Table of Contents:

A. Agency Overview

B. Multispecies studies

C. By species

D. Other related studies

Appendix 1. Review of Canadian Groundfish Fisheries

Appendix 2. Reports published

Appendix 3. Staff

REVIEW OF AGENCY GROUNDFISH RESEARCH, STOCK ASSESSMENT AND MANAGEMENT

A. Agency overview

Fisheries and Oceans Canada (FOC), Science Branch, operates three facilities in the Pacific Region: the Pacific Biological Station (PBS), the Institute of Ocean Sciences (IOS) and the West Vancouver Laboratory (WVL). These facilities are located in Nanaimo, Sidney and North Vancouver, B.C., respectively. Division Heads at these facilities report to the Regional Director of Science (RDS). Personnel changes within the Region Science Branch in 1998 include the appointments of Dr. Laura Richards as the Acting RDS and Mr. Ron Kadowaki as the Acting Head of the Stock Assessment Division (STAD). The current Division Heads in Science Branch are:

Groundfish research and stock assessments are conducted primarily in two sections of the Stock Assessment Division, Fish Population Dynamics (Sandy McFarlane, Head) and Assessment Methods (Jeff Fargo, Head). The Assessment Methods Section includes the Fish Ageing Lab.

Management of groundfish resources is the responsibility of the Pacific Region Groundfish Coordinator (Ms. Marilyn Joyce) within the Fisheries Management Branch. Fishery Managers receive advice from STAD through the Pacific Scientific Advice Review Committee (PSARC, formerly the Pacific Stock Assessment Review Committee). The Chair of PSARC (Dr. Max Stocker) advises the Regional Management Committees on stock status and biological consequences of fisheries management actions and works in consultation with the Canadian Stock Assessment Secretariat (CSAS) in Ottawa.

A new Oceans Directorate within DFO was formed in 1998 to "lead the development and implementation of a national strategy for oceans management based on the principles of:

• sustainable development;
• integrated management of activities in estuaries, coastal and marine waters; and
• the precautionary approach".

The Oceans Strategy is defined by portions of the Ocean’s Act which include basic authorities for:

• the establishment of Marine Protected Areas;
• the establishment and enforcement of marine environmental quality guidelines, criteria and standards designed to conserve and protect ecosystem health; and
• the development of management plans, including integrated coastal zone management plans.

B. Multispecies studies

1. Globec Program

GLOBEC Canada is a collaborative program funded for four years jointly by NSERC (Research Partnerships) and DFO (Priority Allocations, A-base). The program sunsets in 2000 but proposals are under development for a second four year program. The collaboration involves fifty scientists from seven universities (Memorial, Dalhousie, Laval, UQAR, Queen's, UBC and UVic), five government laboratories (NAFC, BIO, IML, IOS and PBS). Strong links exist with other national programs, e.g. in the US and Norway, and with the developing GLOBEC International effort.

GLOBEC Canada will examine how living marine resources are affected by variability of their physical environment. Marine ecosystems undergo large interannual to decadal fluctuations. These large swings affect almost every fishery, and are becoming equally apparent in time series of ocean climate and plankton indices. The multidisciplinary integration of field and modeling studies in GLOBEC Canada will increase this causal-level understanding. The relevance of GLOBEC includes, but is not limited to, climate change trends associated with global warming. A major focus will be naturally-forced interannual to interdecadal fluctuations and their effects on target populations through recruitment variability of individual species and changes in overall community structure. Simultaneous research programs are proposed for Atlantic and Pacific coasts. The dual coast effort is justified by the need for national integration and the unique characteristics of the east and west coast ecosystems. Scientific themes shared by both coasts include:

• Importance of seasonality and timing match between critical physical and biological events (shifts in these are like to be among the strongest climate change signals).
• Amount and timing of freshwater inputs, and effects on physical mixing and transport patterns.
• Importance of advective coupling among mesoscale sub-regions and between the open ocean and continental margins.

Pacific Component

Pacific Ocean fish and zooplankton communities undergo large and ecologically/economically significant fluctuations over years to decades. Stock collapses and extreme failures of steady-state fisheries forecast models have tended to accompany major shifts in the marine climate. There is increasing evidence that these large changes in fishery yield are environmentally, rather than purely fishery harvest, driven. Although several important west coast fisheries are already managed using various proxy indices of ocean conditions (specific examples include Barkley Sound sockeye, Vancouver Island herring, sablefish, and hake), present indices are based on correlation’s with convenient proxy variables. They incorporate minimal verification through knowledge of the underlying mechanisms. Management indices based solely on hindcast correlation’s have a history of breaking down over time, either permanently or during specific oceanic events. Consequences are often severe: loss or major error of management advice, resulting in conservation and social crises and the loss of millions of dollars to the Canadian economy. What is needed to make the indices more reliable is understanding and quantification of the causal processes underlying the correlation’s.

