C S A S S C C S

C S A S S C C S
CSAS
SCCS
Canadian Science Advisory Secretariat
Secrétariat canadien de consultation scientifique
Proceedings Series 2002/030
Série des compte rendus 2002/030
Proceedings of the PSARC Invertebrate
Subcommittee Meeting,
November 25-28, 2002
K. West
Invertebrate Subcommittee Chair
Fisheries and Oceans Canada
Pacific Scientific Advice Review Committee
Pacific Biological Station
Nanaimo, British Columbia V9T 6N7
January 2003
© Her Majesty the Queen in Right of Canada, 2002
© Sa majesté la Reine, Chef du Canada, 2002
ISSN 1701-1280
www.dfo-mpo.gc.ca/csas/
Proceedings of the PSARC Invertebrate
Subcommittee Meeting,
November 25-28, 2002
K. West 1
Invertebrate Subcommittee Chair
Fisheries and Oceans Canada
Pacific Scientific Advice Review Committee
Pacific Biological Station
Nanaimo, British Columbia V9T 6N7
January 2003
1
Fisheries and Oceans Canada
555 West Hastings Street
Vancouver, British Columbia V6B 5G3
PACIFIC SCIENTIFIC ADVICE REVIEW COMMITTEE (PSARC)
INVERTEBRATE SUBCOMMITTEE MEETING
SUMMARY ...................................................................................................................................... 2
SOMMAIRE..................................................................................................................................... 4
INTRODUCTION............................................................................................................................ 8
General Subcommittee Discussion and Concerns .............................................................. 8
DETAILED COMMENTS FROM THE REVIEWS......................................................................... 8
I2002-01: A Phase ‘0’ review of the biology and fisheries potential of the marine
gastropods Astraea gibberosa, Euspira lewisii, Fusitriton oegonensis, Nucella
lamellosa, and deep water snails of the family Buccinidae ................................................. 8
I2002-02: Evaluation of an intensive fishery on Dungeness Crab, Cancer magister,
in Fraser Delta, British Columbia.......................................................................................... 10
I2002-03: Pandalus hypsinotus, Humpback shrimp: An assessment and management
framework for directed fisheries based on results from the Drury Inlet Humpback
Shrimp Research Program..................................................................................................... 12
I2002-04: Sea Cucumber quotas based on British Columbia survey data...................... 13
I2002-05: Geoduck stock assessment framework in British Columbia ........................... 15
I2002-06: Survey protocol for the removal of allowable numbers of northern
abalone, Haliotis kamtschatkana, from areas in British Columbia for use as
broodstock in aquaculture..................................................................................................... 17
I2002-07: A review of the biology of opal squid (Loligo opalescens Berry), and of
selected loliginid fisheries .................................................................................................... 18
STOCK STATUS REPORTS....................................................................................................... 20
APPENDIX 1: WORKING PAPER SUMMARIES....................................................................... 21
APPENDIX 2: PSARC INVERTEBRATE SUBCOMMITTEE MEETING AGENDA
NOVEMBER 25-28, 2002 ............................................................................................................. 27
APPENDIX 3: LIST OF ATTENDEES & REVIEWERS.............................................................. 28
_______________________________________
1
SUMMARY
The Pacific Scientific Advice Review Committee (PSARC) Invertebrate Subcommittee
met November 25-28, 2002 at the Pacific Biological Station in Nanaimo, B.C. The
Subcommittee reviewed seven working papers and three stock status reports.
Working Paper I2002-01: A Phase ‘0’ review of the biology and fisheries
potential of the marine gastropods Astraea gibberosa, Euspira lewisii, Fusitriton
oegonensis, Nucella lamellosa, and deep water snails of the family Buccinidae
This paper presented a review of the biology and fisheries of marine gastropods and
deepwater snails. As interest in the potential for the development of a fishery for marine
gastropods and deepwater snails was of a general nature, and with no specific species
or harvest method requested, the paper was not a traditionally focussed Phase 0 report.
The Subcommittee recommended that any fishery development follow the New
Emerging Fisheries Policy guidelines and a focussed phase 0 be conducted on each
potential species. The poor life history information on most species in our region and
the corresponding known recreational harvest and bycatch of these species was a
concern to the Subcommittee and warrants further investigation.
Working Paper I2002-02: Evaluation of an intensive fishery on Dungeness
Crab, Cancer magister, in Fraser Delta, British Columbia
This paper examined the potential effects of excessive handling of crabs in an intensive
crab fishery in the Fraser River area. It addressed three specific concerns: (1) does
excessive handling of sub-legal crabs reduce recruitment; (2) what is the impact of
intensive fishing on yield and profit; and (3) what scientific criteria could managers use
to close the fishery? The Subcommittee concluded that there is no evidence of
detrimental impacts of excessive handling of sub-legal crabs on recruitment but that this
may be due to the short data series. The Subcommittee recommended that the models
and approaches based on Catch Per Unit Effort (CPUE) data and instar modelling as
presented in this paper be used in discussions among fisheries management, science,
and industry on alternative management approaches and intensive fishing problems for
crabs on the B.C. coast. However, they felt each area will need to be examined
individually to determine their appropriate parameter values.
Working Paper I2002-03:
Pandalus hypsinotus, Humpback Shrimp: An
assessment and management framework for directed fisheries based on results
from the Drury Inlet Humpback Shrimp Research Program
This paper presented the biology of the Drury Inlet humpback shrimp population, from
two research cruises, including age structure, changes in sexual condition over time,
natural mortality, and fecundity. The selectivity of different fishing gear (trap and trawl)
was examined and recommendations regarding how to manage recruitment overfishing
in directed humpback shrimp fisheries using a fixed exploitation rate and a fixed
2
escapement target were provided. The Subcommittee concluded that the assessment
methodologies and management options were acceptable, and must take into account
gear type and location. The Subcommittee recognized that there are a number of ways
to manage and assess humpback shrimp fisheries, and concurs with using an F-based
target reference point for trap and trawl fisheries. In addition, fixed exploitation based on
in-season CPUE estimates or spawner index can be used for trap fisheries. The
Subcommittee felt that the biological parameters derived from the Drury Inlet study
should be utilized to manage new and existing humpback fisheries, until area-specific
data can be collected.
Working Paper I2002-04: Sea Cucumber quotas based on British Columbia
survey data
This paper provides the survey results and density estimates, from seven dive surveys
conducted since 1998. Survey results showed that the lower 90%CI of density estimates
is higher than the baseline density of 2.5 c/m-sh. The parameters and procedures used
to calculate the quotas are documented and mean weights are reevaluated for all open
areas using the market sampling data. The Subcommittee recommended that the open
Pacific Fisheries Management Areas (PFMAs) should be grouped into three categories
– surveyed, unsurveyed good habitat, and unsurveyed areas of concern (suspected poor
habitat or over harvested) - to assign density estimates. For the surveyed areas, the
lower 90% CI of density from the survey is recommended. For the unsurveyed areas
with good habitat, the new baseline density estimate of 5.08 sea cucumbers per metre
of shoreline (c/m-sh) is recommended. For the third category, unsurveyed areas with
exposed shoreline or a history of low stock abundance, the original density estimate of
2.5 c/m-sh would be kept. The Subcommittee also recommended research into the
appropriateness of using area versus shoreline length in quota calculations for sea
cucumbers.
Working Paper I2002-05: Geoduck stock assessment framework in British
Columbia
The paper presents a review of the current approaches to the assessment of geoducks
in the Pacific Region. It evaluates the uncertainties in the key components of the present
approach, and recommends improvements and changes where necessary. The
Subcommittee noted that there are some areas of the coast that have large
discrepancies in the estimated biomass compared to the biomass perceived by the
industry. These areas should be priorities for re-assessment/survey, and may help to
understand the uncertainties and assumptions in the present process. The
Subcommittee noted that the lower 10% error in area has been confirmed by the
analysis for the North Coast. However, for the South Coast, the anecdotal information
suggests the uncertainty is much larger and the error maybe greater than 10%. The
Subcommittee recommended that a high priority be put on resolving inaccuracies in bed
area estimates. The Subcommittee also felt that any future assessment frameworks
3
should take into account factors that include minimal densities, oceanography,
recruitment and mortality factors such as sea otter predation.
