Dynamic trophic linkages in a large estuarine system – support for supply-driven dietary changes using delta generalized additive mixed models

• Main Authors: Buchheister, Andre, Latour, Robert J
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2015
• Subjects: Northwest Atlantic
• Online Access: http://hdl.handle.net/1807/70977; http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2014-0441

Trophic dynamics within aquatic systems are a predominant regulator of fish production and an important consideration for implementing ecosystem approaches to fisheries management. We analyzed ten years of fish diet data from Chesapeake Bay, USA to 1) evaluate the effects of environmental variables on trophic interactions of 12 common predatory fishes, 2) infer dynamics of four key prey groups (mysids, bay anchovy, bivalves, and polychaetes), and 3) evaluate whether interannual dietary trends were coherent among predators and regulated by prey availability. Based on delta generalized additive mixed models (delta-GAMM), predator length was the most important covariate in modeling prey consumption. When significant, latitude, temperature, and depth effects were largely similar across predators for a given prey. Annual patterns of mysid and bivalve consumption each showed a single, dramatic peak shared by multiple predators with varied feeding preferences and distributional characteristics, but annual trends were not correlated with available survey-based measures of prey availability likely due to methodological differences. Overall, the coherence in consumption patterns across predators was consistent with supply-driven dynamics controlled by regional and annual changes in prey availability. Also, the novel application of delta-GAMM to fish diet data was useful in characterizing the dynamics of poorly sampled prey groups and the trophic interactions for ubiquitous species from the Northwest Atlantic Ocean. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.