Analyses of Bering Sea bottom-trawl surveys in Norton Sound: absence of regime shift effect on epifauna and demersal fish

Abstract This study retrospectively examined evidence of ocean climate regime shift effects on epifauna and demersal fish of Norton Sound, Alaska, northeast Bering Sea, based on triennial bottom-trawl surveys from 1976 to 2002. Throughout the period, benthic fauna was dominated by sea stars (48–78%)...

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Bibliographic Details
Published in:ICES Journal of Marine Science
Main Authors: Hamazaki, Toshihide, Fair, Lowell, Watson, Leslie, Brennan, Elisabeth
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 2005
Subjects:
Ecology
Aquatic Science
Ecology, Evolution, Behavior and Systematics
Oceanography
Bering Sea
Norton Sound
Alaska
Online Access:http://dx.doi.org/10.1016/j.icesjms.2005.06.003
http://academic.oup.com/icesjms/article-pdf/62/8/1597/29124048/62-8-1597.pdf
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Summary:Abstract This study retrospectively examined evidence of ocean climate regime shift effects on epifauna and demersal fish of Norton Sound, Alaska, northeast Bering Sea, based on triennial bottom-trawl surveys from 1976 to 2002. Throughout the period, benthic fauna was dominated by sea stars (48–78%), followed by cods (5–19%), flatfish (5–15%), sculpins (1.5–7%), and crabs (2–6%). From 1976 to 2002, the cpue index of total species increased exponentially (4.5% y−1) by threefold with some declines in 1991 and 1999. The increase was also observed in sea stars (5.1% y−1), flatfish (6.1% y−1), and crabs (2.5% y−1). However, trends of cods and sculpins were mixed. Regression analysis showed the cpue index of total species to be positively correlated with survey years and bottom-water temperature. However, bottom-water temperature, when considered by itself, was not significant. Results suggest that regime shifts caused biomass increases of Norton Sound epifauna and demersal fish.

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