The Northwest Fisheries Science Center (NWFSC) provides scientific and technical support to the National Marine Fisheries Service (NMFS) for management and conservation of the Northwest region's marine and anadromous resources. Research is conducted in cooperation with other federal and state agencies, and academic institutions. The Center's four divisions conduct applied research to resolve problems that threaten marine resources or that impede their use. The Fishery Analysis and Monitoring Division is the focus for most of the research reported by the NWFSC to the US-Canada groundfish TSC.

Programs in the four NWFSC divisions span diverse research areas. The Coastal Zone and Estuarine Studies Division is the Center’s largest division. It strives to understand and mitigate the impacts of habitat alterations (primarily hydroelectric dams) on anadromous species and conducts genetic research on salmon in support of the Endangered Species Act. The Environmental Conservation Division (ECD) monitors chemical pollutants and health in coastal ecosystems throughout the United States. A major part of this effort is the development of methods to determine the health effects of pollutants on marine organisms. For instance, the ECD has studied the effects of pollution on various groundfish species such as sole, flounder, and halibut. Some effects that have been directly linked with particular types and levels of pollution have been developed for use as early indicators, or biomarkers, of habitat degradation and impacts on population. The Utilization Research Division provides information to enhance the quality, safety and full utilization of seafood products. The seafood biochemistry program of this division has identified enzymes responsible for softening edible portions of some commercial species of groundfish, which renders the fish unmarketable. Current research in this program has recently identified a natural inhibitor, found in potatoes, for one of these enzymes, and will focus on development and use of other inhibitors. The Fishery Analysis and Monitoring Division provides stock assessment of west coast groundfish species. This division develops models for managing multispecies fisheries, designs programs to provide information on the magnitude and characteristics of the bycatch in commercial fisheries, and studies methods for reducing bycatch and improving survival rates of captured bycatch species. An integral component of the stock assessment and bycatch research programs will be marine fish ecology research. These field and laboratory studies on the population biology of key groundfish species will include investigations of multispecies biological interactions, recruitment strategies, and responses of various life history stages to fishing pressure and environmental changes.

The Center's main facility and laboratories, including a state-of-the-art water recirculation facility, is located in Seattle. The major components of the groundfish research are conducted at the NWFSC Newport Laboratory at the Hatfield Marine Science Center in Newport, Oregon. Other Center research facilities are located in Pasco, Big Beef Creek, Mukilteo, Manchester, Washington; Hammond and Clatskanie, Oregon; and Kodiak, Alaska.

For more information on Northwest Fisheries Science Center programs, contact Center Director Dr. Usha Varanasi at (206) 860-3200.

1. Research

Fishermen targeting behavior - A project in collaboration with the University of Washington is investigating the consequences of changing monthly limits on the west coast trawl fishery for sablefish, Dover sole and two species of thornyhead rockfish. Monthly vessel limits are imposed on the landings of each species in order to prevent premature attainment of the annual quotas. These limits decrease the operational flexibility of the vessels and cause discard of fish caught in excess of the limits A set of limits that would control harvest, provide high economic return, and minimize discard is desired. The best combination of limits is not known because the species vary in price, location (primarily depth) and cost of fishing. A better understanding of fishermen’s response to these factors could lead to improved management of this fishery. The project involves dynamic programming to investigate fishermen’s behavior while interacting with these patterns under the constraints of the monthly limits. This analysis includes data from previous observer studies, ongoing fishery logbook data, and resource survey data.

2. Stock Assessment

Sebastes complex assessment - The first assessment of the minor rockfish species was conducted in 1996 and included in the PFMC’s 1995 Stock Assessment and Fishery Evaluation. The methodology utilizes new statistical procedures to apportion unspecified rockfish catch among the many Sebastes species and draws upon previous examination of rockfish species assemblages to divide the Sebastes complex into shelf and slope assemblages, and north and south assemblages. Within each assemblage, assessment models for single species and for groups of species are developed and tuned to trends in abundance from the triennial trawl survey, and to trends in fishing effort obtained from the trend in estimated fishing mortality for abundant, target species in the assemblage. Further details on this approach are described in the shelf and slope rockfish assessment sections below.