The Pacific component will study interactions within a high nutrient and predominately pelagic ecosystem. The research will emphasize food web pathways leading to production of the most important (in commercial value and/or ecological impact) west coast finfish species: salmon, herring and hake. Target processes and species will include: alongshore and cross-shore advection, seasonal cycle of upwelling, horizontal currents and water mass boundaries (physical environment), euphausiids and copepods (zooplankton), and both adult and juvenile finfish. The conceptual model for the west coast GLOBEC program three advectively- and biologically-linked ecosystems operating at increasing spatial scales (west coast of Vancouver Island, central and north B.C. coasts, open NE Pacific Ocean). The three regions are highly interconnected. Each has important, seasonally variable, and physically-driven exchanges of nutrients and plankton with its surroundings. Each also contains large populations of migratory fish. In particular, Pacific salmon integrate, over the course of their life cycle, the consequences of ocean physical and biological processes occurring in both coastal and offshore regions.

Current projects funded by GLOBEC-CANADA are listed below and more details can be obtained for each project by visiting the GLOBEC-CANADA web site at www.globec-canada.mun.ca.

• Effects of Current Patterns on Primary Productivity and Zooplankton Biomass and Implications on Feeding Patterns of Larval Fish - Allen, Foreman, Harrison, Mackas, Perry, Thomson, and Whiticar
• Hindcast Models of Currents and Temperatures along the British Columbia Continental Margin - Crawford and Cummins
• Biophysical Modelling for the Western Continental Margin of Vancouver Island - Foreman, Ware, Thomson, and Harrison
• Sockeye Salmon Migration and Foraging Behaviours: Acoustic Tracking Experiments - Hawryshyn
• A coupled ocean general circulation and marine foodweb model of the subarctic Pacific - Hsieh and Denman
• Gulf of Alaska Zooplankton - McKinnell and Mackas
• State-of-the-Ocean Time Series - Pacific Continental Margin - Thomson, Mackas, Ware, Perry, Hargreaves, Harrison, Hyatt, McFarlane, Shaw, Stull, and Gower
• Zooplankton and Oceanographic Effects on Ocean Salmon Growth - Welch and Perry

C. By species

1. Pacific cod

i. Research programs

The P. cod assessments in areas of the BC outside Hecate Strait suffer from a general lack of information. The use of observer data in these assessments will be investigated in 1999, as will the potential use of industry-based surveys.

ii. Stock assessments

Assessment of the Hecate Strait Pacific cod abundance was conducted using MULTIFAN CL, a catch-at-length model that integrates length frequency and catch-age analysis. A new Pacific cod abundance index from the Hecate Strait flatfish survey was added to the assessment in 1998 and this greatly improved the precision of the recruitment estimates for the stock. The assessment indicates that stock biomass was at a historical low in 1994-96 and that there has been a slight increase in the past 2 years. Recruitment estimates are low with the last 9 year-classes being below the long-term average. This is the longest run of below average year-classes in the time series which dates back to 1956. Stock projections indicate that the stock will decline in the next 2 years. Given these forecasts it would be prudent to consider lower fishing mortality rates in the 1999-2000 fishing year.

No analyses were conducted for Pacific cod on the west coast of Vancouver Island because of a lack of biological samples from this stock in recent years. However, fishermen attending the assessment meeting expressed concern about Pacific cod abundance in this area and recommended closing the winter spawning area to fishing due to vulnerability of the spawning aggregations.

2a. Rockfish - offshore

Slope Rockfish

i. Research programs

There were no research surveys in 1998 and there are no plans for surveys in 1999.

ii. Stock assessment

For assessment purposes, slope rockfish include seven species: Pacific ocean perch, yellowmouth rockfish, redstripe rockfish, rougheye rockfish, shortspine/longspine thornyheads, and shortraker rockfish. These are managed within six major areas (3C, 3D, 5AB, 5CD, 5ES, 5EN), giving a total of 42 species-area combinations. Historically, these 42 assessment units have been managed with reference to a benchmark stock of Pacific ocean perch in Area 5AB. A catch-at-age analysis of this stock occupied a central role in the assessment. This assessment differs from past reports in three principal respects:

1. We use a new trawl observer database to examine abundance ratios among species and areas.
2. We use information gathered from experienced members of the industry, and we record some of their concerns.
3. We do not include a new catch-at-age analysis of the benchmark stock. No new data are available to alter substantially the 1997 analysis.

As preparation for this report, we have created a networked client-server database for the trawl observer data (item A), and we have held meetings with industry to incorporate fishermen’s knowledge directly into our analysis (item B).

