques. Dans le présent document, nous offrons une description détaillée du
vi
site et faisons état des méthodes de levé hydrographique et de traitement des échantillons
utilisées dans le lac Osoyoos afin d'évaluer : 1) les conditions limnologiques (température,
oxygène, transparence de l'eau, concentration de nutriments, structure de la communauté de
plancton, etc.) dans l'habitat de croissance principal du lac; 2) les changements saisonniers
annuels de l'abondance et des caractéristiques biologiques des saumons rouges juvéniles; et 3)
l'abondance d'autres espèces de poissons limnétiques. De nombreux relevés mensuels ou
infra-mensuels ont été réalisés entre 2013 et 2015, car nous avions besoin d'observations
détaillées sur le terrain afin de nous en servir comme : a) variables de réaction essentielles pour
déterminer si les augmentations de l'abondance des saumons rouges adultes frayant dans la
rivière Okanagan recommandées par le MPO (Hyatt et Rankin 1999) étaient accompagnées
d'augmentations proportionnelles des niveaux d'abondance du recrutement d'alevins dans le
lac Osoyoos et de la production subséquente des saumoneaux et des adultes qui reviennent
frayer; b) données de « contrôle » des profils saisonniers et annuels de croissance et de survie
des alevins de saumon rouge d'origine sauvage par rapport aux alevins provenant des
écloseries qui ont été introduits dans le lac Skaha ou le lac Osoyoos dans le cadre d'un projet
de restauration du stock de l'Okanagan Nation Alliance; et c) données d'« intervalle entre les
contrôles » afin de surveiller la production annuelle des alevins et des saumoneaux sauvages à
la suite du déploiement des outils de gestion du poisson et de l'eau en 2004 comme système de
soutien des décisions en vue d'améliorer les décisions de gestion de l'eau « favorables aux
poissons » dans le système de la rivière et du lac Okanagan (Hyatt et al. 2015). Les
observations annuelles et saisonnières effectuées dans le lac Osoyoos sont consignées dans le
présent rapport tandis que les observations comparatives faites dans le lac Skaha sont publiées
dans un rapport statistique complémentaire (Hyatt et al. 2015).
ACKNOWLEDGEMENTS
This work was supported with funding from several sources including: the Douglas County,
Grant County, and Chelan County Public Utilities of Washington State, the Pacific Salmon
Commission and Fisheries and Oceans Canada. Equipment, expertise, and training of
personnel in field survey techniques were provided by Fisheries and Oceans Canada. We are
grateful for the support provided by managers of the ONA Fisheries Program (Deana Machin
and Howie Wright) and the BC Interior Area of DFO (Barrie Rosenberger, Elmer Fast, Lester
Jantz, and Dean Allan). In aggregate, the ONA, DFO, BC-FLNRO, Zotech Services and Summit
Environmental provided a large roster of field and laboratory personnel who participated in
various phases of the work over the past 10 years including: K. Alex, N. Audy, R. Benson, R.
Bussanich, B. Bissel, C. Cooper, R. Ferguson, S. Folks, A. Friesen, S. Hooley, E. Johnson, T.
Johnston, B.T. Kozlova, A. Neil, J. Paul, T. Peterson, B. Phillips, J. Pizzey, S. Squakin, C.
Tonasket, D. Tom, L. G. Traxler, S. Wiens, and S. Wolski.
INTRODUCTION
One hundred years ago, several sockeye salmon (Oncorhynchus nerka) populations spawned
in the Columbia River watershed (Fryer 1995). Since that time, dams, overfishing and habitat
destruction have reduced the number of self-sustaining populations to two. One population
remains in the Wenatchee River, Washington State and the other in the Okanagan River, British
Columbia. Adult sockeye bound for the Okanagan Valley, begin their up-stream migration during
May-June, negotiate 10 fishways placed at dams in the Columbia and Okanagan rivers, and
arrive at Osoyoos Lake during late June through early September (Allen and Meekin 1980,
Chapman et al. 1995, reviewed in Hyatt and Rankin 1999). They generally hold in the lake until
late September when they move north into the Okanagan River where peak spawning generally
occurs by mid-October (Stockwell and Hyatt 2003). In April-May, newly hatched age 0+
juveniles move down-stream to Osoyoos Lake where they rear for one summer, over-winter,
and leave as age 1+ smolts in April-May of the next year.
During the period 1953-1972 total sockeye salmon returns (potential spawners plus catch) to
the Okanagan River averaged 72,368. During 1973-2004, average returns declined to 35,687.
During 1953-72, average annual exploitation by the commercial fishery and First Nations
averaged 57 %. After 1972, exploitation was reduced to 11 % (Chapman et al. 1995, Hyatt and
Rankin 1999, Hyatt et al. 2003) but stock declines continued such that fewer than 10,000 adult
fish returned in 4 of 6 years from1994-1999. In response to these declining returns, the threeparty (Fisheries and Oceans Canada, Okanagan Nation Alliance, BC Forests Lands and Natural
Resource Operations) Canadian Okanagan Basin Technical Working Group (COBTWG) was
formed in 1996-97 to coordinate stock assessment and restoration projects. Both types of
projects required standardized assessments of annual to seasonal changes in environmental
conditions along with biological traits of adult sockeye spawning in the Okanagan River
(Stockwell and Hyatt 2001, 2003) and juvenile sockeye rearing in Osoyoos Lake (Hyatt and
Rankin 1999). The Okanagan Nation Alliance also embarked on a program designed to reestablish sockeye salmon in the upper Okanagan River and Skaha Lake. After several years of
project design and risk assessment (Okanagan Nation Alliance 2001, 2002, 2003), the
COBTWG concluded that sockeye salmon should be stocked, on an experimental basis, into
Skaha Lake (Peters et al. 1998). One of the objectives of this program was to quantify rates of
growth and rates of egg-to-smolt survival for hatchery-origin sockeye in Skaha Lake relative to
their wild-origin siblings in Osoyoos Lake.
Data originating from the most recent decade of field surveys of biophysical and chemical
conditions in Osoyoos Lake are highly relevant to assessments associated with several ongoing
projects (Okanagan sockeye management, Okanagan Lake and River System water
management, Sockeye reintroduction to Skaha Lake, Okanagan River Restoration Initiative)
and are documented in the tables of the current report. Similar data originating from field
surveys of Skaha Lake are published in a companion Data Report (Hyatt et al. 2015).
2
OSOYOOS LAKE SITE DESCRIPTION
PHYSICAL DESCRIPTION
Osoyoos Lake (Figures 1, 2 and 3), measures 16 km in length, has a surface area of 23 km2, a
volume of 0.40 km3, maximum depth of 63 m, mean depth of 14 m, and an average water
residence time that is very short (weeks) and varies greatly depending on the amount of
snowpack plus summer rainfall in the Okanagan Valley. The North Basin of Osoyoos Lake
measures 7.5 km in length, has a surface area of 990 ha (933 ha of usable limnetic fish habitat),
a volume of 0.25 km3, a maximum depth of 63 m, mean depth of 21 m, and an average water
residence time measured in weeks. The North Basin of Osoyoos Lake is entirely within
Canadian territory and is the only section of the lake where age-0 sockeye can survive during
the summer (Hyatt and Rankin 1999; Rensel 1995, 1996, 1997, and 1998).
WATER CHEMISTRY
A review of water quality trends in the Okanagan watershed between 1970-2001 (Jensen and
Epp 2002) showed that although the number of people living in the Okanagan Valley increased
from 100,000 in 1970 to approximately 300,000 in 2001, extensive abatement efforts from
municipal sewage treatment facilities reduced phosphorus loads into the Okanagan watershed
from 59,148 kg y-1 in 1970 to 2,643 kg y-1in 2001. During 1970-2001, there were marginal
increases in total phosphorus (TP) loading from other sources. Phosphorus loading from farm
lands decreased from approximately 4,000 to 2,000 kg y-1. Loading from forestry remained
unchanged at approximately 8,000 kg y-1 and loading from other non-point sources (industry,
roads, storm water, soil erosion, dust-fall, and other unidentified watershed sources) also
remained unchanged at approximately 40,000 kg y-1. Loading from septic tanks doubled from
approximately 6,000 to 12,000 kg y-1. The net effect of loading reductions from municipal
sources combined with slight increases from other sources was a 55 % reduction in total loading
into the Okanagan River watershed, and indicators of water quality in Lake Okanagan and
Skaha Lake showed improvement.
In Osoyoos Lake during 1970-99, the results were more mixed. Osoyoos Lake North Basin
spring epilimnetic total phosphorus (TP) fell from a range of 23-37 µg L-1 in 1969-70 to 15 µg L-1
in 2001, but fall epilimnetic TP remained relatively constant at about 12 µg L-1, increasing
slightly during 1995-2001. Osoyoos Lake North Basin spring and fall total nitrogen remained
relatively unchanged at 250-350 µg L-1. Spring and fall chlorophyll a concentrations were
variable but remained in the range of 5-15 µg L-1. Similarly, over the 40 year monitoring period,
Osoyoos Lake North Basin Secchi depths remained relatively unchanged at 2-6 m. These
trends suggest that despite substantial up-stream reductions in nutrient loading, Osoyoos Lake
North Basin epilimnetic nutrient concentrations, algal biomasses, and water clarity have
remained relatively static for 40 years (1970-2001). On the other hand, these negative or
unchanged epilimnetic trends contrast with Osoyoos Lake hypolimnetic fall TP concentrations
that have declined from 50-80 µg L-1 during 1975-80 to 5-15 µg L-1 during 2000-04. This trend is
strongly correlated with results from up-stream Okanagan and Skaha Lakes, and may signal
that water quality improvements in Osoyoos Lake are simply lagging behind improvements seen
in the upstream lakes.
3
OSOYOOS LAKE FISH HISTORY AND METHODS 1997-2005
In the early 1970’s the Osoyoos Lake fish community comprised 20 species (Northcote et al.
1972). By 2004, the total had increased to approximately 28 species including several species
of bass, bullheads, suckers, chub, perch, dace, sculpins, and carp (COBTWG 2004).
Anadromous salmonids include chinook (Oncorhynchus tshawytscha), steelhead (O. mykiss),
and sockeye (O. nerka). Sockeye are orders of magnitude more common than the other two
species, and cohabit with small numbers (< 2% of the total) of kokanee (O. nerka).
During 1997-2001 pelagic fish (principally juvenile sockeye salmon) densities were estimated at
night using a Simrad EY-M, 70 kHz, single beam, echosounder with 75 W of power output,
pulse width 0.6 ms and a Time Varied Gain circuit to control for attenuation losses due to
increasing target depth. During 2002-05, pelagic fish densities were estimated at night using a
Simrad EY-500, 70 KHz sounder with 50 W power output with pulse width at 0.2 ms and a
Time Varied Gain circuit. During 2006-13 pelagic fish densities were estimated at night using a
split-beam Biosonics DT-X, 200kHz sounder with 300 W power, pulse width at 1 ms and a 6.6°
transducer. The methods used during 2006-13 will be detailed later in this data report. Crosscalibration of the two Simrad machines showed that they produced similar results. Comparisons
of pelagic fish abundance estimates from the Simrad and Biosonics (“Sonar 5”) echosounders
were conducted during 2005-06. Survey data were collected on 14 sampling dates from four
lakes (Skaha Lake = 4 dates, Osoyoos Lake = 5, Woss Lake = 2 and Vernon Lake = 2). During
each sampling date, complete lake surveys were conducted simultaneously by two survey
crews following identical survey transects. Total density estimates ranged from 300-4000 fish
ha-1. The relationship between total densities derived from Simrad versus Biosonics was:
Simrad = 111+0.9*Biosonics (n = 14, R2 = 0.94)
From this, we concluded that density estimates from Simrad and Biosonics units were
correlated over a wide density range (100-4000 fish ha-1). Additional details regarding
transducer design and counting methods are provided in, Hyatt et al. (1984), Hyatt and Stockner
(1985), Gjernes et al. (1986), and Hyatt et al. (2000).
During 1997-2005, fish biosamples were collected throughout the sampling period using a midwater trawl net (2 m x 2 m mouth opening x 7.5 m long) (stretch mesh ranging from 5.0 cm at
the mouth to 1.3 cm knotless nylon at the cod end). The nets were towed only at night, and
surveys were based on 5-15 trawls per sampling session. Numbers of seasonal biosamples
were the same as for echosounding. On some dates after each trawl set, fish were immediately
removed from the net, held on ice, and then weighed at the end of the sampling session. On two
dates, fish were frozen before processing. Weights were corrected for the effects of freezing
using the expression [fresh weight = 0.124 + 1.0077 * thawed weight] (Shields and Carlson
1996). On four dates, fish were preserved in ethanol before processing. Weights were corrected
for the effects of ethanol using the expression [fresh weight = preserved weight/0.868429] (P.
Rankin, Pacific Biological Station, unpublished data). On two dates, fish were preserved in
formalin and weights were corrected using the expression [(preserved weight) / 1.1151].
4
METHODS 2005 - 2013
WATER CHEMISTRY
Osoyoos Lake water chemistry was sampled at two stations located at (Stations 1 and 6, Figure
3). Samples were taken at monthly intervals from May-October. At each station, Secchi depth
was recorded and oxygen-temperature profiles were measured in 1 m intervals to 24 m depth
then at 4 m intervals to 50 m or 4 m from bottom (depending on the water depth). In the
epilimnion, water chemistry samples were collected using a Van Dorn bottle at 1, 5, 10 m
depths. Water from the three depths was integrated and then sub-sampled to yield: 1 nutrient
(nitrogen) sample stored in a clear 250 mL bottle, 1 TP sample stored in the clear 250 mL bottle,
2 chlorophyll a samples stored in 1 L brown bottles and 1 phytoplankton sample stored in a 500
mL clear plastic bottle and treated with Lugol’s solution. During collection, all water samples
were held in coolers in the dark. In summary, at the end of the day for each lake, the field crews
had collected a total of 4 chlorophyll samples and 2 phytoplankton samples (one epilimnetic
sample from each station), 6 TP samples and 6 nutrient samples (three from each station).
Osoyoos Lake hypolimnetic samples were collected at 20 and 45 m. Samples were treated as
above. At the laboratory, 500 mL of each chlorophyll a sample was passed through a 0.45 μm
filter. Details are in Lawrence et al. (2007). All samples were couriered to the provincial water
chemistry laboratories in Burnaby, B.C. (PSC Analytical Services laboratory, Burnaby, British
Columbia). The analytical protocol followed the methods of Bran and Luebbe Inc. (1987) and
Eaton et al. (1995, 1998).
PHYTOPLANKTON
All samples were collected at the two water chemistry sites (stations 1 and 6, Figure 3). All
phytoplankton samples were treated with Lugol’s solution and stored in the dark. At the
laboratory, the Osoyoos Lake samples were combined and processed using the Utermöhl
technique. Through the season, 6-7 samples were collected at monthly intervals. All taxa were
identified to genus (many to species). Densities, cell sizes, cell shapes, and biovolumes were
recorded. One of the objectives of the phytoplankton counting procedure was to assess the
relative availabilities of edible (grazable) and non-edible (non-grazable) algae. We quantified
"edibility" based on size, toxicity, and digestibility. Single cells or colonies < 30 µm width or
length were considered edible (Cyr 1998; Cottingham 1999) unless they were classified as
being either "toxic" or "digestion-resistant" (defined below). Microcystis was always classified as
being "toxic". Other genera were assumed to be non-toxic. Algae with thick gelatinous sheaths
can pass through Daphnia guts undigested (Stutzman 1995) and were considered to be
digestion-resistant, independent of size. More methodological detail is given in Hyatt et al.
(2005) and McQueen et al. (2007).
ZOOLANKTON
In Osoyoos Lake, zooplankton were sampled at stations 2, 4, 6, 8, 10 (Figure 3) using a vertical
haul net (0-30 m night-time hauls, 100 µm mesh, 0.5 m net diameter, net length 3 m, Rigosha
flow-metered). Samples were collected every 2-3 weeks. Each sample was washed out of the
plankton net using water saturated with carbon dioxide and were then preserved in 5.5%
buffered and sugared formalin and returned to the laboratory. In the laboratory, the five samples
were combined to produce one volume-weighted “combined” sample for each lake for each
5
sampling date (Lawrence et al. 2007). Because each of the samples had different sampling
efficiencies (measured with a Rigosha flow-meter), each station sample was suspended in
water so that each one mL of sample contained water from 10 L of lake water. For each station,
10 mL (containing plankton from 100 L of lake water) from each sample jar was then added to a
“combined” sample jar. Since there were 5 stations in each lake, the combined sample jar
contained 50 mL of sample representing the zooplankton found in 500 L of lake water (100 L
collected at each of five stations). The original samples were then re-filtered to remove excess
water, re-suspended in 5.5 % formalin and relabelled to record the loss of a certain percentage
of the sample.
All zooplankton were identified to species, measured and eggs counted. Dry weight lengthweight regressions were used to calculate biomass for each individual (Allen et al. 1994).
Cladocera and copepods (adults and copepodids) were identified to species. Edmondson
(1959) was the principal taxonomic reference, but also Dussart and Fernando (1990) for
Cyclopoida, Korinek (1981) for Diaphanosoma, and Lieder (1983) for bosminids. Eggs per
female were counted for all species. To calculate biomass, body lengths of all animals were
measured using a semi-automated counting and measuring system (Allen et al. 1994). Because
Holopedium gibberum (Yan and Mackie 1987) was not found, corrections for contraction due to
preservative were not applied to any of the species encountered in Skaha or Osoyoos lakes
(Campbell and Chow-Fraser 1995). Animal weights were estimated using length-weight
regressions summarized in Girard & Reid (1990).
Mysis relicta
In Osoyoos Lake, M. relicta were sampled every 3-6 weeks (depending on the time of year) at
stations 1-10 (Figure 3) by means of a vertical haul net (0-30 m night-time hauls, 300 µm mesh,
1.0 m net diameter, net length 3 m, Rigosha metered). Samples were preserved in 5.5%
buffered and sugared formalin. In the laboratory, each individual animal was measured for total
length (measured as the distance from the tip of the rostrum to the end of the telson), sex, and
developmental stage. Embryos from gravid females were counted. From these counts, we
calculated densities and wet weight biomasses. We also calculated length and weight
frequencies which to be used for production analysis.
Mysid diets were assessed from direct inspection of gut contents of juveniles (2-10 mm length)
and adults (11-22 mm) collected from each sample. During 2006-08, only 30 specimens were
examined on each sampling date. During 2009-13, we attempted to examine at least 100
specimens on each sampling date. The foregut of each mysid was removed to a glass dish,
dissected, and examined under a light microscope. Each identifiable zooplankton part was
scored as one individual consumed. Mean weights for each prey type were taken from
zooplankton field samples collected at the same time as the Mysis. Average proportion of prey
found per Mysis gut was calculated as the relative biomass (prey counts * mean prey weight) of
each prey type per gut.
OSOYOOS LAKE SOCKEYE AND KOKANEE
In Lake Sampling
Osoyoos Lake fry were sampled 5-7 times (depending on the year) between June and March of
the following year. In Osoyoos Lake the age-0 fry were comprised of very few resident kokanee
and large numbers of wild (2005-13) sockeye. Hatchery-origin sockeye fry were also present in
samples during 2010, 2012 and 2013. Biosamples were collected using a 3m x 7m mid-water
trawl designed by Enzenhofer and Hume (1989). The net was towed only at night, at up to 6
6
depth strata exhibiting significant numbers of acoustics targets, and surveys were based on 515 trawls per sampling session. On each night, the trawl target was 300+ fish comprising
juvenile sockeye and various age classes of other nerkids. After each trawl set, fish were
immediately removed from the net and held on ice.
Laboratory Processing
All hatchery-origin sockeye fry were subjected to thermal treatments to induce a unique,
identifiable mark on their otoliths prior to release in all years. Consequently, during years when
age-0 hatchery fry were known to be in the lake (2010, 2012, 2013), otoliths were removed and
placed in dry vials from all fish within size groups likely to contain hatchery-origin fish (i.e. <5cm
in June, <6cm in July and August, <6.5 cm in September, <7.5 cm in October, <8 cm in
November and winter). During all years, (2005-13) stomach contents were removed from
approximately 30 age-0 sockeye and from all of the other nerkids larger than the size classes
noted above. For all fish selected for diet analysis, stomachs were removed and placed in vials
with ethanol, scales were removed and placed in a scale book, otoliths were removed and
placed in dry vials, and the fish body was placed in a plastic bag in ethanol.
From 2006-12, all identifiable zooplankton in each of the selected stomachs were counted as
species or genus. During 2013, the stomach contents from two groups of 30 age-0 fish were
combined (i.e. contents from the first group of 30 and contents from the second group of 30
were treated separately) and a plankton splitter was used to subsample the zooplankton in each
group. This procedure resulted in higher stomach counts per fish and perhaps improved
accuracy. The stomachs from larger nerkids were individually sampled as in previous years. In
all years, the taxonomic counts were transformed into % biomass for each taxonomic group
based on the assumption that mean taxonomic weight for each group of zooplankton was equal
to the average taxonomic weight for individuals captured in zooplankton samples taken on each
sampling date. After processing, data from each fish were associated with a unique fresh length,
fresh weight, age (scales), diet (stomach analysis), and sockeye or kokanee designation
(otolith).
Assessment of Age-Specific Fish Densities
During 2005, acoustic surveys of Osoyoos Lake for fish abundance were conducted on fives
dates using a Simrad EY-500, 70 KHz sounder with 50 W power output with pulse width at 0.2
ms and a Time Varied Gain circuit. During 2006-13, acoustic surveys were completed on 5-7
dates (depending on the year) using a Biosonics DT-X echosounder (200 kHz sounder with 300
W power, pulse width at 1 ms and a 6.60.transducer). Density estimates from echo-integration
analysis were used to determine numbers of fish and these data were later used to estimate fish
mortality throughout the late summer, fall, and winter periods.
Combined data from echosounding, otolith, and scale-age analysis provided estimates of wild
(all years) and hatchery-origin (2010, 2012, 2013) age-0 sockeye and older nerkid densities.
Because densities of larger fish were relatively low, our concern was that biosamples alone
could not be reliably used to estimate densities of larger kokanee. Even though the trawl net
was large (mouth opening 3 x 7 m), some of the larger fish may have escaped so that
proportions based on trawl estimates would be biased in favour of age-0 sockeye. To correct for
this problem, we combined the acoustic and trawl data to estimate fish densities.
The methods used to assign each fish to the appropriate “taxonomic” category (age-0 sockeye
or older nerkid length, weight, age), were as follows: (1) Total fish densities were assessed from
acoustics data collected using a Biosonics DT-X sounder. (2) Fish size-frequency distributions
7
were estimated using Sonar5-Pro software. (3) Lengths and weights were recorded from each
fish caught in 3m x 7m trawl net sets. (4) During 2010, 2012, 2013, “taxonomic” designations for
small fish were based on the presence or absence of marked otoliths (marked = hatchery
sockeye and absence = wild sockeye). (5) During all years, ages of larger fish (larger nerkids)
were assessed from scales. (6) For each sampling date, length frequencies based on Sonar-5
analysis, trawl-based lengths plus weights and trawl-based ages were combined to assign all
pelagic targets to one of 4 groups (i) nerkids <15 cm known from the trawl samples to be almost
entirely age-0 sockeye, (ii) age-1 smolts or kokanee known to be age-1 from scale data, (iii)
larger nerkids length 15-33 cm known from scale samples to be nerkids age 2 and 3, and (iv)
fish larger than 33 cm which we assume to be a mixture of lake whitefish and returning adult
sockeye. (6) For each group, the trawl-based data combined with echosounder-based density
estimates, were used to calculate densities and biomasses of all size classes of fish.