For more information please contact Dr. Jean Rogers at jrogers@sable.nwfsc-hc.noaa.gov or at (541) 867-0153

Fishery logbook analysis - The NWFSC/FAM is examining whether catch per effort data taken from trawl logbooks of the west coast groundfish fishery can be standardized to provide quantitative measures of relative abundance for application in multispecies groundfish assessments. Data from individual vessel logbooks from the states of California, Oregon, and Washington are being analyzed for the period of the mid-1980's to early 1990's. Individual vessel’s fishing histories will be examined for changes in fishing pattern and species composition through time. An analysis of spatial patterns in multispecies catch rates for the west coast groundfish fishery is being conducted, and the effects of changing management measures, such as single-species trip limits, on catch rates are being evaluated. Catch rates are being standardized using a general linear modeling. Preliminary results indicate that depth, area, vessel, and seasonal effects are all important factors. This study is focusing on development of standardized catch rates as measures of abundance for the deep-water complex consisting of sablefish, thornyheads, and Dover sole. It may be expanded to include other species as well.

For further information, contact Dr. Jon Brodziak at jbrodzia@sable.nwfsc-hc.noaa.gov or at (541) 867-0243.

b.) Stock Assessment

Quantitative stock assessments on many of the west coast shelf species were conducted for the first time in 1996. Only four of the shelf rockfish (yellowtail, canary, bocaccio, and chilipepper) have been previously assessed and none of those assessments have been coastwide. In keeping with their primary centers of abundance, assessments for yellowtail and canary rockfishes encompass only the northern areas (primarily off the coasts of Oregon and Washington), and assessments for bocaccio and chilipepper rockfish only the southern areas. The 1996 assessment of the remaining shelf species and areas was conducted with several levels of resolution: 1) all previously unassessed species in the combined slope and shelf assemblages; 2) only the combined shelf species; and 3) bocaccio north of California, yelloweye, sharpchin, and redstripe rockfishes assessed separately. Bocaccio and yelloweye have been quantitatively assigned to the shelf complex, the other species may overlap into the slope assemblage. Limited data exists on the remaining shelf species, and those which do exist are imprecise. Biological data on commercial catches are routinely obtained only in California. Accurate landings data are not available because the remaining shelf species are landed in mixed-rockfish categories, with little port sampling for species composition. Discarding at sea has likely been substantial due to lack of market for either the species or the small sizes of fish in the catch. Survey data are often highly variable due to occasional large catches and/or few catches of the species. To augment the limited data, an index of Washington and Oregon commercial trawl effort were used to help estimate trends in biomass. Estimates of the rate of fishing mortality for canary rockfish were used as the index. This is based on the assumptions that fishermen direct effort on the entire complex, and relative effort between the species is constant over time. Comparison of the yellowtail and canary fishing mortality rates indicate that these assumptions have validity.

For more information please contact Dr. Jean Rogers at jrogers@sable.nwfsc-hc.noaa.gov or at (541) 867-0153

3.) Slope Rockfish

b.) Stock Assessment

In previous work on the slope rockfish species, only Pacific ocean perch has had a complete quantitative assessment leading to an accepted allowable biological catch and harvest guideline. Assessments for darkblotched and splitnose rockfish did not provide sufficient information to establish a numeric ABC. A stock assessment of the remaining species was completed in 1996. The assessment was conducted on several levels of resolution: 1) all previously unassessed species in the combined slope and shelf assemblages 2) only the combined slope species and 3) darkblotched, splitnose, yellowmouth, and silvergray rockfishes assessed separately. Silvergray rockfish is included in the slope assemblage, but may overlap into the shelf assemblage. As with the shelf assemblage, limited data exists on the remaining slope species. To augment the limited data, estimates of trawl fishing mortality for Pacific ocean perch were used as an index effort. As with the shelf assemblage, this is based on assumptions that fishermen direct effort on the entire complex, and relative effort between the species is constant over time.

