1. Eastern Bering Sea Walleye Pollock
The focus of this chapter is on the Eastern Bering Sea (EBS) region. The Aleutian Islands region (Chapter 1A) and the Bogoslof Island area (Chapter 1B) are presented as separate sections. Changes in the input data The 2007 NMFS summer bottom-trawl survey (BTS) abundance at age estimates were compute...
| Main Authors: | , , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.219.7499 http://www.afsc.noaa.gov/refm/docs/2007/EBSpollock.pdf |
| Summary: | The focus of this chapter is on the Eastern Bering Sea (EBS) region. The Aleutian Islands region (Chapter 1A) and the Bogoslof Island area (Chapter 1B) are presented as separate sections. Changes in the input data The 2007 NMFS summer bottom-trawl survey (BTS) abundance at age estimates were computed and included for this assessment. The NOAA ship R/V Oscar Dyson was diverted from planned survey research in the Gulf of Alaska this summer to add a mid-water echo-integration trawl (EIT) survey for the EBS. This was the first complete survey conducted by this vessel in this region. Age composition estimates were derived from the population-at-length estimates using the 2007 BTS age-length key. The 2006 age composition estimates were updated using EIT age data (last year the BTS age-length key was used). The EIT survey also extended into the Russian zone and covered part of the Navarin Basin. The BTS biomass estimate was 4.3 million t, up by 42 % from the 2006 estimate of 3.0 million t but still only 87 % of the long-term mean of the bottom-trawl survey since 1982. The 2007 EIT survey biomass estimate was 1.88 million t, up slightly from last year’s survey but only 55 % of the long-term mean for this survey (since 1979). Both surveys indicate that the 2006 year class is strong and that the 2005 yearclass is now apparently below average. |
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