Fish Density and Echosounder Sampling Errors
Most field samples collected from a single lake over a period of time (i.e. time series) raise an
inferential statistics issue around the calculation of confidence intervals. Even when each
sample in the time series is represented by several subsamples taken from different locations in
the lake, inferential statistics and confidence intervals may have limited utility due to pseudoreplication (Hurlbert 1984, Millar and Anderson 2004). In Osoyoos Lake this applies to all of our
samples for water chemistry (n = 2 samples per time period), phytoplankton (n = 2), zooplankton
(n = 5), Mysis (n = 10), but is especially important for fish (n= 14 transects).
When estimating fish density we acoustically sampled 14 transects per nightly sample period,
calculated average fish density per transect and combined the weighted averages (numbers per
ha) accounting for the effects of depth and transect length (Hyatt and Stockner 1985, Gjernes et
al. 1986, MacLennan and Simmonds 1992, Hyatt et al. 2000). This method allowed us to
calculate both mean density and a confidence interval. However, the confidence interval may
not apply to our estimate of μ the population mean. This is because lake is the experimental unit
and the between-transect confidence interval reflects between-transect variability (i.e. transect
is the experimental unit). On each sampling date we calculated these between-transect CIs and
they have all been reported in the 2005-2013 annual reports. Typically, CIs around the lakewide mean abundance on all transects ranged from 10-30% of the mean.
For fish, we recognize that it may be possible to use techniques such as Monte Carlo
simulations to apply confidence intervals to our daily estimates, but we decided 9 years ago that
these methods would contribute little to our ultimate goal of estimating population densities at
key times in the year. There were several reasons for this decision. Density estimates obtained
on any one day are strongly influenced by fish distribution on a given set of fixed transects
which we have assumed are representative of the lake-wide population. Previous experience
(McQueen et al. 2007) shows that when a lake is surveyed on successive days or when two
boats sample the same lake on the same day, the results are almost identical. This is to be
expected and does not deal with the underlying issue of potential pseudo-replication because
areal distributions of fish observed within the lake over such a short interval will be relatively
static. However, consecutive surveys repeated within a given year at intervals of several days to
a few weeks also generate estimates that are usually similar. Because the limnetic fish that are
the subject of our ATS work are highly mobile and undertake not only diel vertical migrations but
also maintain horizontal movements of a few body lengths per second, it is virtually certain that
their distributions on survey transects involving relatively small between-transect distances (tens
of meters to a few hundred meters) will differ after periods of several days to a few weeks.
Accordingly, the absence of significant differences in limnetic fish abundance between these
8
surveys is interpreted by us to suggest that the all-transect mean of abundance, identified on a
given date, is representative of the lake-wide abundance of limnetic fish. If so, the confidence
intervals determined around the all-transect means from surveys are applicable as estimates of
uncertainty in our estimates of the lake-wide abundance of limnetic fish.
The above noted results contrast with those obtained from sequential acoustic surveys crossing
seasonal boundaries beginning in late May to early June, when estimates of mean density
separated by two or more months of time often exhibit statistically significant differences.
Inspection of the density data shown in Table 9 reveals that age-0 population densities achieve
peak abundance between spring to early summer as age-0 fry recruit offshore from river and
nearshore areas of the lake. Significant seasonal declines in numbers commonly occur by late
summer to fall (August to November) and then remain relatively stable through to late winter
(i.e. February). This pattern is almost certainly due to the dynamic interaction of ongoing
recruitment and high mortality rates that are known to affect resultant fry abundance during the
early part of their life-history allowing us to conclude that the data are generally “well-behaved”
with respect to an underlying biological model of expected recruitment-and-mortality over time.
Given the dynamic changes observed between spring and summer, we largely rely on two
density estimates per lake-year to characterize annual to seasonal changes in O. nerka
abundance. The first is a “summer-fall density” estimate based on the average of all samples
collected from August-November after full recruitment to the limnetic zone is certain to have
occurred. The second estimate is “presmolt density” based on the average of all samples
collected from October-winter after which both spring recruitment and spring-summer mortality
outcomes are complete. We have chosen these time periods because the August-November
estimate is useful for assessments of the impacts of the fish on their zooplankton prey over the
summer production interval. By contrast, the October-winter average of juvenile sockeye density
is our most reliable index of annual production of smolts destined to migrate seaward at age-2 in
May-June after a single summer and winter of lake residence. When calculating survival, our
recommended starting point is always to estimates of total egg “deposition” or hatchery fry
releases, and for Osoyoos Lake our recommended standardized survival estimates are egg-tofall fry (average Aug-Nov) and egg-to-presmolt (average Oct-winter).
Densities of Presmolts versus Smolts
Because there are no explicit counts or estimates of smolts as they leave Osoyoos Lake in the
spring of each year, we recommend the use of presmolt density as a surrogate for smolt
density. The relationship between acoustically derived presmolt densities and weir-based smolt
densities has been a continuing challenge for fish biologists, and what little published work there
is, suggests that the relationships may be lake-specific (Hyatt et al. 2005). In response to this
concern, Hyatt and Stockwell, DFO, Nanaimo (pers. com.) compared presmolt data from
Osoyoos Lake with smolt data gathered at Rocky Reach Dam. Of the several dams on the
Columbia, only Wells Dam and Rocky Reach Dam involve passage of sockeye that are solely of
Okanagan origin. Rocky Reach Dam personnel have conducted a sampling program each
spring since 2004, to assess relative abundance of sockeye smolts. For brood years 2002-10,
Hyatt and Stockwell (unpub. data) found a highly significant relationship between pre-smolt
abundance estimates based on annual acoustic surveys of juvenile sockeye in Osoyoos Lake
versus those based on cumulative seasonal sampling each year at Rocky Reach Dam
(Osoyoos presmolt abundance = 0.0924*RRH cumulative smolt count – 53703) (R2 = 0.98,
n=9). This relationship is based on data derived from two sampling programs run entirely
independently of each other, employing radically different sampling techniques. However, the
units of abundance are different. At Rocky Reach Dam, a cumulative smolt count is obtained
over several weeks of daily sub-sampling of smolts that utilize a fish-bypass structure. Although
9
this provides a relative index of annual abundance the index was not designed to be confidently
scaled up into estimates of the actual number of smolts moving past the dam each year. By
contrast, the acoustic and trawl-survey (ATS) based abundance estimates of presmolts are
obtained from surveys typically completed in 1-2 nights and designed to inform us of the
instantaneous, mean abundance of juvenile sockeye present in the lake on each date. Transect
locations were selected to be representative of all limnetic regions of the lake anticipated to
contain juvenile sockeye. Thus, mean abundance estimates from all transects, when expanded
to account for the entire volume of the limnetic zone, are assumed to represent the entire in-lake
population of juvenile sockeye. Thus, we suggest late season (fall-winter) ATS estimates of
abundance are likely useful not only as relative abundance indicators but also as reasonable
approximations of the total numbers of smolts produced each year.
Units and Conversions
To facilitate comparisons with other studies, we have presented data for phytoplankton
(mm3·m-3), zooplankton (μg·L-1 dry weight), Mysis (mg·m-3 wet weight) and fish (kg·ha-1 wet
weight) in units that are traditionally used by limnologists and fisheries biologists. However, to
simplify between trophic-level comparisons our conversions are based on the following
assumptions and conventions. (1) To convert from μg·L-1 to g·ha-1 it is known that μg·L-1 equals
1 mg·m-3, and 1 ha = 10,000 m2. We sampled zooplankton and Mysis using vertical hauls
between 0-30 m and assumed that average zooplankton biomasses in this region represented
zooplankton biomass at all depths. To convert from mg to g we divided by 1000. Therefore to
convert μg·L-1 or mg·m-3 to g·ha-1 we multiplied by (30*10,000)/1000 = 300. (2) A literature
survey suggested that wet:dry ratios for crustaceans and juvenile fish ranged from 10-16%
(Downing and Rigler 1984, Hewett and Johnson 1992). Throughout we have assumed dry
weight to be 14% of wet weight. (3) Therefore, to convert Osoyoos Lake zooplankton biomasses
from
μg·L-1 dw to g·ha-1 ww, we multiplied by 2100 and to convert M. relicta biomasses from
-1
mg·L ww or mg·m-3 ww, to g·ha-1ww we multiplied by 300.
10
RESULTS
OSOYOOS LAKE WATER TEMPERATURES
Table 1. Osoyoos Lake temperature profiles (OC). Profiles are averaged from data collected
near the north end of the North Basin and the more southerly Monashee sites (Figure 3,
numbers 1 and 5). Shaded area approximates water temperatures generally known to be
avoided by juvenile sockeye due to temperature preferences < 17°C (Brett 1952, 1964, Levy
1990, 1991) and/or oxygen preferences > 4ppm (Davis 1975, Brett and Blackburn 1981). No
data available for blank cells.
Depth (m)
26-Apr-05
17-May-05
01-Jun-05
20-Jun-05
12-Jul-05
22-Aug-05
30-Aug-05
08-Sep-05
13-Sep-05
27-Sep-05
04-Oct-05
02-Nov-05
Year 2005 Osoyoos Lake Water Temperatures (°C)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
11.9
11.6
11.0
10.2
10.0
9.4
9.0
8.8
8.6
8.4
7.7
8.0
7.9
7.7
7.5
7.4
7.3
7.2
7.1
7.1
7.0
6.8
6.6
6.6
16.7
16.3
15.8
15.4
14.8
14.3
13.9
13.2
12.5
11.5
10.6
9.9
9.3
8.6
8.3
7.9
7.9
8.0
7.7
7.6
7.4
7.2
7.2
7.2
18.1
18.0
17.8
17.6
17.3
16.8
16.5
16.3
15.8
15.1
12.2
9.8
9.0
8.7
8.3
8.1
8.0
7.9
7.8
7.7
7.6
7.4
7.4
7.3
18.4
18.1
18.0
17.9
17.8
17.6
17.1
16.5
15.6
14.2
13.2
11.6
10.5
9.6
9.0
8.6
8.3
8.1
8.1
8.0
7.8
7.6
7.5
7.5
20.7
20.6
20.5
20.4
20.4
20.3
20.2
19.8
19.2
17.8
15.2
13.8
12.1
10.8
9.9
9.2
8.9
8.5
8.3
8.2
7.9
7.8
7.8
7.8
21.9
21.8
21.8
21.8
21.8
21.7
21.5
21.4
21.2
20.8
20.0
17.9
15.7
12.6
10.7
9.9
9.2
8.8
8.5
8.3
8.1
8.0
7.8
7.9
20.8
20.7
20.6
20.5
20.5
20.4
20.4
20.4
20.3
20.0
19.9
19.5
17.1
13.9
10.8
9.6
9.2
8.7
8.5
8.3
8.1
8.0
7.9
7.8
19.8
19.8
18.2
18.2
18.2
18.2
18.2
18.2
18.2
18.2
18.2
18.2
18.1
18.0
17.9
16.5
14.0
11.7
9.9
9.3
8.8
8.6
8.3
8.1
8.1
7.9
16.3
16.3
15.0
15.0
15.0
15.0
15.0
15.0
15.0
15.0
15.0
15.0
15.0
15.0
15.0
14.7
14.4
14.0
12.3
11.1
9.6
9.1
8.4
8.3
8.1
8.1
11.3
11.3
11.3
11.4
11.4
11.4
11.3
11.4
11.3
11.3
11.3
11.3
11.3
11.3
11.3
11.2
11.1
11.0
11.0
10.9
9.4
8.9
8.5
8.4
19.6
19.5
19.4
19.3
19.2
19.1
18.2
15.7
11.2
10.5
9.5
8.9
8.5
8.2
8.1
8.0
7.9
16.3
16.3
16.2
15.8
15.1
13.0
14.1
15.9
12.7
9.3
8.9
8.5
8.5
8.2
8.1
8.1
7.9
11.3
10.3
7.6
9.2
7.3
6.8
6.6
6.4
6.2
6.1
6.1
6.0
5.9
8.7
8.0
7.8
7.7
7.6
7.6
7.4
7.2
6.8
23-Oct
12.4
16-Oct
12.9
02-Oct
21.8
21.6
21.6
21.6
21.5
21.5
21.4
21.6
20.6
19.0
17.7
16.6
15.3
14.0
12.8
11.5
10.5
9.8
9.4
9.2
9.0
7.8
8.7
8.7
26-Sep
18-Jul
23.8
23.5
23.1
21.8
21.6
21.3
20.7
19.2
18.7
17.7
17.0
16.5
15.8
14.7
12.9
11.4
10.4
9.4
9.1
9.0
8.6
8.4
8.3
8.2
8.0
7.9
7.8
7.6
19-Sep
04-Jul
17.5
17.3
17.1
17.0
16.9
16.6
16.4
16.0
16.1
15.3
14.7
13.9
13.0
12.2
11.2
10.7
9.8
9.1
8.8
8.7
8.4
8.2
8.1
8.0
7.9
7.8
7.6
7.6
11-Sep
12-Jun
15.8
15.7
15.3
15.1
14.7
14.2
14.4
13.6
06-Sep
23-May
8.9
8.6
8.0
8.4
7.9
8.2
7.7
8.0
7.7
7.9
7.6
7.8
7.5
7.7
7.5
7.6
30-Aug
24-Apr
3.4
3.4
3.4
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
21-Aug
24-Jan
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
21.7
21.7
21.7
21.7
21.6
21.4
21.2
21.1
20.8
20.7
20.4
19.6
16.4
14.3
12.8
11.9
11.0
10.3
9.9
9.5
9.1
8.9
8.8
8.8
8.7
8.7
8.6
8.6
20.1
20.1
20.2
20.2
20.2
20.2
20.2
20.1
20.1
19.9
19.6
19.3
18.6
16.3
13.5
11.3
10.6
10.0
9.6
9.4
9.0
8.9
8.8
8.7
8.7
8.7
8.6
8.6
20.5
20.4
20.4
20.3
20.3
20.2
20.0
19.8
19.8
19.7
19.6
19.3
19.2
16.8
14.1
12.1
10.8
10.3
10.0
9.6
9.1
8.9
8.8
8.7
8.8
8.7
8.7
8.6
20.3
20.2
20.2
20.1
20.0
19.9
19.9
19.8
19.7
19.6
19.5
19.4
19.3
17.8
12.8
11.7
10.8
10.4
9.9
9.6
9.1
8.9
8.8
8.7
8.7
8.7
8.6
8.6
18.2
18.3
18.3
18.2
18.2
18.2
18.1
18.1
18.0
17.9
17.9
17.9
17.6
16.9
14.4
12.5
11.3
10.7
10.2
9.8
9.2
9.0
8.9
8.8
8.8
8.8
8.7
8.7
17.6
17.6
17.5
17.4
17.2
17.1
17.1
17.0
16.9
16.9
16.8
16.8
16.8
16.6
16.4
14.6
11.8
10.8
10.4
9.9
9.2
9.0
8.9
8.8
8.7
8.7
8.7
8.7
16.9
16.8
16.8
16.7
16.7
16.7
16.6
16.6
16.5
16.4
16.4
16.3
16.2
16.0
15.8
14.7
13.3
10.5
9.9
9.6
9.1
9.0
8.9
8.9
8.8
8.8
8.7
8.7
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.4
14.3
13.9
11.6
10.3
9.7
9.2
9.0
9.0
8.9
8.9
8.9
8.8
8.8
13.2
13.2
13.2
13.2
13.2
13.2
13.1
13.1
13.1
13.1
13.1
13.1
13.1
13.1
13.1
13.1
13.0
13.0
12.1
11.3
9.4
9.2
9.1
9.1
9.0
9.0
8.9
8.8
11
Depth (m)
Year 2006 Osoyoos Lake Water Temperatures (°C)
26-Jun-07
2-Aug-07
13-Aug-07
24-Aug-07
4-Sep-07
10-Sep-07
18-Sep-07
25-Sep-07
17.6
17.5
17.5
17.4
17.0
16.6
16.5
16.3
15.6
14.2
13.6
13.3
12.9
12.4
11.7
11.3
9.8
9.3
8.9
8.7
8.4
8.2
8.1
8.1
8.1
8.0
8.0
8.0
20.2
20.1
19.7
19.6
19.4
18.9
18.5
18.3
17.9
17.1
16.2
14.8
13.3
12.3
11.1
10.4
9.9
9.6
9.4
9.2
8.9
8.7
8.5
8.5
8.5
8.4
8.4
8.4
24.2
23.5
22.9
22.5
22.3
22.0
22.0
21.9
21.6
21.2
21.1
20.8
19.4
17.7
16.6
15.1
13.4
13.4
10.5
10.1
9.9
9.6
9.4
22.7
22.0
21.8
21.4
21.2
21.1
21.4
20.9
20.8
20.7
20.6
19.3
18.9
17.6
15.4
13.1
10.8
10.5
10.4
9.9
9.5
9.3
9.1
9.1
9.1
9.0
9.0
8.9
21.1
20.8
20.8
20.7
20.6
20.5
20.5
20.5
20.4
20.3
20.1
20.0
19.9
15.7
12.8
11.2
10.5
10.1
9.7
9.5
9.3
9.1
9.0
9.0
9.0
9.0
8.9
8.9
20.1
20.0
20.0
20.0
20.0
19.9
19.9
19.8
19.7
19.6
19.5
19.2
18.9
16.7
13.4
11.8
10.7
10.1
9.8
9.6
9.3
9.2
9.1
9.1
9.0
9.0
9.0
9.0
19.1
18.9
18.8
18.8
18.8
18.7
18.7
18.7
18.7
18.6
18.5
18.4
18.3
18.3
17.9
16.0
11.0
10.4
10.0
9.8
9.4
9.2
9.1
9.1
9.1
9.0
9.0
9.0
18.0
18.0
18.0
18.0
18.0
18.0
18.0
18.0
18.0
17.9
17.9
17.8
17.8
17.6
16.8
14.1
12.0
10.9
10.5
10.0
9.5
9.3
9.2
9.1
9.1
9.1
9.1
9.0
16.8
16.7
16.7
16.7
16.7
16.7
16.7
16.6
16.6
16.6
16.6
16.6
16.6
16.4
15.7
14.5
12.3
10.2
9.8
9.6
9.4
9.3
9.2
9.2
9.1
9.1
9.1
9.0
14.9
14.9
14.9
14.9
14.9
14.9
13.8
11.6
9.6
9.4
9.3
9.2
9.2
9.1
9.1
5-Nov-07
11-Jun-07
14.4
13.8
13.6
13.3
13.2
13.2
13.1
12.9
12.6
11.9
10.9
10.3
9.5
9.2
8.6
8.4
8.3
8.2
8.1
8.0
7.7
7.5
7.5
7.4
7.4
7.3
7.3
7.2
9-Oct-07
14-May-07
9.1
8.4
8.2
8.1
8.0
7.9
7.9
7.8
7.7
7.7
7.7
7.7
7.6
7.6
7.5
7.4
7.4
7.4
7.3
7.2
7.2
6.9
6.7
6.5
6.2
6.1
6.1
6.0
4-Oct-07
17-Apr-07
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
13.8
13.8
13.9
13.9
13.9
13.9
13.9
13.9
13.9
13.9
13.9
13.9
13.8
13.8
13.8
13.6
13.2
13.2
12.4
11.7
9.8
9.5
9.3
9.3
9.2
9.2
9.1
9.1
10.5
10.4
10.4
10.3
10.3
10.3
10.3
10.3
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.2
10.1
10.1
10.1
10.0
9.9
9.7
9.5
9.3
9.2
9.2
12
Depth (m)
Year 2007 Osoyoos Lake Water Temperatures (°C)
18-Mar-08
07-Apr-08
17-Apr-08
20-May-08
09-Jun-08
24-Jun-08
07-Jul-08
21-Jul-08
28-Jul-08
11-Aug-08
27-Aug-08
07-Sep-08
22-Sep-08
19-Oct-08
18-Nov-08
04-Dec-08
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
4.3
4.2
4.2
4.2
4.2
4.2
4.2
4.4
4.2
4.2
4.1
4.2
7.0
6.8
6.6
6.4
6.3
6.2
6.1
6.1
6.0
5.9
5.8
5.7
5.5
5.4
5.4
5.4
5.3
5.3
5.3
5.3
5.2
5.1
4.9
4.8
4.8
4.7
4.7
4.7
8.3
7.9
7.6
7.5
7.3
7.1
6.9
6.8
6.7
6.5
6.4
6.3
6.3
6.2
6.1
6.0
6.0
6.0
5.9
5.9
5.8
5.7
5.5
5.5
5.5
5.4
5.3
5.3
14.2
14.2
14.1
13.6
12.8
12.4
12.2
11.2
10.9
10.7
10.5
10.3
10.0
9.5
9.0
8.5
8.2
7.9
7.6
7.5
7.3
7.1
7.1
7.0
6.9
6.8
6.7
6.5
16.3
16.2
16.0
15.9
