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AUKE BAY LABORATORY (ABL) (cont.)

Ocean Carrying Capacity Program

Bering-Aleutian Salmon International Survey Planning Meeting

Jack Helle (group chairman), Ed Farley, and Jim Murphy of ABL attended a BASIS (Bering-Aleutian Salmon International Survey) Working Group meeting in Petropavlovsk, Kamchatka, Russia in May 2004. BASIS is a North Pacific Anadromous Fish Commision (NPAFC) program that coordinates research on salmon in the Bering Sea.

The group discussed the annual report of BASIS activities in 2003 and reviewed 2004 cruise plans for the BASIS research vessels Sea Storm (USA), TINRO (Russia), and Kaiyo maru (Japan). Scientists from the AFSC participate in BASIS cruises aboard the Sea Storm, and have also worked aboard the Kaiyo maru and the TINRO. The group reported that the BASIS web page is now available on the NPAFC website (http://www.npafc.org/BASIS); BASIS information is also available on the ABL website (http://www.afsc.noaa.gov/abl/occ/basis.htm).

Dr. Shigehiko Urawa gave a presentation titled, “The use of Genetic Stock Identification to Determine Distribution, Migration, Early Marine Survival, and Relative Abundance of Chum Salmon in the Bering Sea”, summarizing the preliminary results of BASIS research. Highlights from the presentation include: 1) less than 5% of the chum salmon caught by the ” during 2002 research were mature, 2) most of the immature chum salmon were distributed north of latitude 58°N, 3) Russian and Japanese stocks dominated the catch and were mainly distributed between longitudes 175°E and 170°W, and 4) western Alaska immature chum salmon stocks were mainly distributed within the offshore regions of the eastern Bering Sea.

Trey Walker of the University of Washington and Jim Murphy of the AFSC discussed a BASIS high-seas tagging project funded by the North Pacific Research Board. Salmon will be tagged in the Bering Sea and Gulf of Alaska in 2004 from the research vessels Wakatake maru and Kaiyo maru. Murphy described an aluminum “live box” based on a Norwegian design, which will be constructed and evaluated on the Sea Storm trawl in 2004. Norwegian researchers have had good success capturing Atlantic salmon suitable for tagging using this device. Usually salmon are descaled during trawling and are not suited for tagging.

By Jack Helle

Habitat Program

Partnerships Are Key to the Nutritional Ecology Laboratory

Researchers in ABL’s Nutritional Ecology Laboratory examine the lipid dynamics of forage fishes to understand energy perfusion through the Gulf of Alaska and Bering Sea ecosystems. Laboratory scientists use quantitative chemistry to identify where fish obtain energy and how they allocate that energy between growth, reproduction, and storage. The laboratory depends on partners within the AFSC and in other agencies to supply samples. Combining nutritional ecology expertise with systematic field sampling allows researchers to better understand energy acquisition and allocation in wild populations.

The methods used can be applied to numerous research questions—since 2001, the laboratory has worked with a range of partners. A recently completed project with the U.S. Forest Service used fatty acids to trace the flow of energy from marine environments into the tissues of juvenile salmonids reared in fresh water. This work is being expanded in a cooperative study with the University of Alaska and the Kachemak Bay Research Reserve in Homer, Alaska. Work with the Steller Sea Lion Research Initiative has produced a detailed picture of the seasonal variation in energy content of sea lion prey in southeastern Alaska. The data will ultimately be compared with a similar data set developed by the University of Alaska in Kodiak.

One outgrowth of laboratory analysis of seasonal variation in energy content is a bioenergetic model relating growth and energy storage in pollock. The nutritional ecology laboratory assisted the AFSC’s Resource Assessment and Conservation Engineering (RACE) Division in describing the proximate composition and energy content of forage species in the Aleutian Islands. A comparison of the nutritional value of Aleutian Islands forage species with those from southeastern Alaska is the subject of a presentation at the upcoming Lowell Wakefield Fisheries Symposium.

A project in conjunction with the ADF&G demonstrated the utility of fatty acid analysis as a tool for separating herring stocks in the northern Gulf of Alaska and Prince William Sound. The Exxon Valdez Oilspill Trustee Council is currently reviewing a proposal to continue that work. Earlier work with the council demonstrated the energetic costs associated with larval metamorphosis in Pacific sand lance and suggested that the costs of metamorphosis may account for spatial variation in the lipid content of newly metamorphosed herring larvae.

Researchers from the nutritional ecology laboratory and the U.S. Fish and Wildlife Service are currently evaluating the energetics of young-of-the-year fish by studying chum salmon fry in the Kuskokwim River and estuary. In 2001, the laboratory partnered with the RACE Division and the Northwest Fisheries Science Center to examine the availability of organochlorines in the Gulf of Alaska and Bering Sea food webs. The data set from this study is currently the largest data set describing organochlorine loads in fish from Alaskan waters, the first report of which will be made at the Lowell Wakefield Fisheries Symposium.

By Ron Heintz


Emigrant Salmonid Counts at Auke Creek

Through June 2004 at the Auke Creek weir, there were 120 consecutive days of weir operations, and fish counting, sampling, and marking. The weir was installed on 2 March and operated in the downstream mode until 30 June, when the structure was modified to capture upstream migrants. This was the 25th consecutive year of total downstream counts of all emigrant salmonids at Auke Creek.

The 2004 emigration of pink salmon fry was the largest since 1993, and the fifth-highest on record at Auke Creek. The production of pink salmon fry from the 2003 spawners was 32 fry per female spawner, nearly average for Auke Creek. The midpoint of emigration was 12 April (the average is 21 April). Nearly 170,000 pink salmon fry emigrated in 2004, about 55,000 more than the average for 1972-2004. The 2004 emigration is the second-highest number of odd-year brood pink salmon fry since the 1971 brood.

Emigration timing of other salmonids at Auke Creek was 4-8 days earlier than average. The sockeye salmon smolt count was above average, while coho salmon, Dolly Varden, and cutthroat trout counts were below average. The 2003 sockeye salmon smolt count of 21,106 was 4,000 fish above the average for 1980-2004. Yearling smolts accounted for 30% of emigration, and averaged 4.5 g in weight and 81 mm in length; age-2 smolts averaged 11 g and 111 mm. Yearling and age-2 sockeye salmon smolts were above the average size observed over the last two decades.

The coho salmon smolt emigration of 4,581 was the fourth-lowest count on record for Auke Creek. The long-term average for 1980-2004 is 6,181. Auke Lake coho salmon smolt production has been decreasing since 1980. The Dolly Varden count for 2004 of 3,955 was the fourth-lowest on record and the lowest in two decades.

The 1980-2004 average Dolly Varden migration is 6,304; Dolly Varden emigrations have steadily decreased since 1995. A total of 136 cutthroat trout were counted during the downstream migration at Auke Creek, significantly less than the average of 261; cutthroat trout numbers have been decreasing since 1994.

Several cooperative studies are under way at Auke Creek through an agreement with NMFS, ADF&G, and the University of Alaska Fairbanks. Cutthroat trout projects at Auke Creek, tagging and recovery of downstream migrants, and population estimate work in Auke Lake were successfully concluded for the 2004 spring season.

By Jerry Taylor

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