research series - nprb

2 0 0 2 - 2 0 0 8 r e s e a r c h s u m m a r y

FISH & INVERTEBRATES Alaska’s Ocean Bounty

Patrick Endres | Alaska Stock.com

North Pacific research Board

ReseaRch seRies

The North Pacific Research Board (NPRB) was established by Congress

in 1997 to develop a comprehensive science program of the highest

caliber that provides a better understanding of the North Pacific, Bering

Sea, and Arctic Ocean ecosystems and their fisheries.

The NPRB carries out science planning, prioritizes pressing fishery management and ecosys-

tem information needs, coordinates with other ocean science programs, competitively selects

research projects, and communicates research results to diverse audiences.

Since its founding, the North Pacific Research Board has developed a comprehensive program of

marine research. The Science Plan, developed with guidance from the National Research Council

of the U.S. National Academies of Sciences, serves as the foundation for annual requests for pro-

posals organized by major research themes, including:

• Lower Trophic Level Productivity

• Fish Habitat

• Fish and Invertebrates

• Marine Mammals

• Seabirds

• Humans

• Other Prominent Issues

• Integrated Ecosystem Research

• Other Research and Partnerships

The annual requests for proposals result in the majority of the funded projects, which are

numbered by the year they were funded (e.g., #201 funded in 2002). The Board also supports

integrated ecosystem research programs that look in-depth at Alaska’s major ocean ecosystems,

with a program ongoing in the Bering Sea and in development for the Gulf of Alaska.

This research summary describes research funded from 2002 through 2008.

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NORTHPACIFICRESEARCHBOARD: : SCIENCEPROGRAM: : FISH&INVERTEBRATES 3

fish and inveRtebRates

A major goal of the Board is to improve our ability to manage and protect the healthy,

sustainable fish and wildlife populations that comprise the ecologically diverse marine

ecosystems of the North Pacific, and provide long-term, sustainable benefits to local

communities and the nation. This is a very large task, considering that the marine regions off

Alaska support rich and vast assemblages of fish and invertebrates, and the largest fisheries in

the U.S. These assemblages are extremely important not only economically, but also ecologically

and socially. If fishing is the human activity that has the greatest impact on both targeted and non-

targeted populations in the North Pacific, as the National Research Council contends, resource

managers must know how the ecosystem functions, and understand the life histories and distri-

butions of the fish stocks themselves and how they are influenced by fishing and changes in their

environment.

Studies funded in this category fall within five broad topics which together address pressing

fishery management issues and marine ecosystem information needs:

• stock assessment research and development

• bycatch reduction

• causes of major species decline

• implications of ecosystem change on fishery management

• management tools

Through 2008, the Board supported 76 fish and invertebrate projects for just under $14 million,

of which 47 have been completed. Researchers have studied a variety of forage species, jellyfish,

squid, crab, sculpin, skates, sharks, salmon, rockfish, halibut, pollock, cod, Atka mackerel, and other

groundfish species. Projects are split fairly evenly between the Gulf of Alaska and the Bering Sea,

with a few projects taking place in the Arctic Ocean, reflecting the different degrees of importance

of commercial fisheries throughout Alaska.

The complex factors that influence the behavior of fish and drive the fluctuations of their populations

require all four research approaches described in the NPRB Science Plan (monitoring, modeling,

process, and retrospective studies). The majority, however, have focused on processes in order

to increase our understanding and ability to forecast future changes. Several involve cooperative

research projects with industry and/or communities, and draw upon local and traditional knowledge.


202 Application of new sonar technology to reducing salmon bycatch in pollock fisheries. C. Rose

204 NPAFC salmon tagging. V. FedoRenko, J. Helle

205 Genetic stock identification of W. AK sockeye salmon. J.seeb, R. Wilmot

208 Environmental cues for herring spawning. G. kRuse, d. musGRaVe

209 Two species of rougheye rockfishes in the northern Gulf of Alaska. a. GHaRRett

210 Nutritional quality of Alaska fish for predators. m. Castellini

303 North Pacific Anadromous Fish Commission Cooperative Research: Use of genetic stock ID to determine the distribution, migration, early marine survival, and stock abundance of sockeye and chum salmon in the Bering Sea. s.abe, J. seeb, s. uRaWa, R. Wilmot

305 Monitoring and modeling predator-prey relationships. P. liVinGston

306 Species identity and life history of Hematodinium, the causative agent of bitter crab syndrome in northeast Pacific snow (opilio) and Tanner (bairdi) crabs. l. HauseR, P. Jensen, F. moRado, d. Woodby

308 Forage fishes in the western Gulf of Alaska: Variation in productivity. k. bailey, J. duFFy-andeRson, J. naPP, J. Paakkonen, m. Wilson

310 Estuaries as essential fish habitat for salmonids: Assessing residence time and habitat use of coho and sockeye salmon in Alaska estuaries. m. bisHoP, s. PoWeRs, G. ReeVes

311 Establishing a statewide data warehouse of salmon size, age, and growth records. b. aGleR

314 Thermal habitat preferences of Pacific halibut and the potential influ-ence of hydrographic variability on a local coastal fishery. t. loHeR, H. mCCaRty

317 Pre-season forecast of Bristol Bay sockeye salmon migration timing based on oceanographic and biological variables. G. RuGGeRone

319 Retrospective study of pigmented macrophage aggregates as markers of Pacific herring population health. G. maRty

321 Evaluation of alternative hypotheses to explain the collapse of the Kvichak sockeye salmon: A project to catalyze a comprehensive, hypotheses-driven research program. m. link, G. RuGGeRone

325 Video monitoring aboard Bering Sea factory trawlers —a pilot study. s. andeRson, m. buCkley

327 Early marine ecology of juvenile chum salmon in Kuskokwim Bay, Alaska. l. HaldoRson, n. HillGRubeR, C. ZimmeRman

401 Survey strategies for assessment of Bering Sea forage species. m. benField, e. bRoWn, J. CHuRnside, n. HillGRubeR, J. HoRne, s. PaRkeR stetteR, m. siGleR

404 Alaska Marine Information System. d. kieFeR, k. stoCks

407 Kelp-grazer interactions in Kachemak Bay, Alaska: grazing activity, chemical defenses and resource allocation. k. iken

417 Reproductive ecology of Atka mackerel, Pleurogrammus monopterygius, in Alaska. s. atkinson, n. HillGRubeR, R. lautH, s. mCdeRmott

418 Abundance, life history, and population demographics of Spiny Dogfish, squalus acanthias. V. GalluCCi, G. kRuse

419 Modeling of multispecies groundfish interactions in the eastern Bering Sea. P. liVinGston

420 Interannual and spatial variation in population genetic composition of northeastern Gulf of Alaska young-of-the-year Pacific ocean perch. a. GHaRRett

502 Integration of ecological indicators for the North Pacific with emphasis on the Bering Sea: A workshop approach. a. byCHkoV, J.oVeRland

503 Arctic Ocean synthesis. R. HoPCRoFt

504 Analysis of ongoing salmon programs. e. knudsen

505 Walleye pollock in the Eastern Bering Sea: A spatially explicit model.t. Quinn

506 Factors influencing the mortality of tagged walleye pollock captured using a trawl net. R. Foy

508 Female reproductive output of snow crab in eastern Bering Sea. d. aRmstRonG, b. eRnst, t. essinGton, P. liVinGston, l. oRensanZ

509 Retrospective analysis of Kodiak red king crab. G. kRuse

510 Skate life history and demography. G.Cailliet, d. ebeRt

511 Spiny dogfish in Alaska. V. GalluCCi, G. kRuse

512 Juvenile Pacific Ocean perch genetics, phase 2. a. GHaRRett

521 A profiling echosounder for North Pacific monitoring. d. maCkas, s. VaGle

522 Reproductive biology of Atka mackerel. s. atkinson, m. Canino, n. HillGRubeR,

s. mCdeRmott

523 Pollock recruitment and stock structure. m. doRn, a. HeRmann, s. HinCkley,

J. HoRne, b. meGRey, C. PaRada

524 Productivity of capelin and pollock. J. duFFy-andeRson, P. liVinGston,

e. loGeRWell, m. Wilson

525 Modeling multispecies groundfish interactions. P. liVinGston

531 Seabird-fish models. W. sydeman

605 Modeling growth and survival of early life-stages of Pacific cod in response to climate-related changes in sea ice conditions in the Bering Sea. m. beHRenFeld, l. Ciannelli, m. daVis, t. HuRst, b. lauRel, a. stoneR

606 Modeling climate effects on interdecadal variation in southeastern Bering Sea jellyfish populations. m. b. deCkeR

610 Adaptation to a changing world: Molecular evidence for selective mortality in walleye pollock larvae. k. bailey, m. Canino, l. HauseR

617 Migration patterns of Pacific halibut in the southeast Bering Sea. t. loHeR, b. noRCRoss

618 Spatial and temporal patterns in Pacific cod reproductive maturity in the Bering Sea. el. loGeRWell, s. neidetCHeR

619 Connectivity between Greenland halibut (Reinhardtius hippoglossoides) spawning and nursery areas in the eastern Bering Sea: A paradigm for offshore spawning flatfish species. k. bailey, l. Ciannelli, J. duFFy-andeRson,

a. mataRese

620 Estimating movement rates of Pacific cod (Gadus macrocephalus) in the Bering Sea and the Gulf of Alaska using mark-recapture methods. d. GundeRson, P. munRo, d. uRban

621 Diet and trophic ecology of skates in the Gulf of Alaska (Raja and bathyraja spp.): Foundational ecological information for ecosystem-based management of demersal resources. G. Cailliet, d. ebeRt

Fish and invertebrates projects


622 Analysis of fall, winter, and spring predation of key Bering Sea and Gulf of Alaska groundfish through food habits and stable isotope analysis. k. aydin, b. milleR

623 Tools to assess Hematodinium life history and impacts on Tanner crabs. C. FRiedman, l. HauseR, F. moRado

624 Modeling transport and survival of larval crab: Investigating the contraction and variability in snow crab stocks in the eastern Bering Sea using individual-based models .d. aRmstRonG, b. eRnst, a. HeRmann, s. HinCkley,

G. kRuse, b. meGRey, J. naPP, J. m. (lobo) oRensanZ, C. PaRada

625 Assessment of Bristol Bay red king crab resource for future management action—a new approach. G. Conan, s. HuGHes

627 Identifying life history characteristics of squid in the Bering Sea. n. biCkFoRd, b. noRCRoss

628 Understanding the population dynamics of an abundant non-target species group: Life history and demographics of large sculpin species in the Bering Sea large marine ecosystem. k. aydin, a. HolloWed, R. ReuteR

629 Assessment of female reproductive effort and maternal effects in Pacific Ocean perch: Do big old females matter?s. HePPell, s. HePPell, P. sPenCeR

630 Food web linkages: Forage fish distribution and ecology in core areas of predator distribution in the Aleutian archipelago. m. aRimitsu, J. Piatt , V. byRd

704 *Developing the Alaska Marine Information System. m. JoHnson

711 Quantification of unobserved injury and mortality of Bering Sea crabs due to encounters with trawls on the seafloor.m. daVis, J. GauVin, J. munk, C. Rose, a. stoneR

712 Bycatch characterization in the Pacific halibut fishery : A field test of electronic monitoring technology. J. CaHalan, W. kaRP, b. leaman, J. Watson,

G. Williams

713 Predicting snow crab growth and size with climate warming in the northern Bering Sea. J. loVVoRn

714 Developing biological reference points for crustacean fisheries: Reproductive potential of Bristol Bay red king crab and eastern Bering Sea snow crab. G. eCkeRt, G. kRuse, k. sWiney

715 Life history and population dynamics of four endemic Alaska skates: Determining essential biological information for effective management of bycatch and target species. G. Cailliet, d. ebeRt

716 Evaluating acoustics for squid assessment in the Bering Sea. J. HoRne

728 Herring synthesis: Documenting and modeling herring spawning areas within socio-ecological systems over time in the southeastern Gulf of Alaska. V. butleR, m. moss, t. tHoRnton

731 Temperature data collections on Bering Sea groundfish vessels to evalu-ate temperature at depth and catch rates for target and bycatch species in order to reduce bycatch and increase knowledge of how ecosystem variables affect fishing. J. GauVin, J. ianelli, P. stabeno

809 Evaluation of echosign data in improving trawl survey biomass esti-mates for patchily-distributed rockfish. d. Hanselman, P. sPenCeR

810 Assessment of rockfish species in untrawlable habitat using advanced acoustic, optical, and trawl technologies. d. demeR, m. maRtin, C.RooPeR,

t.s WebeR, m.Wilkins, C. Wilson, m. ZimmeRmann

811 Development of a quantitative PCR assay for simultaneous identi-fication and enumeration of planktonic red king crab (Paralithodes camtschaticus) larvae. G. eCkeRt, P. Jensen, J. moRado

812 Reproductive indices of male snow crabs (Chionoecetes opilio) from the Bering Sea: Analysis of hormones, reproductive structures, and behavior. s. tamone

813 Determining the implications of uncertainty in snow crab recruitment using management strategy evaluation. a. Punt, b. tuRnoCk

814 Recruitment mechanisms for tanner crabs in the eastern Bering Sea.e. CuRCHitseR, a. HeRmann, G. kRuse, J. naPP

815 Pacific cod (Gadus macrocephalus) migration and distribution related to spawning in the eastern Bering Sea: A mark-recapture experiment on a large geographic scale. m. ConneRs, P. munRo

816 Estimating source contribution and dispersal histories of Pacific cod recruits using otolith elemental composition. t.HuRst, J. milleR, J. moss

817 A landscape genetics approach to Pacific cod (Gadus macrocephalus) population structure in the Bering Sea and Aleutian Islands; investiga-tion of ecological barriers to connectivity between potentially distinct population components. i. sPies

825 Assessment of Bristol Bay red king crab resource for future management action: Implementing a cooperative approach. s. HuGHes

* discussed in Other Research Partnerships

Jack Helle


photograph of a hot spot with large concentrations of seabirds and marine mammals.

