Status of Stocks and Multispecies Assessments Program -
Fisheries Interaction Team

Enhancement of Ability to Assess Atka Mackerel

Atka mackerel are a dominant component of groundfish biomass in the central and western Aleutian Islands, and they form a major diet item for endangered Steller Sea Lions in this region (Sinclair, in Press).  Atka mackerel also support a small but locally important commercial fishery.  A high-quality assessment of Atka mackerel biomass would enhance efforts to regulate the fishery and would provide important information about the ability of the fish community to support Steller Sea Lions.  Atka mackerel biomass is presently assessed through a combination of size-structured modeling and estimates of biomass from the triennial Aleutian Islands Survey (SAFE 2001).  However, the biomass assessment based on survey data has a very high uncertainty, due to highly localized and densely schooled behavior of this species. This project involves simulation modeling studies to develop a biomass estimation method based on a mixture-distribution estimator.  This estimation method would utilize RACE groundfish trawl catch data and a statistical representation of the spatial distribution of Atka mackerel.  Other proposed studies to develop specialized trawl gear for Atka mackerel are related to this project, in that the gear developed would be used in later years to augment survey data.  This effort will also utilize data collected during ongoing tagging studies of Atka mackerel movement. 

Contact

For more information, contact Liz Conners at liz.conners@noaa.gov or 1-206-526-4465.