We demonstrated that the new database offers much information about the trawl fishery in each of the 42 assessment units. Major conclusions from our analysis include the following:

1. As stated by industry members, CPUE varies substantially with depth. Spatial stratification can be used to qualify tows by depth in each assessment unit. (Fig. 1).
2. Commercial slope rockfish tows that occur in similar times and places as research survey tows give similar profiles of CPUE in relation to depth, as least according to limited data currently available.
3. Analysis of heavily fished blocks shows little evidence of stock depletion, except possibly for the thornyhead species.
4. Industry abundance estimates conform more closely to recent yield and quota recommendations than to various indices computed here, based on effort qualification and spatial stratification (Table 1).

Recognizing the need for further analysis and lacking evidence for substantial change at this time, we recommend that the 1998 yield options be extended to 1999.

Table 1. Rank of twelve quantities in relation to abundance estimates from experienced fishermen. Closest agreement with industry opinion corresponds to the lowest score. The six most highly ranked quantities come directly from historical data. The remaining six quantities are computed from 1997 tow data in the observer database.

Figure 1. Depth ranges (25% to 75% quantiles) with the 50% quantile point for each assessment unit (species-area combination), based on 1997 observer data.

Shelf rockfish

i. Research Programs

Shelf rockfish research focussed on analysis of the acoustic data produced during the Jan-Feb widow rockfish acoustic cruise and preparation for the 1999 January cruise. The fish distribution, as shown in the acoustic signals from the 1998 cruise, was presented in 3-D imagery over a 2-D image of the bathymetry. The cruise was able to generate multiple images because the aggregation was surveyed 20 times, every two hours. The set of images was used to examine diel vertical and horizontal movement away from the shelf break.

The variance estimates for each of the surveys were developed using spatial analysis. Individual estimates were derived using specific variograms or a global variogram. The inferred CV based on analysis each suvey ranged around 10%. The actual observed CV among the 20 survey estimates was approximately 30%.

ii. Stock assessments

Total shelf rockfish landings were 7,800 t in 1997. Interim assessments were provided for silvergray, widow, yellowtail and canary rockfish. Recommendations for these species are unchanged from the previous year. The ranges for silvergray rockfish in PMFC Areas 3C+3D (Vancouver Island), 5A+5B (Queen Charlotte Sound), 5C+5D (Hecate Strait) and 5E (West Coast Vancouver Island) are 150-425 t, 350-700 t, 125-400 t, and 175-300 t, respectively. Recommended yield ranges for the canary rockfish stocks of Area 3C+3D and Area 5A+5B are unchanged at 350-525 t, and 200-400 t, respectively. The recommended coastwide yield range for widow rockfish is unchanged at 1,100-3,000 t.

The yield recommendation for the coastal yellowtail rockfish fishery (Areas 3D-5E) was 2,000-4,025 t. The yield recommendation for the yellowtail rockfish stock of PMFC Area 3C fishery (south Vancouver Island) is combined with the northern Washington fishery (Areas 3C-US and 3B) for a range of 1,100-2,400 t based on a re-assessment of the stock by U. S. biologists.

2b. ROCKFISH - inshore

i. Research programs

Industry funded programs

Since 1997, an annual allocation of 5% of the overall inshore rockfish TAC has been directed to fund research. A research program directed at the collection of biological samples and catch per unit effort (CPUE) data was initiated in September of 1997 and was continued in May of 1998. The primary intent of the program was to determine whether population age distribution and catch rate differs between two inshore rockfish populations harvested from locations designated as "heavily" fished and "lightly" fished. Chartered fishing vessels set standardized gear directed at catching yelloweye rockfish (Sebastes ruberrimus) and redbanded rockfish (S. babcocki) at locations off the north-western coast of Vancouver Island and the south-western Queen Charlotte Islands.

Collaborative research with the Washington Department of Fish and Wildlife in the southern Gulf Islands was conducted in July 1998. This joint project was proposed by DFO to assess the potential of habitat-based stock assessment methods for inshore rockfishes. For this project, each of seven study sites were subjected to three surveys:

• acoustic assessment of the seabed to classify and map seabed habitat types using QTC-View technology;
• video assessment of reef fishes to estimate density and size composition by seabed habitat type;
• commercial fishing to determine overall species compositions, catch rates and age/size composition of the catch.

The work attempts to identify, in a non-subjective manner (acoustics), physical habitat types and their associated densities of inshore rockfishes (video). By interpolating the seabed classification data and constructing seabed maps, inshore rockfish abundance and biomass within each study site may be estimated by seabed class using associated density and size information. The relationship between catch rate and species composition from the fishing survey and the habitat-based stock size estimates may also be determined. The methodology has application to stock assessment and the evaluation of marine protected areas.