15.8
15.7
15.6
15.1
14.7
14.0
12.9
12.0
11.0
9.9
9.1
8.4
8.2
8.1
8.0
7.9
7.8
7.6
7.6
7.5
7.5
7.5
7.5
7.5
18.7
18.7
18.7
18.6
18.6
18.6
17.3
16.9
16.3
15.6
15.1
14.3
12.6
11.7
9.6
8.8
8.6
8.5
8.4
8.3
8.1
8.0
7.9
7.9
7.8
7.8
7.8
7.8
21.5
21.4
21.1
21.0
20.8
20.3
19.1
18.1
17.3
17.0
16.2
14.0
12.2
10.1
9.4
9.0
8.9
8.6
8.5
8.4
8.2
8.0
8.0
8.0
8.0
7.9
7.9
7.9
24.0
23.7
23.5
23.0
22.6
21.6
20.9
20.3
19.0
17.9
17.3
15.9
14.1
12.3
11.3
10.4
10.0
9.7
9.6
9.2
8.9
8.7
8.5
8.5
8.5
8.4
8.4
8.4
22.2
22.2
22.2
22.2
22.2
22.1
22.0
21.9
21.6
20.3
17.4
15.7
12.9
11.8
10.9
10.0
9.6
9.4
9.2
9.0
8.8
8.6
8.5
8.5
8.4
8.4
8.3
8.3
21.7
21.5
21.4
21.2
21.0
21.0
20.7
20.7
20.4
19.3
18.6
17.7
15.5
13.6
11.9
11.1
10.5
10.2
9.7
9.4
9.1
8.9
8.8
8.8
8.7
8.7
8.7
8.6
20.1
20.2
20.2
20.2
20.2
20.2
20.2
20.2
20.0
19.8
19.5
17.9
16.9
15.0
14.3
12.9
11.7
10.8
10.3
9.9
9.3
9.1
8.9
8.9
8.8
8.7
8.7
8.7
18.3
18.3
18.3
18.3
18.3
18.2
18.2
18.2
18.1
18.0
18.0
18.0
17.6
17.1
13.0
12.0
10.9
10.2
9.9
9.8
9.6
9.3
9.2
9.3
9.2
9.1
9.0
8.9
16.8
17.0
17.0
17.1
17.1
17.1
17.1
17.1
17.1
17.1
17.0
16.9
16.8
15.6
13.7
11.8
10.7
10.3
9.9
9.6
9.3
9.1
9.0
9.0
9.0
8.9
8.9
8.9
12.3
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.3
12.0
12.0
11.9
11.8
11.5
9.7
9.4
9.2
9.2
9.2
9.1
9.1
9.0
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.0
9.0
9.0
8.9
9.1
9.0
9.0
9.0
9.0
6.4
6.6
6.6
6.7
6.7
6.7
6.7
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.9
6.8
6.7
6.9
6.9
6.9
6.9
6.9
4.2
4.2
4.2
4.2
4.2
4.2
4.2
4.1
4.1
4.1
13
Depth (m)
Year 2008 Osoyoos Lake Water Temperatures (°C)
11-May-09
25-May-09
08-Jun-09
29-Jun-09
13-Jul-09
27-Jul-09
11-Aug-09
24-Aug-09
31-Aug-09
10-Sep-09
14-Sep-09
21-Sep-09
28-Sep-09
05-Oct-09
22-Oct-09
27-Nov-09
17-Dec-09
5.9
5.8
5.8
5.7
5.7
5.7
5.7
5.6
5.6
5.5
5.5
5.4
5.4
5.4
5.3
5.3
5.3
5.2
5.2
5.2
5.2
5.0
5.0
5.1
5.1
5.0
4.9
4.8
12.5
12.3
12.2
11.9
11.7
11.6
11.1
10.0
9.1
8.5
8.4
8.0
7.7
7.3
7.2
7.1
7.1
6.6
6.9
6.8
6.7
6.6
6.5
6.5
6.5
6.4
6.4
6.4
15.8
15.6
15.4
15.3
15.0
14.8
14.5
14.2
13.9
13.2
12.2
10.6
10.0
9.5
8.9
8.5
8.2
8.1
8.0
7.9
7.5
7.4
7.3
7.3
7.2
7.1
7.1
7.0
19.1
18.9
18.8
18.7
18.6
18.5
18.0
15.7
13.5
12.3
11.6
10.8
10.3
9.8
9.5
9.1
8.9
8.8
8.7
8.4
7.8
7.6
7.5
7.4
7.4
7.4
7.3
7.3
19.0
18.9
18.9
18.8
18.6
18.2
17.8
17.2
16.6
15.5
13.6
11.8
10.8
10.3
9.3
8.9
8.6
8.4
8.2
8.2
7.9
7.9
7.8
7.8
7.7
7.7
7.7
7.7
21.8
21.7
21.6
21.3
21.1
20.8
20.2
19.4
18.3
16.2
13.8
11.8
10.3
9.6
9.2
8.9
8.7
8.6
8.5
8.4
8.2
8.1
8.0
8.0
7.9
7.8
7.8
7.7
24.5
24.1
23.4
23.1
22.9
22.6
21.9
21.0
19.9
19.0
17.6
15.6
13.2
12.1
10.8
10.3
9.7
9.1
8.8
8.7
8.3
8.1
8.0
8.0
8.0
7.9
7.9
7.9
22.1
22.3
22.3
22.4
22.4
22.2
22.0
21.8
21.1
20.4
17.7
15.1
12.7
11.3
10.7
10.1
9.7
9.3
9.0
8.7
8.3
8.1
8.0
7.9
7.9
7.9
7.9
7.8
21.7
21.3
21.0
21.0
20.9
20.8
20.7
20.5
20.3
19.8
19.4
18.3
15.4
11.0
9.6
8.8
8.6
8.3
8.3
8.2
8.1
8.3
8.0
8.0
8.0
22.5
22.0
21.6
21.5
21.3
21.2
21.1
21.0
20.9
20.6
19.9
18.6
16.6
12.1
10.9
10.2
9.4
9.2
8.9
8.7
8.5
8.3
8.2
8.2
8.1
8.1
8.0
8.0
19.7
19.7
19.6
19.6
19.6
19.6
19.6
19.6
19.5
19.3
18.6
18.3
17.7
14.0
13.1
12.0
10.8
9.8
9.3
8.9
4.4
8.2
8.1
8.1
8.1
8.0
8.0
8.0
19.8
19.6
19.5
19.5
19.5
19.4
19.3
19.2
19.2
19.1
19.0
18.8
17.8
15.7
12.7
11.0
9.8
9.3
8.9
8.7
8.4
8.2
8.1
8.1
8.1
8.1
8.0
8.0
18.7
18.8
18.8
18.8
18.6
18.8
18.8
18.7
18.7
18.6
18.6
18.4
17.9
16.8
15.8
11.6
10.1
9.4
9.0
8.7
8.4
8.2
8.2
8.1
8.1
8.1
8.0
8.0
17.7
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.6
15.4
10.4
9.9
9.2
8.8
8.7
8.4
8.3
8.3
8.2
8.2
8.2
8.1
8.1
15.1
15.2
15.2
15.1
15.1
15.1
15.1
15.1
15.1
15.1
15.0
15.0
15.0
14.7
14.3
13.7
12.4
11.3
10.0
9.7
8.8
8.6
8.4
8.3
8.3
8.2
8.2
8.1
12.0
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.9
11.7
10.1
9.6
8.9
8.6
8.5
8.5
8.4
8.4
8.4
8.3
7.0
7.1
7.2
7.2
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.3
7.4
7.4
7.3
7.3
7.3
7.4
7.4
7.4
7.4
7.4
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.8
3.8
3.8
3.8
3.8
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
15-Apr-09
Depth (m)
Year 2009 Osoyoos Lake Water Temperatures (°C)
16-Apr-10
10-May-10
01-Jun-10
14-Jun-10
29-Jun-10
19-Jul-10
26-Jul-10
09-Aug-10
16-Aug-10
23-Aug-10
30-Aug-10
06-Sep-10
14-Sep-10
20-Sep-10
27-Sep-10
02-Oct-10
18-Oct-10
15-Nov-10
15-Dec-10
3.1
3.1
3.1
3.1
3.1
3.1
3.1
3.1
3.1
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.1
3.1
3.2
3.1
3.1
10.0
9.6
8.8
7.9
7.6
7.3
7.2
6.9
6.8
6.7
6.6
6.6
6.5
6.5
6.5
6.5
6.4
6.4
6.4
6.4
6.4
6.3
6.3
6.3
6.3
6.3
6.2
6.3
12.2
12.0
11.6
11.3
11.1
11.0
10.9
10.8
10.7
10.3
10.0
9.7
9.6
9.3
9.1
9.0
8.9
8.7
8.4
8.4
8.1
7.9
7.8
7.7
7.6
7.5
7.4
7.3
16.3
16.0
16.0
16.2
16.2
16.0
15.6
14.8
14.7
12.0
10.9
10.4
10.2
9.5
9.1
8.8
8.7
8.6
8.5
8.4
8.3
8.2
8.0
8.1
8.0
8.0
8.0
7.9
17.9
17.7
17.3
16.6
16.3
15.9
14.5
13.6
13.4
12.5
11.5
11.3
10.8
10.6
10.2
9.5
9.2
9.0
8.8
8.7
8.6
8.6
8.5
8.4
8.3
8.3
8.3
8.2
19.8
19.9
19.9
19.9
19.8
19.1
17.8
16.3
15.1
15.0
14.3
13.0
12.1
10.6
9.7
9.2
9.2
9.1
8.9
8.8
8.4
8.1
8.6
8.5
8.1
8.5
8.5
8.4
21.7
21.4
21.3
21.1
20.4
19.9
19.5
18.4
17.1
15.4
13.9
12.8
11.3
10.6
9.8
9.6
9.4
9.3
9.2
9.2
9.0
8.9
8.9
8.9
8.9
8.8
8.8
8.9
22.7
22.7
22.7
22.3
21.8
21.3
20.7
19.9
18.9
16.4
15.1
13.4
11.5
10.2
9.8
9.6
9.5
9.4
9.3
9.3
9.2
9.1
9.0
9.0
8.9
8.9
8.9
8.9
22.3
22.3
22.3
22.3
22.3
22.2
21.3
19.8
18.3
16.2
14.5
12.9
11.5
10.8
10.3
9.8
9.7
9.5
9.4
9.3
9.1
9.0
9.0
8.9
8.9
8.9
8.9
8.8
23.7
23.3
22.9
22.3
22.2
21.9
21.8
21.6
21.2
20.1
17.1
14.5
12.3
11.3
10.6
10.1
9.7
9.6
9.4
9.3
9.2
9.1
9.0
9.0
9.0
8.9
8.9
8.9
21.0
21.0
21.0
21.0
20.9
20.9
20.9
20.9
20.6
20.3
18.8
17.4
15.2
13.3
11.6
10.3
10.0
9.7
9.6
9.5
9.3
9.2
9.1
9.1
9.1
9.2
9.1
9.0
19.7
19.6
19.5
19.5
19.4
19.4
19.4
19.3
19.0
18.7
18.3
16.6
13.6
11.8
11.1
10.3
10.1
9.9
9.8
9.6
9.3
9.2
9.1
9.1
9.0
9.0
9.0
9.0
18.3
18.3
18.3
18.4
18.4
18.3
18.3
18.3
18.3
18.3
18.2
18.1
17.4
12.6
11.5
10.8
10.3
10.0
9.9
9.7
9.5
9.4
9.3
9.2
9.2
9.1
9.1
9.1
17.6
17.7
17.7
17.6
17.6
17.6
17.5
17.4
17.3
17.2
17.0
16.3
15.6
14.7
12.1
11.0
10.3
10.0
9.9
9.7
9.5
9.3
9.3
9.2
9.2
9.1
9.1
9.1
17.1
17.1
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
16.1
14.5
13.7
11.8
10.4
9.9
9.7
9.4
9.3
9.2
9.2
9.1
9.1
9.1
9.0
17.1
17.0
17.0
16.9
16.8
16.8
16.8
16.7
16.7
16.7
16.6
16.6
16.6
15.4
14.1
12.1
11.5
10.4
10.1
10.0
9.6
9.5
9.4
9.3
9.3
9.2
9.2
9.2
17.0
17.0
16.8
16.7
16.5
16.4
16.3
16.2
16.1
16.1
16.0
16.0
15.9
15.9
14.6
12.5
12.3
11.3
10.4
10.1
9.8
9.6
9.5
9.4
9.4
9.3
9.3
9.3
13.4
13.5
13.5
13.5
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.4
12.7
11.4
10.5
9.7
9.5
9.4
9.4
9.3
9.2
9.2
9.2
9.8
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.8
9.6
9.3
9.3
9.2
9.2
9.2
4.4
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
16-Feb-10
Depth (m)
Year 2010 Osoyoos Lake Water Temperatures (°C)
10-May-11
31-May-11
16-Jun-11
20-Jun-11
14-Jul-11
18-Jul-11
03-Aug-11
09-Aug-11
16-Aug-11
22-Aug-11
29-Aug-11
07-Sep-11
15-Sep-11
22-Sep-11
28-Sep-11
06-Oct-11
11-Oct-11
16-Oct-11
03-Nov-11
16-Nov-11
29-Nov-11
18-Dec-11
6.9
6.9
6.8
6.8
6.8
6.7
6.7
6.7
6.6
6.4
6.3
6.3
6.2
6.1
5.9
5.7
5.6
5.6
5.6
5.6
5.6
5.6
5.5
5.6
5.5
5.4
5.4
5.4
11.6
11.5
11.2
10.8
10.5
10.2
9.9
10.0
9.9
9.9
9.8
9.8
9.7
9.6
9.5
8.9
8.6
8.2
8.0
7.8
7.1
7.0
6.8
6.8
6.7
6.6
6.6
6.6
13.5
13.4
13.1
12.6
12.3
12.1
11.9
11.7
11.5
11.3
11.2
11.0
11.0
10.9
10.8
10.6
10.3
10.1
9.9
9.5
8.4
7.7
7.5
7.3
7.2
7.2
7.0
6.9
16.2
16.2
16.1
16.0
15.8
15.7
15.2
14.9
14.8
14.1
13.8
13.2
12.8
11.8
10.9
10.5
10.2
9.9
9.5
9.1
8.6
8.2
8.0
8.0
7.8
7.6
7.5
7.2
15.3
15.2
14.9
14.9
14.8
14.7
14.5
14.4
14.4
14.2
14.1
14.0
13.5
12.8
12.6
12.0
11.5
11.1
10.6
10.4
9.2
8.5
8.3
8.0
7.8
7.6
7.5
7.3
20.0
20.0
20.1
20.1
20.0
20.0
19.9
19.8
19.7
19.1
18.9
17.8
16.7
15.1
13.0
11.5
11.0
10.3
9.9
9.5
9.2
8.9
8.7
8.6
8.4
8.3
8.1
8.0
20.2
20.0
20.0
19.9
19.9
19.9
19.7
19.7
19.4
18.9
18.6
18.4
16.8
15.2
13.7
12.3
11.7
10.9
10.3
9.8
9.2
8.9
8.7
8.6
8.4
8.3
8.0
7.8
20.7
20.7
20.8
20.7
20.7
20.7
20.6
20.5
20.4
20.2
19.8
18.9
17.2
15.6
13.9
13.1
12.3
11.3
10.6
10.2
9.5
9.1
9.0
8.9
8.7
8.5
8.4
8.2
22.6
22.6
22.6
22.6
22.6
22.1
21.8
21.5
21.3
21.0
20.7
19.4
18.0
16.4
13.3
12.2
11.2
10.5
10.1
9.8
9.3
9.1
8.9
8.9
8.8
8.7
8.6
8.5
21.0
21.0
21.0
21.0
21.0
21.0
21.0
21.0
20.9
20.8
19.8
19.3
18.6
17.2
15.0
13.8
12.4
11.3
10.7
10.4
9.6
9.3
9.1
9.1
8.9
8.8
8.6
8.4
22.6
22.5
22.3
22.1
21.8
21.7
21.4
21.2
21.1
20.8
20.1
15.1
18.4
16.8
15.7
13.6
11.9
10.9
10.3
10.1
9.5
9.2
9.1
9.0
8.8
8.7
8.5
8.4
23.1
23.0
22.9
22.7
22.6
22.2
22.0
21.5
21.1
20.7
20.3
19.0
17.3
16.6
14.7
13.0
12.0
11.2
10.3
10.0
9.4
9.2
9.1
9.0
8.9
8.8
8.6
8.3
21.8
21.3
21.1
20.8
20.6
20.5
20.3
20.1
20.0
20.0
19.9
19.8
19.4
17.8
15.9
13.9
12.4
11.4
11.0
10.5
9.7
9.4
9.2
9.1
8.9
8.8
8.6
8.4
20.7
20.7
20.7
20.7
20.7
20.7
20.5
20.3
20.1
20.0
19.8
19.2
17.4
16.1
15.1
12.2
11.4
10.8
10.3
9.9
9.3
9.2
9.1
9.0
8.8
8.7
8.5
8.3
18.7
18.7
18.7
18.7
18.6
18.6
18.6
18.6
18.5
18.5
18.5
18.5
18.5
18.3
18.1
14.6
11.7
11.0
10.6
10.3
9.6
9.4
9.2
9.2
9.1
9.0
8.9
8.6
17.9
17.9
17.9
17.9
17.8
17.8
17.7
17.7
17.6
17.6
17.6
17.5
17.2
17.0
16.1
14.3
13.9
12.1
11.4
10.8
9.7
9.4
9.3
9.2
9.1
9.0
8.9
8.5
15.9
15.9
16.0
16.0
16.0
16.0
16.0
16.0
16.0
15.9
15.9
15.8
15.8
15.8
15.7
15.6
15.5
15.3
13.3
11.5
9.8
9.4
9.3
9.1
9.0
8.9
8.8
8.7
15.9
15.9
16.0
16.0
16.0
16.0
16.0
16.0
16.0
15.9
15.9
15.8
15.8
15.8
15.7
15.6
15.5
15.3
13.3
11.5
9.8
9.4
9.3
9.1
9.0
8.9
8.8
8.7
13.9
14.0
14.0
14.1
14.1
14.1
14.1
14.1
14.1
14.1
14.1
14.1
14.1
14.0
13.9
13.9
13.9
13.7
13.6
12.9
10.0
9.5
9.4
9.3
9.2
9.0
8.8
8.7
10.6
10.7
10.7
10.7
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.8
10.9
10.6
10.4
9.8
9.4
9.1
8.9
8.8
8.6
8.3
8.3
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.5
8.4
8.6
8.6
8.5
8.5
8.5
6.9
6.9
6.9
6.9
6.9
6.9
6.9
7.0
7.0
7.0
7.0
6.9
6.9
6.9
6.9
6.9
7.0
6.9
6.9
6.9
6.9
6.9
6.8
7.0
7.0
6.9
6.9
6.9
4.8
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.6
4.6
4.6
4.6
4.6
4.6
4.6
4.6
4.6
4.6
4.6
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
20-Apr-11
Depth( m)
Year 2011 Osoyoos Lake Water Temperatures (°C)
20-Apr-12
29-Apr-12
22-May-12
11-Jun-12
16-Jul-12
26-Jul-12
07-Aug-12
13-Aug-12
20-Aug-12
27-Aug-12
04-Sep-12
11-Sep-12
17-Sep-12
24-Sep-12
30-Sep-12
11-Oct-12
29-Oct-12
17-Nov-12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
6.9
6.9
6.8
6.8
6.8
6.7
6.7
6.7
6.6
6.4
6.3
6.3
6.2
6.1
5.9
5.7
5.6
5.6
5.6
5.6
5.6
5.6
5.5
5.6
5.5
5.4
5.4
5.4
12.0
12.0
11.9
11.6
10.8
9.7
9.4
9.2
8.8
8.4
8.0
7.7
7.5
7.3
7.1
7.0
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
6.0
6.0
5.9
5.9
13.6
13.3
13.3
13.2
13.0
12.9
12.6
12.2
12.0
11.8
11.4
10.5
9.3
8.5
8.1
7.9
7.7
7.6
7.5
7.4
7.1
7.0
6.9
6.9
6.8
6.8
6.7
6.7
14.9
14.6
14.6
14.0
13.9
13.7
13.5
13.5
13.4
13.4
12.8
12.4
11.4
11.0
9.4
8.8
8.2
7.9
7.7
7.6
7.3
7.3
7.2
7.2
7.2
7.2
7.1
7.1
22.5
22.5
22.4
22.2
21.8
21.6
20.3
18.6
17.6
16.7
16.1
15.5
13.7
12.8
11.3
9.8
9.1
8.7
8.4
8.2
7.8
7.6
7.5
7.5
7.5
7.5
7.5
7.4
22.4
22.0
21.9
21.8
21.8
21.6
21.3
21.1
20.6
20.0
18.9
17.0
15.3
14.0
12.8
11.6
10.3
9.5
9.1
8.7
8.0
7.8
7.7
7.7
7.7
7.6
7.6
7.5
23.8
23.6
23.2
23.0
22.4
22.0
21.8
21.6
21.4
20.3
19.3
18.0
15.4
13.5
12.6
11.5
10.1
9.5
8.9
8.5
8.1
7.9
7.8
7.8
7.7
7.7
7.6
7.6
23.8
23.8
23.6
23.3
23.2
22.8
22.5
22.4
22.2
20.7
18.6
17.2
15.8
13.3
11.8
10.1
9.3
8.8
8.5
8.3
8.1
7.9
7.9
7.8
7.8
7.8
7.7
7.7
24.4
24.4
24.4
24.4
24.3
24.3
24.0
23.7
22.8
22.0
19.8
16.2
13.8
11.4
10.2
9.5
9.0
8.7
8.5
8.4
8.1
8.0
7.9
7.8
7.8
7.8
7.7
7.7
21.9
21.9
21.9
21.9
21.9
21.9
21.8
21.8
21.8
21.7
21.6
19.9
14.9
12.2
11.1
9.6
9.1
8.9
8.7
8.4
8.1
8.0
7.9
7.9
7.9
7.9
7.8
7.8
20.2
20.1
20.0
20.0
19.9
19.9
19.9
19.8
19.8
19.7
19.6
19.3
18.2
16.1
11.8
10.5
9.7
8.9
8.6
8.5
8.2
8.1
8.0
8.0
8.0
7.9
7.9
7.9
19.0
19.2
19.0
19.1
19.1
19.1
19.1
19.0
18.9
18.9
18.7
18.5
17.4
15.2
12.6
10.6
9.4
9.2
9.0
8.8
8.5
8.4
8.3
8.2
8.2
8.2
8.2
8.1
18.6
18.6
18.5
18.5
18.5
18.4
18.4
18.3
18.2
18.2
18.0
17.8
17.7
17.0
14.8
11.6
10.3
9.7
9.2
8.9
8.5
8.4
8.2
8.2
8.2
8.2
8.2
8.2
18.6
18.6
18.6
18.5
18.5
18.4
18.3
18.2
18.1
18.0
18.0
17.8
17.7
17.2
15.7
11.7
10.0
9.4
9.0
8.8
8.5
8.4
8.3
8.3
8.2
8.2
8.2
8.2
18.0
18.0
18.0
18.0
17.9
17.8
17.8
17.8
17.8
17.7
17.7
17.6
17.3
16.8
16.3
14.6
12.3
10.1
9.4
9.0
8.5
8.4
8.3
8.3
8.2
8.2
8.2
8.1
15.6
15.6
15.4
15.3
15.3
15.2
15.2
15.2
15.2
15.1
15.1
15.0
14.9
14.9
14.7
14.0
12.9
11.3
10.5
9.5
8.9
8.6
8.4
8.5
8.5
8.4
8.4
8.4
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.4
11.4
11.4
11.4
11.4
11.4
11.4
11.4
11.4
11.1
10.4
8.9
8.8
8.6
8.6
8.5
8.5
8.5
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.8
8.7
8.7
8.5
17
Depth
(m)
Year 2012 Osoyoos Lake Water Temperatures (°C)
24-Apr-13
15-May-13
21-May-13
28-May-13
06-Jun-13
19-Jun-13
24-Jun-13
03-Jul-13
09-Jul-13
15-Jul-13
22-Jul-13
30-Jul-13
06-Aug-13
15-Aug-13
19-Aug-13
26-Aug-13
05-Sep-13
12-Sep-13
16-Sep-13
23-Sep-13
10-Oct-13
16-Oct-13
23-Oct-13
06-Nov-13
13-Nov-13
19-Dec-13
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
9.1
9.0
8.9
8.9
8.6
8.2
8.1
7.8
7.8
7.8
7.7
7.7
7.6
7.5
7.4
7.3
7.1
7.0
6.9
6.9
6.7
6.6
6.3
6.3
6.2
6.0
5.8
5.7
15.0
14.1
13.6
13.0
12.9
12.7
12.6
12.4
12.2
12.2
11.7
11.5
11.1
10.8
10.5
10.1
9.7
9.3
9.0
8.5
7.9
7.6
7.4
7.4
7.1
7.0
6.6
6.5
14.5
14.5
14.5
14.4
14.4
14.2
14.2
14.1
14.0
13.8
13.5
11.8
11.5
10.7
9.7
8.9
8.7
8.7
8.5
8.3
8.0
7.7
7.5
7.5
7.4
7.1
6.8
6.6
15.1
15.1
15.0
15.0
14.9
14.9
14.7
14.6
14.5
13.3
13.0
12.6
12.3
11.7
11.5
11.2
10.7
10.1
9.4
9.2
8.5
8.2
8.0
8.0
7.9
7.8
7.4
7.1
17.5
16.6
16.1
15.7
15.4
15.3
15.2
15.1
14.9
14.6
14.4
14.3
14.1
13.3
13.0
12.4
11.0
10.2
9.7
9.4
8.6
8.4
8.2
8.2
8.0
7.7
7.5
7.4
18.3
18.2
18.0
17.9
17.9
17.8
17.8
17.6
17.5
16.6
15.9
15.3
14.7
14.4
14.0
13.0
11.7
11.0
10.5
9.9
9.0
8.8
8.6
8.5
8.4
8.2
7.9
7.6
19.0
19.0
18.9
18.8
18.6
17.9
17.7
17.5
17.2
16.9
16.8
16.5
16.0
15.1
14.3
13.1
11.7
10.6
10.2
9.7
8.9
8.8
8.7
8.5
8.4
8.1
7.9
7.7
21.8
21.5
21.4
21.1
20.6
20.2
20.1
19.7
18.9
18.3
17.9
17.3
17.0
16.5
14.7
13.3
11.9
10.7
10.0
9.6
9.0
8.9
8.7
8.8
8.4
8.3
8.0
7.9
22.0
22.0
21.9
21.9
21.8
21.7
21.6
21.6
21.4
20.8
20.0
17.1
15.5
14.5
13.6
12.4
11.0
10.2
9.9
9.6
9.1
8.9
8.8
8.7
8.6
8.3
8.1
7.9
21.0
21.0
21.0
20.9
20.9
20.9
20.8
20.7
20.4
19.9
19.3
18.1
15.9
15.4
15.1
14.2
13.3
12.0
10.7
10.2
9.4
9.1
9.0
9.0
8.8
8.5
8.3
8.3
22.6
22.6
22.5
22.4
22.1
21.7
21.5
21.3
21.3
21.1
20.6
19.6
17.8
16.6
15.2
13.7
12.9
11.2
10.5
10.4
9.5
9.2
9.0
9.0
8.9
8.5
8.3
8.0
23.2
23.2
22.9
22.9
22.7
22.5
22.4
22.4
22.3
22.1
21.6
20.2
18.7
16.8
15.4
14.1
13.0
11.5
10.5
10.2
9.4
9.2
9.1
9.0
8.9
8.7
8.3
8.2
23.5
23.3
23.2
23.1
23.0
22.9
22.9
22.6
22.4
22.2
21.9
21.4
18.6
16.0
14.8
13.4
12.2
11.1
10.2
9.9
9.5
9.2
9.1
9.1
9.0
8.7
8.4
8.1
24.5
24.5
24.5
24.5
24.8
24.1
23.4
23.1
22.6
21.6
20.4
19.0
17.3
15.6
13.6
11.6
11.2
10.9
10.3
10.1
9.5
9.3
9.2
9.2
9.1
8.8
8.5
8.5
23.9
23.9
23.8
23.6
23.5
23.4
23.4
23.3
22.6
21.8
21.3
20.3
19.0
17.9
16.4
15.0
13.4
12.2
11.2
10.4
9.6
9.3
9.2
9.1
9.0
8.9
8.8
8.5
22.1
22.1
22.2
22.2
22.2
22.2
22.2
22.2
22.2
22.1
22.1
21.8
17.8
16.5
15.1
12.9
12.0
11.0
10.5
10.0
9.7
9.4
9.3
9.2
9.1
9.0
8.8
8.3
21.7
21.7
21.7
21.7
21.7
21.6
21.6
21.5
21.4
21.4
20.9
20.5
20.2
16.6
14.6
13.8
12.0
10.9
10.4
10.1
9.6
9.4
9.3
9.3
9.1
8.9
8.7
8.6
22.1
22.0
21.8
21.5
21.3
21.2
21.2
21.2
21.2
21.1
20.9
20.8
20.5
19.9
16.2
13.5
12.3
11.5
10.8
10.3
9.6
9.4
9.3
9.2
9.1
8.9
8.8
8.7
21.9
21.7
21.6
21.6
21.6
21.6
21.5
21.5
21.5
21.5
21.5
21.3
20.7
18.3
14.0
12.9
11.4
11.1
10.7
10.3
9.7
9.5
9.4
9.3
9.2
9.0
8.8
8.6
19.5
19.5
19.5
19.5
19.5
19.5
19.5
19.5
19.5
19.5
19.4
19.4
19.4
19.1
18.5
15.8
13.3
10.8
10.4
10.2
9.7
9.5
9.4
9.3
9.2
9.1
8.8
8.6
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.2
14.2
14.2
14.2
14.2
14.0
13.8
13.4
13.2
12.3
9.9
9.7
9.6
9.4
9.3
9.0
8.9
8.8
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.4
13.3
13.1
12.9
12.6
12.2
10.3
9.6
9.4
9.4
9.3
9.1
9.0
8.8
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.7
12.6
12.6
12.6
12.5
12.5
12.3
10.2
9.8
9.7
9.5
9.4
9.3
9.0
8.9
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.1
9.8
9.6
9.4
9.1
9.0
8.8
9.6
9.7
9.7
9.7
9.7
9.7
9.7
9.7
9.7
9.7
9.7
9.6
9.6
9.6
9.6
9.6
9.6
9.6
9.6
9.6
9.6
9.6
9.5
9.5
9.4
9.2
9.2
9.0
3.3
3.3
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
18
Depth (m)
Year 2013 Osoyoos Lake Water Temperatures (°C)
19
OSOYOOS LAKE OXYGEN CONCENTRATIONS
Table 2. Osoyoos Lake oxygen profiles (mg/L). Profiles are averaged from data collected at the
north end of the North Basin (#1, Figure 3) and the Monashee sites (#5, Figure 3). Shaded area
(when present) approximates oxygen concentrations known to be generally avoided by juvenile
sockeye (i.e. oxygen < 4µg L-1, Davis 1975, Brett and Blackburn 1981). No data available for
blank cells.