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The National Marine Fisheries Service annually reports to Congress on the status of fisheries under a federal fishery management plan and identifies their status – overfished, not overfished, approaching an overfished condition, or unknown. These conditions do not distinguish if a stock has declined due to natural or human factors.

We need to understand how these factors interact and influence populations so resource management can adapt. Fishery councils place stocks into different tiers depending on how much information they have, with fewer data result-ing in more cautionary considerations. Given the varying amounts of information known about different species and the uncertainty in resulting stock assessments, scientists are continually gathering more information about target and bycatch species, as well as improving upon stock assess-ment techniques, methods, and models.

The Board has funded 49 projects (29 of which are com-pleted) for over $9.3 million related to stock assessment research and development, ranging from the development of new methodologies to assessing a variety of forage

species, squid, rockfish and planktonic stages of commer-cially important species, to improving existing assessment technologies, integrating ecosystem indicators into assess-ment models, making these models more spatially explicit, and better understanding the general foraging, behavioral, and population ecology of the species of interest.

New Methods for Assessing Difficult SpeciesState and federal management agencies routinely assess stocks of exploited fishes and invertebrates, but some spe-cies are difficult to study. We lack information on forage species, including myctophids, euphausiids, sandlance, capelin, and gadids, which are important prey for large fishes, seabirds, and mammals.

Forage species occur in sometimes dense patches in space and time, and these ephemeral hotspots influence the structure and function of marine ecosystems. Yet survey methodologies do not yet accurately measure these prop-erties, nor have different types of surveys been compared to each other to determine which approaches or combina-tion would provide the best information.

Stock Assessment Research and Development

SoMe oF The MoST ChalleNGiNG iSSueS For FiSherieS MaNaGeMeNT iNvolveS The aCCuraTe aSSeSSMeNT oF FiSh populaTioNS.


fish & inveRts :: stock assessment Research & development

Testing Techniques for Finding Forage Species Project 401

iN projeCT 401, reSearCherS evaluaTed diFFereNT techniques to characterize forage species in the slope, shelf, and nearshore regions of the southeast Bering Sea using ship-based (acoustics, midwater trawls, MultiNet, beach seine, jig, rov) and aerial remote-sensing tech-nologies, including lidar. aerial surveys can rapidly cover large areas and are cheaper than ship-based surveys, but cannot provide information deeper than 20-50 meters.

during ship-based surveys, acoustics profile the water column to the seafloor and direct sampling provides bio-logical information, such as species composition, but the survey is comparatively slow and may not capture ephem-eral events. Ship surveys detected patchy prey at middle depths of 100–300 meters along the slope and nearshore, but dispersed prey at shallow depths of less than 100 meters and in deep water of more than 300 meters over the slope, indicating that eastern Bering Sea slope and shelf regions differ in forage species composition, distri-bution, and abundance. Ship-based surveys also identified unique types of aggregations as well as several intense surface foraging events involving many birds, fish schools, whales, and zooplankton. a typical event measured about ten kilometers across and lasted for about three days.

Both lidar and acoustics recorded similar spatial patterns in forage species distribution, but most of the forage spe-cies remained below the lidar penetration depth at more than 24 meters, even at night.

Given these findings, a compromise between the advan-tages and limitations of each approach appears to be that shelf, slope and nearshore regions should be surveyed separately, and that broad-area aerial surveys can direct ship-based surveys to regions of interest.

on june 17, fish schools reappear and reform the hot spot as well as a secondary hot spot between Unalaska and akutan islands.


Testing profile eco-Sounder Project 521

SCieNTiSTS MoST FrequeNTlY uSe aCouSTiCS To measure and monitor the vertical biomass distribution of key forage species, validated by vertical net tows. Nearly all of the food for pacific salmon, pollock, and other important pelagic predators funnels through either large calanoid copepods (mostly Neocalanus spp.) or through midwater micronekton, which are primarily myctophid fishes and small squids about 5-10 centimeters long.

Both groups live primarily in waters between 400 and 1200 meters deep. Copepods migrate seasonally to deeper water for a prolonged deep dormancy, while the fishes and squids migrate twice a day between the surface and the mesopelagic depths occupied by the dormant copepods.

When they migrate up to the sea surface to feed on cope-pods, the micronekton in turn are a major source of food for pacific salmon and other top predators. Knowing the biomass and distribution of these zooplankton and micronekton is key to understanding variations in food sup-ply for their predators, especially in autumn and winter, when upper ocean food sources are scarce.

Year-round monitoring of both large copepods and micronekton is problematic. For most of the year, nearly all of the monthly total biomass occurs at depth, where sam-pling with nets is difficult, time consuming, and expensive. project 521 focused on adapting a moderate-cost, high-frequency echosounder to allow in situ profiling to ocean depths of at least 1000 meters. researchers modified exist-ing sonar technology to target the size, power consumption, data-compression, and depth requirements and attached it to argo profiling floats.

a series of unexpected technical problems in 2006 and early 2007 prevented full field testing of the new profiling eco-sounder, but information suggests that this technology will deliver very useful biological data from mesopelagic layers of the subarctic pacific.

Life cycle of Neocalanus plumchruus (left) and breakdown by size and depth of its predation mortality (right).



using acoustic Technology to Survey Squid Project 716

Squid are aNoTher iMporTaNT, BuT poorlY uNderSTood CoMpoNeNT of the Bering Sea. prevalent in the diets of northern fur seals, Steller sea lions, and other marine mammals, squid represent significant bycatch in the Bering Sea walleye pollock fishery. Gaps in our knowledge of squid life history and distribution data limit our ability to effectively manage squid stocks, although we do know that squid populations are generally volatile and strongly tied to environmental conditions, such as temperature.

The National Marine Fisheries Service acknowledges that a directed squid fishery in the Bering Sea and aleutian islands ecosystem could quickly develop, but to set catch and bycatch rates for squid, they need quantitative stock information. No one has comprehen-sively surveyed squid in the Bering Sea and so there are no reliable biomass estimates.

Squid are difficult to assess with conventional trawling. acoustics provide an alternate approach, surveying large distances over short time periods and providing snapshots of organisms throughout the water column. project 716 is evaluating the potential of using acoustic technology to assess Bering Sea squid by examining methods used to charac-terize acoustic energy from squid assemblages in the waters north of the aleutian archipelago and along the southern portion of the shelf break near unimak island, called the horseshoe region. Specimens collected through midwater or bottom trawls will be used to verify the identity of species of squid in the area and will provide life history information. Scientists expect to calcu-late a squid density index and a catch per unit effort based on the systematic acoustic data and the trawl catches, respectively.

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Counting rockfish in untrawlable habitats Project 810

The haBiTaT preFereNCeS oF CerTaiN FiSheS MaKe stock assessment surveys problematic. rockfish aggregate in untrawlable rocky areas, yet constitute an important com-ponent of marine ecosystems and commercial fisheries in alaska with an ex-vessel value exceeding $11 million in 2006.

a constant problem in estimating groundfish biomass using trawl surveys is the unknown, but presumed signifi-cant amount of the continental shelf that is not fishable with the survey trawl. To estimate the total biomass for a spe-cies, catch per unit effort data from a survey are generally expanded across entire regions regardless of the propor-tion of untrawlable ground within the area. There is some evidence that untrawlable areas can have different species assemblages and different size classes or abundances of the same species than trawlable areas, potentially resulting in significant effects on the accuracy and precision of bot-tom trawl survey biomass estimates.

project 810 is comparing rockfish abundance between trawlable and untrawlable areas to improve assessments of rockfish abundance. The study aims to evaluate the abil-ity of using advanced remote sensing acoustic and optical

instruments to estimate abundance, including an eK60 echosounder operating at five frequencies, a multibeam echosounder (Me70) to identify school characteristics, and an autonomous underwater vehicle (auv) with a 38 khz echosounder, and a stereo drop camera to measure length. a semipelagic trawl will be fished near the sea-floor to verify species identification and size. results will be used to develop a methodology that will scale up to entire surveys of the untrawlable areas of the Gulf of alaska and aleutian islands, allowing scientists to compare spe-cies composition, abundance, and size between trawlable and untrawlable areas.

the noaa Fisheries aUv is configured with a 38 khz split-beam echosounder, stereo cameras, ctd, and 300 khz adcp.



detecting patches of rockfish Project 809

eveN WiThiN TraWlaBle areaS, SurveYS do NoT count everything everywhere and scientists extrapolate the data to a larger region, making a series of assump-tions about the nature of the fish distribution. in the case of rockfish, these estimates are often highly variable and thus less precise, in part, because of the patchy distribution of these fish. project 809 is using improved acoustic technol-ogy (specifically echosign data) to better allocate sampling effort during stock assessment surveys so as to better rep-resent high-density rockfish patches and thus decrease biomass estimate variability. D

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identifying red King Crab larvae Project 811

a KeY CoMpoNeNT To developiNG aCCuraTe SToCK assessments and predicting year-class strength is to under-stand the dynamics governing early life history stages. The alaska red king crab fishery was one of the most economi-cally important, single-species fisheries in the world with a landed value of uS $265 million in 1980, before its col-lapse in 1981-82 that led to a total closure of the Bristol Bay fishery in 1983. Stocks have not shown any substantial recovery, and researchers believe that the planktonic lar-val dispersal and recruitment for red king crab, like that for many other species, are major determinants of the struc-ture and dynamics of its population.

Crab larvae are patchily distributed in time and space, requiring extensive sampling efforts to track larval disper-sal and understand larval dynamics. a major impediment to analyzing large numbers of plankton samples is the time required to sort and individually identify zooplankton via light microscopy. identification is tedious and not always reliable, making large-scale plankton surveys cost-prohib-itive due to the time and expertise required per sample.

To tackle this problem, project 811 is developing a dNa-based assay (qpCr) for the simultaneous identification and enumeration of red king crab larvae in plankton sam-

ples. The assay will advance sampling techniques, which will facilitate comprehensive studies of red king crab larval dynamics. if successful, such an assay should support devel-opment of similar protocols for Tanner, snow, and blue king crab larvae.

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improving existing assessment Technologies Projects 625, 825

iMproviNG populaTioN eSTiMaTeS iNvolveS More than just developing new technologies for assessing dif-ficult species, but also ensuring the accuracy of current methodologies, especially in light of significant uncertain-ties about gear selectivity and catchability. Such is the case for the Bristol Bay red king crab, which for more than 30 years has been annually assessed by trawl surveys to determine crab densities, biomass estimates, guideline harvest levels, and biological parameters for sustained yield management.

project 625 developed and conducted an alternative, cost-effective survey for Bering Sea crab resources that eliminates or greatly reduces bias and uncertainty in the estimates of crab biomass for all relevant life stages of crab. Based on a successful pilot study by the Bering Sea Fisheries research Foundation in cooperation with

the National Marine Fisheries Service and the alaska department of Fish and Game in 2005, a full survey of 241 random site tows was conducted over approximately 24,000 square nautical miles in 2007.

The new survey gear, sampling methodology, and geo-sta-tistical approach proved highly effective and lowered the uncertainty of the abundance estimates for large male Bristol Bay red king crab of about 37% from the standard NMFS survey over the past ten years to about 13%. results also showed significantly higher estimated mean abundance and reduced variance from the Bering Sea Fisheries research Foundation survey for all sizes and sexes as compared to the National Marine Fisheries Service survey. recognizing that one survey season, although promising, does not set a new standard, project 825 continues this effort with another full-scale side-by-side assessment in 2008.

photos from the 2007 bsFrF trawl showing footrope configuration along wing sections (upper) and the throat section (lower).

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fish & inveRts :: stock assessment Research & development :: ecology :: behavioral ecology

Salmon on the high Seas Project 204

projeCT 204 TaGGed alMoST 1,500 SalMoN iN The Bering Sea to determine where they go in the open ocean and what factors affect their survival. Better understanding of the distribution patterns, habitat use, and movements of asian and North american salmon migrating in the Bering Sea and North pacific ocean helps determine which com-petitive feeding dynamics between different stocks and species may be negatively affecting the growth, maturation rates, and survival of salmon in the Bering Sea.

The tags employed in this study recorded sea temperature, depth, salinity, and daily position. almost 8% of the tags have been recovered to date, and the recorded informa-tion suggests that different species preferred different depth ranges. Chum and chinook prefer deeper water (58–130 meters) than sockeye, while pink and coho salmon are found in waters 22–46 meters deep. Temperatures of the water, on the other hand, varied widely.

researchers concluded that fish choose depth over temper-ature and that these depths may remain relatively constant across water masses and ocean areas. Whether warming ocean temperatures will lead to increases in depths pre-ferred by both salmon and their prey remains to be seen.


Young Salmon in estuaries Project 327

projeCT 327 FoCuSed oN ChuM SalMoN aNd Their Behavior iN eSTuarieS in the last stage of their migration from fresh to salt water, in this case, Kuskokwim Bay. during this period, young fish undergo the energetically costly process of physiologically adapting from fresh to marine water and often experience high mortality rates.

This project studied the patterns of estuarine distribution, diet, body condition, and growth of juvenile salmon in Kuskokwim Bay to better understand the factors regulating this population at this life stage. Scientists found that the timing of outmigration and spatial distribution of juvenile chum salmon in the bay are critically important to their feeding success, and hence to their growth patterns and subsequent chances of survival. as sea surface temperatures increased from 7˚C in May to 16˚C in june, fish lost energy density with size and season, and models indicated that the lowest growth potential for juvenile chum salmon occurred in inshore habitats. Combined, these factors illustrate the delicate balance between different environmental factors needed to properly prepare young salmon for the ocean period of their life, thus influencing how we may assess these stocks at sea.

Ecology

Counting and estimating the number of any given species at a specific point in time and place is complex. determining why a given number of these species are there, or perhaps more critically, why they may not be there, may be even more complicated as it requires in-depth knowledge of their behavioral, foraging, and population ecology. understanding these aspects, however, is crucial to properly assessing and predicting population status.

Behavioral Ecology The Board has funded a variety of behavioral ecology studies focused mostly on salmon, pacific halibut, and pacific cod.