Working Paper I2002-06: Survey protocol for removal of allowable numbers of
northern abalone, Haliotis kamtschatkana, from areas in British Columbia for
use as broodstock in aquaculture
This paper reviews the data collected during 6 surveys conducted for abalone
broodstock purposes and proposes survey protocol and broodstock removal
considerations. The Subcommittee recommended acceptance of the protocol and
recommendations developed in the paper. The Subcommittee accepted the 90% CI
and continued use of a 1% harvest rate. The Subcommittee felt that if a more
precautionary approach was required, the 1% harvest rate should be lowered. The
Subcommittee recognized that the current abalone culture facilities are in the
developmental stage wherein culture techniques are still being refined. Consideration of
genetics, disease and productivity should be incorporated into the overall program.
Working Paper I2002-07: A review of the biology of opal squid (Loligo
opalescens Berry), and of selected loliginid fisheries
This paper provided information on the taxonomy, description, distribution, life history,
age and growth, reproduction, trophic relations, parasites and disease, population
structure and dynamics of opal squid. Loliginid squid fisheries in California, Oregon,
Washington and British Columbia were reviewed, including the effort, landing,
assessment and management where information was available. Similar species in the
N. E. Atlantic and Chokka squid, L. vulgaris reynaudii, harvested in South Africa were
also reviewed. The Subcommittee recommended that any development of B.C. opal
squid fisheries occur within the context of the New Emerging Fisheries Policy. Any
expansion should be through a phased development of the fishery dependent on
development of essential fisheries information and assessment and management
frameworks. The Subcommittee also felt that the ecosystem impacts of development of
B.C. opal squid fisheries be investigated given the implications concerning this species
as a forage species.
SOMMAIRE
Le sous-comité des invertébrés du Comité d'examen des évaluations scientifiques du
Pacifique (CEESP) s’est réuni à la Station biologique du Pacifique, à Nanaimo, en
Colombie-Britannique, du 25 au 28 novembre 2002 pour passer en revue sept
documents de travail et trois rapports sur l’état des stocks.
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Document de travail I2002-01 : Examen de phase 0 de la biologie et du potentiel
halieutique des gastropodes marins Astraea gibberosa, Euspira lewisii,
Fusitriton oegonensis et Nucella lamellosa, et de buccins benthiques de la
famille Buccinidae
Sont passés en revue dans ce document la biologie et le potentiel halieutique de
gastropodes marins et de buccins benthiques. Comme l’intérêt dans le potentiel de
développement d’une pêche de gastropodes marins et de buccins benthiques est de
nature générale et aucune espèce ou méthode de récolte particulière n’est mise en
cause, le document n’est pas un rapport de phase 0 régulier. Le sous-comité
recommande que le développement de toute pêche se fasse conformément aux lignes
directrices de la Politique pour les pêches nouvelles et qu’un examen ciblé de phase 0
soit effectué pour chaque espèce présentant un potentiel halieutique. Le peu de
données disponibles sur le cycle vital de la plupart des espèces retrouvées dans la
région, ainsi que sur les prises récréatives et les prises accessoires, préoccupe le
sous-comité, qui est d’avis que d’autres études sont requises.
Document de travail I2002-02 : Évaluation d’une pêche intensive du crabe
dormeur, Cancer magister, dans le delta du Fraser, en Colombie-Britannique
Sont examinés dans ce document les effets potentiels de la manutention excessive du
crabe dormeur lors de la pêche intensive de l’espèce qui est pratiquée dans le delta du
Fraser. Trois questions sont abordées, à savoir : (1) si la manutention excessive des
crabes de taille non réglementaire réduit le recrutement; (2) quel est l’impact de la
pêche intensive sur le rendement et le profit et (3) quels critères scientifiques les
gestionnaires pourraient utiliser pour fermer la pêche. Le sous-comité conclut que rien
n’indique que la manutention excessive des crabes de taille non réglementaire a des
effets adverses sur le recrutement, mais que cela peut être imputable à la courte série
de données disponible. Il recommande que les gestionnaires des pêches, les
scientifiques et les intervenants de l’industrie se servent des modèles et des approches
reposant sur des données sur les prises par unité d’effort (PUE) et la modélisation des
stades larvaires, tels que présentés dans le document, lors des discussions portant sur
d’autres approches de gestion et les problèmes inhérents à une pêche intensive du
crabe dans les eaux de la Colombie-Britannique. Par contre, le sous-comité est d’avis
que chaque zone de pêche doit faire l’objet d’un examen indépendant afin de
déterminer les valeurs de paramètre appropriées.
Document de travail I2002-03 : Évaluation de la crevette à front rayé, Pandalus
hypsinotus, et cadre de gestion pour la pêche dirigée reposant sur les résultats
du Programme de recherche sur la crevette à front rayé de l’inlet Drury
Sont présentées dans ce document des données sur la biologie de la population de
crevette à front rayé de l’inlet Drury recueillies dans le cadre de deux croisières de
recherche, y compris la structure par âge, les changements dans la proportion des
sexes au fil du temps, la mortalité naturelle et la fécondité. Est aussi examinée la
5
sélectivité de divers engins de pêche (casier et chalut) et sont ensuite présentées des
recommandations pour la gestion de la surpêche du potentiel reproducteur lors des
pêches dirigées de l’espèce reposant sur un taux d’exploitation fixe et une cible
d’échappement fixe. Le sous-comité conclut que les méthodes d’évaluation et les
options de gestion sont acceptables et doivent prendre en compte le type d’engin et le
lieu de pêche. Il reconnaît qu’il existe divers moyens de gérer et d’évaluer les pêches de
la crevette à front rayé et approuve l’utilisation d’un point de référence cible reposant sur
F pour les pêches au casier et au chalut. Il considère aussi qu’un taux d’exploitation fixe
reposant sur des estimations des PUE faites en saison ou un indice de l’abondance
des reproducteurs peut être utilisé pour la gestion des pêches au casier. Le
sous-comité est d’avis que les paramètres biologiques provenant de l’étude de l’inlet
Drury devraient servir à la gestion des pêches existantes et nouvelles de la crevette à
front rayé jusqu’à ce que des données sur chaque pêcherie soient recueillies.
Document de travail I2002-04 : Quotas d’holothurie reposant sur des données
de relevé recueillies en Colombie-Britannique
Sont présentés dans ce document les résultats et les estimations de densité provenant
de sept relevés en plongée effectués depuis 1998. Les résultats de relevé ont révélé
que le plus faible intervalle de confiance à 90 % des estimations de la densité était plus
élevé que la densité de référence de 2,5 holothuries par mètre de rivage. Les
paramètres et les procédures servant au calcul des quotas sont documentés et les
poids moyens pour toutes les zones ouvertes sont réévalués en regard des données
d’échantillonnage du marché. Le sous-comité recommande que les secteurs
d’exploitation des pêcheries du Pacifique soient groupés en trois catégories – secteurs
relevés, secteurs à habitat adéquat non relevés et secteurs préoccupants non relevés
(surexploités ou à habitat présumé inadéquat) - pour assigner des estimations de la
densité. Dans le cas des secteurs relevés, le sous-comité recommande d’utiliser la plus
faible densité à un intervalle de confiance à 90 %; dans le cas des secteurs non relevés
à habitat adéquat, la nouvelle estimation de référence de la densité de 5,08 holothuries
par mètre de rivage et dans le cas des secteurs non relevés à rivage exposé ou ayant
une histoire de faible abondance, la première estimation de la densité de 2,5
holothuries par mètre de rivage. Le sous-comité recommande en outre que des
recherches soient menées sur la pertinence de l’utilisation du secteur par opposition à
la longueur du rivage dans le calcul des quotas d’holothuries.
