Fisheries, Subsistence, and Habitat
Publications Searchable Database

Search Again
Division: Commercial Fish
Title: A survey of weathervane scallops in Kamishak Bay, Alaska, 2001
Author: Bechtol, W. R., R. L. Gustafson, and J. L. Cope
Year: 2003
Report ID: Alaska Department of Fish and Game, Division of Commercial Fisheries, Regional Information Report 2A03-31, Homer
Abstract: During 12-17 May 2001, the Alaska Department of Fish and Game conducted an area-swept survey of the weathervane scallops Patinopecten caurinus located in Kamishak Bay, Lower Cook Inlet, Alaska. A total of 38 successful tows, each 1.0 nautical mile (nmi) in length and representing a unique station, were made with the survey dredge. Nine tows were repeated between two stations during the survey as part of a video assessment study. Aggregate weight of material retained by the survey dredge from the 38 unique stations totaled 6,373 kg (14,049 lb), and catch weights of individual tows ranged from 22 to 503 kg (49 to 1,108 lb). Debris, primarily mud and gravel, accounted for 3,679 kg (8,111 lb), or 57.7% of the aggregate survey catch. Aggregate scallop catch among all tows was 2,334 kg (5,146 lb). Scallop catches rates ranged from 0.0 to 212.6 kg/nmi (0.0 to 468.6 lb/nmi). The survey used an adaptive design in which the Kamishak Bay scallop bed was defined to include only stations where catch was equal or greater than 9.1 kg/nmi (20.0 lb/nmi). Mean scallop catch and 95% confidence interval (95% C.I.) for stations within the defined bed was 92.1 ±26.8 kg/nmi (203.0 ±59.1 lb/nmi). Based on an estimation of the scallop bed encompassing 52 nmi2 , the scallop population biomass was 3,637 ±1,058 metric tons (8.0 ±2.3 million lb). A total of 5,517 individual scallops were caught; catch abundance among tows ranged from 0 to 513.9 scallops/nmi. Mean catch abundance and 95% C.I. within the defined bed was 211.9 ±62.1 scallops/nmi, estimated population abundance and 95% C.I. within the defined bed was 8.4 ±2.5 million scallops. Based on estimated population biomass and a mean meat recovery rate of 6.37%, harvesting the population at the maximum regulatory allowance of 20,000 lb was recommended in 2001 as this would result in an instantaneous harvest rate of 3 .92%, substantially below estimated natural mortality.
Keywords: Weathervane scallops; Kamishak Bay; survey; vessel; gear; sampling; data collection; catches; size; age; growth; sexual maturity; population estimate; harvest guideline; abundance; biomass; mortality; bycatch; Tanner crab; king crab