Additionally, a side-scan sonar survey was conducted in three of the seven study sites. A comparison of the remote technologies for detection of seafloor "habitat" will be conducted using the video assessment for "groundtruthing".

Oceans Directorate funded programs

A three-year research program to investigate the temporal and spatial genetic biodiversity of two marine fish species that occur at Bowie Seamount was initiated in 1998. Bowie Seamount is located 180 km off the coast of northern B.C. and has been proposed as a pilot marine protected area. The two existing fisheries at Bowie Seamount are for sablefish and rockfishes. Genetic (DNA) libraries for yelloweye rockfish (S. ruberrimus) and sablefish (Anoplopoma fimbria) and primers for screening of 3 to 6 polymorphic loci in each species were developed. In 1999, DNA samples will be collected from Bowie Seamount and regions in the northern and southern coastal fishing area for both species to be used for genetic population surveys. The maintenance of genetic diversity is critical for the long-term survival of exploited marine organisms and the fisheries they support.

ii. Stock assessment and fishery management

The 1999 inshore rockfish stock assessment outlined a number of resource concerns. In B.C., biologists and managers are faced with several fundamental problems that include:

• unknown fishery removals (catch in major sectors poorly known, discard mortality);
• inability to limit removals across all fishing sectors
• extremely long rebuilding time from depressed population levels;
• data and management mismatched to the scale of depletion;
• lack of a time series of data under stable management actions;
• no precise, cost-effective means of estimating abundance.

Advice to managers included:

• reduce fishery removals from all sources, using catch restrictions and improved fishing practices;
• initiate a strategic planning process for assessment and management to include the Groundfish Management Unit, Stock Assessment Division, Recreational Fisheries Division, and industry representatives;
• consider closed areas as a management tactic to augment preservation of intact populations and to limit removals;
• improve estimates of fishery removals, including discard mortality.

1. Research programs

In 1998, cost-recovered funding was allocated to cover salaries, contracts and purchases for research projects that were approved by the Sablefish Finance Committee and the Science Branch of the Department of Fisheries (DFO) and Oceans. The committee consists of industry and DFO representatives whose mandate is to ensure that research is conducted in a cost-effective manner. Secondarily, the industry representatives have provided input regarding the direction of the proposed research.

Trap survey

A coastwide trap survey, including mainland inlets of the central coast were conducted during Oct/Nov. The goal of the surveys was to monitor the age composition of the population and to tag fish for studies of migration and abundance. The current form of the survey has been conducted annually since 1991. Sets were made at discrete depths (100fm intervals between 150 and 650 fm) at pre-selected stations. A total of 89 sets were made at 15 stations offshore and four inlet stations. A total of 22,004 fish were tagged and approximately 3500 fish were sampled for length, sex, maturity and otoliths collected for ageing.

Ageing method review

DFO has not conducted production ageing of sablefish since 1996. Poorer than average precision prompted re-examination of the break and burn method and ageing criteria being applied through examination of known-age and OTC injected fish. Some fish were recaptured up to 20 years after being injected with oxytetracyline (OTC). After 20 years the OTC mark is clear in most otoliths. Our examination of these otoliths confirmed that sablefish are long lived and grow slowly after maturity. Annuli that formed beyond the OTC mark could be difficult to interpret in broken and burnt sections. However, polished thin sections improved the clarity of annuli. Despite improved preparations, annuli in some sections were difficult to distinguish, resulting in annuli counts after the OTC mark that did not correspond exactly to the years at liberty of the recaptured fish. Further work to refine the revised technique is planned for 1999.

Climate and year-class success

It has recognized for some time that the production of strong year-classes of sablefish is linked to changes in the environment specifically, copepod abundance and egg and larval distribution. We have been examining the relationship between climate change and sablefish recruitment with the ultimate goal of identifying long-term patterns in sablefish year-class success and using this information to develop long-term management plans. Climate-ocean systems can abruptly shift from one stable state to another and these stable states, or regimes, persist on decadal scales (i.e. ten-twenty years). In the upwelling domain off the west coast of Canada, changes in regime states translate into regime states of wind direction which have implications for spring upwelling intensity and timing that ultimately affect recruitment of sablefish.

In collaboration with Russian climatologists, we developed an index of atmospheric circulation in the north Pacific. The index, along with the Aleutian Low index, identified a potential regime shift in 1997/98. In addition, we developed an index of year-class success for sablefish using data from commercial and research catches, larval surveys, discard information and changes in trawl fishery catch per unit effort. The relative year-class success of sablefish exhibits persistent decadal scale patterns and shifts between periods of relative good or poor success that correlate with climate-ocean regime shift years. The patterns of the year-class index also suggest that a recent potential regime shift may end the recent period of average year-class success.