For more information please contact Dr. Jean Rogers at jrogers@sable.nwfsc-hc.noaa.gov or at (541) 867-0153.

4.Thornyheads

b. Stock Assessment

The last stock assessment of shortspine and longspine thornyheads was completed in 1994. The projected yields at F35% for the area north of Pt. Conception, California to the Canadian border were about 980 tons for shortspine thornyheads and 7,780 tons for longspine thornyheads. Fishermen have been encouraged to fish in deeper waters in order to achieve the yield for longspine thornyheads without overharvesting shortspine thornyheads. Shortspine thornyheads prefer shallower water, and those found in deeper water are generally the larger fish of that species.

Thornyheads are fished and surveyed in a complex of slope species including Dover sole and sablefish. New assessments for the thornyheads are being undertaken by the FAM in coordination with other west coast stock assessment experts. Changes to the assessment will include the addition of West Coast survey data from the 1995 and 1996 slope surveys, as well as the 1995 triennial survey which was conducted over a deeper depth range than in previous years. Since there is a growing fishery for thornyheads in the area south of Pt. Conception, this area may be considered in this stock assessment. Other plans include further use of logbook information, improved estimation of discard rates, and sensitivity analysis regarding assumptions made about the survey information.

For more information please contact Dr. Jean Rogers at jrogers@sable.nwfsc-hc.noaa.gov or at (541) 867-0153.

5.Sablefish

a. Research

WEST COAST

Sablefish bathymetric ecology - The 1994 assessment of west coast sablefish highlighted the importance of accurate modeling of depth-specific population characteristics. The most recent slope trawl surveys indicate that about 30% of the stock biomass is in water deeper than 500 fathoms. Fishery and survey samples indicate that most of these deep-living sablefish are old. Explicitly modeling migration from shallow water to the >500 fathom depth zone improved the assessment model’s overall fit to the data. The migration rate (about 4% per year) was estimated indirectly by the assessment model, rather than on direct estimation of rates of dispersion into deep water. Independent determination of the extent of such movement would greatly increase the confidence that could be placed in the model. In addition, the old, deep-living component of the population was assumed to have the same weight-specific reproductive output as sablefish living in the presumably more productive shallow zone. Direct estimation of depth-specific maturation and fecundity would evaluate this assumption.

In 1995 a collaborative study with Oregon State University was initiated to measure depth-specific reproductive output of sablefish and to conduct a pilot tagging study to estimate rates of dispersion into deep water. Reproductive samples were collected in the Eureka area on the NOAA slope trawl survey and off central Oregon on a local fishing vessel. The tagging work began in early 1996 and the reproductive research has been continuing. Preliminary analysis of these samples indicates reduced reproductive output by the deep-living individuals.

Survival of discarded sablefish - Monthly vessel limits are used in the groundfish fishery to spread the catch and effort throughout the year. These limits cause discard when vessels high-grade to retain more valuable sizes or when vessels inadvertently capture fish in excess of their limit. Discarded fish have been assumed to have nil survival, but sablefish appear to be hardy animals, especially young sablefish captured in shallow water. Evaluation of the actual survivorship of discarded sablefish will improve the assumptions made in the stock assessment and fishery evaluation, and may lead to fishermen education programs that could improve survivorship of sablefish. FAM began support of two survival studies in 1995. First, initial stages for expansion of coldwater aquarium facilities at Newport, Oregon were funded. This facility will be used by researchers in the NMFS/AFSC to study sablefish behavior is response to fishing gear under realistic temperature and light regimes. Second, a collaborative study with the University of Washington was initiated to measure survival of sablefish under field conditions. During the summer of 1996 a pilot field study was carried out. Sablefish were caught with trawls then return to the seabed in cages to measure their mortality over a several day period. This methodology has been used successfully to study the post-capture survival of halibut in the North Pacific.