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Migration patterns of pacific halibut Projects 314, 617

paCiFiC haliBuT SupporT oNe oF The STroNGeST fisheries in the Gulf of alaska and Bering Sea and aleutian islands. landings between 2000–2006 averaged over 71 million pounds annually, and are worth approximately $170 million ex-vessel. The halibut fishery is especially important to small communities in western alaska, where they harvest approximately 2.5 million pounds per year. around the pribilof islands, harvest shortfalls led to speculation that the harvest and changing environmental conditions impacted local abundance and/or accessibility to small vessels that fish close to the shore. projects 314 and 617 focused on water temperature preferences and migration patterns of pacific halibut.

Scientists participating in project 314 supplied mem-bers of the local fishing fleet with recorders that could be attached to their longline gear during normal fishing operations to measure bottom temperature and fishing depth. researchers compared these data with daily catch rates, using logbook information and the total weight of fish landed after each trip.

The data did not demonstrate a direct relationship between temperatures and catch within-season, although fleet-wide catch was lowest in 2003, which was warmer on average than 2002 and 2004. The results suggest that halibut do not respond strongly to temperatures within the observed range over short periods, but that local abundance may be influenced by spring temperature prior to commencement of the fishery, with warmer water yielding fewer fish or fish that are harder to capture.

project 617 investigated the question of harvest and the movement of fish. if fish range widely, then the current large area management approach (one stock extending from California through the Bering Sea) may be adequate. if, on the other hand, movement of individual halibut is relatively limited, as suggested by local depletion in the Bering Sea, then areas may be self-recruiting and local area management plans may more accurately reflect pacific hali-but population structure.

researchers tagged 24 adult pacific halibut with externally attached pop-up archival transmitting tags in summer, and released them on the southeastern Bering Sea continental shelf/slope area. in February of the following year, the tag released from the fish, floated to the surface of the ocean, and transmitted the stored data to overhead satellites. results showed that none of the pacific halibut moved out of the region during the winter spawning season, support-ing the concept that fish in this region may belong to a separate group from those in the Gulf of alaska.

The data also revealed geographically localized groups of pacific halibut along the aleutian island chain. all of the fish tagged there displayed residency, with their movements possibly impeded by passes between islands. Mid-winter aggregation areas of pacific halibut are assumed to be spawning grounds, of which two were previously unidenti-fied and extend its presumed spawning range about 1000 kilometers west and about 600 kilometers north of the nearest documented spawning area.

overall, halibut seemed to follow three general behavioral patterns, including dispersal to the continental slope, con-tinental shelf residency, and feeding site fidelity. Several additional research projects conducted by the international pacific halibut Commission and others are currently under-way to help better understand the seasonal movements and population structure, and this behavioral information will help refine some assumptions of pacific halibut biology and ecology.

Location of major known spawning grounds for pacific halibut. From St. Pierre, 1984.

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Movements of pacific Cod Project 620

projeCTS 620 aNd 816 FoCuS oN The MoveMeNT oF pacific cod and implications for stock structure and man-agement. in 1996, the cod fishery caught a record 240,590 metric tons, but catches as of 2005 have declined to about 170,000 metric tons. pacific cod are harvested almost year-round with the concentrated trawl fishery in winter off unimak island called “cod alley” and steady longline and pot fishery over the slope and southeastern Bering Sea.

Besides their economic importance, pacific cod also play an important ecosystem role as a major predator of other marine organisms and as winter prey for marine mammals, such as Steller sea lions. To adequately balance ecological needs and commercial wants, we need to accurately assess the size and boundaries of stocks. resource managers cur-rently identify two stocks of cod in alaska, one in the Gulf of alaska and one in the Bering Sea and aleutian islands. project 620 was a modeling study in which four existing pacific cod tagging datasets were compiled into one to quantify pacific cod movement and to estimate survival and exploitation rates.


distribution of juvenile pacific Cod Project 816

The GraphiC repreSeNTaTioN oF The compiled movement data discussed in project 620 and other previous research indicated that the unimak pass–alaska peninsula area may likely represent the primary source for disper-sal of Bering Sea cod larvae. Fish spawned in this region, or transported through unimak pass from Gulf of alaska spawning areas, would be carried into Bristol Bay by the Bering Coastal Current with possible transport northward toward the pribilof islands. determining this connectivity and dispersal behavior has great implications for manage-ment, yet it is still unknown if larvae and early juveniles follow spatially discrete dispersal pathways depending on the location and tim-ing of spawning, or if individuals from different regions are intermixing throughout their devel-opment phases.

project 816 is attempting to solve this puzzle by using otolith elemental composition to quantify and visualize spatial and temporal patterns in the distribution of juvenile pacific cod collected in the eastern Bering Sea in relation to known spawning distributions, major current fields, and other gadid species.

a graphical presentation of minimum distance traveled and direction of movement of tagged pacific cod in the eastern bering sea. data presented here were based on Fit study only. each arrow represents three or more recoveries, except the one fish captured in russian waters.

although movement could be presented graphically, the four original datasets were too disjointed, either in time or space, to allow a quantitative representation of move-ment rates among regions of the Bering Sea or between the Gulf of alaska and the eastern Bering Sea. The model produced estimates of survival and exploitation rates, but these were considered “not very precise and biased due to the non-controlled nature of the tagging studies in all four datasets.” a well-designed mark-recapture study is needed to fill these gaps, so the Board funded project 816.

© B. Guild Gillespie/www.chartingnature.com



Capturing live Walleye pollock Project 506

TaGGiNG STudieS help SCieNTiSTS aSSeSS Move-ment and stock structure, but only if the results properly represent the natural processes. if care is not taken, tagged fish may be impaired in ways that alter their natural behavior, and thus provide faulty information. project 506 evaluated the feasibility of capturing live walleye pollock with a closed-codend trawl net, which researchers hoped to use for large-scale tagging surveys of pollock in the Bering Sea and Gulf of alaska.

a closed-codend trawl net pools fish in calm water as the net is brought on deck. live pollock from ten trawl samples were placed in laboratory holding tanks for 30 days to ana-lyze survival rates as a function of trawl depth, fish length, and catch density.

From nine of these samples, survival after 30 days was low, with pollock suffering significant scale loss during capture. But from one sample, the survival rate was nearly 50% after the codend unexpectedly overfilled with fish, plugging the codend pool.

This outcome suggested that captured pollock benefit from being within dense aggregations of fish, preventing them from harmful contact with the sides of the net or swimming to exhaustion. Fish length also positively correlated with survival rates. The effects of depth resulted in some pollock displaying persistent symptoms of barotrauma, suggest-ing that pollock caught in deep water adjust poorly once brought to the surface.

overall survival rates of the ten trawl samples were not sufficiently strong to endorse a full-scale tagging sur-vey without further testing. however, information gained from this study indicated that satisfactory survival may be achievable by targeting dense aggregations of large fish, and carefully de-gassing any individuals with symptoms of disorientation or swimbladder distension.

the noaa trawl net with chafing gear attached, being lifted onto the survey vessel deck after a tow.

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fish & inveRts :: stock assessment Research & development :: ecology :: foraging ecology

Foraging Success of Capelin and juvenile pollock Project 524

For BoTh eColoGiCal aNd CoMMerCial reaSoNS, project 524 looked at the forage requirements and interac-tion between pollock and capelin to better understand their productivity. using mid-water trawls, researchers collected fish for stomach contents analysis off of Kodiak island, and recorded physical (CTd) and biological (zooplankton) data. The previous year, investigators found spatial overlap between capelin and pollock, with both species foraging on euphausiids, suggesting the potential for competition.

in 2005, however, only juvenile (age-0) pollock were dis-tributed in the cool, high-salinity waters coincident with the distribution of the bulk of their preferred prey, euphausiids, whereas capelin distribution was more wide-spread and coincident more with the distribution of copepods, their dominant prey that year.

although capelin and pollock ate different prey in 2005, capelin occurring with pollock often had reduced foraging success compared to capelin occurring alone. This sug-gests that juvenile pollock were the superior competitor of the two species and that the exclusion of capelin from for-aging on euphausiids has negative consequences for their growth, and perhaps even their survival. We still need to further examine the potential for resource limitation and to study in more detail the interactions been capelin and juve-nile pollock and its effects on their respective productivity.

Foraging Ecology The Board funded two foraging ecology projects—one project studies how oceanography, prey distribution, and competition can determine foraging success, survival, and productivity of capelin and juvenile pollock, and the other project focused on the diet and ecosystem role of skates in the Gulf of alaska.

Walleye pollock is a key species in the alaska groundfish complex and a target species for one of the world’s largest fisheries. juvenile pollock are prey for other groundfish, such as pacific cod, arrowtooth flounder and pacific halibut, as well as for marine mammals and seabirds. Capelin, while not important commercially, are an important forage fish in alaska, serving as important prey for seabirds, groundfish, and marine mammals.

distribution of euphausiids(sa m2 nm-2) in august 2004 based on 120-38khz acoustic differencing overlaid on water temerature (˚c) at 75 meters.



fish & inveRts :: stock assessment Research & development :: ecology :: Population ecology

disease in herring populations Project 319

iNCreaSed KNoWledGe aBouT CriTiCal liFe-hiSTorY parameters is not only crucial for commercial species, but also for those that support valuable resources and play important roles in subsistence. pacific herring encompass all of the above.

herring range throughout coastal regions of the North pacific. They are a critical source of high-energy food for other fish and marine mammals, such as Steller sea lions, and are highly valued in commercial and subsistence fish-eries. pacific herring first spawn as three- to five-year olds and live as long as 15 years. Mature herring spawn yearly,

Population Ecology The study of how populations interact with the environment, and the dynamics and demography of species populations makes population ecology a large and important field of research that provides critical life-history information needed to build accu-rate population and stock assessment models. its importance is reflected in the $4.3 million the Board dedicated to 23 projects focused on this subject through 2008, spread across numerous species of commercial and ecological importance, including skates, dogfish, squid, sculpin, crab, herring, salmon, pollock, cod, atka mackerel, halibut, and rockfish.

but the population has abundant year-classes only every few years, likely connected to environmental factors, nutri-tional stress, exposure to contaminants, and disease.

our understanding of the detailed ecological and evo-lutionary impacts of disease in marine systems is very general, and for herring is particularly poor. as a result, project 319 focused on identifying a biological “marker” that could show if pacific herring were affected by disease in the past, so that scientists could determine the existence of disease before populations decrease in the future, and thus shed light into one of the parameters affecting herring

population trends.

researchers used 1,300 historic fish liver samples collected in prince William Sound from 1988 and 1994 to study how age, gender, season, and disease affected the amount of small round struc-tures called pigmented macrophage aggregates (pMa) normally found in fish organs. The study showed that pMa are excellent permanent biomarkers of pop-ulation level stress in pacific herring that remain with a year class until the fish die. differences in pMa volume between the 1988 and 1994 fish supported the idea that a stress-related population decline of herring occurred sometime between 1992 and 1994 due to a disease out-break, and not immediately following the 1989 Exxon Valdez oil spill.

Clupea pallasii. pigmented macrophage aggregates in the livers from two, six-year-old male pacific herring sampled in 1994. Micrographs within a column are from serial sections of the same liver; micrographs within a row were stained with the same reagents. Magnification is the same for all images.

F E A t u R E P R O J E C tfish & inveRts :: stock assessment Research & development :: ecology :: Population ecology

Skates in alaska’s Seas Projects 510,621,715

combined, these three projects have provided

the first quantitative information on age,

growth, and reproductive biology of eight alaska

skate species, none of which had been

previously studied in alaska waters.

SKaTeS are CoMMoN, BoTToM-dWelliNG CarTilaGiNouS FiSheS ThaT Serve important ecological functions as top predators and compete with other groundfish. Four species inhabit the outer continental shelf and upper continental slope environ-ments of the Gulf of alaska—big, longnose, aleutian, and Bering skates.

We know little about what skates eat in alaska waters, which severely limits effective management of skates and co-occurring species. project 621 aimed to provide quan-titative information on their feeding ecology by collecting individuals caught during the fishery independent trawl surveys of the National Marine Fisheries Service and alaska department of Fish and Game in the western Gulf of alaska in the summers of 2005-2007.

all skates of the four study species were identified, sexed, measured, and stomach con-tents were preserved for identification and analysis. all skates ate primarily shrimp and crab, although aleutian and Bering skate diets differed among years, with euphausiids comprising a much greater proportion during 2007, and relatively fewer shrimp.

This first systematic quantification of skate diets in this region provided crucial informa-tion for multispecies trophic models, ultimately allowing more effective ecosystem-based management plans. Stomach samples from 2,060 skates were collected in the Gulf of alaska during 2005–2007. researchers continue to investigate the sources of variability, such as body size or location and depth of capture, in skate diets.

Life Histories of Skates using the skates collected as part of project 621, projects 510 and 715 derived informa-tion on their age, longevity, growth, and reproductive biology. Skates are commonly taken as bycatch in groundfish fisheries in the Gulf of alaska and eastern Bering Sea, and in 2005, approximately 620,000 pounds of skates were caught as bycatch but mostly discarded.

While skate susceptibility to fishing pressure has been well documented, we lack enough knowledge of their life histories to assess stocks and implement sustainable manage-ment plans. Knowing more about skates has recently become even more important with the emergence of directed fisheries for big and longnose skates in the Gulf of alaska.