Document de travail I2002-05 : Cadre d’évaluation des stocks de panope de la
Colombie-Britannique
Sont passées en revue dans ce document les approches actuelles à l’évaluation de la
panope dans la Région du Pacifique, sont évaluées les incertitudes entourant les
éléments clés de l’approche actuelle et sont recommandés des changements et des
améliorations lorsque nécessaires. Le sous-comité prend note des grands écarts entre
la biomasse estimative et la biomasse perçue par l’industrie dans certains secteurs de
la côte. La réévaluation ou le relevé de ces secteurs devrait être une priorité, ce qui
6
permettra peut-être de comprendre les incertitudes et les hypothèses du processus
actuel. Le sous-comité remarque que l’analyse pour la côte nord a confirmé la marge
d’erreur de 10 % dans la superficie. Par contre, dans le cas de la côte sud, l’information
anecdotique donne à penser que le niveau d’incertitude est beaucoup plus élevé et que
la marge d’erreur pourrait être supérieure à 10 %. Le sous-comité recommande que
l’on donne une haute priorité à la résolution des erreurs de précision dans les
estimations de la superficie des gisements. Il est en outre d’avis que tout cadre
d’évaluation future devrait tenir compte de certains facteurs, dont les densités
minimales, les facteurs océanographiques, le recrutement et les causes de mortalité,
comme la prédation exercée par la loutre de mer.
Document de travail I2002-06 : Protocole de relevé pour le prélèvement d’un
nombre autorisé d’ormeau nordique, Haliotis kamtschatkana, dans les eaux de
la Colombie-Britannique aux fins d’établissement de stocks de géniteurs de
culture
Sont passées en revue dans ce document les données recueillies lors de six relevés
effectués aux fins de prélèvement d’ormeaux reproducteurs et sont proposés un
protocole de relevé et des recommandations relatives au prélèvement de
reproducteurs. Le sous-comité recommande que le protocole et les recommandations
soient approuvés, entérine l’intervalle de confiance à 90 % et accepte que le
prélèvement continue à se faire à un taux de 1 %. Il est d’avis que si une approche plus
prudente était requise, ce taux devrait être réduit. Il reconnaît en outre que les
installations de culture de l’ormeau existantes sont au stade de développement, les
méthode de culture étant en voie d’être mises au point. Le programme devrait tenir
compte de la génétique, des maladies et de la productivité.
Document de travail I2002-07 : Examen de la biologie du calmar opale (Loligo
opalescens Berry) et de quelques pêches de Loliginidae
Sont présentées dans ce document des renseignements sur la taxinomie, la
description, la distribution, le cycle vital, l’âge, la croissance, la reproduction, les
relations trophiques, les parasites et les maladies, ainsi que sur la structure et la
dynamique des populations de calmar opale. Sont ensuite passées en revue les pêches
du calmar de la famille des Loliginidae pratiquées en Californie, en Oregon, dans l’État
de Washington et en Colombie-Britannique, y compris l’effort, les débarquements, les
évaluations et la gestion lorsque des données étaient disponibles, ainsi que des
espèces semblables de l’Atlantique Nord-Est et le calmar chokka, L. vulgaris reynaudii,
pêché en Afrique du Sud. Le sous-comité recommande que tout développement de la
pêche du calmar opale en Colombie-Britannique se fasse dans le contexte de la
Politique pour les nouvelles pêches, c’est-à-dire qu’il soit échelonné en fonction de
l’élaboration de l’information essentielle sur les pêches et de cadres d’évaluation et de
gestion. Le sous-comité est en outre d’avis que les effets sur l’écosystème du
7
développement de pêches du calmar opale dans les eaux de la province soient étudiés
étant donné les répercussions qu’elles pourraient avoir sur cette espèce fourrage.
INTRODUCTION
The PSARC Invertebrate Subcommittee met November 25-28, at the Pacific Biological
Station in Nanaimo, British Columbia. An external participant from Pacific Rim National
Park attended the meeting and observers from Heiltsuk Fisheries, Pacific Coast
Shrimpers Cooperative, Underwater Harvesters Association, Pro Quota Group,
Cowichan Tribes, Penelakut Tribes, TNBC Consulting, and Pacific Sea Cucumber
Harvesters Association also attended the meeting. The Subcommittee Chair, K. West,
opened the meeting by welcoming the participants. During the introductory remarks the
objectives of the meeting were reviewed, and the Subcommittee accepted the meeting
agenda.
The Subcommittee reviewed seven Working Papers. Summaries of the Working
Papers are in Appendix 1. The meeting agenda appears as Appendix 2. A list of
meeting participants, observers and reviewers is included as Appendix 3.
General Subcommittee Discussion and Concerns
The issue of correct mapping of Pacific Fisheries Management Area (PFMA)
boundaries onto the new electronic Canadian Hydrographic Service (CHS) charts was
noted by the Subcommittee. The Subcommittee felt that this issue was a region wide
one and recommended that the resources required to place the PFMA boundaries onto
the new electronic CHS charts be provided by Region.
DETAILED COMMENTS FROM THE REVIEWS
I2002-01: A Phase ‘0’ review of the biology and fisheries potential of the marine
gastropods Astraea gibberosa, Euspira lewisii, Fusitriton oegonensis, Nucella
lamellosa, and deep water snails of the family Buccinidae
K.E. Charles and R.M. Harbo **Accepted pending major revisions
Rapporteur: Ray Lauzier
This paper was a Phase 0 paper to provide a summary of the biological, ecological and
fisheries potential of marine gastropods and deep water snails in the Pacific Region.
There was agreement among reviewers and the Subcommittee that this paper
demonstrates a good effort to gather a great deal of material together, with an extensive
bibliography and a section on Aboriginal knowledge. However, both the reviewers and
the Subcommittee agreed that in its present draft form, this manuscript lacked a
cohesive structure, synthesis and assimilation of information into focussed conclusions
8
or recommendations. There is a great deal of critical editing that is required to bring this
manuscript up to acceptable research document standards. Given the wide range of
species and information types, sound structure for this document is crucial.
The authors commented that there was no concrete proposal for a particular species or
a particular harvest method, therefore this is not a traditionally focussed Phase 0 paper.
It was meant to be a background document in anticipation of requests from interested
stakeholders.
The Subcommittee agreed that the scientific research required on these animals
includes: basic biology, critical spawning densities, critical densities for juvenile
recruitment and ecosystem impacts. Required stock assessment studies include:
population distribution, abundance estimates, size at age at sexual maturity, and
spawning times and locations.
Further considerations should include: aboriginal use, potential impacts on abalone,
toxicity and recreational use. Management considerations could include: stewardship
incentives, licence limitation, area licensing, individual quotas, closed areas, and refuge
areas.
It was recognized with the poor life history information on most species in our region and
the proponent-pays aspect of the new and emerging fisheries guidelines means that
there will be high costs of gathering sufficient data, to be borne by industry and/or
government, for fishery development. These species appear to be marginal for
developing responsible/sustainable fisheries as the cost of acquiring an adequate
information base could be daunting and may outweigh economic benefits. Still, this
Phase 0 provides good background information on the species and reveals the
challenges ahead.
The question was asked whether there are obvious next steps, and whether there are
outstanding issues that could be emphasized for further development. It was considered
to be extremely difficult to amalgamate this group of species and treat as a single entity.
The Subcommittee agreed that major revisions were required, including clear
recommendations in the paper.
The Subcommittee recognized that there is presently a recreational fishery for Moon
Snails. There is also the issue of bycatch of various species in other West Coast
fisheries, such as the prawn and crab fisheries. In other countries, snails and whelks are
caught exclusively as bycatch, and then landed commercially.
Conclusions
There are major gaps in biological information for these species. Some of the species
have been shown to be vulnerable to over-fishing in other jurisdictions.