12-Jul-05
2-Aug-05
22-Aug-05
10.2
10.3
10.4
10.4
10.7
11.1
11.2
11.2
11.2
11.2
11.1
11.1
11.0
11.0
11.0
11.0
11.0
11.0
11.1
11.1
11.4
11.6
11.6
11.6
11.6
11.5
11.2
10.7
9.9
9.9
9.9
9.9
9.9
9.9
9.9
10.1
10.1
10.2
10.3
10.2
10.7
10.5
10.4
10.5
10.5
10.5
10.6
10.6
10.7
10.8
10.8
10.5
11.1
10.9
10.7
10.5
10.1
10.2
10.2
10.2
10.2
10.1
10.1
10.2
10.3
10.5
10.8
10.8
10.9
10.9
10.9
10.9
10.8
10.7
10.7
10.8
10.8
10.9
11.0
11.6
11.5
11.4
10.1
9.7
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.5
9.6
9.8
10.0
10.4
10.2
10.1
10.2
10.1
10.0
10.0
9.9
9.9
10.0
10.1
10.0
9.7
10.0
7.7
7.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
10.0
10.1
10.1
10.0
10.1
10.0
9.8
9.8
9.7
9.7
9.6
9.5
9.7
9.4
9.2
10.1
9.2
7.7
4.1
9.2
9.2
9.2
9.2
9.2
9.2
9.2
9.1
9.1
9.1
9.1
9.1
8.9
8.9
8.8
8.1
7.9
7.9
7.9
7.8
7.8
7.9
7.6
6.8
7.3
5.9
4.6
4.3
9.6
9.6
9.6
9.6
9.6
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
8.9
8.6
8.2
8.0
7.8
7.8
7.6
7.6
7.7
7.6
7.8
7.4
6.7
5.1
4-Nov-05
20-Jun-05
10.4
10.5
10.6
10.6
10.6
10.7
10.8
11.1
11.3
11.5
11.6
11.7
11.7
11.7
11.7
11.8
11.8
11.9
11.8
11.8
11.9
11.9
12.0
11.9
11.3
11.3
11.2
4-Oct-05
31-May-05
12.1
12.5
12.7
12.8
12.8
12.9
12.9
13.0
13.0
13.0
13.0
13.0
13.0
12.9
12.9
12.9
12.9
12.9
12.8
12.8
12.8
12.7
12.6
12.5
12.6
12.5
12.3
11.9
22-Sep-05
17-May-05
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
27-Apr-05
Depth (m)
Year 2005 Osoyoos Lake oxygen concentrations µg L-1
10.1
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
9.7
9.6
9.5
9.3
9.1
8.3
8.0
7.7
7.3
6.9
6.4
20
Depth
(m)
24-Jan-06
24-Apr-06
23-May-06
12-Jun-06
04-Jul-06
18-Jul-06
21-Aug-06
30-Aug-06
06-Sep-06
11-Sep-06
19-Sep-06
26-Sep-06
02-Oct-06
16-Oct-06
23-Oct-06
Year 2006 Osoyoos Lake oxygen concentrations µg L-1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
12.7
12.6
12.5
12.5
12.5
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.4
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
12.3
8.9
12.2
12.2
12.3
12.3
11.9
12.2
12.1
12.2
12.1
12.3
12.1
12.3
12.1
12.2
12.1
12.2
12.1
12.2
12.1
12.1
10.2
10.2
10.2
10.2
10.2
10.3
10.2
10.3
9.9
9.8
9.7
9.7
9.6
9.6
9.4
9.3
9.2
9.2
9.1
8.9
8.9
8.9
9.0
9.0
9.1
9.2
9.2
9.2
9.2
9.1
8.9
8.5
8.8
8.7
8.7
9.0
8.9
9.0
9.2
9.1
9.1
8.8
8.5
8.3
8.0
7.7
7.5
7.4
7.2
7.1
7.2
7.3
7.5
7.5
7.6
7.5
7.4
7.1
6.3
7.0
7.0
7.0
6.9
8.6
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.1
7.6
7.5
6.9
6.3
6.3
6.3
6.3
6.3
6.4
6.5
6.6
6.6
6.6
6.4
6.6
9.5
9.5
9.5
9.5
9.4
9.3
9.1
8.8
8.3
8.1
7.7
6.9
3.6
3.6
3.8
4.1
4.4
4.7
4.9
5.0
5.1
4.9
4.6
4.6
4.5
4.5
4.5
4.4
8.6
8.6
8.6
8.6
8.6
8.6
8.6
8.3
8.3
8.1
7.6
7.0
6.3
4.6
3.5
3.6
4.0
4.2
4.4
4.3
4.4
4.0
4.0
3.3
3.9
3.9
3.9
3.8
9.2
9.3
9.3
9.3
9.2
9.1
8.9
8.5
8.3
8.2
8.1
7.9
7.3
4.7
3.5
3.4
3.7
3.9
4.0
4.2
4.3
4.1
3.8
2.5
3.7
3.6
3.6
3.5
9.4
9.5
9.5
9.5
9.5
9.4
9.3
9.0
8.9
8.7
8.6
8.4
8.2
7.0
4.0
3.7
3.8
4.1
4.2
4.3
4.3
3.9
3.5
3.0
3.5
3.4
3.4
3.1
9.4
9.3
9.3
9.3
9.3
9.2
9.2
9.2
9.1
9.0
9.0
9.0
8.9
7.9
6.1
3.6
3.2
3.2
3.3
3.6
3.7
3.1
3.1
2.3
2.9
2.9
2.8
2.6
9.7
9.7
9.8
9.8
9.8
9.8
9.7
9.6
9.6
9.5
9.4
9.5
9.5
9.4
9.3
7.4
3.9
3.5
3.4
3.4
3.2
3.1
3.0
2.9
2.7
2.6
2.5
2.4
9.3
9.2
9.1
9.1
9.1
9.0
9.0
9.0
8.9
8.7
8.4
8.3
8.2
8.0
7.7
6.8
5.4
3.4
2.9
2.8
2.8
2.5
2.2
2.1
2.1
2.0
2.0
2.0
9.5
9.5
9.5
9.4
9.4
9.4
9.4
9.4
9.3
9.3
9.3
9.3
9.2
9.3
9.3
9.3
8.4
6.0
4.1
2.8
2.3
2.0
1.8
1.6
1.5
1.5
1.5
1.5
9.8
9.5
9.5
9.5
9.5
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
8.8
7.6
3.5
2.1
1.7
1.6
1.4
1.3
1.2
1.1
10.3
10.4
10.4
10.3
12.2
10.3
12.1
12.1
12.0
12.0
11.8
11.8
11.8
11.8
11.8
10.4
10.3
10.2
10.3
10.1
10.1
10.0
10.0
10.0
21
8.9
8.9
8.9
8.9
8.8
8.9
8.9
8.8
8.7
8.4
8.2
7.7
7.4
6.2
4.0
3.8
4.6
4.3
4.2
4.4
4.4
4.4
4.2
4.2
4.2
4.2
4.1
4.1
9.6
9.4
9.4
9.4
9.3
9.3
9.2
9.1
9.0
9.0
9.0
8.8
8.4
8.3
7.9
5.8
4.5
4.2
4.2
4.3
4.3
4.2
3.9
4.1
4.0
3.9
3.8
3.8
9.8
9.7
9.7
9.6
9.6
9.6
9.6
9.6
9.6
9.2
9.2
9.1
9.0
8.5
6.8
5.3
5.0
4.5
4.3
4.2
3.8
4.2
4.1
3.7
3.6
3.6
3.6
3.5
10.6
10.5
10.5
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.5
10.5
10.4
9.9
7.1
5.7
4.9
4.4
3.8
3.8
3.7
3.6
3.5
3.4
3.4
3.3
3.3
9.3
9.3
9.2
9.2
9.2
9.2
6.3
6.0
3.3
2.7
2.5
2.5
2.5
2.5
2.4
5-Nov-07
9.8
9.8
9.8
9.8
9.7
9.7
9.7
9.6
9.5
9.3
9.0
8.5
8.0
5.1
4.6
5.0
5.3
5.5
5.8
5.9
5.9
5.7
5.5
5.6
5.6
5.6
5.5
5.4
9-Oct-07
7.2
8.3
8.7
8.8
8.7
8.7
8.7
8.6
8.6
8.6
8.9
8.5
8.0
6.8
6.4
6.1
6.1
5.6
5.6
5.8
5.8
5.8
5.7
5.6
5.6
5.5
5.4
5.4
3-Oct-07
25-Sep-07
8.1
7.9
8.6
8.8
8.8
8.4
8.4
8.3
8.2
7.7
7.7
7.3
6.8
6.5
6.0
6.0
6.0
5.8
6.0
5.9
5.9
5.9
5.9
18-Sep-07
9.9
10.0
10.1
10.2
10.1
10.2
10.1
9.8
9.6
9.6
9.5
9.0
8.6
8.4
8.4
8.4
8.4
8.5
8.4
8.4
8.5
8.4
8.1
8.5
8.4
8.4
8.3
8.3
10-Sep-07
2-Aug-07
9.9
9.8
9.8
9.8
9.8
9.8
9.7
9.7
9.7
9.6
9.4
9.1
9.1
9.1
9.0
9.0
9.2
9.2
9.3
9.3
9.4
9.4
9.2
9.2
9.1
9.1
9.1
9.1
4-Sep-07
26-Jun-07
11.7
11.8
11.9
11.9
11.8
11.8
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.6
11.6
11.6
11.5
11.5
11.5
11.5
11.5
11.3
11.2
11.2
11.2
11.2
11.2
11.2
24-Aug-07
11-Jun-07
12.1
12.7
12.9
12.9
13.0
13.0
13.0
12.9
12.9
12.9
12.9
12.9
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.9
12.8
12.8
12.7
12.7
12.6
12.6
13-Aug-07
14-May-07
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
17-Apr-07
Depth (m)
Year 2007 Osoyoos Lake oxygen concentrations µg L-1
10.0
9.9
9.8
9.8
9.8
9.8
9.7
9.7
9.7
9.7
9.5
9.6
9.5
9.5
9.4
9.2
8.4
8.3
8.1
6.1
4.6
3.3
2.8
2.4
2.3
2.2
2.2
2.1
10.6
10.1
9.8
9.6
9.5
9.4
9.4
9.3
9.3
9.2
9.2
9.1
9.1
9.0
8.4
8.7
8.5
8.0
8.3
8.2
8.2
8.4
8.0
6.3
5.0
2.8
1.9
1.5
18-Mar-08
07-Apr-08
17-Apr-08
20-May-08
09-Jun-08
24-Jun-08
07-Jul-08
21-Jul-08
28-Jul-08
11-Aug-08
27-Aug-08
07-Sep-08
22-Sep-08
19-Oct-08
18-Nov-08
04-Dec-08
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
13.3
13.6
13.6
13.6
13.7
13.7
13.6
13.8
13.6
13.7
13.6
13.7
14.5
14.8
15.2
15.4
15.4
15.5
15.6
15.6
15.7
15.7
15.8
15.7
15.7
15.5
15.5
15.5
15.5
15.4
15.4
15.4
15.4
15.3
15.2
15.0
15.0
14.9
14.9
14.8
14.0
14.3
14.6
14.8
15.0
15.1
15.1
15.1
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.1
15.1
15.1
15.1
15.1
14.9
14.9
14.8
14.8
14.8
11.2
11.2
11.2
11.3
11.5
11.6
11.7
11.8
11.7
11.7
11.7
11.6
11.6
11.6
11.6
11.7
11.7
11.7
11.7
11.8
11.8
11.7
11.5
11.5
11.4
11.4
11.3
11.3
10.5
10.4
10.3
10.3
10.2
10.2
10.2
9.9
9.8
9.6
9.5
9.5
9.6
9.7
9.9
10.0
10.1
10.1
10.1
10.1
10.1
10.0
10.0
9.9
9.9
9.9
9.9
9.8
9.2
9.2
9.2
9.2
9.2
9.1
8.9
8.8
8.6
8.5
8.2
7.9
8.2
8.1
8.3
8.2
8.2
8.3
8.3
8.3
8.3
8.3
8.3
8.2
8.2
8.1
8.1
8.1
9.2
9.3
9.3
9.3
9.3
9.2
9.0
8.8
8.5
8.4
8.1
7.8
7.9
8.2
8.3
8.3
8.4
8.4
8.4
8.4
8.4
8.3
8.1
8.2
8.2
8.1
8.1
8.1
9.7
9.7
9.7
9.7
9.7
9.7
9.5
9.3
9.0
8.7
8.1
7.6
7.5
7.6
7.7
7.8
7.9
8.0
8.0
8.0
8.0
8.1
7.8
7.9
7.8
7.8
7.8
7.8
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.1
9.0
8.5
7.6
7.6
6.9
6.8
6.8
7.0
7.2
7.3
7.2
7.4
7.4
7.3
7.2
7.1
7.1
7.0
6.9
6.7
9.3
9.3
9.4
9.3
9.2
9.2
8.9
8.8
8.8
8.3
7.9
7.4
6.7
6.3
6.2
6.1
6.2
6.2
6.3
6.4
6.4
6.4
6.3
6.3
6.3
6.2
6.2
6.1
9.2
9.2
9.1
9.1
9.1
9.0
9.0
8.9
8.8
8.5
8.2
8.0
7.1
6.0
5.5
5.3
5.1
5.2
5.2
5.3
5.5
5.5
5.4
5.3
5.3
5.2
5.2
5.1
9.9
9.9
9.9
9.9
9.9
9.9
9.9
9.8
9.7
9.7
9.7
9.6
9.6
9.2
7.4
6.7
5.9
5.8
5.7
5.6
7.2
6.5
6.1
6.2
5.9
5.7
5.4
5.3
11.3
11.1
11.0
10.9
11.0
10.9
11.0
11.0
11.0
11.0
11.0
10.9
10.7
9.0
7.1
7.2
6.3
5.8
5.7
5.5
5.3
5.1
4.8
5.0
5.0
4.9
4.9
4.9
12.1
11.9
11.8
11.7
11.6
11.6
11.6
11.6
11.5
11.4
11.4
11.3
11.3
11.2
11.1
10.8
10.5
10.3
10.0
9.7
6.7
5.5
4.7
4.3
3.8
3.6
3.4
3.2
10.2
9.8
9.5
9.4
9.2
9.2
9.1
9.1
9.1
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
8.5
8.5
8.4
7.9
7.6
11.7
11.2
10.9
10.7
10.5
10.4
10.4
10.3
10.2
10.2
10.1
10.1
10.1
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
9.9
9.9
9.9
9.9
9.9
13.7
13.7
13.7
13.7
13.7
13.6
13.6
13.5
13.5
13.5
22
Depth (m)
Year 2008 Osoyoos Lake oxygen concentrations µg L-1
11-May-09
25-May-09
08-Jun-09
29-Jun-09
13-Jul-09
27-Jul-09
11-Aug-09
18-Aug-09
24-Aug-09
31-Aug-09
10-Sep-09
14-Sep-09
21-Sep-09
28-Sep-09
05-Oct-09
22-Oct-09
17-Dec-09
14.4
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.5
14.4
14.4
14.4
14.3
14.4
14.3
14.3
14.3
14.3
14.2
14.1
14.1
14.1
14.1
14.1
13.9
13.9
11.7
11.9
11.9
11.9
11.8
11.8
11.7
11.8
11.7
11.5
11.4
11.4
11.3
11.3
11.2
11.2
11.1
11.1
11.1
11.0
11.0
10.9
10.9
10.8
10.8
10.1
10.8
10.8
11.1
11.1
11.2
11.2
11.3
11.3
11.3
11.3
11.3
11.3
11.4
11.2
11.0
10.8
10.6
10.8
10.7
10.7
10.7
10.7
10.6
10.6
10.5
10.5
10.4
10.4
10.4
10.3
9.6
9.7
9.8
9.8
9.8
9.7
9.8
10.2
10.5
10.4
10.2
10.0
9.8
9.7
9.6
9.6
9.6
9.6
9.6
9.6
9.7
9.6
9.6
9.5
9.5
9.4
9.4
9.4
9.3
9.4
9.3
9.3
9.3
9.3
9.3
9.2
9.1
9.0
8.8
8.6
8.4
8.2
8.1
8.2
8.2
8.2
8.2
8.2
8.1
8.1
7.9
7.9
7.8
7.8
7.8
7.7
9.3
9.4
9.5
9.6
9.6
9.6
9.7
9.8
9.4
9.2
9.1
8.6
7.7
7.7
7.6
7.5
7.5
7.5
7.5
7.5
7.4
7.3
7.3
7.4
7.3
7.1
7.1
7.0
9.4
9.5
9.5
9.5
9.4
9.3
9.3
9.1
8.9
8.9
9.1
9.3
8.2
7.4
7.2
7.0
7.0
6.9
6.9
6.8
6.8
6.7
6.6
6.6
6.6
6.5
6.4
6.3
8.7
8.6
8.5
8.5
8.3
8.2
8.0
7.9
7.6
7.4
6.5
6.3
5.7
5.6
5.6
5.6
5.6
5.7
5.7
5.8
5.9
5.8
5.7
5.6
5.6
5.5
5.5
5.5
8.5
8.6
8.5
8.4
8.2
8.1
7.9
7.8
7.6
7.4
9.7
9.7
9.6
9.5
9.3
9.1
8.8
8.0
7.7
6.9
6.7
6.1
4.9
4.9
5.3
5.7
5.7
5.8
5.8
5.9
5.8
6.0
5.4
5.4
5.5
8.8
9.1
9.1
9.1
9.0
8.9
8.7
8.6
8.4
8.2
7.5
6.5
5.4
5.6
4.9
4.8
4.8
4.9
5.0
5.0
5.1
5.0
4.9
4.7
4.7
4.6
4.5
4.5
9.1
9.0
9.0
8.9
8.9
8.8
8.7
8.7
8.6
8.4
7.6
7.1
5.4
4.5
4.3
4.3
4.4
4.3
4.4
4.5
4.7
4.6
4.5
4.5
4.4
4.4
4.3
4.2
9.6
9.6
9.5
9.4
9.3
9.1
8.9
8.8
8.6
8.4
8.1
7.8
7.1
5.6
4.9
4.1
4.2
4.2
4.3
2.3
4.4
4.3
4.2
4.2
4.1
4.1
4.0
3.9
9.2
9.1
8.9
8.8
8.7
8.6
8.4
8.2
8.0
7.7
7.5
7.3
7.0
5.9
5.1
3.9
3.6
3.7
3.7
3.8
3.9
3.8
3.7
3.7
3.6
3.5
3.4
3.3
9.8
9.7
9.6
9.5
9.5
9.4
9.4
9.3
9.2
9.2
9.2
9.1
9.1
9.0
7.3
4.4
4.0
3.9
3.8
3.8
3.7
3.7
3.6
3.7
3.7
3.6
3.5
3.4
9.5
9.4
9.3
9.2
9.2
9.1
9.1
9.0
9.0
9.0
8.8
8.7
8.7
8.6
8.3
7.7
6.9
5.5
4.4
4.1
3.6
3.4
3.3
3.3
3.2
3.1
3.1
3.0
10.8
10.6
10.5
10.4
10.4
10.3
10.3
10.3
10.2
10.2
10.2
10.2
10.1
10.1
10.1
10.1
10.1
10.0
9.5
7.0
5.5
4.3
3.6
3.3
2.9
2.7
2.6
2.5
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
12.0
11.9
11.9
11.9
11.9
11.9
4.9
5.0
5.0
4.8
4.8
4.8
4.7
23
1
2
3
4
5
6
7
8
9
1
0
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
2
0
2
4
2
8
3
2
3
6
4
0
4
4
8
5
2
15-Apr-09
Depth (m)
Year 2009 Osoyoos Lake oxygen concentrations µg L-1
16-Feb-10
16-Apr-10
10-May-10
01-Jun-10
14-Jun-10
29-Jun-10
19-Jul-10
26-Jul-10
09-Aug-10
16-Aug-10
23-Aug-10
30-Aug-10
06-Sep-10
14-Sep-10
20-Sep-10
27-Sep-10
02-Oct-10
18-Oct-10
15-Nov-10
15-Dec-10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.3
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.2
14.1
14.1
14.1
14.1
14.0
14.0
14.8
14.9
14.9
14.9
14.8
14.7
14.6
14.5
14.2
14.1
14.0
13.9
13.8
13.7
13.7
13.6
13.6
13.6
13.6
13.6
13.6
13.5
13.5
13.6
13.6
13.6
13.5
13.5
12.4
12.6
12.8
12.8
12.8
12.9
12.9
12.8
12.7
12.6
12.6
12.5
12.5
12.2
12.1
12.1
12.0
11.9
11.8
11.7
11.7
11.6
11.6
11.5
11.5
11.5
11.5
11.4
16.4
16.6
16.7
16.7
16.8
16.8
16.7
16.4
16.2
15.1
14.9
14.7
14.6
14.4
14.4
14.4
14.3
14.3
14.1
14.3
14.1
14.3
14.1
14.3
14.3
14.0
14.3
14.3
10.0
10.1
10.2
10.1
9.9
9.8
9.7
9.5
9.2
9.0
8.8
8.7
8.7
8.5
8.7
8.7
8.7
8.6
8.6
8.6
8.6
8.5
8.5