These two projects revealed maximum age estimates for aleutian and Bering skates of 17 and 13 years, respectively, with no significant differences between the growth of females and males for either species. researchers estimate that aleutian skates reach maturity at ten years, and Bering skates become mature at seven years, with resulting demographic models projecting annual population growth rates of 25% for aleutian skates, 36% for Bering skates, 33% for big skates, and 20% for longnose skates.

project 715 continues these research efforts as it studies the age, growth, and reproduc-tive biology of four additional alaska skate species (commander skate, whiteblotched skate, whitebrow skate, and mud skate). Combined, these two projects have provided the first quantitative information on age, growth, and reproductive biology of eight alaska skate species, none of which had been previously studied in alaska waters.




life histories of dogfish Projects 418, 511

BeCauSe MaNY elaSMoBraNChS, iNCludiNG SKaTeS and sharks, grow slowly, mature late, and have few young—characteristics that make them especially vulner-able to fisheries exploitation—we need details on these species-specific traits to develop realistic stock assessment models and establish sustainable management. projects 418 and 511 investigated the abundance, life history, and population demographics of spiny dogfish to conduct a preliminary stock assessment based on bycatch data.

in the Gulf of alaska, dogfish have long faced fishing pres-sure in significant quantities as bycatch in commercially valuable sablefish, salmon, halibut and other fisheries. No one knows the impact of this fishing mortality on dogfish populations in the Gulf of alaska, and no stock assessment had been completed prior to these studies.

researchers collected dogfish through targeted sampling cruises, state and federal assessment surveys, and oppor-tunistic fishery bycatch samples between 2004 and 2007 across the Gulf of alaska. They also drew on observer data, survey catch per unit effort (Cpue) and logbook informa-tion, then used ageing technologies validated in the lab to model the most appropriate age and growth curves for spiny dogfish.

using dogfish samples, investigators analyzed predomi-nant prey species and regional variability in the diet, and, using the catch-per-unit-effort data, established a stan-dardized index of relative abundance. This index, coupled with a surplus production model, allowed them to calculate the potential risk of fishing to spiny dogfish.

The studies found that dogfish primarily eat herring, smelt, and other forage fishes, with shrimp being the most abun-dant non-fish portion of their diet. Male and female spiny dogfish showed similar growth rates until 30 years of age, after which females grew faster and larger than males and lived longer. dogfish catch rates varied with year, area, depth and vessel, and models estimated that dogfish may be at 80%-90% of their theoretical population carrying capacity in the Gulf of alaska.

Given our current life-history knowledge, it appears that the population would decline under relatively low rates of fishing mortality, with harvest strategies targeting juveniles and subadults leading to the greatest risks to sustainability. These results are currently being folded into the forth-coming NpFMC stock assessments for spiny dogfish and provide the critical tools needed to build a full population dynamics model.

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Life history studies reveal that dogfish grow slowly, mature late, and primarily eat herring, smelt, other forage fishes, and shrimp. dogfish face fishing pressure as bycatch in commercial fisheries.



Squid life histories Project 627

The NorTh paCiFiC FiSherY MaNaGeMeNT CouNCil manages squid and sculpin as part of their “other species” category, which has an aggregate quota that also includes taxonomically and biologically dissimilar groups such as sharks and octopi. researchers assume that squid biomass is huge and mostly concentrated in the Bering Sea basin waters. Squid play an integral role in the trophic web as predators of larval fish and zooplankton, and as prey for larger fish and marine mammals, with as much as 1,000,000 metric tons of squid consumed as prey.

despite squid’s ecological importance, and extremely high abundance in the Bering Sea, we know little about their life histories. project 627 filled in some of these gaps by collecting gonatid squid from research cruises, and oppor-tunistically from commercial fisherman, then removing stomachs for diet analysis, and inner ear bones (statolith) for determining age by counting the daily rings. researchers

also used chemical signatures embedded within the stato-lith to estimate the degree of squid movement between hatching and capture locations.

although limited sample sizes did not permit detailed diet analysis, it appears that in summer, Berryteuthis magister mainly ate euphausiids and gadids, whereas B. anonychus ate arrow worms, fish, and euphausiids, Boreoteuthis bore-alis ate fish, euphausiids, and amphipods, and Gonatus kamtschaticus ate squid, fishes, crabs, and euphausiids. This is the first diet baseline information for these species. Scientists found that B. magister, which made up most of the available samples, complete their life cycle in about one year. juveniles and adults appear to occupy different parts of the water column, indicating that the hatching and capture locations are not the same and that B. magister hatch at three or more different hatching locations along the Bering Sea slope.


ecological role of Sculpin Project 628

projeCT 628 FoCuSeS oN SCulpiN, WhiCh represent a significant portion of fishery bycatch in alaska, with an average of 6,658 metric tons or 22% of the “other species” catch total from 1997–2004. The study focuses on determining age, growth, reproductive biology, food habitats, and other life history parameters to improve stock assessments models and to better understand the ecological role of four abundant large scul-pin species (bigmouth sculpin, great sculpin, plain sculpin, and the yellow irish lord) in the Bering Sea. Samples were collected during the summer 2006 Noaa eastern Bering Sea continental shelf and the aleutian islands survey conducted by the alaska Fisheries Science Center, as well as dur-ing the fall, spring, and winter of 2007-2007 using field contractors.

photographs of plain sculpin otoliths aged using the surface and the break and bake method. a shows large early years on the surface and the break and bake method. b shows a small 1st year on the surface, but normal size on the break and bake.



The reproductive Biology of Female Snow Crabs Project 508

BY 2004, The reCoMMeNded GuideliNe harveST level for the snow crab fishery dropped to 6% of the 1991 historical maximum of 328 million pounds. The geographic range of snow crabs in the eastern Bering Sea has con-tracted substantially towards the northwest, but no one knows how this reduced range is affecting recruitment. project 508 analyzed existing data from trawl surveys conducted between 1978–2003 by the National Marine Fisheries Service, and from immature crab taken from cod stomachs.

results showed that the early benthic life history for crabs at depths of 50 to 100 meters in the eastern shelf of the Bering Sea lasts for an average of six years—from settle-ment to terminal molt when females reach maturity or males reach adulthood. Towards the north shelf, life history events tend to be delayed due to colder temperatures, presumably because of a combination of biennial brood-ing and lower molting frequency at higher latitudes.

Females live for up to 14 years, including six to seven years of reproductive life. Males may live up to 18 years. The study confirmed and expanded previous results showing that female recruitment over the last 25 years occurred in a regular cycle of four pulses, with a six- to seven-year period.

The cyclical signal in the abundance of recruitment to the mature female and male populations appears to have a pervasive effect on virtually every aspect of snow crab life history and population ecology—female size at maturity, egg clutch fullness, sex ratios, and average age past-termi-nal molt among others. The research suggests that using aggregate indices of spawning biomass…as a surrogate for female effective reproductive output in conventional stock assessment can be seriously misleading, obscuring interpretable patterns in the case of stocks that, like snow crab in the eastern Bering Sea, show strong geographic structure. This is particularly so when biological process are strongly governed by environmental gradients, geographic features, and patterns of circulation and other hydrographic processes, as is the case for this species.

the geographic range of snow crabs in

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Male Snow Crabs Projects 812, 714

projeCT 812 iS addiNG To our reNeWed uNder-standing of crab reproductive biology by focusing on male snow crabs, particularly on the physiological difference between males that have reached terminal molt and are thought to be mostly responsible for mating, and indi-viduals in stages before the terminal molt that are already reproductively mature.

a more detailed understanding of the factors that con-tribute to successful mating and maximal fertilization of a clutch could support more refined population models. project 812 is thematically synergistic with project 714, which is examining the relationship between the amount of sperm in the spermathaeca (sperm load) of Bristol Bay king crab, and the percentage of the clutch that is fertilized.

project 714 is also assessing egg quality and larval fitness relative to female size and reproductive history to incor-porate these reproductive potential indices into stock assessment models, which currently only use a crude mea-sure of reproductive output based on total female biomass.


Tanner Crab abundance Project 814

projeCT 814 FoCuSeS oN TaNNer CraBS, aNd aiMS to investigate the causes of the wide swings in Tanner crab abundance over the last 15 years, seemingly due to extreme recruitment variability. understanding the pro-cesses driving this variability would let fishery managers set sustainable biological catch and overfishing limits, and provide a basis for evaluating impacts of climate variability.

The study will apply a process-oriented, simulation model to explore the effects of stock biomass on recruitment through density-dependent relationships. investigators will also look at how bottom temperature affects gonadal development of maturing adults, and how wind impacts the supply of nutrients leading to primary and second-ary production favorable to larval crab feeding. The study also examines mixed-layer temperatures on productivity of copepod nauplii as prey of larval crab, and the advection of larval crabs to suitable nursery areas distant from the cold-pool predators such as pacific cod, and cannibalistic subadult and adult crabs.

estimated male tanner crab recruitment in bristol bay, during 1976-1996. recruit-ment occurs approximately seven years after egg hatching.

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F E A t u R E P R O J E C tfish & inveRts :: stock assessment Research & development :: ecology :: Population ecology

reproductive Biology of atka Mackerel Projects 417, 522

aTKa MaCKerel SupporT a MulTi-MillioN dollar commercial fishery and are important food for fish, sea-birds, and marine mammals in the marine ecosystem of the aleutian islands. resource managers need to know more about atka mackerel life histories to best manage this valu-able species.

projects 417 and 522 proposed to learn more about how temperature affects the development of embryos, how maturity and fecundity differ and change among areas during the reproductive season, and to describe male guarding behavior of egg masses.

using National Marine Fisheries Service atka mackerel tag recovery cruises, researchers collected atka mackerel and their egg masses from inside and outside Trawl exclusion Zones, then mapped their distribution by reproductive condition. They determined female maturity and fecundity across different geographic areas, and used parentage analyses of embryos produced in both captive and natural populations to assess the mating system and patterns of egg cannibalism by adults.

The reproductive ecology of atka mackerel turned out to be more complex than previously assumed. atka mack-erel spawn only in specific portions of their habitat, mostly inside the Trawl exclusion Zones, with males, females, and immature fish living in different areas during the spawn-ing season. depending on water temperatures, eggs can take up to 100 days to hatch, meaning that adults could be spawning and guarding nests for up to six months a year. The study revealed that fecundity and maturity are dependent on growth patterns, with mature females (3-4 years old) in better body condition being more productive.

The study also found that although males mostly fathered the eggs they were guarding, sneaking behavior by other males resulted in egg batches produced by multiple parents.

overall, variations in behavioral and environmental factors can lead to spawning systems with seasonal influences on the temporal and spatial distributions of the adult popula-tion, and it turns out that females are able to regulate their fecundity in response to area and year-specific variations in the environment. incorporating this information into stock assessment models and fishery management will greatly enhance our ability to successfully assess and manage this species and fishery.

the 21 stages of embryonic development for Pleurogrammus monopterygius. egg diameter = 2.66 millimeters.

atka mackerel egg masses.

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Map of spatial atka mackerel fishing controls, including the nMFs statistical areas, steller sea lion critical habitat, and trawl exclusion Zones. also includes three study sites of amchitka island.



reproduction of pacific ocean perch in the Bering Sea Project 629

The idea ThaT larGe FeMaleS MaTTer a GreaT deal to the population due to their high reproductive potential applies to a variety of species, including pacific ocean perch. in this long-lived and commercially important species of rockfish, age and size of females could poten-tially be mediating recruitment variability. project 629 is investigating the size- and age-specific female reproduc-tive effort of ocean perch and incorporating these data into age-structured population models to determine if and what maternal effects play an important enough role to be taken into account in stock assessment models.


life histories of pacific Cod Projects 618, 815, 817

projeCT 618 aiMS To ideNTiFY The SpaTial aNd temporal patterns in spawning and maturity of commer-cially and ecologically valuable pacific cod in the Bering Sea. Monthly maps of cod maturity stages, based on data collected by observers on commercial vessels, help deter-mine the location and timing of cod spawning. Maturity data collected at St. paul island and from the National Marine Fisheries Service Bering Sea trawl surveys and fisheries observers, lets researchers assess the spatial dif-ferences in cod maturity schedules to better understand the potential for climate-driven shifts in fish distribution to impact cod life history parameters.

Distribution of CodFollowing up on the recommendation made in project 620, project 815 will tag 12,000 fish and quantitatively esti-mate movement rates in the eastern Bering Sea between pre-spawning distributions in the fall to spawning distribu-tions in the late winter and early spring. understanding this movement is critical to adult life history. This project is the first study specifically designed to relate geographic distributions and movement on scales necessary for identi-fying potentially separate spawning stocks. doing so gives resource managers insight to harvest decisions that can preserve the health of these cod stocks as components of a larger system.

Boundaries for Gene Flowusing landscape genetics as an alternate approach to determining whether there are discrete populations of cod with the Bering Sea and aleutian islands management area is the focus of project 817. landscape genetics is a rela-tively new approach for examining population structure, but has the potential to identify and correlate clear physical boundaries, such as oceanic passes, deepwater canyons, and current systems, to gene flow (index for the amount of individuals moving between areas). The complex and var-ied physical environment of the Bering Sea and aleutian islands lends itself to such a study and if successful, results would complement movement information inferred from the tagging study (project 815), and substantially add to our understanding of the population dynamics of this species.

Late stage pacific ocean perch larvae.

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Greenland halibut Collapse Project 619

quaNTiFYiNG The iMporTaNT CoNNeCTiviTY BeTWeeN spawning and nursery areas for Greenland halibut is the focus of project 619. Greenland halibut used to be one of the most important commercial flatfish species of the eastern Bering Sea, with landings in the late 1970s far exceeding the 2005 combined landings of all other com-mercial large flatfish species, such as pacific halibut, arrowtooth flounder, and flathead sole.

however, since the late 1970s when landings measured 80,000 tons, a dramatic decline in recruitment resulted in landings of about 2,000-3,000 tons during the three years before the onset of this project. The collapse of this stock is in strong contrast to the increase of other flatfish spe-cies of the eastern Bering Sea and the causes for these

differences, and for those leading to the ongoing recruit-ment failure, remain poorly understood.

a critical aspect of the Greenland halibut life history appears to be the transport of eggs and larvae from their deepwater spawning areas across the slope to suit-able nursery locations on the shelf. it is the hope of this project that understanding how evolving physical condi-tions of the Bering Sea affect this transport pathway will provide critical insight into the recruitment dynamics of Greenland halibut, and possible other deepwater spawn-ing flatfish. researchers are employing a combination of field and laboratory work as well as modeling to achieve these objectives.