9
The Subcommittee recognized that the New Emerging Fisheries Policy guidelines in the
Pacific Region should be followed. Species specific reviews should be conducted prior
to fisheries development. The Subcommittee had specific concerns with possible
impacts of the recreational fishery on moon snails in B.C.
Recommendations
The Subcommittee accepted this paper pending major revisions to be re-reviewed by
the original reviewers and the Subcommittee Chair.
1. The Subcommittee recommended that the species should be examined on an
individual basis, and that any fishery be developed under the New Emerging
Fisheries Policy guidelines.
2. The Subcommittee recommended that the recreational moon snail fishery needs to
be examined with respect to its fishery impacts and the potential public health
concerns considering the ability of this species to generate a toxin.
3. The Subcommittee recommended that by-catch issues in on-going commercial
fisheries (i.e. prawn, crab) need to be examined.
I2002-02: Evaluation of an intensive fishery on Dungeness Crab, Cancer
magister, in Fraser Delta, British Columbia
Z. Zhang, W. Hajas, A. Phillips, D. Rutherford, K. Fong **Accepted subject to revisions**
Rapporteur: Ian Perry
This paper examined the potential effects of excessive handling of crabs in an intensive
crab fishery in the Fraser River area. It addressed three specific concerns: (1) does
excessive handling of sub-legal crabs reduce recruitment; (2) what is the impact of
intensive fishing on yield and profit; and (3) what scientific criteria could managers use
to close the fishery?
One reviewer noted that the ratio of caught sub-legal males and females to legal males,
and in-season CPUE data, may change from year to year and stock to stock, therefore
weekly in-season and multiple-year CPUE data should be collected and analyzed before
using as a sole criteria to close a fishery. The second reviewer believed that the first
objective, to determine whether the reproductive capacity of crab stocks is affected by
an intense fishery, has largely not been achieved. Extensive exploration of longer time
series of catch and survey data using a more realistic, and more complex, population
reconstruction model is needed to achieve this objective. In addition, this reviewer felt
that the per-recruit analyses are inadequate because the assumption of constant
recruitment is inappropriate, and a stationary per-recruit analysis is incapable of
capturing the long-term effects of high fishing pressure. The instar-based approach also
10
suffers many of the same inadequacies as the CPUE-based approach. A more
comprehensive length-based population dynamics model should be developed to
assess stock status and perform stochastic simulations.
The Subcommittee accepted the authors’ replies to the reviewers’ comments. In
particular the authors responded that the study used the only data available - waiting for
more data would delay providing advice; and that more complex models are not
necessarily “better” and may have even greater data requirements than the simpler
models used in this study. The Subcommittee noted that this was a first analysis which
could be improved once more data are available. The data are sufficient, however, to
construct yield per recruit models and to estimate F0.1 reference points to identify
potential effects of frequent handling on future yields from this stock. The paper would
benefit from a comparison of the CPUE-based and instar modeling approaches to
estimate the handling impacts. The models developed in this paper may not be able to
identify the number of crabs to be gained next year by reducing excessive handling this
year, but they can identify when continued fishing this year will begin to impact next
year’s harvest – this is the basis for the 70% limit determined by the F 0.1 reference point.
Conclusions
There is no significant evidence of a decline in sub-legal crab recruitment in the Fraser
River delta. The lack of evidence may be due to the short data series available.
There is evidence that excessive handling of sub-legal crabs can reduce future yields
and reduce future profits in the fishery in the Fraser River area. Methods to reduce
handling include reducing the overall exploitation rate (for example to 65-75% from the
present >90% of legal-sized males in the Fraser River area) and/or to determine a
critical ratio of under-sized to legal sized crabs in the catch beyond which fishing would
stop. Reducing exploitation, to a rate similar to an F0.1 reference point, has been used
with other species to protect against recruitment overfishing. Such approaches would
represent important changes in management actions requiring the collection of data on
exploitation rates and discard ratios in-season, e.g. an on-grounds monitor program.
Other measures could also be considered to reduce negative impacts of handling, such
as longer soak times, larger escape rings, and/or adjustments to the length of the fishing
season. The Subcommittee felt that an approach using ratios of retained to undersize
crabs should be broadly applicable to regions beyond the Fraser River with intensive
crab fisheries, although “critical ratios” may need to be determined by areas depending
on handling mortality and other parameters.
Recommendations
The Subcommittee accepted the paper subject to revision;
1. The Subcommittee recommended that the models and approaches based on CPUE
data and instar modelling as presented in this paper be used in discussions among
11
fisheries management, science, and industry on alternative management
approaches and intensive fishing problems for crabs on the B.C. coast. However,
each area will need to be examined to determine their appropriate parameter
values.
I2002-03: Pandalus hypsinotus, Humpback shrimp: An assessment and
management framework for directed fisheries based on results from the Drury
Inlet Humpback Shrimp Research Program
J.S. Dunham, J.A. Boutillier, D. Rutherford, K. Fong **Accepted subject to revision**
Rapporteur: Beth Bornhold
The purpose of this paper was to begin development of an assessment and
management framework for directed fisheries on Humpback Shrimp.
The
Subcommittee agreed that the recommendations in the paper should be more focused.
There are three main management options, each requiring different types of
assessment, which should be more clearly defined in the text, 1) Fixed exploitation
(quota), using fishery independent information, 2) Fixed exploitation using CPUE from
fishery dependent information, and 3) fixed escapement, for example a spawner index.
The first is applicable for use in both trap and trawl fisheries, while the other two are only
applicable for use in trap fisheries.
One of the reviewers noted that the
recommendations could be better presented in stepwise statements or in a flow chart of
decision rules depending on type of gear being fished and area where the fishery takes
place. The authors agreed that some further clarification of the recommendations was
required.
The Subcommittee discussed applying the Drury Inlet findings to existing humpback
fishery areas, until area specific data are collected.
The biological parameters
measured in Drury Inlet would be a useful starting point as the assessment was
conservative, and the parameters identified are within the range identified for shrimp
trawl in other areas of B.C. The Subcommittee recognized that care should be taken
when applying the results in other areas.
Conclusions
The Subcommittee recognized that utilizing historical logbook data, with criteria such as
a minimum catch (in this case >1000 kg) and dominant species (humpbacks greatest %
of catch), is appropriate for determining areas of directed humpback fisheries. Other
sources of information are also available and should be explored.
The Subcommittee recognized that there are a number of ways to manage and assess
humpback shrimp fisheries, and concurred with using an F-based target reference point
for trap and trawl fisheries. In addition, fixed exploitation based on in-season CPUE
estimates or spawner index can be used for trap fisheries.
12
The biological parameters derived from the Drury Inlet study should be utilized to
manage new and existing humpback fisheries, until area-specific data can be collected.
The Subcommittee concluded that the assessment methodologies and management
options are acceptable, and must take into account gear type and location.
The Subcommittee recognized that the by-catch from trawl gear was greater and more
diverse than from trap gear in Drury Inlet, however it should be noted that quantity and
diversity of by-catch is area and gear specific.
The Subcommittee recognized that surveys designed to assess shrimp biomass should
be done using trawl and trap gear.
The trap gear was more selective for large shrimp compared with trawl gear. This is an
important consideration while assessing growth over fishing or measuring the impact of
the fishery on the population structure.
Recommendations
The Subcommittee recommended that the paper be accepted subject to revisions.
1. The Subcommittee recommended that the framework proposed for the assessment
and management of a humpback shrimp fishery be accepted.
2. The Subcommittee recommended that the proposed framework be applied to any
new or existing areas of directed humpback shrimp fisheries.
3. The Subcommittee recommended that area-specific biological parameters be
collected as per the proposed methodologies and framework. The biological
parameters from Drury Inlet should be used, while area-specific data are collected.
