Diet and Feeding Of Menhaden Using Barcoding Identification Based On Cox1 Sequences

Atlantic menhaden is a key forage species that serves as a trophic link between the plankton and predator fishes and birds. Menhaden diets derive from filtration of the water columns, consuming phytoplankton and zooplankton. The diet of these is likely to change as ocean warming and acidification change plankton composition. Identification of food organisms is difficult because the prey organisms are small and fairly easily digested such that traditional microscopic identification of stomach contents is somewhat limited and may not provide the clearest insights into the predator-prey interactions of these forage fishes. Moreover, traditional diet analysis methods often ignore stomach contents that are not recognizable. When digestion is well advanced, traditional approaches cannot identify any prey, potentially excluding important information. In doing so, the understanding of larger scale processes such as food web interactions and energy flow through an ecosystem can be biased. This project is to develop and verify molecular techniques, based on cox1 DNA, to provide an unambiguous tool to identify species in stomach contents of these fish and to compare them with those found in plankton. Existing molecular databases (National Center for Biotechnology Information and Barcode of Life) will be utilized for identification of gut and plankton species. Identification by barcoding will also be verified by traditional microscopic methods. With this technique in hand, the study can be expanded in the future to investigate the effects of climate change on the diet and feeding of menhaden.