Walleye pollock in the Gulf of alaska Project 523

FeMale WalleYe polloCK SpaWN MillioNS oF eggs, but 99% of these die before the end of their first year, due to high levels of predation, transport by ocean currents out of their preferred habitat, and a lack of food. project 523 developed and used a physical-biological model to simulate the physical environment and the early life history of walleye pollock in the Gulf of alaska for a bet-ter understanding of the processes that influence walleye pollock recruitment, and how recruitment may fluctuate as climate changes. part of this study also looked at the rela-tionships between spawning locations and nursery areas of walleye pollock in the North pacific.

The study showed that young pollock that were spawned in outer Cook inlet, Shelikof Strait, the Semidi islands, as well as in the Shumagin region, may all be using the Shumagin island region as a nursery area. Contrary to pre-vious assumptions, the model indicated that many young pollock hatched in the Gulf of alaska may eventually end up in the Bering Sea, especially if they were spawned on the outer edges of the continental shelf or slope or in the Shumagin region.

This result raises two important ecological and manage-ment questions. are the Gulf of alaska and Bering Sea walleye pollock populations really separate, as reflected in the current management scheme, or is recruitment in the Bering Sea affected by spawning in the Gulf? and is the

Shumagin island region a self-sustaining population, or are all the young fish produced in this region “lost” to the Bering Sea? results from this modeling effort need to be validated with field observations, but if they are, the pre-dicted survivorship and transport from the model could be added to the annual stock assessments of walleye pollock.

Map a: regions where modeled pollock eggs were released for the years 2000-2004.

Map b: positions of particles (correspond-ing to eggs, yolksac larvae, feeding larvae, and juveniles) during the simulation on august 1, 2000.



Tracking juvenile Sockeye Salmon Project 205

deTerMiNiNG The GeoGraphiCal BouNdarieS oF different fish populations and quantifying the connectivity between different areas are important aspects of population ecology and species management, and help in determining population trends. researchers traditionally relied on tag-ging individual fish and receiving tag returns from fisheries. in recent years genetics, specifically microsatellite loci and single nucleotide polymorphism (SNp, pronounced “snip”, a small genetic change or variation in the dNa), have been increasingly used to track migration, survival, and stock structure of commercially important fish species.

using these genetic markers, project 205 tracked the migration and relative survival of juvenile sockeye salmon populations exiting Bristol Bay and the eastern Bering Sea. data were collected from across the entire eastern Bering Sea using the National Marine Fisheries Service ocean Carrying Capacity (oCC) surveys of 1999-2002, and com-pared to juvenile reference samples. unfortunately, the oCC experimental design for sampling juvenile sockeye salmon differed every year in both sampling locations and time of year, precluding a systematic analysis of the data.

results showed that these genetic techniques could be suc-cessfully applied to these types of studies and confirmed that stocks originating from throughout Bristol Bay head out into the bay at about the same time and migrate along the northern alaska peninsula in a southeasterly direction.

Some data suggested that the more northerly-derived fish, along with all the other stocks, can migrate northeasterly in some years, but given the single sampling observation period it is difficult to predict where these fish migrated later in the season. a comprehensive analysis of the interplay between ecological and oceanographic factors became the focus of project 303.

september stock distributions (except r1-aug) in the bering sea for immature sockeye salmon collected in 2002 and 2003. sample sizes of successfully genotyped fish are indicated.

Dustin Pillips



Where do pacific ocean perch Go? Projects 420, 512

paCiFiC oCeaN perCh deSCriBed aS parT oF projeCT 629 were also the subject of projects 420 and 512, which used genetics to determine interannual and spatial varia-tion in northeastern Gulf of alaska young-of-the-year perch. an important question for this species and other rockfishes is how far individuals move between the release from their mothers until they reproduce about six years later, and how this relates to the size of current management areas. if these areas are much larger than the dispersal distances, uneven harvests may erode potential production and must be carefully considered in stock assessments and manage-ment regimes.

Between 1998 and 2003, researchers collected young-of-the-year pacific ocean perch opportunistically during surveys of juvenile salmon in the Gulf of alaska and Bering Sea. They genotyped each fish at the same 14 microsatellite loci used during a previous adult ocean perch study, which served as a reference. The genetic composition of the col-lections of the young ocean perch was compared within and among sampling areas within a collection year, as well as among years for a particular sampling areas. areas dif-fered from each other within a year, confirming that pacific ocean perch in alaska have a strong localized population structure. although they have the opportunity and abil-ity to disperse long distances during their life times, they do not, which means that harvested fish originate close to

where they are caught. Noted differences between years at the same geographic locations suggest that the month of capture or differences in oceanographic conditions can produce differences in distribution patterns from year to year. Clearly, the sampling scale of adult fish at about 400 kilometers was much larger than the scale of the population structure, and it appears finer-scale sampling is needed to build accurate models that can evaluate the effects of dif-ferent management approaches.


identity of rougheye rockfish Project 209

projeCT 209 eMploYed GeNeTiCS To deTerMiNe whether rougheye rockfish is really two different species currently managed as one. Fishermen target commercially valuable rougheye rockfish, often harvesting to the maxi-mum level allowed in bycatch guidelines. if two distinct species exist and scientists could identify visual cues for telling them apart, it would be a substantial contribution to conservation and management.

using two independent types of genetic markers to dis-tinguish between species, the study confirmed that there are two distinct species, with very few naturally occurring hybrids between them. although one type generally had lighter coloration, there was too much visual and mor-phological overlap to currently allow for a quick and easy distinction in the field.

The population genetic survey did show that one species dominated along the aleutian Chain and in the Bering Sea, but that both were present in the northeastern Gulf of alaska. Scientists are continuing this work to develop molecular methods which may be more rapidly applied in the field in the future. in the meantime, we still know little about the ecological differences between these two closely related species.

Map of collection sites and geographic groupings of adult pop (palof 2008). Geographic groupings are: Queen charlotte islands (Qci), cross sound (css), Yakutat (YaK), cordova (cor), Kodiak (Kod), shumagins (shU), akutan (aKU), central aleu-tians (aLe), Western aleutians (WaL), southern bering sea (sbs), and central bering sea (cbs). solid black lines delineate management areas.


Environmental Issues in recent years, however, and with increased concern about changing climate ocean conditions, the explicit examination of environmental factors driving population dynamics has received more attention, and the Board funded three projects that fall into this category through 2008.

fish & inveRts :: stock assessment Research & development :: improving stock assessment Models :: environmental issues

Forecast Model for Bristol Bay Sockeye Salmon Project 317

projeCT 317 developed a pre-SeaSoN ForeCaST model for Bristol Bay sockeye salmon based on oceano-graphic and biological variables that influence the timing of returning adults. The run of Bristol Bay sockeye salmon occurs within a narrow time span, typically between late june and late july, so migration timing has a significant effect on the interpretation of in-season abundance of Bristol Bay sockeye salmon. The run size entering the fish-ing districts during this one month has ranged from 2.2 to 61 million sockeye salmon. researchers developed a statistical model to relate historical migration timing to environmental, biological, and fishery information. results

showed that the migration of Bristol Bay sockeye salmon can be predicted from sea surface temperature in the North pacific ocean if coupled with one or more other vari-ables, such as length of adult salmon, river temperature, or harvest rate. The observed runs were consistent with in-season projections made from pre-season migration timing estimates and historical cumulative daily run size data. The study showed that migration timing forecasts can be used to adjust in-season forecasts of sockeye salmon abun-dance returning to each fishing district, which represents an improved tool for harvest management of Bristol Bay sockeye salmon.

ImprovIng Stock ASSESSmEnt modElS

The number, size, age, location, condition, fecundity, behavior, and many other parameters eventually end up in a stock assess-ment model that calculates the amount of fish that may be caught the following year. Traditional stock assessment models focus on a single species and in the past did not explicitly take the influence of environmental variability on life history parameters into account. Those impacts were implicitly integrated by the updated biological information, such as counts, being used.

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Can Seabird diets predict Fish returns? Project 531

aNoTher projeCT aiMed aT iMproviNG BriSTol BaY SoCKeYe SalMoN reTurNS uSed SeaBird dieTS aS biological indices. Some seabirds eat the same food as fish of commercial interest, potentially responding to changes in the marine environment in similar ways, and thus could be useful in understanding and forecasting fish abundance. Seabirds are the most conspicuous of all marine organisms, which makes them easier to study than fish.

project 531 employed statistical methods to relate when seabirds breed and their reproductive success on St. lazaria island in Southeast alaska, and the pribilof archipelago in the Bering Sea, with the biomass of pacific herring in Sitka Sound and sockeye salmon returns to Bristol Bay, respectively.

Scientists set out to see whether the bird data could pre-dict the fish/fisheries. in Southeast alaska, the breeding time of common murres related positively to Sitka herring spawning biomass four years later, explaining 61% of the variation in herring biomass and thus substantially improv-ing forecasting abilities. The study speculated that murres may breed later in years when conditions are more favor-able for larval and juvenile herring growth and survival, which in turn affects recruitment.

in the eastern Bering Sea, researchers found that the hatch-ing dates of eggs of red-legged kittiwakes on St. paul island and the number of young raised to fledging per breeding pair varied relative to prey availability and explained 42% of the sockeye returns three years later.

The study concluded that this link indicates that both the birds and salmon are responding to changes in the avail-ability and/or quality of available prey and that variation in seabird breeding parameters is affected by the same parameters as those affecting salmon survival at sea. The three-year lag between the bird and salmon information supports previous evidence that the first and/or second year at sea is important in determining sockeye year-class strength.


environmental effects on Snow Crab populations Project 813

projeCT 813 Will iNTeGraTe aN aNalYSiS oF The effects of environmental variables on recruitment directly into the stock assessment model for snow crab. This study is developing scenarios for future recruitment of snow crab and evaluating management strategies based on exist-ing control rules given uncertainty in future recruitment success.

Ryan Kingsbery


Spatial Issues More species appear to have spatial stock structure than previously thought. once spatial scales and the connections of popula-tions between areas become more clearly defined, researchers need to integrate these considerations into the stock assessment models or they won’t weigh into the management decision process. The Board has funded two projects to this effect, one for pollock and one for snow crab.

fish & inveRts :: stock assessment Research & development :: improving stock assessment Models :: spatial issues

Modeling populations of Walleye pollock Project 505

BeFore The STarT oF projeCT 505, The STaNdard eastern Bering Sea walleye pollock stock assessment model had no spatial dimension. Currently there is only sparse infor-mation on the degree, size-dependent differences, and actual routes of seasonal migrations by eastern Bering Sea walleye pollock. during cold years, researchers hypothesize that wall-eye pollock tend to be more offshore as they get older and that there is a general movement from the northwest to the southeast. This project successfully extended the existing stock assessment model into a two-region (northwest and southeastern areas of the eastern Bering Sea), two-season (winter and summer), and age-specific movement model.

Movement between the two regions was estimated based on sparse empirical data, and thus had low precision. The study concluded that a mark-recapture study is needed before such a model has sufficient accuracy to be applied to management, but the successful development of the model structure is an important first step in that direction.

fish & inveRts :: stock assessment Research & development :: improving stock assessment Models :: spatial issues

Modeling Snow Crab population dynamics Project 624

The CoMMerCial iMporTaNCe oF SNoW CraB, Their recent population decline, and geographic range contrac-tion were previously described under project 508. project 624 is working on coupling an individual-based model of larval snow crab with an existing hydrodynamics and food model, and integrating information on the distribution of crab larvae in the eastern Bering Sea. These coupled mod-els help scientists investigate the spatial stock structure of female snow crab and its relationship to transport of larval stages, as well as the relationship between the ice-edge phytoplankton bloom and larval and early settler survival.

despite the contraction in range and decline in abundance of the spawning female population, there have been some strong recruitment years based on a combination of changes in prevailing currents, expansion of the summer cold pool, (which benefits post-settlement survival), and less cod predation on early settlement juvenile crab due to fewer cod. results from this study should provide new insight into spatial and environmental population drivers and thus prove useful for management purposes.

the bottom trawl survey division between the northwest(nW) and southeast (se) regions of the eastern bering sea. areas 2, 4 and 6 are part of the nW and areas 1, 3 and 5 are part of the se.


New Models Single-species stock assessment models, even if amplified to take into account environmental and spatial issues, do not include species interactions, such as competition, that can severely impact population dynamics. as a result, current stock assessment models are still far from the ecosystem approach to management required to deal with today’s challenges. Managing fisher-ies in the Bering Sea and aleutian islands with an ecosystem approach requires understanding the predator-prey relationships between fished and unfished marine resources, as well as resource overlap between different species of commercial interest. Continued monitoring of predator/prey relationships and the development and improvement of multispecies and ecosystem models will aid in these goals, and thus the Board has funded four interrelated studies which either support development of new multispecies models or enhancement of existing ones.

fish & inveRts :: stock assessment Research & development :: improving stock assessment Models :: new Models

predator/prey Models for pollock and Mackerel Project 305

projeCT 305 propoSed To iMprove eSTiMaTeS oF predation mortality of walleye pollock and atka mackerel, both of which are eaten by other fishes, marine mammals, and humans. researchers analyzed more than 20,000 stomachs from a variety of groundfish species in the Bering Sea and aleutian islands and added the information to a multispecies predator/prey model.

The study revealed that major predators sampled in the eastern Bering Sea tended to consume more walleye pol-lock on the continental shelf than on the slope, and that in the aleutians, important prey for groundfish included walleye pollock, atka mackerel, and myctophids. Based on this new information, the updated multispecies statistical model provided substantially more precise estimates of mortality due to predation, a crucial factor in stock assess-ment models.


Multispecies Models for pollock Projects 419, 525

projeCT 419 FolloWed up oN The WorK oF projeCT 305 by integrating new diet information into the multi-species virtual population analysis and the multispecies forecast model. New estimates of pollock (age-1) preda-tion mortality turned out to be larger than the previous estimates. For older age groups, the opposite trend was observed.

preliminary results from the multispecies simulation also suggested that the estimates of average long-term walleye pollock spawning biomass are larger than the single-species estimates. researchers agreed that they need to perform a more detailed review of the new stomach content data and the modeling process before extensive forecasting with this updated model can be used in the management arena. project 525 is taking this process a step further, recognizing that these models need to consider not only predator-prey relationships, but also the impacts of the fishing on them.