I2002-04: Sea Cucumber quotas based on British Columbia survey data
S. Campagna and C. Hand **Accepted subject to revisions**
Rapporteur: Russell Mylchreest
The authors describe the survey methodologies and results, and the analytical
techniques used to calculate quotas for the giant red sea cucumber Parastichopus
californicus. The paper is a good start to improve the initial assumptions in adaptive
management. With some clarification this paper will be a useful documentation of
recommendations and concerns regarding the sea cucumber fishery.
13
Discussion occurred on the concept of surveying all areas open to harvest vs the
benefits of re-surveying areas to assess fishery impacts. The authors pointed out that
there are limited resources and therefore a need for an assessment framework to define
the priorities for survey activities. Consideration should be given to conducting regular
surveys in experimental areas. This would help evaluate trends in the areas open to the
fishery.
The estimation of mean sea cucumber weight was discussed and it was agreed that
further investigation should compare weights from surveys and weights from market
samples to determine if there are significant differences. Also sampling methods
employed by port validators should be reviewed to address possible biases in
sampling.
One reviewer’s suggestion of calculating true density (number of animals per area)
instead of number of animals per metre of shoreline was discussed and it was agreed
that such investigation should be pursued before effort is put into a re-calculation of
shoreline length from digital CHS charts. The use of mean cucumber density (per m2)
data might be used to evaluate density needs for successful spawning and possibly
used as a threshold for commercial fishing. Any changes to stock assessments using
this new method would be reviewed by PSARC. The possibility of using logbook and
CPUE information to help extrapolate densities to unsurveyed areas should be
investigated.
Conclusions
The Subcommittee felt that exploration of alternative calculations of density might be
worthwhile. For example, the density data would allow a calculation of true density
(cucumbers per m2) and an estimate of area might be developed with area
measurements.
The new baseline density of 5.08 c/m-shoreline is regarded as conservative, but the
rationale for application to unsurveyed areas should be expanded.
The Subcommittee felt that the potential biases in utilizing the market weights vs. survey
weights, need to be investigated.
It was noted by the Subcommittee that the new digitized CHS charts now utilized in a
number of fisheries still require the PFMA boundaries to be correctly mapped on them.
Recommendations
The Subcommittee accepted the paper with revisions.
1. The Subcommittee recommended that open PFMA’s should be grouped into three
categories – surveyed, unsurveyed good habitat, and unsurveyed areas of concern
14
(suspected poor habitat or over harvested) - to assign density estimates. The lower
90% CI of density from the survey is recommended for surveyed areas. The new
baseline density estimate of 5.08 sea cucumbers per metre of shoreline (c/m-sh) is
recommended for unsurveyed areas with good habitat. The original density
estimates of 2.5 c/m-sh. is recommended for unsurveyed areas of concern.
2. The Subcommittee recommended removal of shoreline from obvious closed or unfishable areas (e.g. conservation areas, lagoons, other closures) from shoreline
calculations.
3. To prevent localized overharvesting, the Subcommittee recommended assigning
and managing quotas at the finest possible geographic scale.
4. The Subcommittee recommended that research is required on the appropriateness
of using area vs. shoreline length in quota calculations.
5. The Subcommittee recommended that PFMA boundaries need to be correctly
mapped to new digitized CHS charts.
6. The Subcommittee recommended that the potential biases in the mean weight
estimates need to be examined, including comparison of the weights from dive
surveys and the commercial harvest sampling programs be investigated prior to
setting quota options for the 2003 fishery.
I2002-05: Geoduck stock assessment framework in British Columbia
C.M. Hand **Accepted subject to revisions**
Rapporteur: Guy Parker
This paper reviews the current stock assessment approach for geoducks in the
Department’s Pacific Region. The paper discusses the present assessment approach,
and the associated uncertainties.
The Subcommittee discussed some shortfalls and issues not considered in the paper.
Some areas of the coast have large discrepancies between estimated biomass and the
biomass as perceived by the industry (especially on the west coast of Vancouver Island
and Inside south coast waters). As well, the predation mortality by the expanding
populations of sea otters is unassessed but reported to be significant, again particularly
on the WCVI. Therefore, the safety nets in place are less of a reassurance and this may
lead to the necessity for more conservative management.
There was also discussion on size selectivity and whether there was harvest preference
in the fishery for larger animals.
15
Conclusions
The Subcommittee noted that an assessment framework is a work in progress and that
this paper is intended as the first step. There are some areas of the coast that have
large discrepancies in the estimated biomass and the biomass perceived by the
industry. These areas should be priorities for re-assessment/survey, and may help to
understand the uncertainties and assumptions in the present process.
The Subcommittee noted that the practice of extrapolating densities to other unsurveyed
beds for quota calculation is based presently on proximity, and that other approaches
based on individual bed properties should be investigated. The Subcommittee also felt
that the show factors may not be necessary for some areas of the coast and that further
work will be required to assess their value.
It was noted that there had been a shift in fishing harvest effort and licences to the North
Coast region in recent years. North Coast areas have been fished slightly higher than
the mean quota option to accommodate the re-allocation of licences from the West
Coast. This reflects a greater confidence in North Coast biomass estimates. The
Subcommittee noted that the lower 10% error in area has been confirmed by the
analysis for the North Coast by onsite analysis. However, for the South Coast the
anecdotal information suggests the uncertainty is much greater and the error may be
much greater than 10%.
The Subcommittee felt that future biomass estimates in some areas of the coast need to
incorporate sea otter impacts. It was noted that this framework does not apply to areas
impacted by sea otters.
Recommendations
The Subcommittee accepted the paper subject to minor revisions.
1. The Subcommittee recommended putting a high priority on resolving inaccuracies in
bed area estimates.
2. The Subcommittee recommended discontinuing the use of a positive error on bed
area estimates until further review.
3. The Subcommittee recommended reviewing the use of show factor plots to correct
survey density estimates.
4. The Subcommittee recommended investigating the issue of size selectivity in the
fishery as it relates to bias in mean individual geoduck weight estimates.
5. The Subcommittee recommended re-examining parameter estimates for yield
models to determine more site specific exploitation rates.
16
6. The Subcommittee recommended continuing to work towards other approaches
based on individual bed properties for extrapolating density estimates on geoduck
beds.
7. The Subcommittee recommended considering areas of concern, regarding overexploitation or large discrepancies in the assessments, for future study and surveys.
8. The Subcommittee recommended taking into account in future assessment
frameworks, factors that include minimal densities, oceanography, recruitment and
mortality factors such as sea otter predation.
I2002-06: Survey protocol for the removal of allowable numbers of northern
abalone, Haliotis kamtschatkana, from areas in British Columbia for use as
broodstock in aquaculture
J. Lessard, A. Campbell, W. Hajas **Accepted subject to revisions**
Rapporteur: Erin Wylie
The paper provides a precautionary framework and protocols to collect and return
abalone, from areas of B.C., for use as broodstock in aquaculture. The Subcommittee
discussed the use of minimum distance between sites to prevent removals targeting on
abalone aggregations in one area and felt that DFO should approve site selection and
transect locations.
The Subcommittee recognized that the 90% CI of density estimates was an arbitrary
value. The Subcommittee accepted that the 90% CI be used and if a more precautionary
approach is required then the 1% harvest rate could be lowered.
The Subcommittee noted that no broodstock has been returned to the wild to date and
that there may be disease implications associated with transplants.
The Subcommittee noted that collections to date have been predominantly female. The
total number of females from any given sit must not exceed 50% of the recommended
removals. The Subcommittee discussed the lack of protocol for hatchery practices and
its implications to mortality, genetic diversity and disease and the subsequent out
planting of hatchery reared abalone. It was noted that a genetic paper was reviewed by
PSARC which suggested that the number of abalone broodstock used to produce
larvae or juveniles for out-planting to the wild should be at least 50 and preferably 100,
with equal numbers of males and females, in order to maintain genetic diversity in the
enhanced population.
There was also discussion around what the minimum density should be in order to allow
collections. It was pointed out that perhaps abalone populations with higher densities
17
should be left alone as they may be more likely to have reproductive success than
populations with lower densities.
