Effects of variable oceanographic conditions on forage fish lipid content and fatty acid composition in the northern California Current

Marine Ecology Progress Series

Richard D. Brodeur¹  Selina S. Heppell¹  Rosalee S. Rasmussen¹  Marisa N. C. Litz¹  Linda O#x2019Higgins¹  Matthew S. Morris¹  Robert L. Emmett¹ 

关键词: Forage fish;    Small coastal pelagics;    Lipids;    Fatty acids;    Bottom-up effects;    Warm ocean conditions;    EPA;    DHA;   

DOI  :  10.3354/meps08479

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Lipids and fatty acids (FA) were investigated in 4 species of forage fish: northern anchovy Engraulis mordax, Pacific sardine Sardinops sagax, Pacific herring Clupea pallasi, and whitebait smelt Allosmerus elongatus, for their ability to serve as biological indicators of ocean conditions in the California Current large marine ecosystem (CCLME). Samples were collected during the oceanographically contrasting years of 2005 and 2006. Upwelling was severely curtailed in the spring and early summer of 2005, leading to delayed biological productivity, whereas upwelling was relatively normal in spring 2006. Principal components analysis described 78% of the variance within the lipid and FA dataset using the first 2 principal components. We found significant intra- and interspecific, interannual, and seasonal differences in lipid and FA profiles using univariate and permutation-based multivariate analysis of variance. Indicator species analysis showed distinct lipid and FA properties associated with each fish species. Using the ratio of docosahexaenoic acid (C22:6n-3) to eicosapentaeonic acid (C20:5n-3), we detected a transition from a diet composed primarily of dinoflagellate origin in early 2005 to a diet resulting from diatom-based productivity by late summer 2006. This shift was due to interannual differences in primary production, which was confirmed through phytoplankton sampling. Our study demonstrates that lipid and FA biomarkers in the forage fish community can provide information on ocean conditions and productivity that affect food web structure in the CCLME.

【 授权许可】

Unknown