This improved model creates a powerful new analysis tool that will let researchers evaluate a broad range of implica-tions of alternative management policies within a complete multispecies framework. results from these models will pro-vide advice to the North pacific Fishery Management Council on how fisheries affect marine ecosystem dynamics through food web interactions and technological interactions.

comparison of the temporal trend of the predation mortality of age-1 walleye pollock.


The Magnuson-Stevens act defined bycatch as fish which are harvested in a fishery, but which are not sold or kept for personal use, and includes economic discards and regula-tory discards. Such term does not include fish released alive under a recreational catch and release fishery management program. in 1998, the National Marine Fisheries Service report “Managing the Nation’s Bycatch,” expanded the definition to include “discarded catch of any living marine resource plus retained incidental catch and unobserved mortality due to a direct encounter with fishing gear.”

We need to improve mitigation measures designed to reduce the catch of unwanted species, or perhaps of cer-tain age groups of targeted species. incidental harvests of endangered species, such as short-tailed albatross, or bycatch of prohibited species, such as red king crab, pacific herring, chinook and chum salmon, can curtail fisheries and elevate concerns for the effects of fishing on other living resources.

incidental catch of undesirable species leads to increased costs of fishing operations and decreases its sustainability. if bycatch mortality is not adequately monitored, it

Bycatch Reduction

The iNCideNTal CaTCh oF FiSheS, MariNe MaMMalS, Sea TurTleS, SeaBirdS, aNd oTher liviNG MariNe reSourCeS haS BeCoMe a CeNTral CoNCerN oF The CoMMerCial aNd reCreaTioNal FiShiNG iNduSTrieS, reSourCe MaN-aGerS, CoNServaTioN orGaNiZaTioNS, SCieNTiSTS, aNd The puBliC, BoTh NaTioNallY aNd GloBallY

increases the uncertainty concerning total fishing-related mortality, which in turn makes it more difficult to assess the status of stocks. also, concentrated discards can result in localized environmental degradation, and hampers growth of that stock and limits future catch.

The bycatch problem is complex because actions taken to reduce the bycatch of one species can increase that of another, and efforts to reduce bycatch mortality typi-cally change the distribution of the net benefits from the fisheries.

in its Science plan, the Board stated that research priori-ties under this topic should include, but are not limited to, mitigation of seabird and marine mammal interactions with fisheries, new technologies, and methods to reduce bycatch, and studies of survival rates of discarded fish to allow accurate estimation of total fishing mortality. From 2002-2008, the Board funded five projects for $900,000 related to fish and invertebrate bycatch. Seabird and marine mammal-related bycatch studies are expanded upon in their respective sections.


Sampling What predators eat in Fall, Winter and Spring Project 622

a CurreNT KeY ShorTFall oF MulTi-SpeCieS aNd ecosystem models is that most of the diet informa-tion they depend on comes from fish collected during assessment surveys, which typically take place between May and September. different key ecological processes occur during fall, winter and spring, which likely have strong impacts on fish populations and model results, as illustrated by the mismatch between production and consumption estimates of walleye pollock in the Gulf of alaska. To address this shortfall, project 622 is sam-pling predator stomach contents collected by observers during non-survey months from the period 2000-2006 and synthesizing the resulting data on a monthly and geographical scale to provide inputs for future model-ing efforts. particular emphasis will be placed on stable isotope analysis that reveals diets over a longer period of time.

total production of Gulf of alaska walleye pollock (lines and points) 1990-2005, accord-ing to the most recent stock assessment, compared with independent consumption estimates of major predators on pollock.


F E A t u R E P R O J E C tfish & inveRts :: bycatch Reduction

development of New Salmon Bycatch Technologies Project 202

iN 2002, The NprB FuNded projeCT 202 To exaMiNe The FeaSiBiliTY oF using sonar technology to reduce salmon bycatch in the alaska pollock fishery. Salmon are a prohibited species in groundfish fishery management plans and cannot be retained or sold if taken incidentally. pollock fishermen try to avoid salmon “hotspots” to stay under bycatch caps, but the effort costs fishing time and fuel as they seek fishing grounds with lower salmon bycatch rates, which potentially also have smaller pollock concentrations.

researchers developed and attached an advanced dual-frequency identification SoNar (didSoN) to nets to provide higher-resolution images that distinguish between different species of fish entering the net. during capture, pollock con-tinuously moved toward the back of the net, with relatively infrequent, brief efforts to hold position or move slightly forward. Salmon, by contrast, fre-quently moved forward, and swam nearer the top of the net than the pollock.

When the net slowed during retrieval, many salmon swam forward, away from the trawl’s codend, whereas pollock remained in the back of the net. This new information aided researchers in developing and testing a new type of salmon excluder that relies on the differences in body shapes and behavior to separate animals during capture.

By using didSoN to identify species before catching them, chinook salmon bycatch was reduced by 12.9%, while pollock still comprised 95.4% by weight of the groundfish capture, with flatfish and cod being the primary bycatch. active industry interest has motivated continued work to improve and apply these excluders.

orientation of the didson sonar and the area that it imaged on the trawl net.

the difference in salmon and

pollock behavior in nets lets

researchers develop and test a

new type of salmon excluder.

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fish & inveRts :: bycatch Reduction

exploring Temperature and Bycatch rates Project 731

To FurTher preveNT SalMoN BYCaTCh iN The pollock fishery, project 731 is investigating the relationship between water column structure and temperature, and the spatial patterns in the catch of pollock, salmon, and other species. researchers think temperature is one of the strongest factors controlling where pollock live. We know less about the specific temperature preferences for adult and young salmon in the Bering Sea, which project 204 revealed to have substantial variation.

Scientists participating in this study are deploying up to 20 temperature-depth recorders on the trawl nets of Bering Sea fishing vessels to collect the necessary physical data to relate to the catch information. if a significant relationship between temperature and catch rates for pollock, salmon, and other incidental species is found, this could be a quick and useful tool for fishermen to predict bycatch rates of salmon and other species, resulting in more selective “tem-perature-directed fishing.”


electronic Bycatch Monitoring Project 325

To aCCouNT For BYCaTCh WheN aSSeSSiNG FiSh stocks and setting fishing quotas, resource managers need to know the amounts. independently collected at-sea data is essential for science, management, and compliance monitoring objectives. over the past two decades, the traditional method of at-sea monitoring of commercial fish-eries by human observers has grown.

With growing monitoring needs, increasing costs and space limits on smaller vessels hampering human observing pro-grams, technology-based at-sea monitoring has emerged. in partnership with industry, project 325 experimented with hardware and software to develop a verifiable and efficient method of remotely counting bycatch aboard certain trawl vessels that would allow a trained human observer on land to evaluate and process catch data collected remotely at sea.

once the tool was designed, 2.5 terabytes of shipboard video data were collected, which a professional fisher-ies observer viewed to identify at-sea discards by event and, if possible, by species. The reviewer watched videos covering a total of 780 hours of at-sea activities, and deter-mined whether there were any bycatch and discards on each haul. it took only 68 hours to physically review and produce reports on those videos, compressing time by a ratio of 11.5:1. The project successfully demonstrated that electronic bycatch monitoring is feasible and could be con-sidered by management agencies as an additional tool to on-board human observers. technicians secure a downward-looking canera to trawler stern gantry.

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Comparing electronic and human observers in the halibut longline Fishery Project 712

The MajoriTY oF veSSelS operaTiNG iN The pacific halibut fishery are not required to have observers, and their bycatch rates are not well estimated. previous research documented successful electronic monitoring efforts of pacific halibut longline fishing on chartered research vessels, yet the technique was not tested in the commercial halibut fishery, where a much broader range of environmental and physical factors affects the vessel operations.

project 712 is evaluating and comparing electronic video monitoring and human observers of bycatch in a commer-cial halibut longline fishery by conducting a cooperative study with the commercial fishing industry with various ves-sel configurations. The resulting information will be key in determining the most cost-effective, efficient, and precise bycatch monitoring methods for this fishery.


Bycatch Crab Survival Project 711

projeCT 711 addreSSeS The iSSue oF uNoBServed Bering Sea crab injury and mortality after seafloor trawl encounters. Bycatch that comes aboard can be enumerated and included in assessment calculations, but some species suffer injury or mortality without ever being observed and counted. To tackle this problem, researchers are designing a recapture net as well as developing handling and holding procedures onboard commercial vessels. They will stan-dardize reflex impairment observations (a method to tell how well a crab is doing) in the lab, then combine these developments to assess the mortality probabilities of crab that have passed the sweeps, wings, and central footrope of a commercial groundfish trawl.

Still others, including sharks and arrowtooth flounder, play important roles in restructuring the ecosystem. understanding the role of natural and human causes on declines of crab, shrimp, western alaska salmon, Greenland turbot, walleye pollock, and halibut and increases in arrowtooth flounder, other flatfish, sharks, and skates is important to developing management strat-egies that reflect their causes. From 2002-2008, the Board funded six projects in this category focused on crab and salmon for just under $1.4 million.

Causes of Major Species Decline

uNderSTaNdiNG WhY SoMe Major SpeCieS populaTioNS have deCliNed are aMoNG The hiGheST prioriTY eCo-SYSTeM reSearCh NeedS. SoMe SpeCieS, liKe CraB, ShriMp aNd polloCK, are parTiCularlY iMporTaNT oWiNG To Their hiGh eCoNoMiC value While oTherS, liKe WeSTerN alaSKa SalMoN, have CulTural SiGNiFiCaNCe aNd loCal value.

Crab research projects focused on diseases affecting snow and tanner crab, as well as on the mysterious disappear-ance of the populations of red king crab near Kodiak that once supported the largest king crab fishery in the world. Salmon projects looked at the dramatic decline of Kvichak sockeye salmon runs, the distribution of sockeye and chum salmon in the Bering Sea, and life histories of Copper river salmon.

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Much research has focused on climate variability impacts on recruitment and growth for groundfish and salmon, but relatively little work has been done in this respect with crab stocks. Yet their high commercial value makes it important to better under-stand the effects of fishery management and environmental processes on crab abundance.

crAB

fish & inveRts :: causes of decline of Major species :: crab

Bitter Crab Syndrome in Snow and Tanner Crab Projects 306, 623

SNoW aNd TaNNer CraB Were diSCuSSed previ-ously under projects 508 and 814. project 306 studied the causative agent of bitter crab syndrome in these two species as a possible key player in increased natural mor-tality and poor recruitment. a parasitic dinoflagellate (Hematodinium spp.) causes bitter crab syndrome, which is fatal in snow and Tanner crabs. infections occur in crus-taceans of all sizes and ages, but juveniles are particularly susceptible. although the parasite causes death, research-ers know little about its life history, or how crabs become infected, yet our understanding is critical for commercially important crabs in the Bering Sea.

using a series of molecular techniques, researchers identi-fied two species of this parasite: one infects the blue king crab, and one that appears to infect all other decapod hosts studied. investigators identified an assay to better detect the presence of Hematodinium, which is the current focus of bitter crab syndrome monitoring efforts. Scientists

are unable to get parasite samples from the environment, even though they targeted areas of known high infestation prevalence. Whether free-living life history stages exist or at what densities, and which environmental parameters are influencing their abundance, remain to be studied.

project 623 followed up on these problems and is develop-ing an even more precise, quantitative molecular monitoring tool (quantitative real-time polymerase chain reaction) for Hematodinium. researchers hope this improved technique will not only detect the presence, but let us monitor the effects on Tanner crab size frequencies and general popu-lation trends, as well as identify potential infection vectors or reservoirs of the parasite, thereby providing key life his-tory parameters that have eluded us so far. assessing these disease dynamics would greatly aid managers in develop-ing alternative harvest strategies to minimize losses due to Hematodinium infections.

prevalence of bcs in eastern bering sea snow and tanner crabs, 1988-1998.

Chionoecetes baidiChionoecetes opilio


fish & inveRts :: causes of decline of Major species :: crab

red King Crab Mystery Project 509

KodiaK oNCe SupporTed The larGeST red KiNG crab fishery in the world, with peak landings at 94.4 million pounds (43,000 metric tons) in 1965, worth $12.2 million at the time. after 15 years of declines, the fishery closed in 1983, but despite the closure, the red king crab population never recovered. The reasons for the collapse and failure to recover remain a mystery that project 509 set out to solve.

To create prospects of recovery and to learn about future sustainability, researchers constructed a population dynamics model using historical fishery and survey data to estimate abundance, recruitment, and fishing and natural mortality over the years 1960 to 2004. They also used geographical analyses to explore potential fishery and ecological factors in the crab decline.

The study found that during a critical time of fishery devel-opment in the late 1960s, a period of strong recruitment promoted fishery overcapitalization, resulting in unsus-tainable harvest rates, particularly from 1981 to 1982. recruitment failed, resulting in extremely high fishing mortality rates on a declining population of mature males, and producing sex ratios skewed toward females. adverse environmental and ecological changes likely magnified these problems.

The stock has remained low, at less than one million males and has been stable since 1985, suggesting that predation may be preventing stock recovery. This new analysis will contribute to setting appropriate harvest strategies, and also help evaluate proposed stock enhancement activities. Scientists will next look in more detail at the effects of eco-logical and environmental factors on recruitment for this species.


annual harvests (metric tons) of red king crab from the Kodiak Management area during 1950-1982.


sockeye salmon.

