BSFRF Bristol Bay red king crab trawl survey stock assessment, 2007. Hughes & Goodman

The Bering Sea Fisheries Research Foundation (BSFRF) cooperating with the National Marine Fisheries Service (NMFS)
conducted a 40 day assessment survey of Bristol Bay red king crab (BBRKC) in late May-early July 2007 aboard the chartered
120 ft F/V American Eagle using specialized trawl gear, a new survey design and new analytical methods. The BSFRF survey
was coordinated with the long standing NMFS survey of this resource to test the hypothesis that a different trawl design,
a new survey methodology and principals of geostatistics would estimate mean and variance of BBRKC abundance with more accuracy
and precision than the standard NMFS annual trawl survey. Final plans for the 2007 BSFRF assessment survey were completed
in April 2007 following a successful pilot study conducted during the summer of 2005 and testing of purchased survey gear
and trawl mensuration sensors during the fall of 2006. The 2007 BSFRF survey was conducted over an approximate 24,000
square nautical mile region consisting of 241 random site tows. The area swept estimates for each trawl tow were accurately
measured by the trawl mensuration equipment and estimates benefited greatly from use of a new and improved trawl bottom contact
sensor developed by NMFS. The new survey gear, sampling methodology and goestatistics proved highly effective and generated more
precise BBRKC abundance estimates than those from the standard NMFS survey in the same area and time. Precision estimates (95% CI)
for large male BBRKC from the standard NMFS survey have averaged +/- 37% over the past 10 years compared to +/- 13% from the BSFRF
survey. A standard normal test for a difference in population means (Z-test) was used to test the differences between BSFRF and
NMFS surveys. Results showed statistically significant higher estimated mean abundance and reduced variance from the BSFRF survey
for all sizes and sexes of BBRKC. Separate from the assessment survey, the F/V American Eagle and the two NMFS survey vessels
worked together over a two day period and completed a planned pilot study of 20 paired side by side tows. Results are discussed
and being used to design further comparative trials. These datasets were archived as part of the North Pacific Research Board legacy project recovery effort undertaken by Axiom Data Science and NPRB in 2025. The goal of the recovery effort was to assess the NPRB-funded data projects from 2002 to 2014 and archive final data packages that were ready for publication to increase long-term accessibility and discoverability. Data packages were archived as is given limited funding and resources.