8.4
8.3
8.3
8.2
8.2
10.2
10.4
10.4
10.3
10.3
10.1
9.4
9.0
8.8
8.6
8.5
8.4
8.1
8.5
8.3
8.6
8.6
8.1
8.5
8.5
8.5
8.4
8.3
8.2
8.2
8.2
8.1
8.1
11.6
11.6
11.7
11.6
11.6
11.3
11.1
10.4
9.8
9.2
8.5
8.2
8.2
8.3
8.4
8.5
8.6
8.6
8.6
8.6
8.5
8.5
8.2
8.3
8.3
8.2
8.2
8.1
11.5
11.5
11.5
11.4
11.3
11.0
10.4
9.9
9.1
8.1
7.5
7.2
7.4
7.5
7.7
7.7
7.8
7.8
7.8
7.9
7.9
7.9
7.7
7.8
7.6
7.6
7.5
7.5
11.4
11.4
11.4
11.4
11.4
10.9
10.4
9.4
8.0
7.0
6.2
6.2
6.4
6.8
7.2
7.4
7.6
7.7
7.8
7.9
7.9
7.7
7.5
7.8
7.6
7.5
7.4
7.3
12.5
12.6
12.5
12.3
12.1
11.6
11.4
11.1
10.5
8.8
6.6
5.5
5.9
6.2
6.6
6.8
7.1
7.2
7.3
7.4
7.5
7.2
7.0
7.0
6.9
6.9
6.8
6.7
13.4
13.3
13.3
13.3
13.3
13.3
13.2
13.2
13.1
12.7
11.2
9.2
7.7
6.8
6.7
7.6
7.9
8.2
8.4
8.5
8.7
8.7
8.5
8.5
8.3
9.6
8.7
8.4
13.7
13.9
14.0
14.1
14.1
14.1
14.0
13.8
13.1
12.9
12.0
10.0
7.4
6.6
6.5
6.7
6.9
7.2
7.3
7.4
7.5
7.4
7.4
6.8
6.8
6.8
6.7
6.7
11.1
11.1
11.1
10.1
10.5
10.8
10.9
11.1
10.7
10.2
11.1
11.2
10.7
9.9
7.7
6.6
5.8
5.6
5.5
5.4
5.2
5.1
5.0
5.2
5.1
5.1
5.0
5.0
16.6
16.5
16.5
16.8
16.8
17.5
16.9
16.8
16.5
16.0
16.0
14.8
14.2
12.1
10.0
7.8
7.1
6.9
6.8
6.7
6.7
6.7
6.6
6.6
6.5
6.4
6.2
6.0
8.2
8.5
8.7
8.9
9.0
9.1
9.2
9.3
9.4
9.4
9.5
9.2
9.6
8.3
7.3
6.3
4.4
4.3
3.7
3.5
3.4
3.4
3.2
2.9
2.9
2.9
2.9
2.8
9.7
9.8
9.8
9.8
9.8
9.8
9.8
9.7
9.6
9.6
9.6
9.6
9.6
9.0
8.3
6.3
5.1
4.0
3.7
3.4
3.0
2.9
2.7
2.6
2.6
2.5
2.5
2.4
9.8
9.9
10.1
10.2
10.2
10.2
10.2
10.1
10.0
9.9
9.8
9.7
9.6
9.5
9.7
8.8
7.6
6.7
5.4
4.7
4.1
3.7
3.3
3.0
2.8
2.7
2.6
2.6
11.1
10.8
10.7
10.5
10.5
10.4
10.4
10.3
10.3
10.2
10.2
10.1
10.1
10.0
10.0
10.0
10.0
9.7
9.0
7.8
4.4
3.6
3.1
3.0
2.7
2.3
2.2
2.1
12.1
11.8
11.6
11.5
11.5
11.5
11.3
11.2
11.2
11.2
11.2
11.2
11.2
11.1
11.1
11.2
11.1
11.1
11.1
11.1
11.1
9.7
7.8
2.8
2.1
1.9
1.7
1.6
11.6
11.6
11.6
11.6
11.6
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
11.5
24
Depth (m)
Year 2010 Osoyoos Lake oxygen concentrations µg L-1
20-Apr-11
03-May-11
10-May-11
24-May-11
31-May-11
16-Jun-11
20-Jun-11
14-Jul-11
18-Jul-11
03-Aug-11
09-Aug-11
16-Aug-11
22-Aug-11
29-Aug-11
07-Sep-11
15-Sep-11
22-Sep-11
28-Sep-11
06-Oct-11
11-Oct-11
16-Oct-11
03-Nov-11
16-Nov-11
29-Nov-11
18-Dec-11
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
15.5
15.5
15.5
15.5
15.5
15.5
15.6
15.5
15.5
15.5
15.4
15.4
15.4
15.4
15.4
15.4
15.3
15.3
15.2
15.2
15.1
15.1
15.0
15.2
15.2
15.1
15.0
15.0
14.2
14.2
14.3
14.3
14.4
14.4
14.6
14.6
14.6
14.6
14.6
14.6
14.6
14.6
14.6
14.7
14.6
14.6
14.6
14.6
14.6
14.6
14.6
14.6
14.6
14.5
14.5
14.5
11.5
11.6
11.7
11.8
11.8
11.9
11.8
11.8
11.8
11.7
11.7
11.7
11.8
11.8
11.8
11.9
11.9
11.9
12.0
12.0
12.0
12.0
12.0
12.0
11.9
11.9
11.9
11.9
10.8
11.0
11.1
11.0
11.1
11.1
11.1
11.1
11.1
11.1
11.1
11.1
11.1
11.1
11.2
11.2
11.2
11.3
11.3
11.3
11.4
11.4
11.4
11.4
11.3
11.4
11.4
11.4
10.5
10.6
10.6
10.6
10.5
10.5
10.6
10.6
10.6
10.6
10.6
10.6
10.5
10.5
10.5
10.5
10.5
10.5
10.6
10.6
10.7
10.8
10.7
10.8
10.8
10.8
10.8
10.8
10.5
10.1
10.1
10.1
10.1
10.1
10.1
10.1
10.1
10.0
10.1
10.1
10.1
10.1
10.1
10.1
10.1
10.1
10.2
10.2
10.2
10.1
10.0
9.9
9.9
9.9
9.9
10.0
10.4
10.4
10.4
10.3
10.3
10.3
10.3
10.3
10.3
10.3
10.2
10.2
10.1
10.1
10.1
10.1
10.1
10.1
10.1
10.1
10.2
10.2
10.1
9.9
9.9
9.9
9.9
9.9
10.3
10.3
10.2
10.2
10.2
10.2
10.1
10.1
9.9
9.8
9.6
9.5
9.2
9.1
9.0
9.1
9.1
9.2
9.2
9.2
9.2
9.1
8.8
9.0
9.0
8.9
8.9
8.9
9.5
9.4
9.3
9.2
9.2
9.2
9.1
9.1
8.9
8.7
8.6
8.5
8.3
8.2
8.2
8.3
8.4
8.5
8.6
8.6
8.6
8.5
8.1
8.2
8.2
8.3
8.3
8.3
13.5
13.3
13.3
13.2
13.1
13.1
13.0
12.9
12.7
12.6
12.2
11.6
11.0
10.5
10.3
10.2
10.5
10.8
10.9
11.1
11.3
11.1
11.0
10.9
10.8
10.8
10.8
10.8
9.4
9.5
9.5
9.5
9.5
9.4
9.3
9.2
9.0
8.8
8.3
7.9
7.2
7.0
6.6
6.7
6.9
7.0
7.1
7.1
7.0
6.8
6.5
6.5
6.4
6.4
6.4
6.4
8.6
8.6
8.5
8.5
8.4
8.4
8.9
8.3
8.3
8.3
7.4
6.9
6.3
6.1
5.9
5.8
5.9
6.1
6.1
6.1
6.2
6.5
6.0
5.8
5.6
5.6
5.6
5.5
9.5
9.5
9.5
9.4
9.3
9.3
9.2
9.1
8.8
8.6
7.9
7.0
6.4
5.7
5.5
5.6
5.8
6.1
6.2
6.2
6.2
6.0
5.7
5.7
5.6
5.6
5.6
5.6
9.8
9.9
9.9
9.9
9.8
9.6
9.4
8.7
7.9
7.3
6.8
6.3
5.6
5.3
5.2
5.4
5.6
5.7
5.8
5.9
6.0
5.6
5.3
5.1
5.0
5.1
5.2
5.1
10.3
10.4
10.4
10.3
10.1
9.9
9.5
9.3
9.0
8.9
8.7
8.5
8.2
6.8
5.3
5.1
5.1
5.3
5.3
5.4
5.4
5.2
4.8
4.7
4.6
4.6
4.7
4.7
9.5
9.6
9.6
9.6
9.6
9.7
9.5
8.7
8.4
8.2
7.9
7.4
5.5
4.6
4.2
4.3
4.5
4.7
4.7
4.8
4.7
4.1
3.6
3.8
3.8
4.1
4.3
4.0
8.6
8.6
8.6
8.6
8.5
8.5
8.5
8.5
8.4
8.4
8.4
8.4
8.3
8.3
8.0
5.3
4.7
4.2
4.2
4.1
3.9
3.7
3.2
3.4
3.3
3.2
3.2
3.3
8.1
8.0
8.0
8.0
8.0
7.9
7.7
7.8
7.7
7.7
7.6
7.6
7.5
7.1
6.5
5.7
4.6
4.0
3.7
3.6
3.3
3.1
2.9
2.7
2.6
2.5
2.5
2.5
6.1
6.0
6.0
6.1
6.0
6.0
6.0
6.0
6.0
5.9
5.8
5.8
5.8
5.7
5.8
5.8
5.8
5.5
3.9
3.1
2.5
2.2
2.0
1.8
1.8
1.8
1.8
1.8
6.1
6.0
6.0
6.1
6.0
6.0
6.0
6.0
6.0
5.9
5.8
5.8
5.8
5.7
5.8
5.8
5.8
5.5
3.9
3.1
2.5
2.2
2.0
1.8
1.8
1.8
1.8
1.8
9.9
9.7
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.3
9.2
9.2
9.1
8.9
8.9
8.9
8.8
8.7
8.6
7.4
4.3
3.1
2.6
2.3
2.2
2.2
2.1
10.5
9.9
9.6
9.6
9.5
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
9.4
8.9
7.8
6.2
2.9
1.4
1.3
1.3
1.2
6.2
6.2
6.1
6.1
6.1
6.1
6.1
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
5.8
5.7
5.4
5.1
4.7
13.5
13.2
13.0
12.9
12.9
12.9
12.9
12.9
12.9
12.9
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.8
12.6
12.6
12.6
12.6
12.6
18.1
17.7
17.6
17.6
17.6
17.7
17.7
17.7
17.8
17.8
17.9
17.9
18.0
18.0
18.0
18.1
18.1
18.1
18.1
18.2
18.2
18.2
18.3
18.0
18.0
18.1
18.1
18.2
25
Depth (m)
Year 2011 Osoyoos Lake oxygen concentrations µg L-1
29-Apr-12
22-May-12
11-Jun-12
16-Jul-12
26-Jul-12
07-Aug-12
13-Aug-12
20-Aug-12
27-Aug-12
04-Sep-12
11-Sep-12
17-Sep-12
24-Sep-12
30-Sep-12
11-Oct-12
29-Oct-12
17-Nov-12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
10.8
11.0
11.2
11.3
11.3
11.3
11.1
11.1
11.1
10.7
11.0
11.2
11.1
11.1
11.1
11.1
10.5
10.4
10.9
10.9
10.9
10.9
10.9
10.9
10.4
10.0
10.3
10.6
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
11.1
11.0
11.0
10.9
10.7
10.5
10.5
10.5
10.5
10.4
10.5
10.4
10.4
10.1
10.0
10.0
10.1
10.1
10.1
10.1
10.0
10.0
9.8
9.8
9.8
9.8
9.6
9.6
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
8.5
8.4
8.3
8.2
8.3
8.3
8.0
8.0
7.8
7.7
7.5
7.1
6.8
6.6
6.6
6.7
6.7
6.8
6.8
6.8
6.7
6.7
6.7
6.3
6.3
6.2
6.2
6.1
8.7
8.7
8.6
8.6
8.6
8.4
8.3
8.1
7.9
7.6
7.0
6.6
6.2
6.3
6.2
6.2
6.4
6.4
6.5
6.5
6.5
6.5
6.3
6.2
6.1
6.0
6.0
5.9
8.8
8.9
8.9
8.9
8.9
8.7
8.6
8.5
8.2
7.2
6.0
5.6
5.6
5.7
5.8
6.1
6.2
6.3
6.3
6.3
6.2
6.1
5.9
5.9
5.8
5.7
5.7
5.6
8.9
8.9
9.0
9.0
9.1
9.1
9.0
9.0
8.6
8.1
7.6
5.9
5.5
5.5
5.6
5.7
5.9
6.0
6.1
6.1
6.1
5.9
5.7
5.7
5.7
5.7
5.5
5.4
8.7
8.7
8.7
8.8
8.7
8.7
8.7
8.7
8.7
8.7
8.6
8.0
5.5
5.2
5.1
5.3
5.5
5.5
5.6
5.6
5.6
5.4
5.2
5.1
5.0
4.9
4.9
4.9
8.8
8.7
8.6
8.6
8.6
8.5
8.5
8.4
8.2
8.2
8.3
8.2
7.5
5.9
5.2
4.8
4.8
4.9
5.0
5.0
4.9
4.8
4.6
4.4
4.2
4.2
4.2
4.2
9.0
8.8
8.8
8.8
8.8
8.8
8.8
8.7
8.6
8.5
8.3
8.2
7.5
5.5
5.2
4.8
4.5
4.4
4.4
4.4
4.4
4.4
4.3
4.2
4.1
4.1
4.0
4.0
9.2
9.2
9.2
9.2
9.2
9.1
9.1
9.1
8.9
8.8
8.7
8.5
8.4
7.5
6.2
4.6
4.2
4.1
4.1
4.1
4.1
4.1
4.0
3.8
3.8
3.8
3.8
3.8
9.7
9.7
9.8
9.8
9.7
9.7
9.7
9.3
9.0
8.7
8.6
8.5
8.3
8.0
7.2
6.6
4.6
4.2
4.1
4.0
3.9
3.8
3.6
3.8
3.7
3.7
3.7
3.6
9.7
9.6
9.6
9.6
9.5
9.4
9.2
9.2
9.1
9.0
9.0
9.0
8.8
8.3
7.7
6.7
5.2
4.1
3.6
3.5
3.5
3.5
3.2
3.5
3.4
3.4
3.3
3.1
10.1
10.0
10.1
10.0
10.0
9.9
9.8
9.8
9.7
9.6
9.5
9.4
9.3
9.2
9.1
8.7
8.2
6.8
5.1
4.1
3.6
3.2
2.8
2.9
2.7
2.6
2.6
2.5
10.1
9.9
9.9
9.9
9.8
9.8
9.8
9.8
9.8
9.7
8.6
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.7
7.6
5.4
4.1
2.5
2.3
2.2
2.0
1.9
10.5
10.1
10.0
9.9
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.8
9.4
9.4
8.5
6.9
4.9
26
Depth (m)
Year 2012 Osoyoos Lake oxygen concentrations µg L-1
24-Apr-13
15-May-13
21-May-13
28-May-13
06-Jun-13
19-Jun-13
24-Jun-13
03-Jul-13
09-Jul-13
15-Jul-13
22-Jul-13
30-Jul-13
06-Aug-13
15-Aug-13
19-Aug-13
05-Sep-13
16-Sep-13
23-Sep-13
10-Oct-13
16-Oct-13
23-Oct-13
06-Nov-13
13-Nov-13
19-Dec-13
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
32
36
40
44
48
52
13.4
13.5
13.4
13.3
13.3
13.2
13.2
13.1
13.0
12.9
12.9
12.9
12.8
12.7
12.6
12.6
12.6
12.5
12.5
12.5
12.5
12.5
12.5
12.1
12.1
12.1
12.1
12.1
11.0
11.2
11.0
10.9
10.7
10.7
10.6
10.6
10.5
10.5
10.6
10.6
10.7
10.7
10.7
10.8
10.9
10.9
10.9
10.9
10.9
10.8
10.6
10.5
10.5
10.4
10.5
10.4
10.4
10.3
10.3
10.2
10.2
10.1
10.1
10.0
10.0
10.0
10.0
10.2
10.1
10.2
10.4
10.5
10.4
10.3
10.2
10.2
10.1
10.1
10.0
9.9
9.8
9.9
9.9
9.8
10.9
10.9
10.9
10.8
10.9
10.8
10.8
10.8
10.8
10.9
10.6
10.5
10.4
10.4
10.3
10.1
10.1
10.1
10.1
10.0
10.1
9.9
9.9
9.8
9.7
9.7
9.7
9.7
10.2
10.3
10.1
10.0
9.9
9.8
9.7
9.6
9.6
9.5
9.5
9.4
9.4
9.4
9.3
9.3
9.4
9.4
9.2
9.1
9.1
9.1
8.9
8.7
8.6
8.6
8.6
8.5
9.8
9.6
9.4
9.3
9.2
9.1
9.1
9.0
8.9
8.9
8.7
8.5
8.3
8.2
8.2
8.2
8.3
8.3
8.2
8.3
8.3
8.2
8.5
8.0
8.0
8.0
8.0
8.0
10.0
10.0
9.9
9.8
9.7
9.5
9.4
9.3
9.0
8.9
8.9
8.8
8.7
8.5
8.1
8.2
8.3
8.2
8.2
8.2
8.1
8.0
7.8
7.9
7.9
8.0
8.1
8.0
9.9
9.8
9.7
9.6
9.7
9.4
9.3
9.3
9.3
9.1
8.9
8.8
8.7
8.6
8.5
8.4
8.2
8.3
8.3
8.2
8.1
7.9
7.8
7.9
7.8
7.8
7.9
7.8
10.4
10.1
10.0
9.9
10.0
9.8
9.8
9.7
9.6
9.4
9.2
9.1
8.8
8.6
8.6
8.6
8.6
8.6
8.4
8.3
8.3
8.1
7.9
8.1
8.0
8.0
8.0
8.1
10.1
9.9
9.7
9.6
9.6
9.4
9.4
9.3
9.2
9.1
8.9
8.6
8.5
8.2
8.0
8.0
8.0
8.1
8.1
8.0
8.0
7.9
7.7
7.7
7.6
7.5
7.5
7.4
9.5
9.4
9.3
9.2
9.0
8.9
8.6
8.5
8.3
8.2
8.0
7.7
7.2
6.9
7.0
7.1
7.0
7.2
7.3
7.2
7.2
7.2
6.9
6.5
6.6
6.6
6.7
6.6
9.6
9.4
9.1
8.9
8.7
8.5
8.4
8.2
8.1
8.0
7.7
7.3
7.1
6.7
6.6
6.9
6.9
7.1
7.1
7.1
7.1
7.0
6.9
6.7
6.6
6.5
6.5
6.5
10.3
10.2
10.1
10.1
9.9
9.8
9.6
9.4
9.0
8.7
8.4
7.9
7.7
7.0
7.0
7.1
7.2
7.3
7.3
7.3
7.3
7.2
6.9
7.2
7.0
6.9
6.9
6.7
8.0
8.0
7.8
7.7
7.4
7.3
6.9
6.6
6.3
5.8
5.1
4.9
4.7
4.8
5.0
5.3
5.2
5.2
5.2
5.2
5.2
5.2
4.9
4.9
4.8
4.7
4.7
4.5
8.6
8.3
8.1
7.8
7.6
7.5
7.4
7.3
6.7
6.0
5.5
5.0
4.6
4.6
4.7
4.8
4.9
5.1
5.2
5.4
5.3
5.1
4.8
4.6
4.7
4.8
4.7
4.6
7.2
6.9
6.5
6.4
6.5
6.5
6.4
6.4
6.8
6.3
6.0
5.5
5.2
4.5
3.2
2.9
3.0
3.1
3.1
3.2
3.3
3.3
3.2
3.1
3.0
2.9
2.9
2.8
8.1
8.2
8.3
8.3
8.1
8.1
8.0
7.9
7.9
7.8
7.8
7.8
7.7
6.2
4.6
3.5
3.1
3.0
2.9
2.9
2.9
2.9
2.8
2.7
2.6
2.5
2.6
2.5
7.8
7.6
7.8
7.8
8.2
8.1
8.2
8.2
7.9
8.1
7.9
8.0
7.9
7.8
7.3
6.5
5.7
4.1
3.7
3.5
3.5
3.5
3.3
3.5
3.2
3.2
3.1
3.1
9.1
8.8
8.9
8.9
8.9
8.8
8.8
8.8
8.8
8.8
8.7
8.6
8.6
8.5
8.5
8.5
8.4
8.2
7.8
7.1
5.5
4.0
3.1
2.5
2.1
1.8
1.7
1.6
9.7
9.6
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.4
9.3
9.3
9.0
8.2
7.5
5.5
3.0
2.2
2.0
1.6
1.5
1.5
1.4
10.2
10.0
9.8
9.7
9.7
9.7
9.7
9.7
9.6
9.6
9.6
9.6
9.7
9.7
9.8
9.8
9.8
9.8
9.7
9.5
8.7
5.1
3.5
2.9
2.2
1.7
1.5
1.4
10.3
9.8
9.5
9.4
9.3
9.3
9.3
9.3
9.2
9.2
9.2
9.2
9.2
9.2
9.2
9.2
9.3
9.3
9.2
9.2
9.2
8.7
7.8
3.4
1.5
1.0
0.9
0.8
9.7
9.4
9.3
9.2
9.2
9.2
9.1
9.1
9.1
9.1
9.1
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
9.0
8.7
7.9
7.1
6.1
5.6
4.5
13.4
12.6
12.3
12.1
12.0
11.9
11.9
11.8
11.8
11.8
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.7
11.6
11.6
11.6
11.6
11.6
27
Depth (m)
Year 2013 Osoyoos Lake oxygen concentrations µg L-1
28
OSOYOOS LAKE WATER CHEMISTRY
Table 3. Osoyoos Lake water chemistry summary. Chla = Chlorophyll a, TP and TN = total
phosphorus and total nitrogen, Secchi = Secchi depth, Epi = epilimnion and Hypo =
hypolimnion. Blank = no data collected.
