Survey objectives were: determine Tanner crab (Chionoecetes bairdi) stock abundance in the Prince William Sound Management Area; document size and shell age for crabs caught in the region; determine corresponding egg condition of the females caught; record size and number of Pacific cod and other groundfish species in the region.
Survey objectives were: determine Tanner crab (Chionoecetes bairdi) stock abundance in the Prince William Sound Management Area; document size and shell age for crabs caught in the region; determine corresponding egg condition of the females caught; record size and number of Pacific cod and other groundfish species in the region.
The primary objective of the 2020 Tanner crab, Chionoecetes bairdi, large-mesh bottom trawl survey is to develop a new survey area in the inside waters of Prince William Sound. Methodology from the historical trawl survey will be applied to develop new trawl stations with the goal of generating abundance estimates for the surveyed area. Abundance estimates will be generated for current and historical legal-size male Tanner crab for management purposes. Male Tanner crab biological measurements will be collected for estimating size at morphological maturity and mature male crab will be tagged for observing season movement.
A large-mesh bottom trawl survey of Tanner crab Chionoecetes bairdi was conducted in 2020 in the Prince William Sound Area (PWSA; Registration Area E) with the objective of establishing protocols for generating Tanner crab abundance estimates for a newly established survey area. New survey areas in PWSA were developed to assess new commercial fishery districts that were proposed at the 2021 Alaska Board of Fisheries meeting. Proposed fishery districts encompass historical fishing areas and areas fished in the recent commissioner’s permit fishery. Methodology from the historical PWSA trawl survey was applied to develop new trawl stations with the goal of calculating catch per unit effort (CPUE) to estimate abundance of historical legal size and legal-size male Tanner crab in the surveyed area. The 2020 survey produced a CPUE for male Tanner crab that were of the historical legal size of 28.4 crab per nmi2, which was the third lowest observation for any Alaska Department of Fish and Game trawl survey in the PWSA. The estimated abundance of historical legal-size male Tanner crab was 8,214 crab in the survey area, and the estimated abundance for legal-size male Tanner crab was 35,920 crab in the survey area.
A bottom trawl survey was conducted from August 29 to September 6, 2017, to estimate density and infer abundance of Tanner crab Chionoecetes bairdi in Kachemak Bay within the Southern District of the Cook Inlet Area. The survey was conducted aboard ADF&G's research vessel Pandalus using a 400-mesh Eastern otter trawl (large-mesh trawl). The survey caught 1,481 male Tanner crab of which 137 (9%) were of legal size (114 mm carapace width or greater) to produce a mean CPUE of 10.13 crab/nmi (CV = 0.52) and yielded an abundance estimate of 124,965 legal crab. Legal male Tanner crab were caught at 11 of the 38 stations with 90% of the total legal males caught at only 5 stations. The survey caught 1,350 female Tanner crab of which 348 (26%) were mature to produce a mean CPUE of 24.08 crab/nmi (CV = 0.50) and yielded an abundance estimate of 297,126 mature crab. Abundance estimates of legal male and mature female Tanner crab were well below the long-term average of the survey time series.
The eastern Bering Sea bottom trawl survey has been conducted by the National Marine Fisheries Service Resource Assessment and Conservation Engineering group on an annual basis since 1971. The purpose of this survey is to collect data on the distribution and abundance of crab and groundfish resources in the eastern Bering Sea. These data will be used to estimate population abundances for the management of commercially important species in the region. In 2007, 376 standard stations were surveyed and an additional 32 stations were resampled in Bristol Bay at the end of the standard survey due to the offset in timing of the survey and the reproductive maturity of the female red king crab. The point estimate of Bristol Bay red king crab (Paralithodes camtschaticus) legal-sized male abundance was 6% greater in 2007 than 2006, and exceeded the average of 9.6 million crab for the previous 20 years. The point estimate of Pribilof District blue king crab (P. platypus) legal-sized male abundance was 0.1 million crab, which was well below the average of 0.6 million for the previous 20 years. The point estimate of Tanner crab (Chionoecetes bairdi) legal-sized male abundance was 12.1 million crab which is a decrease of 6% from 2006. The point estimate of the large male snow crab (C. opilio) abundance was 495.2 ± 134.8 million crab.
The goal of the large-mesh bottom trawl survey is to provide fishery managers with current stock status information for Tanner crab Chionoecetes bairdi, red king crab Paralithodes camtschaticus, and commercially important groundfish stocks in the Kodiak, Chignik, South Peninsula, and Eastern Aleutian Tanner crab districts of Westward Registration Area J. The large-mesh bottom trawl survey utilizes a 400-mesh eastern otter trawl to survey these districts and provide crab abundance estimates, size frequency distributions, density estimates, and spatial distribution of commercially important crab and groundfish to support fisheries management.
