Figure 1. Atka mackerel 2014 tagging study locations in the western Aleutian Islands and at Seguam Pass in the central Aleutian Islands. Haul locations are where Atka mackerel were caught, tagged, and released.
Fisheries Interaction Team (FIT) staff in the Status of Stocks and Multispecies Assessment (SSMA) program participated in a cooperative Atka mackerel (Pleurogrammus monopterygius) tagging research cruise in the central, and western Aleutian Islands (Fig.1) aboard the chartered fishing vessel Morning Star from 17 May to 11 June. The goal of the ongoing tag release-recovery studies is to determine the efficacy of Atka mackerel trawl exclusion zones. The trawl exclusion zones are areas established around Steller sea lion rookeries to protect critical Steller sea lion habitat and prey resources. During the cruise over 20,000 Atka mackerel were tagged and released at four areas in the western Aleutian Islands (Buldir Island, western Aleutian Island Seamounts, Agattu Island, and Ingenstrem Rock) as well as Seguam Pass in the central Aleutian Islands. This tagging study will help to improve our understanding of the rate of exchange of Atka mackerel between open and closed fishing grounds as well as establish baseline data after a 4-year fishing closure in the western Aleutian Islands. The results from the western Aleutian Islands will be compared to Seguam Pass, which has an established time series of Atka mackerel tagging beginning in 2000.
In addition to tagging, secondary objectives of the cruise included conducting a tag-mortality study and collecting biological samples from Atka mackerel. Atka mackerel habitat was also characterized with oceanographic samples and underwater camera tows at each tagging location. Finally, three projects were conducted at the request of other researchers: 1) attempted recovery of moored hydrophones for a killer whale acoustic predation project at National Marine Mammal Laboratory, 2) collection of Atka mackerel and Pacific cod samples for stable isotope and mercury analysis by Lori Rhea at the University of Alaska Fairbanks, and 3) collection of incidental marine mammal and seabird observations.