In response to identifying the potential regime shift, a larval survey off west coast of Vancouver Island was initiated for April 1999 and will help in an early identification of any changes in sablefish year-class success.

Genetic studies

See Nearshore Rockfish Oceans Directorate funded program.

Research being conducted during 1999 includes:

• a fall trap survey including the release of 15,000 tagged fish
• an April larval abundance survey to add to the series of surveys conducted from 1984-89 and in 1992.
• Continued examination of escape ring performance and the development of a bar system for preventing large sablefish from entering the trap and maintaining a higher overall reproductive potential for the stock.
• Continued examination of the link between climate change and sablefish year-class strength
• Development of a revised ageing method.
• Examination of the potential for inlet survey stations to index recruitment.
• Examination of the initial rapid decline in recovery rates for tagged fish observed in the first year after release.

ii. Stock assessment

A major assessment of sablefish was conducted during 1998. The assessment was based on an integrated catch-age, mark-recapture model that was stratified by area and depth. The unified approach represents a significant improvement over the previous assessment that analyzed catch-at-age and tagging data separately. Estimates of available biomass in 1997 ranged from 43,400 to 51,300t. A recommended yield range of 2,977t-5,052t was proposed based on deterministic projections using varying levels of recruitment and target F levels based on the current F (_Current), 0.8F_currrent and 1.2F_current . Under all scenarios with average or below average levels of recruitment the stock is predicted to decline slowly.

During 1999 model development will continue with modifications to incorporate gear-specific age/sex selectivity, sex-specific movement, and inclusion of the full range of available length/sex biological data.

4. FLATFISH

i. Research programs

The biennial trawl survey for groundfish in Hecate Strait in 1998. Trawls were made at 89 stations within the Strait. As in previous surveys the total catch was sorted and weighed and some biological information was obtained for all species caught. However, the major focus of sampling was on Pacific cod and flatfish species. The catch-rate index for Pacific cod, Rock sole and English sole has declined over the last three surveys mainly due to unfavourable environmental conditions. Samples obtained for DNA work for rock sole are being processed. These will be used to confirm our visual observations of the two species of rock sole encountered on this survey. The ‘northern’ species was found was found in northern Hecate Strait, primarily above 54 degrees latitude, and in Dixon Entrance. The ‘southern’ species was commonly observed in the Strait at latitudes below 54 degrees.

ii. Stock assessment

The biomass of Hecate Strait English and Rock soles has been declining due to natural declines in recruitment over the last four years for these species. The fishing reference point F_med is used as an indicator for recruitment overfishing for these stocks. This corresponded to a fishing rate of 0.37 for rock sole and 0.28 for English sole. Spawning stock biomass per recruit analysis indicated that Rock sole and English sole stocks have a 0.94 and a 0.84 probability, respectively, of maintaining their spawning stock biomass with the current fishing rate. Landings of Dover sole from the ‘northern’ stock have decreased in recent years, presumably due to a decrease in abundance, while landings from the southern Dover sole stock have remained stable over the last three years. Both stocks are being harvested near MSY levels. Petrale sole stocks remained at a low level of abundance in 1998. Only incidental landings of this species have been permitted since 1995. Managers have set a by-catch cap of 480 t. The current level of fishing mortality for the stock was estimated at approximately 0.05. The fishery for this species will continue to be non-directed until stocks show signs of recovery from the intensive fishery on spawning aggregations in the 1970s and 1980s.

iii. Management

Flatfish in British Columbia were managed using inter-transferable vessel quotas for the 1997 fishery. Estimates of ‘kept’ catch and ‘discards’ were recorded by species and location by on-board observers in 1997. In the near future we will present the results of temporal and spatial analysis of the observer-based data.

5. Pacific hake

i. Research programs

Strait of Georgia

Review of acoustic methodology used in the Strait of Georgia.

The purpose of this review was 1) to make available to assessment scientists a review of the methods used in six acoustic surveys that were completed between 1981 to 1998 to assess Pacific hake (Merluccius productus) abundance in the Strait of Georgia and 2) to provide a time series of hake biomass standardized to a single target strength value. This includes a description of the evolution of the acoustic system, data collection, analysis, presentation techniques and sources of uncertainty unique to each survey. Additionally we presented a detailed method for calculating biomass based on a length-based Target Strength model. There are several sources of uncertainty in the resulting time series that should be recognized when interpreting Pacific hake abundance using this series including: 1) The 1993 survey is an overestimate due to inclusion of plankton back-scattering; 2) Based on examination of sex ratio and survey timing, all surveys are conservative estimates of biomass; 3) Surveys conducted prior to 1996 using the BioSonics system overestimate the biomass by a factor of 0.70 based on an inter-calibration; and 4) The length-based TS model results in slightly lower biomass estimates for 1997 and 1998 and should be applied to the earlier surveys in the time series.

