During the fourth quarter of 2012, Resource Ecology and Ecosystem Modeling (REEM) program staff analyzed the contents of 4,869 groundfish stomachs. The majority of these samples were from 11 species sampled in the eastern Bering Sea, 1 species from the Aleutian Islands, and 2 species from the Gulf of Alaska. In total, 23,537 records were added to the REEM food habits database. In preparation for stable isotope analysis, 319 muscle and liver tissue samples from Alaskan groundfish were ground, and 673 tissue samples were tinned in preparation for gas isotope-ratio mass spectroscopy. This ongoing project provides additional information on long-term integration of energy transfer in Alaska’s marine food webs.
Analysis of the stomach contents of predators sampled this summer from the Chuckchi Sea has begun. Procedures for laboratory analysis of these samples have been developed to support the dietary descriptions, food web analyses, and project-integration. The detailed identification standards, the regional species assemblages, and the small size of the predators require modifications from the REEM standard procedures for stomach content analysis. Species lists, descriptions, reference materials, and identification techniques are being compiled to achieve the desired level of detail. In addition, fish specimens are being shared among Chukchi Sea investigations, which is requiring additional handling and processing time in the laboratory.
Groundfish stomach samples were collected during the Alaska Department of Fish & Game (ADF&G) surveys and by fishery observers during commercial fishing operations. During the fourth quarter, 820 stomach samples were collected from seven predator species from Pavlov and Marmot Bays in the Gulf of Alaska during ADF&G surveys. Fisheries observers returned 182 stomach samples from three species collected in the eastern Bering Sea, from 44 arrowtooth flounder collected in the Gulf of Alaska, and from 43 arrowtooth flounder collected in Aleutian Islands waters. In preparation for future observer collections, REEM staff assembled 15 stomach collection kits and sent them to Fisheries Monitoring and Analysis Division personnel in Dutch Harbor, Alaska, for deployment on fishing vessels not available to REEM personnel in the Seattle area. REEM staff trained new observers on stomach sampling procedures and instructed them on how the samples are analyzed and how the data is used.
By Troy Buckley, Geoff Lang, Mei-Sun Yang, Richard Hibpshman, Kimberly Sawyer, Caroline Robinson and Sean Rohan