Aleutian Islands Golden King Crab Survey and Tagging Study
The economic importance of the Aleutian Islands fishery for golden king crabs Lithodes aequispina is substantial with over $338 million landed in the fifteen years from 1980-95. Despite the value of the fishery, little is known regarding the abundance, distribution, and basic life history parameters of the golden king crab population. The impact of management measures and fishing practices have been difficult to assess without the baseline survey data needed to monitor the population.
In the absence of regular surveys, ADF&G and National Marine Fisheries Service biologists have collected biological data on golden king crabs from trawlers and crab vessels fishing in the Aleutian Islands. In 1991, ADF&G conducted its first systematic survey of golden king crabs in portions of the former Dutch Harbor and Adak king crab management areas which provided information on the distribution of golden king crabs by depth, size frequency, and growth-per-molt. Approximately 1,250 legal male golden king crabs were tagged during the survey and recoveries were monitored through at-sea observers and ADF&G dockside samplers in the subsequent commercial fisheries. Tag recovery rates were calculated for each area and recovery year, but provided a poor estimate of harvest rates due to incomplete tag recovery monitoring.
In March 1996, the Alaska Board of Fisheries (BOF) passed regulations that combined the Dutch Harbor and Adak king crab management areas into the new Aleutian Islands king crab management area. The 1997 ADF&G Aleutian Islands golden king crab pot survey will sample a portion of the golden king crab population in waters immediately adjacent to 171 W longitude -- the boundary line between the former Adak and Dutch Harbor Management Areas. Systematic survey data will provide a baseline, relative stock index of golden king crabs that can be compared with indices from future triennial surveys and data collected by observers. The opportunity for tagging a portion of the eastern population and subsequently examining most of the commercial catch for recaptures of tagged crabs is possible with 100% observer coverage in the 1997/98 fishery.
Findings from the 1991 golden king crab survey in the Dutch Harbor and Adak Management area including analysis of recovered tagged crabs. (Blau, S.F. and D. Pengilly. 1994.)