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Groundfish Assessment Program

Species Identification Confidence in the Eastern Bering Sea Shelf Survey

The Resource Assessment and Conservation Engineering (RACE) Division has been conducting bottom trawl surveys of the eastern Bering Sea continental shelf since the early 1970s. Information gathered from this summer survey provides fisheries independent population trends that are invaluable for stock assessments and development of management strategies for commercially exploited fish and invertebrate species in the region.

Throughout the history of the survey, changing priorities and limited resources have led to fluctuations in the quality and specificity of field identifications for some taxa. As an increasing number of users request access to survey data for use in a broad diversity of studies, we feel that it is important to provide users with a tool to help assess the confidence level that should be assigned to identifications of each taxon throughout the history of the survey. Therefore, we have created an identification confidence matrix for fishes and invertebrates identified in the survey from 1982 through 2008.

For each survey year, every species was assigned an identification code indicating the level of confidence on correct identification for that time period, with 1 indicating high confidence and consistency, 2 indicating moderate confidence, and 3 indicating low confidence. The index is unavoidably subjective, but was influenced by several factors, including relevant taxonomic literature, available field identification tools, inter-annual reporting trends, and examination of collected specimens. The tables are intended to serve as a general guideline in assessing the relative historical reliability of the species identification data in this time series and will be made widely available through publication and internet as a resource for EBS shelf survey data users.

By Duane E. Stevenson and Gerald R. Hoff


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