For further information, contact Dr. Paul Crone at pcrone@sable.nwfsc-hc.noaa.gov or at

(541) 867-0307

b. Stock Assessment

WEST COAST

The 1997 assessment will follow the general methods used in the previous assessment. New information that will be incorporated into this year’s assessment includes: (1) better understanding of the bathymetric strategies exhibited by sablefish—fishery dependent and independent data clearly indicate that demographic characteristics of this species, such as age/size distributions, are correlated with depth; (2) commercial fishery logbook data will be evaluated in efforts to develop relative measures of abundance that can be used as auxiliary information in the assessment model; and (3) research surveys conducted on the continental slope and biological programs that target the commercial landings have generated new age data (1990s) that will supplement the previously limited time series. The 1997 assessment will provide current estimates of abundance, fishing mortality rates, and projected yields for the sablefish fishery off the U.S. Pacific coast.

Late in 1997, the Fishery Analysis and Monitoring Division will begin cooperative projects with the fishing industry that will allow more detailed biological data to be collected from the commercial sablefish fishery than currently possible given the sampling design now in place. In particular, the current multistage sampling design will be modified to ensure that: (1) samples can be collected in a consistent manner across the various ports along the U.S. Pacific coast; (2) biological data can be summarized using sound statistical techniques (Crone 1995); and (3) the depth-specific attributes of the sample information are captured in the data collection process.

For further information, contact Dr. Paul Crone at pcrone@sable.nwfsc-hc.noaa.gov or at

(541) 867-0307

6. Flatfish

b. Stock Assessment

WEST COAST

Dover Sole

The last assessment for Dover sole was conducted in 1994. A new assessment will be carried out in 1997 by the NWFSC - Fisheries Analysis and Monitoring Division. This assessment will incorporate updated biological information taken from the fishery and resource surveys. In particular, the assessment will include some recently developed age composition data analyzed by the Oregon Department of Fish and Wildlife staff under a cooperative research agreement with FAMD. These data will be used along with historical age composition information to examine regional growth patterns. The assessment will incorporate commercial catch rate indices of abundance derived from trawl logbooks. Considerable time and effort have been focused on building a coastwide logbook database that is essential for the proper standardization of these data. Exploratory work will also be carried on using the CALCOFI larval survey data to index abundance. The assessment will give an updated report on the abundance, fishing mortality rates, and projected yields of the Dover sole resource.

For further information, contact Dr. Jon Brodziak at jbrodzia@sable.nwfsc-hc.noaa.gov or at (541) 867-0243.

1) Age readers - Age composition data are critical for studies of fish growth, recruitment patterns, bathymetric dispersion rates, and application of age-structured assessment methods. A group of three age readers has been added to the ODFW aging group with funding from the NWFSC/FAM. In late 1995 this group started with reading of Dover sole otoliths from the NMFS slope trawl surveys. In 1996 the group progressed to read a backlog of sablefish otoliths from the fishery and is planning to contribute to the reading of otoliths from several rockfish species.

2) Uncertainty in Modeling - A recent technical review of U.S. Pacific coast assessment methods recommended that research be undertaken to explore areas of uncertainty inherent in modeling processes (PFMC 1995). Current research includes an evaluation of the assumed error structure in stock assessment models that use sample estimates of age composition (Crone and Sampson in prep.). This work critically examines the ability of age-structured stock assessment models to describe adequately the stochastic properties of actual catch-at-age data. Sampling estimators and straightforward statistical methods, such as general linear modeling, are used to identify ‘best-fit’ probability distributions (error structures) that can be used in assessment models to describe the actual variability associated with sample estimates of age composition.