Acoustic survey

A hydroacoustic survey of hake in the Strait of Georgia was conducted during March 16-31. A total of 29 sets were made to verify targets and collect biological data. A total of 42,000t of P. hake were present in the Strait. A cruise to monitor the distribution and spawning biology is planned for February 1999.

Offshore

Monitoring programs

The monitoring of catch, estimation of species composition, and biological sampling in the Vancouver INPFC Area fishery was continued through an extensive offshore observer and shore-side monitoring programs.

Triennial hydroacoustic survey

Canadian and U.S. scientists jointly conducted the triennial coastwide hydroacoutic survey of hake during July/August 1998. The survey was first conducted in 1977. The most recent survey was carried out by the NOAA ship Miller Freeman and the DFO ship C.G.S W.E. Ricker. The area surveyed by the Miller Freeman extended from Monterey Bay (36°30' N. lat.) to Queen Charlotte Sound (51° 45' N. lat.). The W. E. Ricker carried out simultaneous survey operations to the north of the area surveyed by the Miller Freeman. A primary goal of the W. E. Ricker survey was to establish the northern limit of the stock during El Niño conditions.

Aggregations of Pacific whiting were distributed throughout much of the area surveyed by NOAA and DFO scientists. Major aggregations were observed off Oregon between Cape Blanco and Coos Bay; near the US-Canada border, between northern Vancouver Island and southern Queen Charlotte Sound, and to lesser extent along the west side of the Queen Charlotte Islands, northern Hecate Strait, and Dixon Entrance. Whiting were found as far north as 58°00' N. lat. in the Gulf of Alaska. The 1998 survey results indicate a moderate decline of about 15% in whiting biomass relative to the previous coastwide survey in 1995. There was also a large northward shift in the distribution of biomass compared to previous surveys. For example, only about 35% of the total biomass in 1998 occurred south of 47/30'N (i.e., Monterey, Eureka, and Columbia INPFC areas) in contrast to nearly 80% which occurred in this area in 1995. The biomass in Canadian waters was nearly triple the level reported in 1995.

Species interaction survey

The 12th annual species interaction trawl survey was conducted in August to assess the impact of Pacific hake and other predators on herring survival and recruitment.

The distribution of juvenile offshore hake has been anomalous since 1994 with young fish, that had previously been restricted to California have been found throughout U.S. and Canadian waters, as far north as 57.8 deg. N.(YOY in 1997). The implications of this shift in recruitment pattern will require considerable research attention since the juveniles are subjected to increased mortality from the fishery and potentially cannibalism. We plan to conduct a survey to monitor the distribution of hake in the Canadian zone during August 1999.

ii. Stock assessment

Strait of Georgia

The fishery in the Strait of Georgia increased slightly in 1997 to 7,773 t from 6582 t, in 1996. Age and growth data continue to indicate strong recruitment during the 1990’s and a coincidental decline in the mean size-at-age. A review of hydoacoustic surveys for the Strait of Georgia is in preparation but preliminary results indicated that the current stock size is estimated conservatively at 42Kt. A major assessment is required to draw the surveys and updated biological data into an appropriate modeling framework. In the interim we propose the status quo which was calculated for the previous assessment by applying low-high risk annual rates of fishing mortality generated for the offshore (west coast of Vancouver Island) stock to the current estimate of exploitable biomass for the Strait of Georgia stock (42Kt). The resulting range in yield is 7,554-14,687 t. Due to uncertainty in the current assessment, including evidence of increasing seal predation we recommend that managers choose a quota from the lower half of the yield range.

Offshore

A major assessment was conducted in 199 by U.S. and Canadian scientists through the Pacific hake working group of the Technical Sub-Committee (TSC). Traditionally, separate Canadian and U.S. assessments were submitted to each nation’s assessment review process. In 1997 a single assessment was tabled but wen through separate Canadian and U.S. peer review. In 1998 a single joint Can./U.S. peer review was conducted. Details of the joint assessment research are included in the P. hake Working Group Report.

6. Dogfish

i. Research programs

Processing and analysis of dogfish tag recoveries was continued. The purpose of this experiment is to assess long-term movements, in particular the rate of exchange between the Strait of Georgia and offshore stocks.

ii. Stock assessment

A major assessment of dogfish has not been conducted for more than five years although catches have been monitored. Landings, in particular hook and line, have increased in recent years although current harvests levels are below the optimal yield in both areas.

