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

• 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

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.