Sampling
Dates
Epi TP
(μg/L)
Epi TN
(µg/L)
10-Mar-05
26-Apr-05
01-Jun-05
12-Jul-05
22-Aug-05
12-Sep-05
04-Oct-05
6
13
10
13
10
4
8
295
250
230
380
310
260
255
06-Mar-06
24-Apr-06
23-May-06
18-Jul-06
21-Aug-06
19-Sep-06
26-Sep-06
23-Oct-06
13
11
5
6
9
4
4
5
290
220
230
230
230
260
250
210
15-Mar-07
17-Apr-07
14-May-07
11-Jun-07
10-Jul-07
14-Aug-07
10-Sep-07
09-Oct-07
05-Nov-07
18
16
370
280
11
14
11
11
250
260
270
420
20-May-08
09-Jun-08
07-Jul-08
21-Jul-08
11-Aug-08
07-Sep-08
10-Oct-08
17
11
12
9
9
9
9
260
230
160
190
160
190
200
Hypo
TP
(μg/L)
Hypo
TN
(µg/L)
2.1
3.6
4.1
4.2
4.5
4.6
6
6
9
12
12
12
24
295
268
243
360
300
310
373
3.5
7.6
3.9
2.7
7.6
4.0
3.2
4.1
4.6
2.3
8.1
7.1
6.9
6.6
6.0
9
10
4
14
18
25
21
37
260
240
200
270
300
360
400
360
5.7
5.2
5.9
5.1
4.5
3.8
4.7
5.1
5.0
3.6
2.9
3.5
3.9
2.6
3.4
3.4
3.4
13
270
12
280
3.6
3.0
2.2
2.7
4.5
1.5
4.4
1.6
3.3
4.4
4.8
3.1
nd
3.4
9
9
15
13
14
15
15
195
210
225
190
155
210
280
Chla
(μg/L)
Secchi
m
29
Epi TP
(μg/L)
Epi TN
(µg/L)
Chla
(μg/L)
Secchi
m
Hypo
TP
(μg/L)
Hypo
TN
(µg/L)
11-May-09
08-Jun-09
13-Jul-09
11-Aug-09
14-Sep-09
22-Oct-09
9
7
7
7
8
8
270
360
160
200
160
220
2.5
4.3
4.4
5.0
4.3
3.0
2.5
2.4
3.5
3.0
3.3
4.2
9
7
7
6
8
9
250
410
195
195
255
285
10-May-10
08-Jun-10
19-Jul-10
16-Aug-10
14-Sep-10
18-Oct-10
4
7
7
9
8
8
100
240
200
120
320
220
5.4
4.0
1.1
3.0
4.4
4.1
2.7
2.0
3.1
3.8
3.5
3.3
5
7
12
9
22
27
100
205
240
290
360
315
24-May-11
20-Jun-11
18-Jul-11
16-Aug-11
15-Sep-11
11-Oct-11
9
9
7
8
6
9
440
270
240
260
230
350
2.2
1.5
2.8
3.6
3.0
3.8
1.0
2.3
3.5
3.5
3.2
3.6
9
14
18
22
7
51
325
280
365
255
380
205
12-May-12
11-Jun-12
16-Jul-12
13-Aug-12
24-Sep-12
29-Oct-12
12
14
11
7
9
13
267
258
268
217
245
429
2.1
3
2.3
2.8
2.1
4.3
2.3
2.7
2.4
4.4
3.7
4.2
11
13
14
19
21
24
298
292
294
308
298
474
21-May-13
25-Jun-13
22-Jul-13
13-Aug-13
23-Sep-13
21-Oct-13
13
11
9
10
8
11
245
261
244
276
247
208
4.8
2.1
2.3
2.5
2.8
4.3
2.1
3.3
3.8
4.2
4.3
3.9
12
13
5
20
27
32
252
304
293
340
343
320
Sampling
Dates
30
OSOYOOS LAKE PHYTOPLANKTON BIOMASS
Cyanophyta
Dinophyta
Cryptophyta
Euglenophyta
Chrysophyta
Haptophyta
Tribophyta
Chlorophyta
Raphidophyta
Bacillariophyta
Table 4. Osoyoos Lake 2005-2013 TOTAL algal standing stock (divisions) expressed as
mm3 m-3, which approximates µg·L-1 wet weight.
Total
25-Apr-05
17-May-05
01-Jun-05
20-Jun-05
12-Jul-05
22-Aug-05
13-Sep-05
04-Oct-05
02-Nov-05
251
167
124
161
533
345
433
321
186
19
18
0
6
56
10
6
2
9
150
22
20
50
71
94
47
49
112
0
0
0
0
0
0
2
0
0
107
120
77
1111
104
42
21
24
28
8
1
3
11
5
1
3
8
7
0
0
0
0
0
0
0
0
0
91
44
44
351
160
69
73
115
42
0
0
0
0
0
0
0
0
0
649
271
68
185
158
104
149
102
55
1275
644
336
1874
1086
665
733
620
439
24-Apr-06
23-May-06
12-Jun-06
04-Jul-06
18-Jul-06
21-Aug-06
05-Sep-06
26-Sep-06
23-Oct-06
360
244
225
113
216
1075
769
847
343
29
30
19
46
2
0
0
8
5
130
252
171
148
163
47
64
106
107
0
0
0
0
0
0
0
0
0
26
182
45
64
20
65
22
16
56
16
2
2
2
1
5
8
2
14
0
0
0
0
0
0
0
0
0
106
86
58
54
23
99
50
23
55
0
0
0
0
0
0
0
0
0
1111
499
233
88
34
56
29
53
93
1777
1296
753
515
460
1346
941
1055
673
14-May-07
11-Jun-07
10-Jul-07
13-Aug-07
10-Sep-07
09-Oct-07
05-Nov-07
852
576
1827
1518
823
881
1295
26
8
35
8
1
7
35
76
62
58
74
82
137
81
0
0
0
0
0
0
0
131
139
50
90
49
39
11
8
23
2
23
14
12
17
0
0
0
0
0
0
0
66
80
153
145
68
93
40
0
0
0
0
0
0
0
338
274
394
382
49
107
334
1498
1162
2518
2240
1086
1277
1812
17-Apr-08
20-May-08
09-Jun-08
07-Jul-08
21-Jul-08
11-Aug-08
07-Sep-08
18-Oct-08
18-Nov-08
358
151
404
499
226
1498
1862
843
369
23
8
13
17
12
13
28
18
10
47
53
77
118
81
36
95
119
105
0
0
0
0
0
0
0
0
0
52
57
72
57
105
23
23
16
9
23
14
16
24
2
9
21
19
3
1
1
11
1
0
0
1
1
1
27
58
44
76
148
121
206
132
36
0
0
0
0
0
0
0
0
0
2049
937
287
174
153
50
163
208
608
2580
1278
923
965
727
1751
2399
1356
1142
Sampling
Date
Cyanophyta
Dinophyta
Cryptophyta
Euglenophyta
Chrysophyta
Haptophyta
Tribophyta
Chlorophyta
Raphidophyta
Bacillariophyta
31
Total
11-May-09
08-Jun-09
13-Jul-09
11-Aug-09
14-Sep-09
22-Oct-09
471
688
179
603
787
542
50
37
39
28
4
19
114
150
43
54
67
98
0
0
0
1
0
0
123
304
33
45
210
125
36
7
22
45
16
2
1
17
0
0
2
3
40
110
65
105
158
45
0
0
0
0
0
0
540
518
1909
83
209
288
1374
1830
2291
964
1454
1121
10-May-10
14-Jun-10
19-Jul-10
16-Aug-10
14-Sep-10
18-Oct-10
460
417
543
639
871
826
30
67
91
142
313
20
194
413
141
94
123
125
0
0
0
7
0
0
198
55
42
72
121
86
92
31
32
33
22
28
4
5
1
0
1
3
17
36
43
433
54
81
0
0
0
0
0
0
753
295
306
306
61
39
1749
1319
1199
1725
1567
1206
24-May-11
20-Jun-11
18-Jul-11
16-Aug-11
15-Sep-11
11-Oct-11
257
39
93
405
1037
580
10
73
93
13
37
3
30
104
71
99
64
157
0
0
0
0
0
0
20
27
91
36
95
20
1
3
5
4
7
9
0
2
1
0
0
3
24
13
25
70
51
33
0
0
0
0
0
0
335
283
331
285
104
256
677
544
710
913
1395
1061
22-May-12
11-Jun-12
16-Jul-12
13-Aug-12
24-Sep-12
29-Oct-12
148
109
154
350
618
370
13
10
4
1
15
17
166
151
43
73
71
28
0
0
2
0
0
0
73
36
24
24
13
16
28
24
2
2
4
7
2
1
4
2
2
5
16
41
35
164
128
37
0
0
0
0
0
0
229
262
170
63
64
113
675
633
438
681
914
594
21-May-13
24-Jun-13
22-Jul-13
13-Aug-13
23-Sep-13
23-Oct-13
276
113
199
234
371
777
8
33
10
17
7
14
175
96
150
62
60
173
0
0
0
0
0
0
266
115
28
58
34
52
2
13
12
13
15
5
5
5
2
1
1
3
52
18
66
55
116
102
0
0
0
0
0
0
521
375
76
50
71
510
1304
769
542
490
674
1636
Sampling
Date
32
Cyanophyta
Dinophyta
Cryptophyta
Euglenophyta
Chrysophyta
Haptophyta
Tribophyta
Chlorophyta
Raphidophyta
Bacillariophyta
Table 5. Osoyoos Lake 2005-2013 EDIBLE algal standing stock (divisions) expressed as mm3
m-3 that approximates µg·L-1 wet weight.
Total
25-Apr-05
17-May-05
1-Jun-05
20-Jun-05
12-Jul-05
22-Aug-05
13-Sep-05
4-Oct-05
2-Nov-05
1
8
3
5
30
4
16
34
34
4
0
0
0
9
4
6
2
6
150
22
20
50
71
94
47
49
112
0
0
0
0
0
2
2
0
0
105
114
19
22
22
42
16
23
18
8
1
3
11
5
1
3
8
7
0
0
0
0
0
0
0
0
0
55
9
25
278
92
62
60
109
27
0
0
0
0
0
0
0
0
0
87
62
41
49
17
24
30
24
26
411
217
110
414
246
233
179
248
230
24-Apr-06
23-May-06
12-Jun-06
04-Jul-06
18-Jul-06
21-Aug-06
05-Sep-06
26-Sep-06
23-Oct-06
2
22
3
4
3
27
22
25
34
25
12
7
46
2
0
0
8
0
130
252
171
148
163
47
64
106
107
0
0
0
0
0
0
0
0
0
19
54
44
53
16
62
15
16
45
16
2
2
2
1
5
8
2
14
0
0
0
0
0
0
0
0
0
36
26
32
47
12
74
35
9
35
0
0
0
0
0
0
0
0
0
143
97
107
28
19
39
13
36
57
371
466
367
328
217
254
157
203
293
14-May-07
11-Jun-07
10-Jul-07
13-Aug-07
10-Sep-07
09-Oct-07
05-Nov-07
38
34
14
17
22
41
10
3
4
10
8
1
2
0
76
62
58
74
82
137
81
0
0
0
0
0
0
0
125
123
36
88
43
35
10
8
23
2
23
14
12
17
0
0
0
0
0
0
0
17
34
111
76
47
70
7
0
0
0
0
0
0
0
124
26
23
36
25
42
35
392
307
254
321
234
339
160
17-Apr-08
20-May-08
09-Jun-08
07-Jul-08
21-Jul-08
11-Aug-08
07-Sep-08
18-Oct-08
18-Nov-08
3
5
17
5
12
34
28
25
3
2
0
6
0
0
4
20
0
0
47
53
77
118
81
36
95
119
105
0
0
0
0
0
0
0
0
0
49
28
62
57
43
21
16
11
9
23
14
16
24
2
9
21
19
3
0
1
11
1
0
0
1
1
0
5
13
17
14
72
103
116
32
15
0
0
0
0
0
0
0
0
0
596
36
131
17
24
14
25
163
471
725
149
337
235
236
221
321
370
607
Sampling
Date
Cyanophyta
Dinophyta
Cryptophyta
Euglenophyta
Chrysophyta
Haptophyta
Tribophyta
Chlorophyta
Raphidophyta
Bacillariophyta
33
Total
11-May-09
08-Jun-09
13-Jul-09
11-Aug-09
14-Sep-09
22-Oct-09
0
3
4
13
63
55
37
10
2
23
4
0
114
150
43
54
67
98
0
0
0
1
0
0
64
304
33
45
210
125
36
7
22
45
16
2
1
17
0
0
2
3
2
24
61
90
51
16
0
0
0
0
0
0
72
154
45
9
19
59
326
669
210
281
432
357
10-May-10
14-Jun-10
19-Jul-10
16-Aug-10
14-Sep-10
18-Oct-10
5
0
4
6
51
93
7
36
6
10
30
1
194
413
141
94
123
125
0
0
0
7
0
0
198
55
42
56
87
63
92
31
32
33
22
28
4
5
1
0
1
3
10
18
21
271
24
63
0
0
0
0
0
0
315
69
21
11
17
12
826
627
269
489
356
388
24-May-11
20-Jun-11
18-Jul-11
16-Aug-11
15-Sep-11
11-Oct-11
0
0
2
9
63
17
0
0
5
3
37
3
30
104
71
99
64
157
0
0
0
0
0
0
14
25
91
36
95
16
1
3
5
4
7
9
0
2
1
0
0
3
0
9
13
32
41
12
0
0
0
0
0
0
78
217
24
17
17
153
123
360
212
200
325
369
11-Jun-12
16-Jul-12
13-Aug-12
24-Sep-12
29-Oct-12
1
1
4
14
12
2
2
1
15
3
151
43
73
71
28
0
0
0
0
0
33
21
18
13
13
24
2
2
4
7
1
4
2
2
5
26
6
49
98
21
0
0
0
0
0
111
35
5
22
36
349
115
154
239
126
21-May-13
24-Jun-13
22-Jul-13
13-Aug-13
23-Sep-13
23-Oct-13
1
2
15
9
7
17
0
10
8
16
7
0
175
96
150
62
60
173
0
0
0
0
0
0
45
115
28
43
34
41
2
13
12
13
15
5
5
5
2
1
1
3
30
11
55
38
67
66
0
0
0
0
0
0
251
38
19
27
15
255
508
291
288
209
205
560
Sampling
Date
34
OSOYOOS LAKE ZOOPLANKTON BIOMASS
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
26-Apr-05
6-Jun-05
22-Jun-05
14-Jul-05
4-Aug-05
25-Aug-05
15-Sep-05
5-Oct-05
2-Nov-05
1.5
2.9
2.5
3.9
5.8
3.3
1.3
2.1
3.6
7.4
22.3
21.5
17.3
14.9
18.4
11.9
11.9
28.3
24.8
74.7
75.8
35.3
34.6
47.4
56.4
69.1
72.1
0.0
1.8
3.5
4.6
11.0
8.6
6.4
0.9
0.2
0.0
5.1
0.3
0.0
0.0
0.3
1.4
3.9
0.1
0.0
8.0
6.9
10.7
40.7
7.7
0.9
2.3
0.1
0.0
9.7
0.4
2.7
21.3
0.8
3.4
3.5
0.3
0.0
0.3
1.6
1.7
1.3
0.8
0.4
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
33.8
124.8
112.5
76.1
129.7
87.3
82.0
93.8
104.6
25-May-06
13-Jun-06
26-Jul-06
17-Aug-06
05-Sep-06
02-Oct-06
24-Oct-06
18-Dec-06
5.2
4.9
5.4
2.6
2.1
4.3
2.2
1.4
28.5
47.6
42.1
55.7
29.2
25.1
12.6
25.7
8.6
16.2
73.3
81.0
63.8
64.7
64.9
81.0
0.2
1.8
17.6
7.6
6.2
3.1
0.2
0.1
0.7
1.4
0.0
0.0
0.0
1.5
0.2
0.6
0.0
1.0
42.8
0.0
0.2
2.1
1.0
0.0
0.0
0.8
17.3
1.7
6.5
1.1
0.5
0.0
0.0
0.2
3.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
43.2
73.9
201.6
148.6
107.9
102.0
81.7
108.8
18-Apr-07
15-May-07
21-Jun-07
26-Jun-07
10-Jul-07
25-Jul-07
17-Aug-07
04-Sep-07
12-Sep-07
25-Sep-07
10-Oct-07
05-Nov-07
17-Dec-07
3.8
6.9
4.6
6.9
4.6
4.1
3.5
2.6
4.0
2.9
1.8
4.1
6.7
33.9
60.9
63.4
72.2
89.2
51.6
25.2
19.1
19.2
23.0
20.7
20.5
18.2
78.7
76.3
42.4
49.3
41.7
28.6
36.7
48.0
64.8
74.1
61.2
87.0
58.5
0.0
0.4
4.7
8.0
3.1
10.1
20.1
8.5
17.9
8.2
0.3
0.0
0.0
0.0
0.0
3.7
1.5
0.0
0.2
0.6
1.9
6.4
5.9
1.2
0.2
0.1
0.0
0.0
43.4
61.6
35.3
0.4
4.5
11.6
20.2
20.5
5.0
0.2
0.0
0.0
0.0
5.7
6.7
18.9
6.6
10.4
6.4
9.6
3.4
2.3
0.5
0.0
0.0
0.0
15.0
22.2
4.3
3.1
0.2
0.1
0.0
0.2
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
116.4
144.5
182.9
228.5
197.2
104.6
101.2
98.1
142.1
138.4
94.1
112.4
83.5
Sampling
Date
Rotifer total
Nauplii total
Table 6. Osoyoos Lake zooplankton biomass 2005-2013. Units are µg per L dry weight. Rotifers
were not included during the first three years of the study.
Total
Sampling
Date
Rotifer total
Nauplii total
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
35
03-Mar-08
07-Apr-08
12-May-08
28-May-08
11-Jun-08
24-Jun-08
08-Jul-08
22-Jul-08
28-Jul-08
12-Aug-08
27-Aug-08
07-Sep-08
22-Sep-08
17-Oct-08
18-Nov-08
04-Dec-08
0.0
2.6
6.7
2.7
0.5
1.1
0.6
0.3
0.8
0.6
0.5
0.5
0.3
0.4
0.6
1.4
3.5
5.4
6.3
9.1
6.3
15.6
8.3
2.8
2.1
1.5
5.1
2.9
3.2
3.1
4.4
7.8
44.1
73.0
59.0
61.1
28.1
64.3
92.8
102.3
63.1
44.4
45.3
31.2
24.5
31.4
28.0
29.9
47.2
87.2
64.0
82.6
10.3
36.6
79.4
46.1
62.9
41.0
48.1
40.6
27.1
40.5
50.9
62.6
0.0
0.0
0.0
0.1
0.0
0.6
1.6
3.0
5.5
6.3
7.6
10.3
5.0
0.2
0.0
0.1
0.0
0.0
0.0
0.2
1.0
7.8
0.4
0.5
0.0
0.0
0.3
0.1
0.8
2.4
0.1
0.1
0.0
0.0
0.0
0.1
0.8
5.2
81.7
67.1
10.4
0.9
0.5
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.2
0.2
6.1
14.4
12.1
8.8
9.2
9.5
9.5
1.6
0.4
0.1
0.0
0.0
0.0
0.0
0.0
0.3
3.5
14.1
5.4
1.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
94.8
168.3
136.0
155.8
47.2
131.7
274.3
250.6
162.3
105.4
116.6
95.3
70.4
79.6
84.3
102.0
11-May-09
25-May-09
08-Jun-09
29-Jun-09
13-Jul-09
28-Jul-09
11-Aug-09
27-Aug-09
14-Sep-09
01-Oct-09
22-Oct-09
27-Nov-09
17-Dec-09
14.3
10.6
14.0
6.7
3.0
1.5
0.3
0.5
0.4
0.5
0.8
3.5
4.0
13.8
13.7
32.9
14.9
8.1
2.3
2.0
1.9
1.9
3.2
1.3
3.2
4.7
118.7
113.5
152.4
93.5
87.6
50.9
17.9
11.1
8.2
17.8
16.0
54.6
34.3
148.8
77.6
82.4
41.4
38.2
38.4
20.1
28.3
20.0
45.8
54.3
31.1
8.4
0.0
0.4
0.7
1.2
1.6
6.7
19.6
9.9
5.5
2.0
0.0
0.2
0.1
0.0
0.7
2.3
4.8
0.1
0.7
1.4
6.2
2.5
1.7
1.6
0.3
0.2
0.0
0.1
7.7
158.7
50.5
4.2
0.9
5.7
1.9
1.4
0.2
0.0
0.0
0.0
0.0
0.1
0.8
1.5
16.1
18.5
7.7
3.4
1.1
0.0
0.0
0.0
0.0
0.0
0.0
3.3
11.0
1.1
0.9
0.4
1.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
295.6
216.5
292.5
325.4
201.6
121.9
81.7
71.7
44.7
73.7
74.1
92.9
51.6
Total
Rotifer total
Nauplii total
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
36
16-Feb-10
16-Apr-10
09-May-10
1-Jun-10
14-Jun-10
29-Jun-10
06-Jul-10
20-Jul-10
26-Jul-10
16-Aug-10
31-Aug-10
14-Sep-10
27-Sep-10
18-Oct-10
13.1
39.4
27.1
1.1
1.3
0.1
0.4
0.2
0.4
0.7
0.7
0.6
0.6
0.2
2.8
4.1
2.2
2.9
12.4
6.2
6.1
3.6
2.7
0.7
2.1
1.9
2.8
3.5
16.6
68.4
81.9
34.9
98.2
90.8
83.2
97.6
128.2
87.5
56.2
31.7
29.1
18.7
2.4
0.1
0.2
0.2
0.3
0.8
3.9
2.0
2.7
5.5
7.7
7.2
12.8
19.6
0.0
0.0
0.7
0.6
0.6
0.7
0.5
0.2
0.8
2.2
6.0
4.0
4.6
0.7
0.0
0.0
0.0
0.2
7.5
11.3
2.4
2.6
1.3
0.0
0.0
0.2
0.4
0.4
0.0
0.0
0.0
0.0
0.2
2.5
6.0
32.5
84.1
0.6
0.4
1.6
6.6
2.9
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.5
1.6
18.4
2.5
1.2
0.4
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.2
1.7
11.5
5.9
1.0
0.5
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.6
0.0
0.0
0.1
0.0
0.0
0.0
0.0
34.9
112.1
112.0
39.9
120.5
112.4
103.2
141.0
233.3
121.7
76.6
48.8
57.9
46.3
10-May-11
31-May-11
15-Jun-11
20-Jun-11
14-Jul-11
20-Jul-11
9-Aug-11
29-Aug-11
22-Sep-11
6-Oct-11
3-Nov-11
16-Nov-11
11.7
5.1
2.4
1.5
0.3
0.2
0.1
0.1
0.2
0.0
0.9
1.0
8.7
4.7
2.6
2.8
3.0
2.5
3.4
5.6
1.6
0.0
2.2
1.0
47.8
25.5
15.3
28.1
22.6
25.3
27.8
27.7
11.1
5.4
15.9
9.8
83.4
35.4
17.4
15.2
16.6
24.3
22.6
30.5
27.4
31.7
39.6
28.3
0.0
0.0
0.1
0.2
1.3
2.0
3.6
5.4
2.9
0.8
0.0
0.0
0.0
0.5
1.4
2.0
0.1
0.1
0.0
0.2
0.7
1.5
5.3
1.0
0.7
0.4
4.3
3.1
5.4
7.1
3.3
6.3
1.0
4.8
6.5
5.4
0.0
0.0
0.0
0.2
1.2
6.1
9.2
3.9
2.0
0.9
4.6
0.2
0.0
0.0
0.0
0.0
1.0
2.5
5.1
0.5
0.1
0.5
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
152.3
71.6
43.5
53.1
51.5
70.1
75.2
80.1
47.0
45.6
75.1
46.7
29-Apr-12
23-May-12
12-Jun-12
26-Jun-12
10-Jul-12
23-Jul-12
13-Aug-12
27-Aug-12
17-Sep-12
30-Sep-12
01-Nov-12
22-Nov-12
21.6
6.6
5.3
3.4
0.9
0.3
0.1
0.1
0.1
0.0
0.3
0.5
2.0
3.5
5.4
7.5
4.6
2.8
2.3
1.3
1.6
5.9
2.0
2.0
29.6
31.5
40.7
55.2
25.0
24.1
21.7
14.0
11.4
12.1
17.3
18.7
5.7
6.0
13.6
45.2
24.0
38.6
55.1
42.7
32.6
39.3
28.5
31.0
0.0
4.2
1.6
1.9
0.1
1.1
3.7
3.5
5.8
4.3
0.2
0.0
0.1
2.3
9.3
2.8
0.1
0.0
0.0
0.1
0.3
0.8
0.2
0.0
0.0
0.2
0.2
2.0
3.2
11.6
13.3
5.3
3.6
5.1
0.4
0.0
0.0
0.0
0.1
0.1
2.0
11.5
4.6
2.5
5.7
5.8
0.6
0.1
0.0
0.0
0.1
1.3
0.9
3.6
2.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
59.2
54.2
76.2
119.5
60.7
93.6
102.7
70.5
61.2
73.2
49.3
52.3
Sampling
Date
Total
Sampling
Date
Rotifer total
Nauplii total
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
37
23-Apr-13
15-May-13
28-May-13
19-Jun-13
03-Jul-13
15-Jul-13
30-Jul-13
15-Aug-13
26-Aug-13
12-Sep-13
23-Sep-13
16-Oct-13
8.7
7.5
8.3
2.9
0.2
0.1
0.2
0.0
0.1
0.0
0.0
0.1
3.4
5.0
5.9
2.2
1.7
2.0
2.5
4.7
1.6
2.0
0.8
1.4
49.6
45.2
25.5
16.6
12.9
20.2
16.5
10.4
39.6
9.2
4.6
10.7
26.6
20.5
20.2
6.4
7.4
9.5
13.3
23.9
23.0
35.1
18.8
36.2
0.0
0.2
1.5
0.6
7.4
7.6
9.2
8.2
6.3
6.5
3.0
0.2
0.0
0.0
0.3
7.9
0.4
0.2
0.2
0.0
0.0
0.5
0.8
0.6
0.0
0.0
0.1
0.1
0.2
1.3
16.6
15.7
1.9
0.7
2.3
1.6
0.0
0.0
0.1
0.6
2.9
9.0
2.7
7.2
11.8
5.5
4.3
1.0
0.0
0.0
0.0
0.0
0.2
0.0
0.3
0.9
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Total
88.4
78.4
61.7
37.3
33.3
49.9
61.4
71.1
84.5
59.6
34.6
51.9
OSOYOOS LAKE ZOOPLANKTON DENSITY
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
26-Apr-05
06-Jun-05
22-Jun-05
14-Jul-05
04-Aug-05
25-Aug-05
15-Sep-05
05-Oct-05
2-Nov-05
Nauplii total
Sampling
Date
Rotifer total
Table 7. Osoyoos Lake zooplankton density 2005-2013. Units are numbers per L. Rotifers were
not included during the first three years of the study.
