Exploring Individual-Level Dietary Variation in Fishes of the Northeast U.S. Continental Shelf

Individual-level dietary specialization represents an important but often overlooked form of ecological variation in predatory fishes. This form of variation has significant implications for our basic understanding of food web structure, as well as for the assessment of natural mortality due to predation. While there is growing interest in the topic of individual specialization in the field of ecology, few researchers working on marine fishes have explored the topic. To fill this gap, we quantified metrics of individual-level specialization for a suite of fishes of the northeast U.S. continental shelf across a 40-year timespan. Our analyses indicated that it is likely that many these marine fishes exhibit a non-trivial degree of individual specialization, and that the degree of this specialization varies substantially through time. These data strongly suggest that individual specialization is more prevalent in marine fishes than was previously appreciated and that it should be given due consideration when describing their trophic interactions. Further, we will discuss the potential utility of individual specialization as a metric of marine fish diversity, how it might complement other dietary metrics (e.g., population means), and its potential application to the field of fisheries management.