For further information, contact Dr. Paul Crone at pcrone@sable.nwfsc-hc.noaa.gov or at

(541) 867-0307

3) Environmental Stress - Studies at the NWFSC are being conducted to assess the impacts of anthropogenic stressors on groundfish assemblages in nearshore marine and estuarine habitats. These investigations have examined the effects of chemical contaminants on a wide range of physiological processes in marine groundfish. Areas studied include toxicopathic disease, especially neoplasia, reproductive function, growth, and immune function. Ecotoxicological modeling studies have also been conducted to link adverse health effects of contaminants on individual fish to potential population level impacts. The primary species studied has been English sole in Puget Sound, though data have also been collected and published on rock sole, starry flounder, flathead sole, and yellowfin sole. As well as detecting toxicant effects of groundfish health, these studies have provided background data on normal growth, reproductive development, and other aspects. An important function of the NWFSC research staff is to conduct assessments of fish injury at sites which are targets for resource damage assessment and restoration actions, in cooperation with NOAA's Damage Assessment and Restoration Center. The NWFSC is also an active participant in cooperative research projects with the Washington Department of Fish and Wildlife to monitor health and habitat quality for groundfish species in Puget Sound, such as the Puget Sound Ambient Monitoring Program. This research is being broadened in conjunction with new capabilities and staff at the NWFSC and in collaboration with state agencies and the BC/WA Transboundary Task Force, to address cumulative effects of multiple stressors on groundfish in the waters of the Pacific Northwest and Canada.

For further information, contact Lyndal L. Johnson @noaa.gov or at (206) 860-3345

3) Full Utilization - Several species of marine fish such as Pacific hake, arrowtooth flounder, and yellowfin sole are subject to tissue softening of varying degree shortly after landing. This softening is often associated with the presence of myxosporean parasites located within the muscle fibers. Research conducted in the NWFSC suggest that this softening is likely due to naturally occurring enzymes, proteases, in the fish muscles whose activities can be amplified by various factors, possibly including the parasites. We have found that these enzyme activities can be sufficiently inhibited by natural proteins present in potato extracts to allow time for processing. Other sources of inhibitors are known including those present in bovine plasma and egg albumin and have been used to varying extent. However, potato extracts appear to be superior, in part because of broad consumer acceptance, relatively low cost, as well as the presence of important antioxidants. Because of the tissue softening problem, species such as Pacific hake are used primarily for surimi preparation with a typical yield of about 15% by weight. The use of enzyme inhibitors helps surimi preparation but more importantly it allows the formation of surimi into final products. In addition, studies at the NWFSC have demonstrated the feasibility of producing high quality surimi and formulation of products from arrowtooth flounder, an abundant and under-utilized species. In surimi production, there are several steps involving extensive washings and hence the loss of muscle proteins and the subsequent low yield. Research with a decanter centrifuge has demonstrated recovery of these muscle proteins and have succeeded in approximately doubling the yield of surimi, a yield nearing that obtained during the production of fish fillets. In fillet production of pollock and cod, the yield of product is approximately 25-30 % and the rest of the carcass may go to waste. Studies at the NWFSC have been evaluating processes to recover more of these carcass wastes for fish, animal, and human products. Studies have demonstrated that fillet trimmings separated from the carcass waste using the decanter surimi technology can be used to produce a high quality surimi resulting in a 15% increase in recovery from the discarded carcass wastes. Also, NWFSC studies have resulted in the development of a unique cooking and drying process including a bone separation step to produce high quality protein meals, oil, and bone meal from carcass wastes for fish, animal, and human uses. Using these techniques, the final waste can be reduced to a negligible amount, greatly reducing the environmental impact of waste disposal. These developments have made possible much higher product yields from fishery resources and the harvest of currently under-utilized species.

For further information, contact Dr. Jerry Babbitt at ffjkb@auora.alaska.edu or at (907) 486-1518