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fish & inveRts :: causes of decline of Major species :: salmon

Kvichak Salmon declines Project 321

KviChaK SoCKeYe SalMoN, oNCe The larGeST sockeye stock in the world with up to 50% of the world’s sockeye production, declined by 73% between 1991-1999 from 1990 stock levels. To find out what caused this dra-matic decline, project 321 examined external human and environmental factors, as well as possible changes in bio-logical characteristics of this species.

researchers found no evidence to support the previously postulated idea that the decline was due to a regula-tory change in the mid-1980s that led to more stable escapement levels. indeed, specific cyclical spawning escapements do not seem necessary to achieve high pro-ductivity of Kvichak salmon. a detailed look at patterns in smolt abundance and survival at sea indicates that the decline was driven by factors influencing marine survival and ocean conditions influencing subsequent processes in freshwater. Several other Bristol Bay stocks also declined during these years, although not as deeply. Those declines

were associated with the ocean age structure of the popu-lations, with age-2 salmon experiencing greater declines as compared to age-3s, likely due to their smaller size.

The authors of the study hypothesize that Kvichak salmon may have declined because of reduced at-sea growth during late marine stages, which produces the highest per-centage of ocean age-2 sockeye in Bristol Bay. in addition to the impacts of these environmental conditions, the study also examined the possible role of beluga whale predation on smolts migrating out to sea. The analysis estimated that approximately two million smolts are consumed by belu-gas in the Kvichak each year, thus reducing the run by less than 2% per year. The absolute effect of these predation rates on smolts on the subsequent return of adult sock-eye salmon was estimated to be an average of 180,000 fish, or about 2%. Given these results, it is unlikely beluga whales could have played an important role in the decline of salmon returning to the Kvichak river.

Salmon are another species of special interest, particularly concerning some of their regional declines and their implication on commercial and subsistence use, but also concerning their ocean migrations and intermingling of stocks on the high seas, effects of fisheries and environmental conditions on ocean survival, and the issue of overall ocean rearing capacity which is being stressed by increasing releases of young salmon from hatcheries around the pacific rim.

SAlmon



distribution of Sockeye and Chum Salmon in the Bering Sea Project 303

projeCT 303 exTeNSivelY aNalYZed The iNTerplaY between ecological and oceanographic factors influenc-ing the distribution and abundance of asian and North american sockeye and chum salmon in the Bering Sea. researchers looked at stock composition at different sta-tions as well as seasonal migration routes and timing.

The study was carried out under the auspices of the Bering-aleutian Salmon international Survey (BaSiS) developed by the North pacific anadromous Fish Commission (NpaFC), and included researchers from the u.S., japan, and russia, who shared access to a common, comprehensive database on salmon distribution and environmental conditions in the Bering Sea.

Because of the large number of collaborators from the three different nations, the coordination and exchange of ecological data proceeded slowly, and while substantial progress was made, this project was not able to fully inves-tigate the factors affecting the oceanic distribution and abundance of each regional stock. Through the genetic analysis of juvenile salmon captured at stations through-out the Bering Sea, however, researchers did determine that asian and North american chum stocks were not ran-domly distributed. japanese salmon roamed the central Bering Sea, similar to russian salmon which also spread into the North pacific ocean. Northwestern alaska salmon,

including fall chum salmon from the Yukon river, were dis-tributed mainly in the eastern North pacific ocean.

researchers hypothesize that fish migrate from hatcher-ies through the Sea of okhotsk, seasonally through the Bering Sea and northwestern Gulf of alaska, then back to japan. For sockeye salmon, u.S. investigators identified a broader distribution of North american stocks than sug-gested by historical tagging studies. Bristol Bay salmon were the most widely-distributed, accounting for more than half the mixtures in all areas except the southwest-ern Bering Sea. russian salmon were primarily detected in the western Bering Sea, and differences were detected in the distributions between the eastern- and the western-Kamchatka peninsula populations. Salmon from the Gulf of alaska were also widely distributed throughout much of the Bering Sea, although at low proportions relative to the pacific ocean production estimates.

data from this project have provided the founda-tion for continuing studies by NpaFC scientists, pacific Salmon Commission studies by the National ocean and atmospheric administration and alaska department of Fish and Game, and are being used by Fish and Game to improve harvest management in Southeast alaska, Cook inlet, and Bristol Bay.

Greg Ruggerone



Copper river Salmon Project 310

SalMoN are aN iNTeGral CoMpoNeNT oF The socioeconomic and ecological landscape of the North pacific. Most species live part of their lives in fresh water, in estuaries and in the open sea. The amount of time that they spend in these habitats varies greatly in the early life histo-ries and migratory behaviors of coho and sockeye salmon, both on local and regional scales.

For sea-going sockeye salmon, time growing up in estu-aries may be critical for survival. project 310 aimed to quantify the spatial and temporal variability in the age that they migrate to sea and the relative contribution of dif-ferent freshwater and marine residence strategies to the surviving spawners in the Copper river watershed.

Scientists estimated the time coho and sockeye salmon spent in estuaries using traditional fisheries sampling techniques—mid-water trawls, fyke nets, and seine sam-ples. They also used micro-chemical analysis of strontium concentration in otoliths of juvenile and adults within the Copper river delta.

Both species spent only a relatively brief period in estua-rine waters, an average of 30 days, but during that time ingested substantial quantities of food, clearly pointing to the critical role of these estuarine habitats to ensure subse-quent marine survival. The authors point out that natural or human-caused alterations to these vital habitats may have serious consequences for sustainable harvest of salmonids.

Deb

orah

Mer

cy

otoliths lay down daily growth rings that take into account the chemical concentra-tions of ambient water chemistry.

Mar

y Bi

shop

researchers sample for coho and sockeye salmon in the copper river delta.


Changes in the ecosystem may at first only affect species and habitats not managed or harvested, yet eventually reverberate through the food web and have unexpected consequences for fishery management.

ideally, new multispecies fishery management strategies should consider the full range of ecosystem change impli-cations to determine acceptable biological catch levels for

Implications of Ecosystem Change on Fishery Management

harveST raTeS MaY Be SuSTaiNaBle For SiNGle SpeCieS, YeT MaY have SiGNiFiCaNT iMpaCTS oN The overall BiodiverSiTY oF The oCeaNS aT The CoMplex, SpeCieS, SToCK, aNd GeNeTiC levelS. FiSh are NoT reMoved eveNlY WiThiN The populaTioN aNd The poTeNTial exiSTS For CoMpeTiTioN BeTWeeN FiSherieS aNd oTher SpeCieS For reSourCeS.

a particular species based on an optimal harvest of a mix of species, rather than solely by the species biomass.

To provide critical information for such implementation, the Board has funded ten projects for just over $1.5 million, focused on the role of climate and forage species in fishery management, as well as on the development of ecosystem indicators.

Most assessments of the potential role of climate and environmental conditions on fish and fisheries consider statistical relation-ships between various climate indices, such as the pacific decadal oscillation, the aleutian low pressure index, and time-series of fish catches and recruitment. although researchers speculate about cause and effect, explicit links between environmental conditions and species composition, fish survival and growth remain largely uncertain.

EnvIronmEntAl chAngE

Ray Morse


fish & inveRts :: implications of ecosystem change on fishery Management :: environmental change

Climate Change and pacific Cod productivity Project 605

ThrouGhouT The 1990s aNd earlY 2000s, reduCed sea ice cover corresponded with a northward spread of commercially important species in the Bering Sea, includ-ing pacific cod. pacific cod have undergone significant shifts in their diet and in their abundance. like other spe-cies in this family, pacific cod are very productive, laying up to 5,000,000 semi-demersal eggs in one batch during the spring spawning season. This makes them particularly vul-nerable to changing environmental conditions during this critical period.

project 605 is investigating the responses of larval/juve-nile stages exposed to varying temperature and food regimes. investigators are designing models to make spa-tially explicit maps of survival probabilities at monthly and annual scales. They are using data taken from lab studies and coupling these with field data on larval and juvenile distributions, temperature and primary productivity to give insight into the link between climate change and pacific cod productivity.


environmental Factors in herring predictions for Bristol Bay Project 208

projeCT 208 iNveSTiGaTed liNKS BeTWeeN eNviroN-mental factors and a variety of population parameters for pacific herring in Bristol Bay. By analyzing historical catch data, the study surmised that after spawning, Togiak her-ring migrate clockwise around Bristol Bay and are harvested in a small food-and-bait fishery off of dutch harbor in july.

herring then migrate northwest along the continental shelf break to the pribilof islands where they spend fall and win-ter. in completing their migration, herring may migrate over 1,000 miles annually, providing an important eco-logical link between primary production and upper-level predators, as well as between nearshore and offshore food webs in the Bering Sea.

The study found recruitment variability depends, in part, on the match between where and when herring larvae emerge with bio-physical conditions, such as the spring plank-ton bloom during March and april. Conditions along the herring migration corridor and in coastal spawning areas also affected the timing of both the arrival and spawning of herring in northern Bristol Bay. researchers concluded that ocean temperature changes near the ice edge, which are controlled by atmospheric pressure gradients over the North pacific ocean, explain most of the interannual vari-ability of herring spawning, and that placing new moorings in these areas to provide more accurate local information would likely further improve herring spawning predictions.

Mik

e M

iller


F E A t u R E P R O J E C tfish & inveRts :: implications of ecosystem change on fishery Management :: environmental change

jellyfish Fluctuations Project 606

a liNK BeTWeeN CliMaTe ChaNGe aNd produCTiviTY iS SouGhT iN project 606 for jellyfish, which have undergone dramatic fluctuations in biomass in the Bering Sea. jellyfish can adversely affect commercial fisheries by clogging nets, by feeding on young fish, and by competing with fish for zooplankton prey.

jellyfish populations respond promptly to changes in physical and biological condi-tions, both by changes in the rates of production of young jellyfish, and by increased feeding and growth in good conditions. To explore the effects of climate change on jellyfish populations in the Bering Sea, this study is using a 27-year time series of jellyfish catches, which extends through two major regime shifts. researchers are exploring links between current flow and jellyfish distribution and abundance, and determining the effects of variations in physical (sea ice, temperature, atmospheric variables, currents) and biological conditions (zooplankton, forage fish) on where jellyfish occur. our increased understanding of how environmental changes influ-ence jellyfish abundance and distribution will help us understand and predict their potential impacts on fish populations in the Bering Sea.

Understanding jellyfish

abundance and distribution

helps us predict their impact

on fish populations in the

bering sea.

trend in jellyfish biomass from standardized trawl surveys in the bering sea since 1975. shown are the total biomass (black line) and subsets for the se (red) and nW (blue) Middle shelf domains. the inset shows the sampling areas on the bering sea shelf.

Russ

ell H

opcr

oft



Growth rates of Snow Crab Project 713

SNoW CraB diSTriBuTioN iN The BeriNG Sea haS shifted north from Bristol Bay to northwest of St. Matthew island, with evidence of decreasing body size from south to north. The commercial importance of snow crab, and inves-tigations into their stock dynamics in the Bering Sea was previously described under projects 508, 624, 812, and 813.

project 713 expands on some of this work and links to project 624, but specifically aims at understanding the rela-tionship between temperature and the growth rate and diets of settled juveniles and adults around St. lawrence island. The study will provide a critical piece of informa-tion in the life cycle of this species by predicting when and where snow crabs may reach marketable size in more northern areas as the climate warms.


Genetic differences in Walleye pollock Project 610

SCieNTiSTS KNoW or iNFer relaTioNShipS BeTWeeN environmental factors like temperature, currents, or primary productivity and fish year-class strength for many species. Yet they are uncertain whether larval and juvenile mortal-ity is random as a consequence of varying environmental parameters, or whether specific genotypes are favored under certain conditions.

project 610 is using population genomics to estimate genetic differences in space and time for walleye pollock in the Bering Sea for two years with contrasting environ-mental conditions, in particular, temperature. Scientists are also identifying molecular markers that undergo selective evolutionary pressure and assessing the scope for adapta-tion to changing climate conditions.


impacts of Grazers on Kelp Project 407

Kelp BedS are hiGhlY produCTive SYSTeMS ThaT play an important role in nearshore carbon fixation. Many different kinds of invertebrates live in kelp beds, and are prey for other species. Greenlings, ronquils, pricklebacks, and sculpins all use kelp beds as feeding grounds, nurser-ies, refuges and spawning grounds. Several commercially important fish species, including herring and halibut, depend on nearshore kelp beds during different parts of their life cycle. Finally, marine mammals, especially sea otters, forage in kelp for sea urchins, clams and other inver-tebrates, and wrap themselves in large blades of bull kelp during resting periods. Such biological diversity and cas-cading trophic systems depend on the abundance, health, and stability of the kelp beds. The persistence and abun-dance of these living habitats are at the mercy of changing environmental conditions and grazing pressure.

To better understand the environmental and biological dynamics controlling the health of kelp beds and impli-cations on fisheries, project 407 specifically investigated the grazer-kelp relationship between the gastropod, Lacuna vincta, and four common kelp species (Nereocystis luetkeana, Agarum clathratum, Saccharina latissima, S. sub-simplex) in Kachemak Bay, alaska. The study showed that L. vincta, which is only a few millimeters long, is seasonally abundant in the shallow subtidal zone and reaches den-sities of 70 snails per square meter in summer. This snail appears to be a driving force in the spatial and temporal

variability of canopy kelp beds in Kachemak Bay, especially of the dominant, canopy-forming species N. luetkeana, which has very limited defense mechanisms against this grazer.

Considering the multitude of factors and their variability from year to year that likely control kelp recruitment and growth as well as grazer recruitment in Kachemak Bay, it is extremely difficult to predict where and when L. vincta will decimate kelp beds. While at present the researchers found that kelp beds are reasonably resilient and can re-establish a few years after decimation, it is unclear how this resilience may change with changing environmental condi-tions. a small but abundant species like L. vincta is difficult to monitor and manage. learning from terrestrial examples of ecological pest control, the authors concluded that a next step would be to identify natural predators of L. vincta within the system to better understand the level of natural control of the grazer within the system.

