Retrospective analysis on the effects of bottom trawl fishing in the Gulf of Alaska and Aleutian islands

Abstract

Commercial bottom trawl fishing effort during 1990-2000 was summarized for the Gulf of Alaska and Aleutian Islands to determine spatial and temporal patterns of fishing effort. Attributes of the benthic community based on research bottom trawl surveys were compared between areas of high and low commercial bottom trawling effort. The total number of bottom trawl tows was estimated to be 133,326 for the Gulf of Alaska, and 47,483 for the Aleutian Islands. For the Gulf of Alaska, the 301-500 m depth range of the Kodiak area had the highest density of bottom trawl tows for the decade with 2.039 trawl tows/km². For the Aleutian Islands, the 101-200 m depth range of the eastern Aleutian area had the highest density of bottom trawls with 1.447 trawl tows/km² in an area of 7,909 km². Fish abundance, fish species richness, and invertebrate biomass differed significantly among locations but did not differ between the two levels of trawl effort. A significant interaction between trawl effort and location indicated that differences in biomass of fish species between levels of trawl effort depended on location. Species composition appeared to be more related to location than to levels of trawl effort.