Conclusions
The Subcommittee recognized that the current culture facilities are in the developmental
stage their culture techniques are still being refined. Consideration of genetics, disease
and productivity should be incorporated into the overall program.
The Subcommittee felt that there was a need to limit the number of females being
collected at any one site to half the total allowable removals and a minimum of 2 sites
over several locations. The Subcommittee found that broodstock collection protocol of
1% of the lower 90% CI of the surveyed available 80 to 120 mm abalone was a
conservative approach and if a more precautionary approach is required then the 1%
harvest rate could be lowered.
Recommendations
The Subcommittee accepted the paper with revisions.
1. The Subcommittee endorsed the estimate of allowable removals as the lower 90%
confidence interval of the 80-120 mm SL density estimate and a 1% removal rate.
2. The Subcommittee recommended acceptance of the survey protocol with the
addition that DFO needs to approve the site and transect locations, as well as the
number of animals and sex ratio to be removed. It was also recommended that
broodstock collections for a project should come from a minimum of 2 sites.
3. The Subcommittee recommended review of the present genetics practices in culture
facilities against the previously published papers.
I2002-07: A review of the biology of opal squid (Loligo opalescens Berry), and of
selected loliginid fisheries
L.C. Walthers and G.E. Gillespie **Accepted subject to revisions**
Rapporteur: Dan Clark
This paper reviews the biology, behaviour and ecology of loliginid squids. It reviews the
assessment and management of fisheries for loliginid squid and provides a focus for
discussion of current issues relating to B.C. opal squid fisheries. The B. C. opal squid
fishery is currently in an undeveloped state, with fewer than 15 licences issued in each of
the last three years, and fewer than five vessels reporting activity in any of those years.
The catch is sold as bait or utilized by the catching vessel as bait for other fishing
activity. Biological information and stock assessment methods are extremely limited.
18
While some precautionary management measures are currently in place (gear
restrictions and permanent area closures), neither of these can address possible
overfishing if effort in the fishery increases or market conditions change and a food
market is developed.
Opal squid are relatively small (smaller than in California), have low fecundity (10,000
eggs per female), are terminal spawners, and the population size fluctuates widely,
presumably influenced by environmental variables. Fishing occurs on spawning
aggregations using deck lights, small mesh seines, jigs, and sometimes dip and
lampara nets. It is not known if the inability of fishers to repeatedly locate spawning
stocks large enough to fish is due to variation in abundance or to differences in
spawning distribution between years. The problem of assessing the stock structure and
movements results in an inability to predict effects of localized overfishing.
The paper highlighted the following strategies to fishery managers:
1. Status quo. This option entails relatively high risk due to poor quality of data used to
monitor the fishery and potential for uncontrolled expansion should market conditions
change.
2. Active development and promotion of an opal squid fishery. This would require:
development of the food market potential (in competition with other world-wide
sources of squid) as opposed to a primary use as bait; development of assessment
and management frameworks, and requirements for fiscal support of assessment
and management from a fishery association.
3. Status quo with limits to effort increases. This option could maintain potential effort
at levels that minimize risk of overharvest and improve fishery-dependent data to
monitor the fishery. This option could range from measures to limit increases in
fishing power of existing licences, and only allow new licences, if sufficient
assessment and management frameworks are developed.
4. Close the fishery. Managers may decide that costs of developing assessment and
management frameworks exceed current and/or future economic returns of the
fishery.
The Subcommittee also discussed implications of harvesting a forage species and
noted that this is a bait fishery, not a fishery for human food, and DFO guidelines rank
bait fisheries lower than human food fishery in importance and desirability.
Conclusions
This is an unlimited fishery with no assessment, little management and poor data. The
Subcommittee felt that the fishery could be allowed to continue at current levels without
an undue conservation risk. Any increase in catch or effort should occur under the New
Emerging Fisheries Policy guidelines.
19
Recognizing the forage fish role of opal squid in the ecosystem, any development of the
fishery should take into account the anticipated forage fish policy.
The Subcommittee agreed that the management strategies presented in the paper
represent the range of strategies available and that an assessment and management
framework would need to be developed depending on the final strategies chosen.
Recommendations
The Subcommittee accepted the paper subject to revisions.
1. The Subcommittee recommended that there should be no increase in effort or
landings (for example from the 10 year average of fishing days and the best estimate
of catch) in the B.C. opal squid fisheries until stock assessment and management
frameworks are developed.
2. The Subcommittee recommended that any development of B.C. opal squid fisheries
occur within the context of the New Emerging Fisheries Policy. Any expansion
should be through phased development of the fishery and dependent on
development of essential fisheries information and assessment and management
frameworks.
3. The Subcommittee recommended evaluating the ecosystem impacts of opal squid
fisheries and the implications concerning this species as a forage species.
4. The Subcommittee recommended that DFO needs to ensure that log books and fish
slip reporting requirements are adhered to in order to improve data quality used in
the assessment of the fishery.
Stock Status Reports
Three stock status reports were reviewed and approved by the Subcommittee:
Humpback Shrimp, Giant Red Sea Cucumber and Coonstripe Shrimp. Once reviewed
and approved these stock status reports will be forwarded to the PSARC Secretariat for
publication in the usual manner.
20
APPENDIX 1: Working Paper Summaries
I2002-01: A Phase ‘0’ review of the biology and fisheries potential of the marine
gastropods Astreaea gibberosa, Euspira lewisii, Fusitriton oegonensis, Nucella
lamellosa, and deep water snails of the family Buccinidae
K.E. Charles and R. Harbo
The marine gastropods under review belong to very diverse groups in not only different
families, but in entirely different orders. In all, five groups or species have been selected
for review. These are the species Fusitriton oregonensis, Euspira lewisii, Astraea
gibberosa, Nucella lamellosa, Neptunea spp. and Buccinum spp. Of these, snails of
the F. Buccinidae are actively fished in the North Atlantic, and have been historically
fished in Alaska. A conspecific of the Red Turban, Astraea gibberosa, the Wavy Turban
Snail, A.undosa, is experiencing directed fisheries in Baja California as well as in the
State of California. Moon snails, Euspira lewisii are only harvested recreationally.
There are no accounts of directed fisheries on Fusitriton oregonensis or Nucella
lamellosa or any conspecifics.
A summary of the biology of these five groups has been presented. In some cases,
there is so much information that much was left out; in other cases virtually no information
is available. A summary of the biological information required to effectively manage
these fisheries is presented, as well as recommended studies, prior to development of a
fishery.
Toxins in northern marine gastropods are discussed, including symptoms of poisoning,
regulating agencies, and toxic species.
A review of active gastropod fisheries of the Pacific United States and British Columbia
is presented, with reference to commercial, recreational, and historical aboriginal
fisheries. A selection of active gastropod fisheries throughout the world is presented,
with particular biological or management problems and solutions highlighted.
Management strategies include area and seasonal closures, size limits, gear
restrictions, prohibition of harvest of some species, limited licensing and area licensing,
and quotas. There may be biological, habitat, assessment or management reasons why
a species may not be a suitable candidate for commercial exploitation.
The authors consider that the costs of collecting the required biological information for
stock assessment and developing management strategies may be prohibitive. The
consideration of a new gastropod fishery should be considered in a priority setting
exercise.
21
I2002-02: Evaluation of an intensive fishery on Dungeness Crab, Cancer
magister, in Fraser Delta, British Columbia
Z. Zhang, W. Hajas, A. Phillips, J.A. Boutillier
The Dungeness crab fishery in British Columbia has been passively managed through
sex and size limits. Only male crabs larger than or equal to 155 mm in carapace width
may be harvested. The fishery is intensive with exploitation rates well over 90% in the
Fraser Delta. The paper attempts to address three specific concerns: (1) is there a
recruitment problem? (2) what is the impact of intensive fishing on yield and profit? (3)
what scientific criteria could managers use to close the fishery?