Hel

oise

Che

nelo

t,


While capelin, eulachon, sand lance, myctophids, and other forage fish are an important component of the North pacific ecosystem, many aspects of their ecology and population dynamics remain unknown. We understand some of the effects of changes in local availability of forage fish to some seabird colonies, and have estimates of their importance as prey for several commercially important fish species. Yet ecosystem-wide implications of forage fish changes on other ecosystem components remain speculative.

little is also known about the effects of large fluctuations of crab, shrimp, flatfish, and sharks on other ecosystem components through competition and predation. as intermediaries in the food web, all of these species are important conveyors of trophic energy through the food web and variation in their productivity impacts many other predators, such as fish, seabirds, and marine mammals.

fish & inveRts :: implications of ecosystem change on fishery Management :: the Role of forage species

Forage Fish productivity Nearshore in the Gulf of alaska Project 308

iN laTe SuMMer, larGe NuMBerS oF SMall, Silver-colored smelts (capelin and eulachon) and brass-colored young-of-the-year walleye pollock, search the coastal waters of the Gulf of alaska for zooplankton. project 308 examined the effects of coastal hydrography and sea-sonality on forage fish productivity as mediated through bottom-up processes in the western Gulf of alaska.

researchers found that the offshore flow near the Shelikof sea valley had high concentrations of krill and large cope-pods. Fish in regions of high krill and large copepod densities ate more of these prey, were larger and in bet-ter condition, had more growth potential, and/or more fish per volume than areas with lower concentrations of prey. Climate-related forcing on hydrographic dynamics in the Gulf of alaska most affected forage fish growth potentials by altering how much food is available. also, nursery areas, especially for pollock, near Kodiak island appeared to pro-vide environmental conditions that tempered wintertime adversity, implying that regional differences in wintertime nursery habitat for this species could be relevant for juve-nile walleye pollock survival and subsequent recruitment of individuals to spawning populations.

thE rolE of forAgE SpEcIES

John

Pia

tt


fish & inveRts :: implications of ecosystem change on fishery Management :: the Role of forage species

Characterizing Forage resources of the aleutian islands Project 630

our laCK oF KNoWledGe aBouT ForaGe FiSh biology or links to predator distribution and abundance extends to the aleutian islands. relatively few studies have described the regional distribution and abundance of non-commercial nearshore and offshore forage resources in the aleutian archipelago, in part, because surveying such a large area is expensive and difficult, and abundance esti-mates are difficult due to the patchiness of schooling fish and invertebrates.

Nevertheless, project 630 opportunistically used estab-lished research platforms to sample prey and quantify ocean climate conditions to gain a better understanding of the ecological relationships between marine predators, prey resources, and marine habitat. using the u.S. Fish and Wildlife Service M/v Tiglax, a vessel that routinely travels throughout the alaska Maritime National Wildlife refuge along the alaska peninsula and aleutian archipelago, researchers recorded acoustic backscatter and measured sea surface temperature and salinity using haul-mounted equipment.

Midwater trawls sampled pelagic forage species and beach seines captured nearshore forage species. Twenty-four spe-cies of pelagic fishes and 30 species of nearshore fishes were documented throughout the study area. Walleye pol-lock, pacific sand lance and spawning capelin dominated the pelagic catch, and young-of-the-year gadids, pacific sand lance and pink salmon dominated the nearshore catch.

a longitudinal gradient of physical oceanography sug-gested cooler, more saline, and nutrient rich conditions in the west (central aleutians) compared to the east (alaska peninsula). researchers found that automated data collec-tion using equipment permanently installed on the vessel is an efficient and cost-effective way to sample the marine environment during travel of the Tiglax. opportunistic sampling of station data—CTd, plankton tows, beach seines—was moderately efficient, while trawling was least efficient of all sampling procedures. however, during nor-mal operations the refuge bore the cost of transit time, leading to great efficiency in spatial sampling. This research platform has enormous potential for monitoring key eco-system components in the Gulf of alaska and aleutian archipelago on seasonal, annual, and decadal time-scales.

Location of study area and major predator core areas routinely visited by the Tiglax. Map of fishing effort by method during summer 2006.

Carrie Eischens


fish & inveRts :: implications of ecosystem change on fishery Management :: ecosystem indicators

using ecosystem indicators in resource Management Project 502

The Board FuNded projeCT 502 To help deFiNe a framework within which to choose and implement the use of ecosystem indicators for management. ecosystem indicators are part of a larger process that considers policy-level goals for an ecosystem, and so should be linked to operational objectives and performance criteria. although the project focused on the Bering Sea, the intent was to provide insights, findings, and recommendations more broadly applicable to the North pacific and adjacent seas.

using a workshop approach, the lead investigators involved the Bering Sea and international community to discuss a variety of topics, including:• development of operational objectives for the south-

eastern Bering Sea ecosystem • evaluation of the ecosystem Consideration chapter of

the SaFe report and the piCeS Marine ecosystems of the North pacific publication

• investigation of methodologies to monitor system-wide structural changes within the marine ecosystem

• identification of steps to validate indicator perfor-mance, improve the monitoring network, and integrate indicators into predictive models

although this project was ambitious and no specific indica-tors were chosen, substantial progress was made, and a series of recommendations was brought forward.

participants noted that ecosystem-level and community-level conservation thresholds are relatively new ideas in marine conservation, and they need further research. existing indicators need to be synthesized into a usable set of parameters, linked to operational objectives, and evaluated using a formal evaluation and selection process available from other disciplines.

While the workshop did not address socio-economic oper-ational objectives for the Bering Sea and North pacific, investigators noted that links between the well-being of people and healthy marine ecosystems require a level of attention comparable to those for ecosystem conser-vation objectives. They concluded that the North pacific Fishery Management Council should play a central role in shepherding the development of these socio-economic objectives and indicators for the southeastern Bering Sea and Gulf of alaska ecosystems.

as we move toward ecosystem-based fishery management, discussions focus on identifying ecosystem indicators that will monitor trends in the ecosystem and help evaluate whether current management measures are achieving their objectives. on a smaller level, fish quality expressed as energy density could be an index for the health of individual fish. project 210 supported the purchase of the equipment necessary to carry out such analyses. Many other species-specific and region-wide environ-mental parameters have been suggested as indicators of ecosystem status. But even though such indicators are reported, and fisheries in the Gulf of alaska, Bering Sea, and aleutian islands are managed very progressively under a suite of ecosystem considerations, we still need to develop a more integrated, formalized approach.

EcoSyStEm IndIcAtorS

illustration of an indicator, reference points, and performance measures relative to an ecosystem operational objective. Modified after Fao (2003).

schematic that matches indicators to objectives using a driver-pressure-state-impact-response approach.


Workshops help bring together regional, national, and international experts to discuss pertinent ecosystem and management questions and develop recommendations to move forward, or to fund the establishment of statewide databases that can be used by researchers and managers to plan and evaluate research needs in a broader context.

recognizing the importance of this role, the Board has funded a variety of activities related to the different ecosystem compo-nents discussed in this report, and from 2002-2008 specifically, six projects related predominately to fish and invertebrates for almost $700,000.

oNe oF The KeY roleS The NorTh paCiFiC reSearCh Board CaN plaY iN alaSKa’S SeaS iS To FoSTer CollaBora-TioN, daTa SYNTheSiS, aNd CoordiNaTioN.

The arctic is changing. Temperatures are rising, and summer sea ice extent is decreasing. rivers are discharging more water, sea levels are rising, permafrost is thawing and coasts are eroding. resident species may shift their ranges and when they repro-duce. ice-dependent species may lose habitat. hunting cultures may disappear, and access to traditional foods may change. Marine shipping access to natural resources and fisheries may increase.

despite these potential changes, relatively little is known about the arctic ocean and northern Bering Sea ecosystems. We urgently need to synthesize knowledge about the biology and oceanography of this region to have a baseline from which to observe and understand ongoing changes.

WorkShopS

Management tools

Eliz

abet

h Eu

bank

s


F E A t u R E P R O J E C tfish & inveRts :: Management tools :: Workshops

arctic Synthesis Workshop Project 503

projeCT 503 BrouGhT ToGeTher 30 experTS aS parT oF aN iNTerNaTioNal workshop focused on the Chukchi and Beaufort seas. participants discussed the state of knowledge, information gaps and research needs in physical and chemical oceanography, sea ice, phytoplankton, microbes, zooplankton, benthos sea floor, fish, seabirds, and marine mammals. They noted possible future efforts that might be undertaken by NprB. in the western arctic, climate change may affect the envi-ronment in two general ways. external changes will be forced through changes in sea ice processes and shifts in the transport rates and properties of pacific waters through the Bering Strait. internally forced changes involve the responses of resi-dent biological populations to altered temperatures and the timing of events in their annual life cycles.

Because each mechanism is system-wide, researchers concluded that these changes will ultimately affect all trophic levels. This will lead to further changes in the pathways and amount of energy transferred to fish, seabird, and marine mam-mal populations, and consequently impact their abundance and distribution.

Based on these two mechanisms, the workshop made several recommendations on how to proceed with future research, including the need for: • data consolidation and analysis• interdisciplinary research approaches • continuation and/or establishment of long-term time-series • collaboration and cooperation between agencies and programs • year-round observations • establishment of research support infrastructure• biogeochemical and ecological modeling • training of taxonomic expertise

Researchers concluded

that climate change

will ultimately affect

all trophic levels.

sea ice as seen from below can support high densities of amphipods (dark blotches above, with close-up shown in inset). some species are only found associated with sea ice and may be at risk as summer sea ice declines.

Jenn

ifer N

omur

a


dAtABASES

fish & inveRts :: Management tools :: databases

electronic Warehouse for Salmon data Project 311

ThrouGhouT alaSKa, huNdredS oF ThouSaNdS of salmon are examined annually for sex and size informa-tion, and scales are collected for age data. This enormous sampling effort over 40-plus years has resulted in millions of data records and scale samples.

although useful for local management needs, there has been no common process or protocol for managing and preserving the historical data and scale samples. project 311 initiated a process for establishing an electronic data

warehouse through which historical salmon sampling and scale pattern data can be maintained and updated annu-ally from collections throughout the state.

designed to inventory all collections, the project estab-lished a steering committee composed of state, federal, and research interests and developed a standardized web-accessible database where the sampling information is now accessible, preserved, and facilitates future research and management (see http://www.taglab.org/).


Salmon research and Monitoring Metadata Project 504

The CoMMerCial aNd CulTural iMporTaNCe oF salmon in alaska is reflected in the number of projects and amount of money that has been invested into better under-standing their biology and forecasting their productivity. Salmon research problems are ecologically complex, cover large expanses of marine, estuarine and freshwater habi-tats, and are being studied by many different organizations and programs.

Concerns have been raised about the efficacy of the millions of dollars annually dedicated to this topic, and whether the most important management-oriented questions are being addressed. project 504 gathered the necessary metadata on salmon research and monitoring, and designed an online database that is easily searchable so that decision-makers could determine whether additional funding is warranted for salmon research and for what research topics. The database contains 457 recent salmon research stud-ies, and 13,533 records of salmon monitoring programs in

alaska, and can summarize the information by species, life history stage, bioregion, disciplinary topic, research issue, and management information needs.

although much effort was spent to collaborate and coor-dinate with all of the relevant organizations involved in salmon research, many researchers did not respond to the request to share their project information. also, the alaska department of Fish and Game, which contributes the larg-est number of salmon research studies in alaska, asked to be withdrawn from the survey.

although the project reported an annual funding level of over $11 million for salmon, it is likely only a portion of what is actually spent. Future efforts to create a living compen-dium of research projects on this or other topics will clearly need established agreements between organizations and a commitment by all involved before going forward.

Scientists have been collecting information about the oceans for over a hundred years, yet in many instances these data are scattered throughout published and unpublished reports all over the world, many in paper format, unavailable to the general public and much of the scientific community. as a result, many questions that we might resolve with previously collected data remain unanswered. New studies are being funded that are potentially redundant to previous or ongoing efforts elsewhere in the world. Given a financial climate of limited funding for ocean research, and an ocean climate that is undergoing dramatic changes that affect us all, it has become more important than ever to bring existing information together in a format usable for management, research, and research planning by all.



herring database Project 728

paCiFiC herriNG iS a BellWeTher SpeCieS For NorTh paCiFiC MariNe eCoSYSTeMS. herriNG roe FiSherieS are among the most lucrative, competitive, and controversial in the region, often pitting commercial and subsistence users against one another. productive spawning areas and times are limited, and the historical population dynamics and technol-ogy of herring are not well understood. Many communities with local and traditional knowledge of herring fisheries claim that historical stocks were larger and spawning areas more numerous, but that they have dwindled due to over-harvesting, predation, disease, development, and climate change.

While shifts in stocks and spawning areas have been reasonably well documented since 1980, no one has synthesized the deeper archaeological, historical, and ethno-ecological records on herring spawning areas and their relation to local eco-systems. project 728 will synthesize this information for Southeast alaska from dixon entrance to Yakutat Bay, where herring and herring roe were traditionally harvested. using published and unpublished archaeological, ethnological, historical and biological records as well as community focus groups in each historical herring stock region, the project will compile historical and spatial information into a database. This will allow researchers to investigate the extent of historic and prehistoric herring spawning and massing areas, link changes in herring spawn extent and intensity to environmental and human factors in the socio-ecological system, and identify sensitive areas for protection and potential restoration of herring spawning.

herring stock assessments from dressel, et al (2005).

2 0 0 2 - 2 0 0 8 r e s e a r c h s u m m a r y

FISH & INVERTEBRATES Alaska’s Ocean Bounty

NORth PACIFIC RESEARCh BOARD

MissionNprB supports research to build a clear understanding of the North pacific, Bering Sea, and arctic ocean ecosystems that enables effective management and sustainable use of marine resources.

Fish & Invertebrates is one in a series of publications produced by the North pacific research Board in support the 2005 Science plan developed with guidance from the National research Council of the u.S. National academies of Sciences.

Find out more by visiting our website at nprb.org1 0 0 7 W e s t t h i r d av e n u e , s u i t e 1 0 0 | a n c h o r a g e , a l a s k a 9 9 5 0 1 | 9 0 7 . 6 4 4 . 6 7 0 0

FiSh haBiTaT FiSh & iNverTeBraTeSoCeaNoGraphY & produCTiviTY

MariNe MaMMalS SeaBirdS huMaNS oTher proMiNeNT iSSueS

research series - nprb

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