9.3
17.0
16.3
21.3
30.3
17.0
7.4
13.2
23.0
2.3
7.7
8.1
6.8
9.9
9.4
5.1
5.8
9.9
9.2
18.7
21.2
9.9
15.2
22.0
22.7
21.3
19.7
0.0
0.1
0.2
0.4
0.5
0.6
0.3
0.1
0.0
0.0
3.7
0.1
0.0
0.0
0.1
1.0
3.0
0.0
0.0
1.3
0.8
1.6
4.2
0.6
0.1
0.5
0.0
0.0
2.2
0.1
0.7
5.0
0.2
0.7
0.8
0.1
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
25-May-06
13-Jun-06
26-Jul-06
17-Aug-06
5-Sep-06
2-Oct-06
24-Oct-06
18-Dec-06
29.3
29.0
30.6
13.3
11.3
21.3
9.2
5.1
16.8
26.6
17.5
18.6
9.0
9.6
6.3
8.2
2.3
4.1
20.0
20.7
18.4
19.3
27.7
18.0
0.0
0.1
0.8
0.4
0.3
0.1
0.0
0.0
0.3
0.9
0.0
0.0
0.0
0.9
0.1
0.3
0.0
0.1
4.6
0.0
0.0
0.3
0.2
0.0
0.0
0.1
3.5
0.3
1.1
0.2
0.1
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
65.0
30.0
17.0
17.0
35.0
36.0
27.0
16.0
18-Apr-07
15-May-07
21-Jun-07
26-Jun-07
10-Jul-07
25-Jul-07
17-Aug-07
4-Sep-07
12-Sep-07
25-Sep-07
10-Oct-07
5-Nov-07
17-Dec-07
16.7
32.0
22.0
33.3
20.9
16.7
15.7
10.8
15.8
13.7
7.6
22.0
38.7
12.5
19.1
22.2
23.2
27.7
13.3
8.3
8.1
6.9
9.1
7.6
7.3
7.1
20.8
17.2
7.5
10.0
9.5
7.6
9.8
11.1
17.2
22.5
16.7
22.2
15.9
0.0
0.0
0.2
0.3
0.2
0.5
1.0
0.4
0.7
0.4
0.0
0.0
0.0
0.0
0.0
2.2
0.8
0.0
0.1
0.3
0.8
3.3
3.3
0.7
0.1
0.0
0.0
0.0
3.5
5.4
2.6
0.0
0.4
1.1
1.9
2.4
0.8
0.0
0.0
0.0
0.0
1.0
1.4
3.2
1.2
1.9
1.2
1.8
0.6
0.5
0.1
0.0
0.0
0.0
0.3
0.4
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
13.4
23.3
35.3
51.3
35.3
76.0
41.3
13.5
11.7
7.6
24.3
13.2
16.3
15.5
25.0
43.3
24.3
22.0
19.2
24.9
12.9
38.5
41.6
42.9
25.3
15.5
16.6
9.4
9.2
13.4
11.0
9.9
13.2
20.6
13.5
20.7
1.9
14.7
27.6
13.8
16.9
10.6
12.2
11.2
8.2
14.2
14.7
19.5
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.1
0.2
0.3
0.4
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.5
5.9
0.2
0.4
0.0
0.0
0.1
0.0
0.4
1.3
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.6
4.8
3.2
0.4
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.1
2.4
2.2
1.6
1.5
1.7
1.7
0.3
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.2
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Sampling
Date
3-Mar-08
7-Apr-08
12-May-08
28-May-08
11-Jun-08
24-Jun-08
8-Jul-08
22-Jul-08
28-Jul-08
12-Aug-08
27-Aug-08
7-Sep-08
22-Sep-08
17-Oct-08
18-Nov-08
4-Dec-08
Rotifer total
Nauplii total
38
0.0
19.0
54.7
23.3
3.6
8.2
4.9
2.7
6.4
5.9
4.5
4.6
3.2
4.5
6.6
12.6
Rotifer total
Nauplii total
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
39
2-Apr-09
11-May-09
25-May-09
8-Jun-09
29-Jun-09
13-Jul-09
28-Jul-09
11-Aug-09
27-Aug-09
14-Sep-09
1-Oct-09
22-Oct-09
27-Nov-09
17-Dec-09
60.0
117.3
86.7
104.0
47.6
22.7
11.7
2.6
4.8
4.2
4.1
9.1
41.3
46.7
29.6
76.0
78.7
165.3
76.7
39.3
12.3
11.6
9.5
10.2
15.9
7.1
19.9
30.7
30.0
30.7
40.2
44.7
40.1
28.3
15.2
6.9
8.9
6.0
7.6
7.4
21.6
15.8
27.1
19.9
11.2
11.3
17.0
13.2
10.9
6.4
7.0
7.6
14.0
21.1
7.0
2.4
0.0
0.0
0.0
0.0
0.1
0.1
0.7
1.1
0.5
0.3
0.1
0.0
0.0
0.0
0.0
0.0
0.1
1.0
3.2
0.1
0.3
0.9
3.8
1.7
1.0
1.0
0.3
0.1
0.0
0.0
0.0
1.4
16.5
3.4
0.3
0.1
0.8
0.2
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.2
3.5
3.6
1.4
0.7
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
16-Feb-10
16-Apr-10
9-May-10
1-Jun-10
14-Jun-10
29-Jun-10
6-Jul-10
20-Jul-10
26-Jul-10
16-Aug-10
31-Aug-10
14-Sep-10
27-Sep-10
18-Oct-10
15-Nov-10
136.6
328.0
198.4
7.0
3.8
1.2
3.0
1.8
4.0
7.4
8.1
6.9
7.5
2.1
5.0
15.9
24.1
14.0
20.5
74.8
30.5
32.7
20.5
16.7
3.8
11.1
9.1
12.3
17.0
17.7
9.0
19.7
28.7
15.1
54.7
50.4
57.3
52.4
55.6
36.7
16.9
11.2
9.4
7.1
7.6
1.6
0.0
0.0
0.0
0.0
0.1
0.7
0.3
0.5
0.9
1.3
1.5
3.5
5.9
13.4
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.3
0.2
0.2
0.0
0.0
0.0
0.0
0.0
0.2
3.7
7.5
1.5
2.2
1.0
0.0
0.0
0.1
0.3
0.3
0.2
0.0
0.0
0.0
0.0
0.0
0.5
1.6
4.5
6.9
0.1
0.0
0.2
0.7
0.5
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.3
3.5
0.4
0.2
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.3
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.2
0.0
0.0
0.0
0.0
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Sampling
Date
Rotifer total
Nauplii total
D. thomasi adults
& copepodids
L. ashlandi adults
& copepodids
Epischura
Bosmina
Daphnia
Diaphanosoma
Leptodora
Other
40
10-May-11
31-May-11
15-Jun-11
20-Jun-11
14-Jul-11
20-Jul-11
9-Aug-11
29-Aug-11
22-Sep-11
6-Oct-11
3-Nov-11
16-Nov-11
114.7
53.3
27.8
16.9
3.5
2.4
1.0
1.6
2.6
0.0
16.0
18.7
49.3
32.7
18.2
18.9
21.0
23.0
23.0
33.3
12.0
0.0
15.2
6.9
17.0
10.9
8.1
14.2
10.5
8.1
8.5
10.9
5.2
1.1
8.3
5.2
28.3
10.0
5.1
5.7
7.2
8.1
6.1
7.5
8.4
6.0
10.8
7.4
0.0
0.0
0.0
0.0
0.1
0.1
0.1
0.3
0.1
0.0
0.0
0.0
0.0
0.7
1.1
1.4
0.1
0.0
0.0
0.1
0.4
0.5
3.0
0.5
0.1
0.1
0.8
0.6
0.9
0.8
0.4
0.8
0.2
0.8
1.6
1.2
0.0
0.0
0.0
0.0
0.3
1.3
1.7
0.8
0.4
0.2
0.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
29-Apr-12
23-May-12
12-Jun-12
26-Jun-12
10-Jul-12
23-Jul-12
13-Aug-12
27-Aug-12
17-Sep-12
30-Sep-12
1-Nov-12
22-Nov-12
179.8
51.0
45.3
31.0
10.3
3.1
0.8
0.9
0.6
0.4
4.2
5.3
8.5
17.0
28.3
40.0
27.7
12.7
14.0
8.8
8.8
32.2
11.0
12.5
7.3
10.2
16.2
26.9
11.4
9.3
8.1
5.0
3.6
5.0
6.6
5.8
0.7
1.8
2.9
11.6
10.3
9.1
11.7
10.4
9.5
11.8
8.0
7.6
0.0
0.2
0.1
0.1
0.0
0.0
0.1
0.1
0.2
0.1
0.0
0.0
0.1
1.0
4.2
1.6
0.0
0.0
0.0
0.0
0.2
0.4
0.1
0.0
0.0
0.0
0.0
0.1
0.4
1.0
0.7
0.3
0.3
0.4
0.0
0.0
0.0
0.0
0.0
0.0
0.4
2.1
0.8
0.5
1.0
1.1
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
23-Apr-13
15-May-13
28-May-13
19-Jun-13
3-Jul-13
15-Jul-13
30-Jul-13
15-Aug-13
26-Aug-13
12-Sep-13
23-Sep-13
16-Oct-13
72.0
60.7
64.0
32.7
2.7
1.7
2.0
0.5
1.3
0.6
0.3
0.0
17.3
25.5
32.0
15.2
11.9
13.6
15.6
29.3
12.7
12.7
5.3
6.6
12.6
13.5
8.8
10.7
8.4
14.7
8.9
9.0
16.3
7.9
4.0
4.2
2.9
3.5
4.1
2.6
3.0
3.5
5.1
11.5
9.8
14.3
9.1
12.0
0.0
0.0
0.1
0.0
0.5
0.4
0.5
0.6
0.6
0.5
0.2
0.0
0.0
0.0
0.1
6.0
0.3
0.2
0.2
0.0
0.0
0.4
0.6
0.4
0.0
0.0
0.0
0.0
0.0
0.1
1.9
1.7
0.2
0.1
0.4
0.3
0.0
0.0
0.0
0.1
0.6
2.0
0.6
1.6
2.8
1.2
1.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Sampling
Date
41
OSOYOOS LAKE MYSIS RELICTA BIOMASS
juvenile
immature male
immature female
adult male
adult female
adult female
- released eggs
gravid female
embryos
Total
Table 8. Osoyoos Lake 2005-2013 Mysis relicta biomass. Units are mg wet weight per m3.
06-Jun-05
14-Jul-05
04-Aug-05
15-Sep-05
05-Oct-05
02-Nov-05
1.76
3.53
1.73
0.00
0.00
0.00
2.61
6.02
10.21
14.23
18.12
11.74
1.73
3.90
9.06
12.21
17.89
12.96
1.03
0.25
0.11
1.51
4.62
3.62
2.70
15.08
15.70
13.19
13.52
4.23
2.28
0.34
0.00
0.00
0.00
0.00
2.70
0.00
0.00
0.00
0.00
0.00
0.24
0.00
0.00
0.00
0.00
0.00
15.04
29.13
36.81
41.13
54.16
32.55
17-Jan-06
29-Mar-06
23-Apr-06
25-May-06
26-Jul-06
18-Aug-06
27-Sep-06
24-Oct-06
18-Dec-06
0.00
0.00
0.00
0.50
1.81
0.20
0.20
0.00
0.00
4.65
3.77
7.37
6.00
18.75
17.21
12.89
1.94
1.32
3.00
3.37
5.29
3.60
15.03
13.23
10.58
2.55
1.32
5.66
1.12
0.17
0.60
0.30
0.10
1.83
0.30
0.71
3.87
0.10
0.00
1.10
11.30
19.25
10.09
0.00
1.62
0.44
0.82
3.16
1.30
0.10
0.00
0.00
0.00
0.00
5.54
2.66
3.43
1.80
0.00
0.00
0.00
0.00
0.00
0.46
0.20
0.20
1.61
0.00
0.00
0.00
0.00
0.00
23.63
12.04
19.62
16.51
47.30
49.99
35.60
4.78
4.96
07-Mar-07
15-May-07
21-Jun-07
10-Jul-07
25-Sep-07
05-Nov-07
17-Dec-07
0.00
0.00
1.20
4.75
0.00
0.00
0.00
4.70
4.50
8.71
15.37
14.68
5.47
3.11
3.50
2.70
5.42
10.91
13.76
5.27
2.59
2.20
1.20
0.60
0.30
6.26
1.76
5.95
0.60
0.00
3.00
10.66
12.78
2.02
7.69
2.90
0.40
1.70
0.50
0.00
0.00
0.41
3.00
0.90
0.40
0.00
0.00
0.00
0.00
0.23
0.05
0.02
0.00
0.00
0.00
0.03
17.13
9.75
21.07
42.49
47.47
14.51
19.78
18-Mar-08
07-Apr-08
12-May-08
08-Jul-08
12-Aug-08
22-Sep-08
18-Nov-08
04-Dec-08
0.00
0.00
0.03
5.45
0.83
0.03
0.00
0.00
4.62
6.03
3.20
8.45
12.77
10.07
6.73
9.10
2.72
4.92
3.60
8.48
7.99
9.33
9.26
13.36
1.21
0.51
0.60
0.00
0.31
2.46
5.91
13.61
0.20
0.20
0.10
7.68
8.11
10.19
5.09
11.02
1.61
1.22
0.20
0.70
0.00
0.00
0.00
0.00
12.95
9.37
4.81
0.00
0.00
0.00
0.00
0.00
0.98
1.02
0.46
0.00
0.00
0.00
0.00
0.00
24.29
23.28
13.00
30.76
30.01
32.09
26.98
47.09
Sampling
Date
juvenile
immature male
immature female
adult male
adult female
adult female
- released eggs
gravid female
embryos
Total
42
02-Apr-09
15-Apr-09
11-May-09
08-Jun-09
13-Jul-09
11-Aug-09
14-Sep-09
22-Oct-09
27-Nov-09
17-Dec-09
0.00
0.00
0.00
0.99
8.22
2.26
0.35
0.03
0.00
0.00
7.17
3.87
12.27
11.04
18.33
15.72
12.70
11.05
4.87
3.05
5.15
5.03
7.99
6.28
15.64
9.48
10.20
14.09
8.98
2.24
5.97
3.15
2.83
1.34
0.62
0.10
1.30
5.96
3.82
2.34
0.10
0.20
0.00
1.38
17.06
7.90
9.80
11.72
3.38
1.23
1.25
2.55
2.54
3.34
0.50
0.00
0.00
0.00
0.00
0.00
6.37
3.62
7.57
2.14
0.41
0.00
0.00
0.00
0.00
0.43
0.46
0.23
0.47
0.11
0.02
0.00
0.00
0.00
0.00
0.02
26.48
18.66
33.68
26.63
60.79
35.46
34.35
42.85
21.04
9.31
16-Feb-10
16-Apr-10
11-May-10
14-Jun-10
16-Aug-10
27-Sep-10
15-Dec-10
0.00
0.00
0.04
2.18
0.46
0.01
0.00
7.36
18.62
10.68
2.80
16.20
19.25
2.10
6.60
14.04
11.27
3.60
14.64
14.71
2.10
5.12
1.31
0.60
0.20
0.31
3.38
1.70
5.04
0.33
0.20
1.50
9.89
11.20
2.40
0.40
6.06
0.10
1.10
0.00
0.00
0.00
7.47
16.17
4.53
0.30
0.00
0.00
0.00
0.54
1.61
0.33
0.01
0.00
0.00
0.00
32.53
58.14
27.75
11.69
41.50
48.55
8.30
10-Mar-11
10-May-11
31-May-11
14-Jun-11
20-Jul-11
09-Aug-11
29-Aug-11
22-Sep-11
06-Oct-11
03-Nov-11
29-Nov-11
20-Dec-11
0.00
0.00
0.01
0.23
0.67
0.35
0.06
0.00
0.02
0.00
0.00
0.00
0.71
1.62
0.30
0.20
1.13
2.20
1.52
3.50
4.74
2.91
5.49
2.11
0.61
0.91
0.00
0.00
0.73
2.20
1.62
2.50
4.55
3.21
8.00
2.41
0.40
0.11
0.10
0.10
0.21
0.80
0.20
2.70
4.23
0.70
5.88
6.06
0.70
0.00
0.00
0.30
0.71
1.91
0.80
2.60
5.63
0.00
6.81
6.02
0.10
0.30
0.00
0.10
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.01
0.31
0.20
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.71
0.09
0.02
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.06
3.62
3.27
0.61
0.93
3.46
7.46
4.20
11.30
19.18
6.83
26.19
17.37
Sampling
Date
juvenile
immature male
immature female
adult male
adult female
adult female
- released eggs
gravid female
embryos
Total
43
19-Mar-12
12-Jun-12
26-Jun-12
23-Jul-12
20-Aug-12
24-Sep-12
01-Nov-12
0.00
1.35
4.36
2.70
0.85
0.16
0.00
1.32
2.90
6.50
3.40
13.40
11.10
18.80
0.30
0.10
2.00
3.00
9.10
8.50
21.50
2.46
1.20
0.30
0.70
0.10
3.00
6.00
0.41
2.60
6.80
4.00
16.20
10.30
9.80
1.23
2.60
1.40
0.00
0.00
0.00
0.00
8.36
2.60
2.30
0.00
0.00
0.00
0.00
0.77
0.13
0.12
0.00
0.00
0.00
0.00
14.85
13.48
23.78
13.80
39.65
33.06
56.10
26-Jan-13
24-Apr-13
28-May-13
03-Jul-13
30-Jul-13
12-Sep-13
13-Nov-13
0.00
0.02
1.37
2.79
3.05
0.44
0.00
6.10
14.56
10.66
4.95
24.42
16.14
6.70
4.40
13.57
7.39
5.55
22.03
12.67
7.30
12.60
2.24
1.63
0.31
1.01
1.02
3.10
5.90
0.60
4.03
6.49
25.94
13.75
3.90
0.30
1.72
0.00
0.21
0.30
0.00
0.00
9.50
17.93
3.19
0.10
0.00
0.00
0.00
0.78
1.15
0.21
0.01
0.00
0.00
0.00
39.58
51.79
28.49
20.39
76.76
44.02
21.01
Sampling
Date
44
OSOYOOS LAKE MYSIS RELICTA DIETS
Number Mysis
processed
Daphnia
Bosmina
Cyclopoid
Calanoid
nauplii
rotifer
Diaphanosoma
Table 9. Osoyoos Lake 2005-2013 Mysis relicta diets as average number of prey per Mysis.
25-May-06
26-Jul-06
18-Aug-06
27-Sep-06
24-Oct-06
12
30
30
30
9
0.167
0.400
0.000
0.133
0.000
0.083
0.000
0.000
0.133
0.200
0.000
0.000
0.000
0.000
0.000
0.083
0.000
0.200
0.100
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
16-May-07
21-Jun-07
10-Jul-07
17-Aug-07
25-Sep-07
05-Nov-07
17-Dec-07
30
19
30
30
30
30
27
0.067
0.211
0.033
0.233
0.233
0.333
0.000
0.033
0.053
0.033
0.133
0.033
0.367
0.037
0.133
0.000
0.067
0.033
0.000
0.000
0.000
0.233
0.000
0.100
0.000
0.000
0.067
0.185
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
12-May-08
11-Jun-08
08-Jul-08
12-Aug-08
22-Sep-08
18-Nov-08
23
19
14
30
31
30
0.000
0.000
0.000
0.033
0.000
0.000
0.087
0.211
0.357
0.067
0.000
0.000
0.478
0.000
0.429
0.000
0.065
0.133
0.043
0.000
0.000
0.067
0.000
0.033
0.000
0.000
0.000
0.000
0.000
0.000
0.478
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
11-May-09
08-Jun-09
13-Jul-09
11-Aug-09
14-Sep-09
22-Oct-09
27-Nov-09
78
104
147
116
104
228
84
0.000
0.010
0.116
0.190
0.510
0.000
0.012
0.000
0.010
0.027
0.078
0.587
0.123
0.250
0.526
0.173
0.075
0.121
0.154
0.070
0.107
0.359
0.067
0.075
0.026
0.087
0.004
0.000
0.000
0.000
0.000
0.009
0.010
0.000
0.000
0.295
0.413
0.129
0.060
0.019
0.026
0.012
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Sampling
Date
Number Mysis
processed
Daphnia
Bosmina
Cyclopoid
Calanoid
nauplii
rotifer
Diaphanosoma
45
14-Jun-10
17-Aug-10
28-Sep-10
18-Oct-10
75
150
124
94
0.000
0.073
0.177
0.255
0.187
0.067
0.032
0.106
0.547
0.333
0.282
0.330
0.000
0.000
0.024
0.000
0.000
0.000
0.000
0.000
0.027
0.047
0.024
0.000
0.000
0.040
0.032
0.000
16-Jun-11
20-Jul-11
22-Aug-11
06-Oct-11
16
56
83
106
0.000
0.018
0.096
0.000
0.188
0.000
0.036
0.340
0.063
0.125
0.181
0.066
0.000
0.036
0.012
0.009
0.000
0.000
0.000
0.000
0.250
0.000
0.000
0.028
0.000
0.000
0.000
0.000
23-May-12
26-Jun-12
10-Jul-12
20-Aug-12
24-Sep-12
01-Nov-12
33
100
100
100
100
100
0.000
0.010
0.020
0.280
0.220
0.060
0.030
0.060
0.080
0.060
0.210
0.120
0.303
0.130
0.310
0.130
0.230
0.400
0.000
0.000
0.000
0.000
0.020
0.080
0.000
0.000
0.000
0.000
0.000
0.000
1.424
0.090
0.060
0.000
0.060
0.040
0.000
0.000
0.000
0.000
0.000
0.000
28-May-13
03-Jul-13
30-Jul-13
15-Aug-13
12-Sep-13
16-Oct-13
100
100
100
100
85
81
0.000
0.030
0.200
0.230
0.059
0.173
0.010
0.130
0.140
0.000
0.059
0.284
0.220
0.130
0.280
0.070
0.094
0.049
0.070
0.010
0.010
0.000
0.000
0.012
0.000
0.000
0.000
0.000
0.000
0.000
0.790
0.130
0.010
0.000
0.012
0.012
0.000
0.000
0.000
0.000
0.000
0.000
Sampling
Date
46
OSOYOOS LAKE FISH LENGTH, WEIGHT, and DENSITY
Table 10. Year 2005-2013 Osoyoos Lake species-specific (sockeye, whitefish) and age-specific
[i.e. (i) nerkids <15 cm known from the trawl samples to be almost entirely age-0 sockeye, (ii)
age-1 sockeye or kokanee known to be age-1 from scale data, (iii) larger nerkids length 15-33
cm and (iv) fish larger than 33 cm which we assume to be a mixture of lake whitefish and
returning adult sockeye], densities, lengths and weights. The numbers in the box include lakewhitefish, adult salmon spawners, and rare occurrences of very large kokanee, very large pike
minnow, and large rainbow trout. The single red number is the late fall estimate of whitefish
densities. The numbers in green are 2013, 2012, and 2010 stocking densities and mean
weights of stocked sockeye salmon fry. During 2005-09, age-1 juvenile sockeye holdovers (i.e.
juvenile sockeye that remained in the lake for a 2nd year) were absent or uncommon and were
not separated from the age-0 nerkids. Although mixtures of sockeye and kokanee could be
present in samples of all size classes of O. nerka comprising our samples, counts of adult
sockeye and kokanee in terminal spawning areas suggest that sockeye likely comprise greater
than 90% of all sub-adult O. nerka samples from Osoyoos Lake. Evidence that annual variations
in juvenile sockeye numbers vary in direct proportion to annual variations in adult sockeye
returns (see Hyatt and Rankin 1999 and Hyatt, unpublished data) also strongly suggest that
kokanee contribute little by way of numbers to the “nerkid” aggregate rearing in Osoyoos Lake
during the years of our investigation.