To address the first concern, we examined the time-series (1995-2000) data on catch
rates for sub-legal crabs. There is no strong evidence that small crabs are becoming
less abundant. However, the time-series is short and we (the authors) don't know the
recruitment status before the intensive fishing, which has existed for a long time. Thus, it
is unknown whether recruitment will increase, if exploitation rate decreases. The impact
of intensive fishing on recruitment is yet to be determined.
To address the second concern, we used a length-based and an instar-based models to
generate biological reference points to be used for managing the fishery. We calculated
yield, revenue and profit per recruit, after some important biological parameters, such as
natural mortality rate, vulnerability of different sized crabs to traps, probability of
moulting, survival rate for newly moulted crabs, were estimated based on scientific
surveys in the Vancouver Harbour. An intensive fishing also results in a great deal of
catch-and-release of sub-legal sized crabs. Continuing fishing at a high ratio of sub-legal
to legal sized crabs in the catch will result in a net loss in yield in the long-term, as some
sub-legal sized crabs will die of handling mortality and could not contribute to the future
yield. We conducted analyses on gain-or-loss in yield for continuing fishing at different
ratios of sub-legal to legal crabs in the catch to determine threshold points, at which gain
is balanced with loss in yield in the long term. To avoid losing yield in the long term, the
ratio of sub-legal to legal crabs in the catch should not be allowed to rise above 19:1,
9.5:1, 6.5:1 or 5:1, if the handling mortality rate is, respectively, 5%, 10%, 15%, or 20%.
We provide the following recommendations to the managers based on these analyses:
(1) The current exploitation rate (> 90%) should be reduced to 65-75%. A level of
reduction in CPUE relative to the CPUE at the beginning of the fishery could be used
to determine when to close the fishery.
(2) A ratio of retained crabs to discards should be used as a means of limiting effort and
protecting stocks in conjunction with using CPUE measures, or in fisheries where it
is difficult to use CPUE because of protracted moulting seasons or.
(3) Efforts should be made to reduce the negative handling impacts. Tools may include
longer soak times, earlier closure of the fishery or adjustment of the fishing season.
22
(4) Industry, management and science should use these models to assist in assessing
the impact of intensive fishing on population dynamics, economic and social benefits for
each fishery and in finding optimal management and assessment schemes.
I2002-03: Pandalus hypsinotus, Humpback shrimp: An assessment and
management framework for directed fisheries based on results from Drury Inlet
Humpback Shrimp Research Program
J.S. Dunham, J.A. Boutillier, D. Rutherford, K. Fong
To develop a biological basis for managing recruitment overfishing in humpback shrimp
fisheries, a humpback shrimp population in Drury Inlet was extensively surveyed by
Shellfish Stock Assessment (StAD) in November 2001 and March 2002 with trawl and
trap fishing gear. Aspects of humpback shrimp biology, including age structure, sex
stage changes over time, natural mortality, and fecundity, were studied. Age 1 shrimp
constituted 58-66% of the population, age 3 shrimp 3-8% of the population.
Approximately 32% of the shrimp were females. Humpback shrimp experienced high
natural mortality (M=2.0). Mean fecundity was 880 eggs per female. Larger, older
female shrimp typically produced a greater number of eggs than smaller, younger
shrimp.
Trap gear, unlike trawl gear, collected proportions of the sexual stages of shrimp that
were biased towards larger older females and did not reflect true population
proportions. Smaller mesh traps collected more small shrimp (males and transitionals).
Trap CPUE estimates derived using age and sex ratios were more variable, and
consequently more useful to managers, than CPUE estimates derived using weight.
To manage recruitment overfishing in trawl and trap fisheries using a fixed exploitation
rate, tow and trap gear are required to accurately estimate shrimp density and biomass
because trap catches in untrawled areas influence overall estimates. Reference Points
(RPs), including Target Reference Points (TRPs) and Limit Reference Points (LRPs),
were determined for trawl and trap fisheries using fishery independent (based on
biomass estimates) and fishery dependent (based on commercial CPUE estimates)
data. Constant harvest rates were used to derive the TRPs, the MSY equation used to
derive the LRPs. Empirical equations, that are useful for data limited fisheries and were
examined in this paper, include biomass dynamic models, Maximum Constant Yield
(MCY), and Annual Yield.
To manage recruitment overfishing in a trap fishery using a fixed escapement target,
monthly TRPs were derived using the MSY equation; monthly LRPs were derived using
shrimp egg production estimates and the natural mortality rate. Results of the spawner
indices indicate that 11-20 female spawners per trap should remain unrecruited to the
fishery in March.
23
Trawl gear by-catch consisted mainly of eelpouts, shiner perch, herring and spiny pink
shrimp. Trap gear by-catch consisted of sea stars, red rock crabs, graceful crabs and
prawns. Trap by-catch was higher in rocky compared to trawlable areas. Small mesh,
compared to large mesh traps, collected higher numbers of by-catch species. Trawl
gear not only collected different animals than trap gear, but greater numbers of them as
well.
Directed humpback shrimp trawl and trap fisheries presently occur throughout the B.C.
coast, in Areas 1, 3, 4, 5, 6, 12, and 13. Recommendations regarding how to manage
recruitment overfishing in directed humpback shrimp fisheries using a fixed exploitation
rate and a fixed escapement target are provided.
I2002-04: Sea Cucumber quotas based on British Columbia survey data
S. Campagna and C. Hand
The sea cucumber fishery has been managed using precautionary quotas based on
conservative estimates of density from surveys conducted in Alaska using a baseline
density of 2.5 c/m-sh. Since 1998, seven dive surveys have been conducted in six open
fishery areas of B.C. Over 2,500 km of shoreline, or 30% of the area that is designated
as commercial has been surveyed. Sufficient data exists to calculate quotas for the
commercial fishery from B.C. surveys. Currently 98 PFMAs (Pacific Fisheries
Management Areas), or 25% of the shoreline, are open to sea cucumber harvest.
This paper provides survey results and density estimates derived from these survey data
sets and are extrapolated to unsurveyed open fishery areas. The parameters and
procedures employed in the calculation of the quotas are documented. Mean weights
are re-evaluated for all open areas using the market sampling data. New quotas are
calculated for all open areas.
Survey results showed that the lower 90%CI of density estimates is higher than the
baseline density of 2.5 c/m-sh. Shoreline reduction for the surveys ranged from 0 to
45%, averaging 13%. New estimates of mean weights resulted in a mean weight
increase for 56 PFMAs, decrease in 22 PFMAs and 17 PFMAs had no new data,
existing mean weight were used.
The authors recommend grouping the PFMAs into three categories to assign density
estimates. The surveyed PFMAs are assigned the lower 90% CI of density estimates
calculated during the survey. The new baseline density of 5.08 c/m-sh, the minimum of
the lower 90% CI of density estimates is recommended for most unsurveyed PFMAs. A
third category including PFMAs with exposed shoreline or history of low stock would
keep the baseline density of 2.5 c/m-sh. New quotas would be higher in nearly all
Pacific Fisheries Management Areas with the exception of PFMA 13, resulting in an
overall increase in quota of 206.8 tonnes coast wide.
24
I2002-05: Geoduck Stock Assessment Framework in British Columbia
C. Hand
A stock assessment framework for the provision of biomass estimates in a quotamanaged geoduck fishery is presented. While quota options are provided to managers
for each of the approximate 1,500 geoduck beds on the B.C. coast, there is a high
degree of uncertainty in these estimates. This framework was driven by the need to
examine the sources of uncertainty in the parameter estimates necessary for biomass
calculation and to prioritize data analysis and future data collection for more effective
stock assessment.
Through collaboration with resource stakeholders, a large amount of fishery-dependent
and fishery-independent data have accumulated, particularly in the last decade. The
methods used to collect and analyze data on geoduck density, mean weight and
geoduck bed area are described, and the errors, biases and assumptions discussed.