7. LINGCOD

1. Research programs
   No research conducted.

2. Stock assessment
   No assessment work conducted. Stock catch monitored and sampled.

8. Walleye pollock

i. Research programs

Monitoring of catches and collection of biological samples were conducted during 1998 for pollock stocks in northern Hecate Strait/Dixon Entrance, Queen Charlotte Strait, the southwest coast Vancouver Island and the Strait of Georgia.

ii. Stock assessment

No assessment work was conducted during 1998.

10. Other

Pelagics - Sardine and Mackeral

In 1992, sardines reappeared in British Columbia waters after a total absence of over 40 years. Sardines were first reported in 1992 in both commercial and research catches of Pacific hake (Merluccius productus). The catches in the hake fishery have continued through to 1998, but are not an indication of sardine abundance as hake are fished at depths greater than 80m, well below the concentrations of sardines in the surface waters. The sardines probably were captured in the hake fishery when the nets were pulled through surface waters. In our research surveys that began in 1997 we caught large numbers of sardines in the surface waters relative to the catches in the hake fishery. This may indicate that sardines were abundant in the surface waters prior to 1997, a notion supported by the initiation of an experimental commercial fishery in 1995.

The abundance off British Columbia appears to be increasing. During July 1997, we estimated abundance using large surface trawls from the Columbia River to the tip of Vancouver Island at 135,000t, of which approximately 60,000t was present off the west coast of Vancouver Island. The large abundance of sardines in the Canadian zone in 1997 was observed prior to the major increase in temperature (August, September) of the surface waters as a result of the 1997 El Niño. The large abundance persisted off British Columbia through 1998. At the same time as large numbers of sardine appeared off British Columbia, the total abundance off California was considered to be unchanged (400,000t). Catches off California have been maintained although there are indications that catches have decreased in 1998. This indicates that the distribution of sardines may have shifted northward in 1997 and 1998. Sardines moved into the Strait of Georgia late in 1998. Additionally, large numbers of other species (Pacific hake and Pacific mackeral) have moved into the Canadian zone in larger numbers and are also moving farther north each year and spawning.

Another change in behaviour was the documented spawning of sardine off the west coast of Vancouver Island. Sardine in spawning condition were sampled off southern Vancouver Island in July 1997, and large numbers of young-of-the-year were captured in the same area in February, March and April of 1998. In February 1998, 31 sets were made in the top 30m off the west coast of Vancouver Island. The catches of sardines from the 1997 year-class were twice that of catches of the 1997 year class of herring (Clupea harengus) in the same sets indicating that these juvenile sardines were a common component of the fish community in the surface waters off Vancouver Island. The young fish have remained off the coast and have been captured throughout British Columbia waters including the Strait of Georgia, northern Hecate Strait and Alaska. Sardines remained abundant and spawned off the west coast of Vancouver Island in 1998 even though El Nino conditions did not persist. Two prior instances of sardine spawning near the British Columbia coast have been recorded (Williamson, PBS unpublished report, 1929; Hart, 1943). In both instances, 1929 and 1939, the authors reported one-year-old sardines in the catch, but the presence of young-of-the-year sardines was always considered to be rare.

Sardines were feeding mainly on phytoplankton (diatoms) and zooplankton (copepods and euphausiids). In 1997, all fish examined (140) were feeding. In 1998, about 28% had empty stomachs (97 out of 347). In addition, during February to April 1998, juvenile sardines were a common prey of salmon captured off the west coast of Vancouver Island.

We believe that the changes we have seen in sardine distribution, abundance and spawning (and the same changes in other fish) indicates a major shift in the dynamics of the ecosystem occurred in waters off British Columbia in the early 1990s. A key to understanding why large fluctuations in sardine abundance occur may be by understanding why they have shifted their range northward. Thus it may be as important to study the impact of the upcoming La Niña on sardines as it was to study the impact of the 1997 El Niño.

D. Other related studies

1. Statistics and Sampling

The principal activities in 1998 included further backfilling of biological data into the comprehensive biological data system (GFBIO), as well as supervising port and observer sampling. A total of 190 samples were collected from commercial landings by DFO employees, while an additional 484 age samples and 988 length frequency samples were collected by contract observers.

APPENDIX 1. REVIEW OF CANADIAN GROUNDFISH FISHERIES

1. Commercial fisheries

All catch figures for 1998 are preliminary. Canadian domestic trawl landings of groundfish (excluding halibut)in 1998 were 84,766 t, a decrease of 6% below the 1997 catch. The major species in the trawl landings were Pacific hake (60%), Pacific ocean perch (7%), turbot (5%), yellowtail rockfish (4%) and dover sole (3%).