04-Aug-05
13-Sep-05
28-Nov-05
18-Jan-05
15-Jul-05
16-May-05
Year 2005 Osoyoos Lake fish summary
3299
14
36
5623
37
5
1934
8
2
1864
12
2
3349
(742)
5665
(1804)
1945
(237)
1878
(344)
Density per ha
Nerkids <15cm (age 0
sockeye
Nerkids between 15-33 cm
Other fish >33cm
4414
44
142
Total fish
(± 95% CI)
4600
(663)
nd
nd
nd
Length (cm)
Nerkids <15cm (age 0
sockeye
Nerkids between 15-33 cm
Other fish >33cm
3.9
5.0
5.8
6.4
7.0
6.9
nd
nd
20.2
nd
20.4
nd
18.7
nd
nd
nd
15.0
nd
Weight (g)
Nerkids <15cm (age 0
sockeye
Nerkids between 15-33 cm
Other fish >33cm
0.4
1.4
2.6
3.0
3.5
3.4
nd
nd
94.3
nd
102.4
nd
77.5
nd
nd
nd
33.4
nd
47
22-Nov-06
05-Dec-06
14-Mar-07
2244
2212
2188
1984
1476
134
24
261
46
273
10
132
19
78
11
2402
(599)
2519
(243)
2471
(322)
2134
(163)
1565
(202)
26-Jul-06
04-Oct-06
17-May-06
Year 2006 Osoyoos Lake fish summary
Density per ha
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
Total fish
(± 95% CI)
Length (cm)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
3.4
5.5
6.5
nd
6.9
7.6
nd
15
nd
nd
ND
nd
0.3
1.9
3.2
nd
3.4
4.3
nn
45.0
nd
nd
nd
nd
Weight (g)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
48
03-Oct-07
15-Nov-07
15-Jan-08
nd
3620
1782
2269
2182
2143
nd
nd
280
43
117
22
95
15
49
3
64
7
3944
(167)
1921
(40)
2412
(62)
2234
(54)
2114
(53)
24-Jul-07
05-Jun-07
16-Aug-07
Year 2007 Osoyoos Lake fish summary
Density per ha
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
Total fish
(± 95% CI)
Length (cm)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
3.6
5.6
6.0
6.8
6.8
7.1
nd
nd
18.6
nd
17.1
nd
19.6
nd
18.8
nd
nd
nd
0.4
2.0
2.2
3.6
3.3
2.6
nd
nd
92.4
nd
66.2
nd
89.6
nd
75.6
nd
nd
nd
Weight (g)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
49
12-Aug-08
05-Sep-08
29-Sep-08
05-Nov-08
04-Apr-09
705
1075
1481
1199
1042
832
nd
14
2
131
20
247
62
199
60
186
43
88
6
nd
nd
720
(112)
1226
(235)
1790
(220)
1459
(184)
1271
(115)
926
(51)
nd
04-Jul-08
Fish Sampled
20-May-08
Year 2008 Osoyoos Lake fish summary
Density per ha
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
Total fish
(± 95% CI)
Length (cm)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
3.4
5
6
6.5
7.2
7.7
8.3
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
18.3
nd
19.4
nd
0.4
1.3
2.1
2.8
4.6
5.6
6.6
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
72.3
nd
91.6
nd
Weight (g)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
50
22-Jul-09
24-Aug-09
28-Sep-09
23-Nov-09
10-Feb-09
10686
10025
9862
7945
6785
7569
8148
219
31
371
93
357
56
417
84
569
142
191
14
123
6
10935
(5333)
10489
(4327)
10275
(913)
8445
(1213)
7496
(388)
7774
(732)
8278
(717)
17-Jun-09
Fish Sampled
19-May-09
Year 2009 Osoyoos Lake fish summary
Density per ha
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
Total fish
(± 95% CI)
Length (cm)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
3.3
4
5.7
6.1
6.6
7
7.2
nd
nd
19.1
nd
11.8
nd
24.1
nd
15.7
nd
18.3
nd
nd
nd
Weight (g)
Nerkids <15cm (most age-0
sockeye)
Nerkids between 15-33 cm
Other fish >33cm
0.3
0.7
2
2.4
3.1
3.4
3.3
nd
nd
91.5
nd
21.9
nd
nd
nd
43.1
nd
66.1
nd
nd
nd
23-Jun-10
12-Jul-10
09-Aug-10
06-Sep-10
02-Oct-10
13-Nov-10
11-Mar-11
155
41
11
988
184
268
41
3
1466
73
363
152
22
1346
288
325
216
82
1085
101
305
185
73
622
163
284
104
18
761
18
155
69
4
669
88
31
31
1
566
(268)
1483
(359)
2077
(309)
2259
(347)
1751
(133)
1194
(196)
1007
(117)
798
(80)
4.3
5.8
8.7
16
nd
5.2
6.6
10.3
20.1
nd
6.2
7.5
10.2
18.2
nd
6.1
7.6
10.5
24.4
nd
6.8
7.7
10.9
18.1
nd
7.3
8.6
11.9
25.8
nd
8.3
9.3
11.4
nd
nd
0.8
2.2
7.8
44.2
nd
1.5
3.3
13.5
102
nd
2.7
4.6
11.9
92.6
nd
2.4
4.7
12.8
181.8
nd
3.3
4.8
14.5
69.2
nd
4.1
6.9
18.9
187.3
nd
6
8.1
15.1
nd
nd
02-Jun-10
31-May-10
Year 2010 Osoyoos Lake fish summary
Density per ha
Wild nerkids <15cm (age-0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Total fish (± 95% CI)
358
463
51
Length (cm)
Wild nerkids <15cm (age-0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
3.3
nd
7.2
16.5
nd
Weight (g)
Wild nerkids <15cm (age-0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
0.2
1.1
3.9
50.1
nd
52
16-Oct-11
28-Nov-11
19-Mar-12
Nerkids <15cm (age-0 sockeye)
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Density per ha
5607
6147
642
933
102
181
13
81
3650
356
184
42
4508
163
18
nd
4976
35
107
5
4376
0
73
3
Total fish
(± 95% CI)
6365
(1700)
7342
(605)
4232
(492)
4688
(308)
5123
(576)
4451
(456)
Nerkids <15cm (age-0 sockeye)
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Length (cm)
4.7
6
11.3
12.9
17.9
17.8
nd
nd
6.4
15.7
19.3
nd
6.9
14
nd
nd
7.2
13.5
17.4
nd
7.8
nd
15.9
nd
Nerkids <15cm (age-0 sockeye)
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Weight (g)
1.1
2.2
17.4
24.7
56.5
67.5
nd
nd
2.8
43.8
96.4
nd
3.5
31.7
nd
nd
3.7
27
59.9
nd
4.9
nd
40.9
nd
29-Jun-11
07-Sep-11
02-Aug-11
Year 2011 Osoyoos Lake fish summary
53
11-Sep-12
11-Oct-12
17-Nov-12
15-Feb-13
Density per ha
3980
898
345
315
52
13
4244
195
170
99
30
4285
352
260
198
55
3074
315
224
108
25
2372
151
107
41
2
2476
317
67
39
4706
(926)
4738
(537)
5149
(390)
3746
(350)
2673
(205)
2901
(180)
Nerkids <15cm (age 0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Length (cm)
4
nd
4.6
9.7
20.1
nd
4.8
5.7
10.9
nd
nd
6.1
7.1
12.3
nd
nd
6.6
7.5
13.2
nd
nd
7.1
8.2
11
nd
nd
7.6
8.1
nd
nd
nd
Nerkids <15cm (age 0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Weight (g)
0.6
0.8
0.9
10.2
96.3
nd
1.1
2
15.8
nd
nd
2.3
3.7
21.4
nd
nd
3.1
4.7
24.9
nd
nd
3.7
6.1
13.4
nd
nd
4.1
5
nd
nd
nd
Nerkids <15cm (age 0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
Total fish
(± 95% CI)
14-Jun-12
24-Jul-12
29-May-12
Year 2012 Osoyoos Lake fish summary
54
03-Aug-13
05-Sep-13
10-Oct-13
06-Nov-13
18-Mar-13
Nerkids <15cm (age 0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
6057
100
214
91
14
6480
133
618
181
31
5254
114
1099
297
51
4080
66
999
291
23
3579
55
1020
222
7
4023
82
1512
123
0
9395
(1870)
6476
(1200)
7443
(506)
6816
(422)
5459
(4883)
4883
(312)
5742
(638)
4.5
5.2
10.9
18.2
nd
5.1
5.9
13.4
nd
nd
5.5
6.6
11.3
49.4
nd
6
6.5
nd
nd
nd
6.5
7.4
15.2
nd
nd
7.4
7.6
10.7
nd
nd
1
1.6
17
75
nd
1.4
2.2
31.7
nd
nd
1.7
3.4
17.1
1273
nd
2.4
3
nd
nd
nd
2.9
4.3
43.7
nd
nd
4.1
4.6
12
nd
nd
Total fish
(± 95% CI)
Nerkids <15cm (age 0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
06-Jun-13
Density per ha
9176
895
69
50
9
05-Jun-13
09-Jul-13
Year 2013 Osoyoos Lake fish summary
Length (cm)
3.7
9.8
18.9
nd
Weight (g)
Nerkids <15cm (age 0 sockeye)
Stocked sockeye <15 cm
Age 1 sockeye or kokanee
Nerkids between 15-33 cm
Other fish >33cm
0.4
0.98
11
80.5
nd
OSOYOOS LAKE FISH STOMACHS
Table 11. Year 2006-2013 Osoyoos Lake fish stomach summary as average numbers of each prey type found in stomachs collected
through the summer-fall from age-0 wild sockeye, age-0 hatchery sockeye stocked in 2010, 2012, 2013, age-1 smolts or kokanee,
age-2 smolts of kokanee.
L. ashlandi copepodids &
adults
E. nevadensis copepodid &
adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Age 0+ sockeye
Nerkids > 15 cm
27
0
24.7
0.0
0.1
1.0
0.1
0.0
0.0
0.0
0.0
0.0
26-Jul-06
Age 0+ sockeye
Nerkids > 15 cm
51
0
69.3
0.1
13.9
0.0
62.0
0.1
0.0
0.1
0.0
0.0
04-Oct-06
Age 0+ sockeye
Nerkids > 15 cm
64
2
22.5
0.0
0.0
0.0
72.4
0.0
0.1
0.0
3.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.4
4.5
0.0
0.0
06-Dec-06
Age 0+ sockeye
Nerkids > 15 cm
43
5
58.4
4.4
0.8
0.0
6.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.6
0.0
0.0
Fish Group
Number stomachs
processed
25-May-06
Sampling
Date
55
D. thomasi copepodids &
adults
2006 Osoyoos Lake fish diets (average number prey per fish)
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
5-Jun-07
Age 0+ sockeye
Nerkids > 15 cm
51
0
54.0
0.0
9.5
1.6
13.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
24-Jul-07
Age 0+ sockeye
Nerkids > 15 cm
21
8
39.1
9.5
0.0
0.0
17.7
0.0
0.0
0.0
4.7
5.3
3.6
17.3
0.0
0.0
0.0
0.0
0.1
0.1
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
16-Aug-07
Age 0+ sockeye
Nerkids > 15 cm
40
2
72.5
91.5
0.0
0.0
24.3
55.0
0.0
0.0
13.1
0.0
1.0
0.5
0.0
0.0
0.1
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
3-Oct-07
Age 0+ sockeye
Nerkids > 15 cm
34
6
59.4
81.7
0.0
0.0
34.1
5.3
0.6
0.0
42.2
147.7
0.0
0.0
0.0
0.0
0.0
0.0
0.1
1.0
0.1
5.0
0.0
0.0
0.0
0.2
0.0
0.0
0.0
0.0
15-Nov-07
Age 0+ sockeye
Nerkids > 15 cm
41
4
52.1
170.8
0.0
0.0
2.1
0.0
0.0
0.0
0.5
2.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
9.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15-Jan-07
Age 0+ sockeye
Nerkids > 15 cm
29
0
51.1
0.0
16.0
0.1
0.0
0.1
0.0
0.0
0.1
0.2
0.0
0.0
0.0
0.0
Sampling
Date
Fish Group
Number stomachs
processed
D. thomasi copepodids
& adults
2007 Osoyoos Lake fish diets (average number prey per fish)
56
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
Age 0+ sockeye
Nerkids > 15 cm
50
0
12.3
34.1
0.3
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
04-Jul-08
Age 0+ sockeye
Nerkids > 15 cm
39
0
1.5
0.0
0.3
0.1
48.2
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
12-Aug-08
Age 0+ sockeye
Nerkids > 15 cm
37
0
16.9
1.0
25.6
0.0
1.9
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
11-Sep-08
Age 0+ sockeye
Nerkids > 15 cm
17
0
0.4
0.0
43.6
0.0
0.5
0.0
0.0
11.9
0.0
0.0
0.0
0.0
0.0
0.0
29-Sep-08
Age 0+ sockeye
Nerkids > 15 cm
39
0
12.5
0.0
29.7
0.0
0.1
0.1
0.1
1.4
0.1
0.0
0.0
0.0
0.9
0.6
05-Nov-08
Age 0+ sockeye
Nerkids > 15 cm
31
6
95.5
59.3
9.2
0.0
14.8
5.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
1.3
2.8
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
Fish Group
Number stomachs
processed
15-May-08
Sampling
Date
57
D. thomasi copepodids
& adults
2008 Osoyoos Lake fish diets (average number prey per fish)
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
Age 0+ sockeye
Nerkids > 15 cm
31
0
43.1
2.3
0.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.5
0.1
17-Jun-09
Age 0+ sockeye
Nerkids > 15 cm
31
2
18.6
0.5
1.0
0.0
0.7
0.5
0.2
0.0
28.0
18.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
22-Jul-09
Age 0+ sockeye
Nerkids > 15 cm
30
0
10.9
0.1
0.8
0.1
33.9
0.8
0.0
0.1
0.0
0.1
0.0
0.0
0.0
0.0
24-Aug-09
Age 0+ sockeye
Nerkids > 15 cm
30
0
20.4
0.3
2.4
2.4
0.3
0.1
0.0
0.7
0.1
0.0
0.0
0.0
0.0
0.0
28-Sep-09
Age 0+ sockeye
Nerkids > 15 cm
28
1
61.2
1.0
4.5
2.0
83.6
1.0
0.4
0.0
6.0
122.0
0.0
0.0
0.0
0.0
1.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
23-Nov-09
Age 0+ sockeye
Nerkids > 15 cm
45
1
58.8
0.0
0.6
0.0
1.2
0.0
0.0
0.0
0.0
0.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Fish Group
Number stomachs
processed
11-May-09
Sampling
Date
58
D. thomasi copepodids
& adults
2009 Osoyoos Lake fish diets (average number prey per fish)
D. thomasi copepodids
& adults
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
fly pupa
17-May-10
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
17
22
3
109.3
206.4
208.7
0.0
0.0
0.0
0.1
12.9
85.3
0.0
0.9
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.4
1.3
0.1
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.5
3.0
0.0
0.8
6.0
0.2
11.9
2.0
21-Jun-10
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
52
14
2
138.2
271.6
0.5
9.9
1.7
0.0
55.6
72.0
0.0
26.1
94.5
0.0
0.5
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.1
0.0
0.1
0.1
1.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.6
0.0
0.4
0.0
0.0
0.3
2.5
0.0
09-Aug-10
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
37
14
1
2.5
3.4
0.0
0.0
0.0
0.0
0.4
3.1
0.0
0.1
0.0
0.0
63.2
113.0
94.0
2.2
9.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
02-Oct-10
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
41
2
1
59.4
33.0
249.0
0.0
0.0
0.0
36.8
19.0
53.0
0.0
0.0
0.0
7.2
2.0
373.0
0.4
0.0
94.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
11.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.6
0.0
2.0
1.8
9.5
0.0
0.3
0.0
0.0
Sampling
Date
Fish Group
59
Number stomachs
processed
2010 Osoyoos Lake fish diets (average number prey per fish)
D. thomasi copepodids
& adults
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
fly pupa
29-Jun-11
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
30
9
5
5.6
32.7
59.6
0.0
0.0
0.0
0.5
0.4
0.4
0.1
0.8
0.4
168.4
255.8
590.8
0.0
0.6
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.2
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
02-Aug-11
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
32
1
0
42.7
0.0
8.8
0.1
41.6
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.3
0.0
0.0
07-Sep-11
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
30
0
3
44.8
0.0
20.3
0.0
51.4
0.1
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
90.3
0.0
65.7
0.0
51.3
2.3
0.0
0.0
4.0
0.3
0.0
0.0
0.0
0.0
0.0
Age 0+ sockeye
Nerkids 4-9 cm
Nerkids > 15 cm
30
0
1
243.9
0.0
7.2
5.6
19.8
0.0
0.0
0.0
0.0
2.0
0.0
0.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4.0
0.0
0.0
0.0
0.0
0.0
0.0
Sampling
Date
06-Oct-11
Fish Group
60
Number stomachs
processed
2011 Osoyoos Lake fish diets (average number prey per fish)
Number stomachs
processed
D. thomasi copepodids
& adults
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
fly pupa
2012 Osoyoos Lake fish diets (average number prey per fish)
14-Jun-12
Age 0+ sockeye
Nerkids 4-9 cm
21
2
9.0
6.5
7.5
9.0
4.2
1.0
0.1
0.0
36.2
98.0
2.9
0.0
0.0
0.0
11.8
59.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
24-Jul-12
Age 0+ sockeye
Nerkids 4-9 cm
30
2
25.7
39.0
13.3
33.0
6.9
6.0
0.3
0.0
5.9
31.0
0.0
5.0
0.0
0.0
48.9
440.0
0.0
0.0
4.4
0.0
0.0
0.0
0.9
3.0
0.0
0.0
0.0
0.0
0.0
0.0
11-Sep-12
Age 0+ sockeye
Nerkids 4-9 cm
29
4
4.0
0.5
2.8
4.5
22.5
4.0
0.0
0.3
4.5
3.3
0.0
0.0
0.0
0.0
1.9
2.0
0.1
1.3
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
17-Nov-12
Age 0+ sockeye
Nerkids 4-9 cm
30
3
3.9
3.0
17.2
6.3
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.3
0.3
0.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Sampling
Date
Fish Group
61
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
fly pupa
larval fish
Wild age-0 sockeye
Hatchery age-0 sockeye
Age 1 nerkids
Age 2 nerkids
30
2
18
4
23.0
26.0
94.1
46.8
5.0
18.0
59.0
324.3
10.0
35.0
120.1
9.5
0.0
0.0
0.0
0.0
5.0
1.0
118.5
7.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
0.0
0.2
0.0
0.0
0.0
0.1
0.3
0.0
0.0
0.1
2.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
7.4
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
09-Jul-13
Wild age-0 sockeye
Hatchery age-0 sockeye
Age 1 nerkids
Age 2 nerkids
30
8
3
1
6.0
6.0
2.0
2.0
2.0
2.0
0.0
0.0
25.0
18.0
0.7
10.0
3.0
3.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
21.0
26.0
0.0
0.0
0.0
0.0
0.3
4.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
8.0
6.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
03-Aug-13
Wild age-0 sockeye
Hatchery age-0 sockeye
Age 1 nerkids
Age 2 nerkids
30
6
1
0
44.0
23.0
14.0
4.0
26.0
18.0
17.0
24.0
102.0
3.0
6.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
8.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
05-Sep-13
Wild age-0 sockeye
Hatchery age-0 sockeye
Age 1 nerkids
Age 2 nerkids
30
7
1
0
7.0
2.0
8.0
6.0
0.0
6.0
8.0
1.0
26.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
0.0
152.0
0.0
0.0
1.0
0.0
0.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Fish Group
Diaphanosoma
D. thomasi copepodids
& adults
04-Jun-13
Sampling
Date
62
Number stomachs
processed
2013 Osoyoos Lake fish diets (average number prey per fish)
D. thomasi copepodids
& adults
L. ashlandi copepodids
& adults
E. nevadensis
copepodid & adults
Bosmina
Daphnia
Leptodora
Polyphemus
Diaphanosoma
Mysis
Chironomid Larva
Sida
Mayfly
Adult Fly
fly larva
fly pupa
larval fish
30
7
0
0
96.0
72.1
296.0
80.7
46.0
23.6
0.0
2.1
0.0
1.4
0.0
0.0
0.0
0.0
0.0
3.6
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.4
0.0
0.0
0.0
0.0
0.0
0.0
06-Nov-13
Wild age-0 sockeye
Hatchery age-0 sockeye
Age 1 nerkids
Age 2 nerkids
30
6
1
0
54.7
47.5
36.7
232.0
116.7
268.3
38.7
15.8
0.0
0.0
0.8
0.0
2.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Number stomachs
processed
Wild age-0 sockeye
Hatchery age-0 sockeye
Age 1 nerkids
Age 2 nerkids
Fish Group
63
10-Oct-13
Sampling
Date
64
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69
Figure 1. Location of the Okanagan River, Skaha and Osoyoos Lakes.
70
Figure 2. Osoyoos Lake bathymetric contours. Depth is in metres. Adapted from map by
Province of B. C.,Fisheries Branch, Inventory Operations, October 1971. Vector file from
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71
Figure 3. Osoyoos Lake North Basin, showing hydro-acoustics survey transects and water
chemistry sampling stations
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