AUKE BAY LABORATORY (ABL)

Alex Wertheimer Receives Wally Noerenberg Award

Alex Wertheimer, a 30-year career scientist at the Auke Bay Laboratory (ABL), recently received the Wally Noerenberg Award for Fishery Excellence from the Alaska chapter of the American Fisheries Society. The award, named after a former commissioner of the Alaska Department of Fish and Game (ADF&G), was established by the Alaska chapter in 1982 and has been given only on eleven other occasions. Wertheimer was recognized for his outstanding contributions to Alaska’s fisheries resources, in particular his work in helping foster the development and preservation of hatchery and wild salmon stocks in the state.

Among his research achievements, Wertheimer has played a major role in developing a salmon stock enhancement program for Alaska through an innovative approach using hatchery fish while protecting and maintaining large wild-stock populations. Much of his current work focuses on the pink salmon hatchery program and the wild salmon stocks in Prince William Sound. He is currently the project leader for early ocean salmon research as part of the ABL’s Marine Salmon Interactions program and has authored or coauthored more than 30 peer-reviewed journal publications.

Wertheimer has served as Principal Investigator on several Exxon Valdez Restoration Studies involving the effects of oil on salmon in the marine environment. He also has played a major role in cooperation with ADF&G in developing a state-wide Escapement Survey Database of salmon populations from almost 4,000 streams and rivers. He serves on numerous committees including the Chinook Technical Committee of the Pacific Salmon Commission, is a former associate editor for Transactions of the American Fisheries Society, and is a journal and symposium reviewer for numerous other national and international technical publications in fisheries science.

Wertheimer’s leadership, broad-ranging technical expertise, and professionalism in dealing with individuals, other agencies, and controversial issues are widely recognized and highly respected. His career in Alaska fisheries embodies what the Wally Noerenberg Award is all about.

By Bill Heard.


Ocean Survival High for Auke Creek Wild Coho Salmon

Research at ABL’s Auke Creek field station includes evaluating the long-term ocean survival of wild coho salmon (Oncorhynchus kisutch). While ocean survival of coho salmon throughout much of their southern range has declined over the previous three decades, in Southeast Alaska, which includes the Auke Creek stock, survival of stocks has been increasing since at least 1980.

Figure 1.  Ocean survival of Auke Creek coho salmon.

Coho salmon studies at Auke Creek are conducted under a cooperative project between NMFS and the ADF&G that began in 1976; the Auke Creek coho salmon stock is one of four wild stocks used as index systems in Southeast Alaska. Ocean survivals of wild coho salmon at Auke Creek are known from 1976, when coded-wire tags were first used on smolts leaving Auke Creek, to 2003 (excluding 1978; Fig. 1 above). The research at Auke Creek relies heavily on the permanent fish-counting weir and wet laboratory space in the hatchery located adjacent to the weir site.

This project includes the annual capture and tagging of seaward-migrant smolts, and capture and enumeration of fish returning to the creek. Auke Creek is the only index site where all smolts are captured and marked, and all adults are captured and examined for marks and tags.

Ocean survival of coho salmon smolts that emigrated from Auke Creek in 2002 was 28%. These smolts left Auke Lake and Auke Creek in 2002 and returned as jacks later the same year and as 1-ocean winter adults in 2003; the 27-year average marine survival for Auke Creek coho salmon is 24%. Coho salmon jacks (all males) are common at Auke Creek and often equal the number of full-sized males from the same smolt cohort. In 2002, 97 jacks returned to Auke Creek, for a 3% return of the smolts marked and released that year; on average, the return to Auke Creek as jacks is 247 fish, or 4% of the smolts.

The return of coho salmon adults to Auke Creek in 2003 was 551 fish, or 16% of the smolts; the average return to Auke Creek is 665, or 12% of the smolts. The harvest of 300 coho adults in the fishery was less than the average of 502, and was a 9% return of smolts. The 2003 fishery harvested 35% of the coho adults returning to Auke Creek, less than the 27-year average of 42%. Scales and size data on the fish returning to Auke Creek were collected and archived in the files at ABL.

A separate study of the effects of coho salmon smolt size and emigration timing at Auke Creek on ocean survival was recently completed. This 5-year study was jointly funded by NMFS and the ADF&G and conducted as a University of Alaska Fairbanks graduate project. The study involved a complex tagging effort at Auke Creek where for each day all smolts were sorted into four size groups and tagged with size- and day-specific tag codes. Tagged mature fish were recovered at Auke Creek weir and in the fishery.

Figure 2.  Ocean survival of Auke Creek coho salmon smolts in four size groups and five emigration periods.

The project showed that there is a complex interrelation between coho salmon smolt size, and emigration time and ocean survival. Within emigration dates, larger smolts survived at higher rates than smaller smolts, and between emigration dates, there was an obvious period during which the highest survivals occurred (Fig. 2 above). Most of the total return, jacks plus adults, originated from the two largest size groups, which together produced 84% of the survivors. Most coho salmon jacks, 43% of the total jack return, originated from smolts greater than 125 mm in length that emigrated in the 10-16 May period.

By Jerry Taylor.

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AFSC Quarterly
Research Reports
Oct-Nov-Dec 2003