Canadian landings of groundfish caught by gear other than trawl in 1998 totalled 8,535 t. Sablefish landing by trap and longline gear accounted for 4,164 t (99% sablefish). Landings of species other than sablefish by longline, handline and troll gear accounted for 4,361 t (49% dogfish, 31% rockfish, and 18% lingcod). Catches incidental to other gear types, including shrimp trawl, seines and gillnets, totalled 10 t (99% unidentified fish).

2. Recreational fisheries

Each year, Fisheries Branch (Fisheries and Oceans Canada) conducts creel surveys of the recreational angling fishery in the Strait of Georgia. Principal target species are chinook and coho salmon. In 1998 these surveys covered only the months of April to October. Provisional estimates of 1998 catches for this 7-month period were 3,291 fish for lingcod, 84,251 fish for all rockfish species and 2,203 fish for halibut. There was no data collected for dogfish in 1998. There was also an estimate of 43,565 fish for other fin fish which includes greenlings and sculpins, as well as other species such as herring.

3. Joint-venture fisheries

In 1998, 57 Canadian catcher vessels delivered Pacific hake and incidental species to seven processing vessels in co-operative fishing arrangements. These fisheries take place off the southwest coast of Vancouver Island (Area 3C). A total of 39,639 t of Pacific hake was processed by 7 Polish vessels. The quotas and catches are outlined below:

4. Foreign fisheries

There were no national or supplemental fisheries for Pacific hake off southwest Vancouver Island (Area 3C) in 1998.

APPENDIX 2. GROUNDFISH RELATED REPORTS PUBLISHED BY THE STOCK ASSESSMENT DIVISION DURING THE PERIOD JANUARY 1, 1998 TO DECEMBER 31, 1998 ARE LISTED BELOW:

PRIMARY

Richards, L.J., and J.T. Schnute. 1998. Model complexity and catch-age analysis. Can. J. Fish. Aquat. Sci. 55: 949-957.

Richards, L.J., and J.T. Schnute. 1998. A statistical framework for analysis of precautionary reference points. p. 185-198. In Fishery stock assessment models for the 21st century. Alaska Sea Grant College Program: AK-SG-98-01.

Schnute, J.T., and L.J. Richards. 1998. Analytical models for fishery reference points. Can. J. Fish. Aquat. Sci. 55: 515-528.

Schnute, J.T., and L.J. Richards. 1998. Statistics, software, and fish stock assessment. p. 171-184. In Fishery stock assessment models for the 21st century. Alaska Sea Grant College Program: AK-SG-98-01.

OTHER PUBLICATIONS

Schnute, J. T., N. Olsen, and R. Haigh. 1999. Slope rockfish assessment for the west coast of Canada in 1998. CSAS Res. Doc. 99/16. 79p.

Workman, G. D., N. Olsen, and A. R. Kronlund. 1998. Results from a bottom trawl survey of rockfish stocks off the west coast of the Queen Charlotte Islands, September 5 to 23, 1997. Can. Man. Rep. Fish. Aquat. Sci. 2457: 86 p.

APPENDIX 3. STOCK ASSESSMENT DIVISION GROUNDFISH STAFF IN 1998

W. Andrews	Sablefish and hake technician
K. Charles	Fish Ageing technician
K. Cooke	Population hydroacoustics estimation
G. Kronkite	Acoustic development methods
R. Kronlund	Analytical programs
J. Fargo	Stock assessment and biology
C. Fort	Herring assessment
D. Gillespie	Fish Ageing technician
R. Haigh	Statistical analysis, exploratory data analysis
V. Haist	Marine fish/Pacific cod stock assessment
L. Hamer	Herring data base management
S. Hardy	Statistics/sampling
S. Janz	Fish Ageing technician
G. Jewsbury	Sablefish and hake technician
T. Johansson	Statistics/sampling
R. Kieser	Population hydroacoustics estimation
D. Little	Fish Ageing technician
G. A. McFarlane	Marine Fish stock assessment, population dynamics and biology, fish/ocean interaction
S.E. MacLellan	Fish Ageing Supervisor
W. Mitton	Sablefish, hake, dogfish and pollock
T. Mulligan	Acoustic development methods
N. Olsen	Analytical programs, statistical analysis
I. Perry	Fisheries oceanography/Shellfish
J. Rankin	Fish Ageing technician
L. Richards	Multispecies stock assessment, mathematical analysis
K. Rutherford	Statistics/sampling
M. Saunders	Groundfish stock assessment and biology
J. Schweigert	Herring stock assessment and stock identification
J. Schnute	Multispecies stock assessment, mathematical analysis
R. Stanley	Shelf rockfish stock assessment biology, sampling studies
R. Tanasichuk	Hake/herring/euphausiid interactions
N. Venables	Statistics/sampling
G. Workman	Technical support
L. Yamanaka	Rockfish stock assessment and biology