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Recruitment Processes Program— Fisheries-Oceanography Coordinated Investigations

Feeding Ecology and Niche Separation of Age-0 Northern Rock Sole and Age-1 Yellowfin Sole in the Eastern Bering Sea

Benthic productivity is an important component in the understanding of fish population dynamics in the eastern Bering Sea. The study of fish-trophic interactions is relevant to understanding benthic production. Feeding success during the early juvenile phase is a significant factor influencing overall survival, which has implications for the number of successful survivors to the fishery.

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Figure 8. Taxonomic composition by standard length for 2008 and 2010. Click to enlarge.  

In order to better understand the factors influencing flatfish feeding success, the feeding habits of two commonly-occurring and commercially important flatfishes are being studied. Specifically, age-0 northern rock sole (Lepidopsetta polyxystra) and age-1 yellowfin sole (Limanda aspera) from the eastern Bering Sea are being examined for diet overlap, prey resource partitioning, and habitat preference. Juvenile northern rock sole and yellowfin sole spatially co-occur in shallow, nearshore waters in the eastern Bering Sea in fall. Collections were made along the nearshore waters during September 2008 and 2010 using a 3-m modified plumb-staff beam trawl. In both years the principal prey were gammarid amphipods and annelids for northern rock sole (Fig. 8). In 2010 northern rock sole diets were more diverse and included bivalves and harpacticoid copepods. Northern rock sole diets were spatially structured in both 2008 and 2010. Northern rock sole and yellowfin sole diets also appear to be age-structured, but structuring was not related to geography in yellowfin sole. In 2008 yellowfin sole diets were diverse and showed no spatial structuring; however, 2010 diets indicate limited spatial structuring within the inner shelf. We will be investigating further with additional statistical analysis on age structure, length of flatfish, and prey field.

This study will improve our understanding of habitat usage and factors that influence recruitment of flatfishes in the eastern Bering Sea.

By Christina Jump, Janet Duffy-Anderson, Kathy Mier, and Dan Cooper




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