Geoduck bed area is identified as the parameter with the most uncertainty and is
recommended as the highest priority to resolve. Current methods of extrapolating
density estimates to unsurveyed geoduck beds assumes that populations that are closer
are more similar than those more distant. It is recommended that more spatially-explicit
approaches be used for extrapolation that utilize all of the available information on geophysical properties of the geoduck bed and the associated characteristics of the
populations within them.
I2002-06: Survey protocol for the removal of allowable numbers of northern
abalone, Haliotis kamtschatkana, from areas in British Columbia for use as
broodstock in aquaculture
J. Lessard, A. Campbell, W. Hajas
A survey protocol and methodology to determine abalone abundance has been in use
for the last three years. The present paper reviews the data collected during 6 surveys
for broodstock purposes and uses these data to determine the appropriate level of
removal. The proposed survey protocol and broodstock removal considerations are
discussed.
These surveys provided little evidence of recovery of abalone populations. During
abalone broodstock collections, more abalone were harvested than was calculated
present at several sites.
A precautionary approach is recommended that include using the lower 90% confidence
interval of the mean of the mature population estimate (81-120 mm shell length) when
calculating the potential number of abalone (i.e., < 1 % of estimated population) to be
removed for broodstock. Abalone is a threatened species and all removal of abalone
from the wild should be minimized.
25
I2002-07: A review of the biology of opal squid (Loligo opalescens Berry), and of
selected loliginid fisheries
L.C. Walthers and G.E. Gillespie
Opal squid are relatively small, short-lived squids that are found only on the west coast of
North America, from Baja California to southeastern Alaska. They are most abundant
off California, where they are the basis of a large fishery worth US $20-30 million
annually. They live approximately 1 year and are terminal spawners, and the squid are
fished while aggregated for mass spawning. The distribution, biology, abundance and
ecology of opal squid in British Columbia is not well known, although they have been a
minor bait fishery for decades.
Opal squid are particularly difficult to assess and manage because of their short life
span. Stock-recruit relationships are weak, and likely driven by environmental
conditions. Abundance, distribution and movements not known, in part because opal
squid are small and highly motile, evading sampling gear traditionally used in surveys for
other species. Age can be determined using statoliths, but it is a time-consuming,
specialized process that makes the use of ages in routine assessments too expensive.
Protracted spawning and differing growth rates within an annual cohort make use of
length-based methods very difficult. The State of California recently spent millions of
dollars over three years to develop recommendations for research and assessment and
a proposed management plan for the species.
The opal squid fishery in British Columbia is managed through gear restrictions, hail
requirements to open areas for fishing and catch monitoring. Number of licences
issued, effort and landings have all declined since the mid-1990’s, to the point where
coast-wide landings data cannot be released publicly because fewer then three vessels
submit records. Primary management concerns are quality of catch monitoring, bycatch
concerns and adverse impacts of gear on habitat. Opal squid are the last remaining
commercial invertebrate fishery that has unlimited licence issue; there are no proactive
controls in place to check expansion of the fishery should market demand change.
Several options are suggested to managers: status quo, active development of the
fishery (with associated assessment and management frameworks), licence limitation,
or complete closure of the fishery in the absence of assessment and management
frameworks. Recommendations presented were: the fishery should not be allowed to
expand in the absence of assessment and management frameworks, development of
the fishery should be in context of the policy for New and Developing Fisheries, and that
the ecosystem impacts of fisheries development should be considered.
26
APPENDIX 2: PSARC Invertebrate Subcommittee Meeting Agenda
November 25-28, 2002
Seminar Room, Pacific Biological Station, Nanaimo, B.C.
25 November
26 November
27 November
28 November
Monday
Tuesday
Wednesday
Thursday
Start 1300
Start 0900
Start 0900
Start 0900
Introductions and Procedures
Introductions and
Procedures
Previous days
unfinished business
AM 1
I2001-06
Survey protocol for the removal
of allowable numbers of the
northern abalone, Haliotis
kamtschatkana for broodstock
in aquaculture
I2002-04
Sea cucumber quotas
based on B.C. survey
data.
Sea Cucumber SSR
Rapporteur’s Reports
Day 3
Finalize committee
report.
Break
AM 2
I2001-05
I2002- 07
Geoduck Stock Assessment
Framework in B.C.
A review of the biology of
opal squid (Loligo
opalescens Berry), and of
selected loliginid fisheries
I2002-01
Coonstripe Shrimp SSR
Lunch
PM 1
Introductions and
Procedures
I2002-02
Phase ‘0’ review of the biology
and fisheries potential of
marine gastropods and deep
water snails.
Rapporteur’s Reports Day
2
Evaluation of an Intensive
Fishery on Dungeness
Crab, Cancer magister, in
Fraser Delta, B.C.
Break
PM 2
I2002-03
Rapporteur’s Reports
Pandalus hypsinotus,
humpback shrimp.
Day 1
Emerging Issues and
Committee
recommendations
An assessment and
management framework
for directed Fisheries
Humpback Shrimp SSR
27
Working Papers for
June 2003
APPENDIX 3: List of Attendees & Reviewers
Subcommittee Chair:
PSARC Chair:
DFO Participants
Kim West
Al Cass
Mon. Tues.
Wed. Thurs.
* Subcommittee Members
L. Barton
J. Boutillier*
B. Bornhold*
D. Bureau
4
4
S. Campagna
A. Campbell*
4
A. Cass (PSARC Chair)
D. Clark
4
L. Convey
J. Dunham
K. Fong
G. Gillespie*
W. Hajas
C. Hand*
R. Harbo*
4
4
4
4
4
4
S. Heizer
4
4
4
4
4
4
4
4
4
4
4
4
4
R. Lauzier*
J. Lessard
J. Morrison
R. Mylchreest*
H. Nguyen
G. Parker*
I. Perry*
A. Phillips
J. Rogers*
D. Rutherford
4
4
4
4
4
4
4
4
4
4
4
D. Tzotzos
B. Waddell
L. Walthers
R. Webb
K. West* (Chair)
E. Wylie
Z. Zhang
4
4
4
4
4
4
4
4
4
4pm
4
4
4
4
T. Johansson
B. Koke*
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
28
4am
4am
4
4
4
4
4
External Participants:
B. Heath* (B.C. Ministry of Fisheries)
Mon.
Tues.
Wed.
H. Holmes (Pacific Rim National Park)
4
4
4
4
Mon.
Tues.
Wed.
4
4
4
Observers:
T. Norgard (Heiltsuk Fisheries)
L. Clayton (Pacific Coast Shrimpers
Coop.)
G. Dovey (Underwater Harvesters
Assoc.)
K. Erikson (Pro Quota Group)
K. Ridgeway (Pacific Sea Cucumber
Assoc.)
R. Sam (Penelakut Tribe)
S. Wood (Pacific Sea Cucumber
Assoc.)
Thurs.
4
4
4pm
4
4
4
4
4
G. Krause
T. Kulchynski (Cowichan Tribes)
G. LaBoucan (Cowichan Tribes)
T. Norgard (TNBC Consulting)
Y. Page
Thurs.
4
4
4
4
4
4
4
Reviewers for the PSARC papers presented at this meeting are listed below, in
alphabetical order. Their assistance is invaluable in making the PSARC process work.
Fu, C.
Hebert, K.
Love, D.
Morrison, J.
Olsen, N.
Perry, I.
Rothaus, D.
Rusch, B.
Rutherford, D.
Sizemore, B.
Sloan, N.
Winther, I.
Zheng, J.
Fisheries and Oceans Canada
Alaska Department of Fish and Game
Alaska Department of Fish and Game
Fisheries and Oceans Canada
Fisheries and Oceans Canada
Fisheries and Oceans Canada
Washington Department of Fish and
Game
Fisheries and Oceans Canada
Fisheries and Oceans Canada
Washington Department of Fish and
Game
Gwaii Haanas National Reserve
Fisheries and Oceans Canada
Alaska Department of Fish and Game
29
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