Regional variation in the annual feeding cycle of juvenile walleye pollock (Theragra chalcogramma) in the western Gulf of Alaska

Wilson, Matthew T. and Buchheister, Andre and Jump, Christina (2011) Regional variation in the annual feeding cycle of juvenile walleye pollock (Theragra chalcogramma) in the western Gulf of Alaska. Fishery Bulletin, 109(3), pp. 316-326.

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Abstract

Juvenile fish in temperate coastal oceans exhibit an annual cycle of feeding, and within this cycle, poor wintertime feeding can reduce body growth, condition, and perhaps survival, especially in food-poor areas. We examined the stomach contents of juvenile walleye pollock (Theragra chalcogramma) to explain previously observed seasonal and regional variation in juvenile body condition. Juvenile walleye pollock (1732 fish, 37–250 mm standard length) of the 2000 year class were collected from three regions in the Gulf of Alaska (Kodiak, Semidi, and Shumagin) representing an area of the continental shelf of ca. 100,000 km2 during four seasons (August 2000 to September 2001). Mean stomach content weight (SCW, 0.72% somatic body weight) decreased with fish body length except from winter to summer 2001. Euphausiids composed 61% of SCW and were the main determinant of seasonal change in the diets of fish in the Kodiak and Semidi regions. Before and during winter, SCW and the euphausiid dietary component were highest in the Kodiak region. Bioenergetics modeling indicated a relatively high growth rate for Kodiak juveniles during winter (0.33 mm standard length/d). After winter, Shumagin juveniles had relatively high SCW and, unlike the Kodiak and Semidi juveniles, exhibited no reduction in the euphausiid dietary component. These patterns explain previous seasonal and regional differences in body condition. We hypothesize that high-quality feeding locations (and perhaps nursery areas) shift seasonally in response to the availability of euphausiid

Item Type: Article
Title: Regional variation in the annual feeding cycle of juvenile walleye pollock (Theragra chalcogramma) in the western Gulf of Alaska
Personal Creator/Author:
CreatorsEmail
Wilson, Matthew T.
Buchheister, Andre
Jump, Christina
Refereed: Yes
Journal or Publication Title: Fishery Bulletin
Volume: 109
Number: 3
Page Range: pp. 316-326
Date: 2011
ISSN: 0090-0656
Issuing Agency: United States National Marine Fisheries Service
Subjects: Biology
Ecology
Fisheries
Item ID: 8710
Depositing User: Patti M. Marraro
Date Deposited: 07 Jun 2012 14:52
Last Modified: 07 Jun 2012 14:52
URI: http://aquaticcommons.org/id/eprint/8710

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