It takes guts to locate elusive crustacean prey

Mobile crustacean prey, i.e., crangonid, euphausiid, mysid, and pandalid shrimp, are vital links in marine food webs. Their intermediate sizes and characteristic caridoid escape responses lead to chronic underestimation when sampling at large spatial scales with either plankton nets or large trawl nets. Here, as discrete sampling units, we utilize individual fish diets (i.e., fish biosamplers) collected by the U.S. National Marine Fisheries Service and Northeast Fisheries Science Center to examine abundance and location of these prey families over large spatial and temporal scales in the northeastern U.S. shelf large ecosystem. Fish biosamplers revealed significant spatial shifts in prey in early spring. Distributions of mysids and crangonids in fish diets shoaled significantly from February to March. Distributions of euphausiids and pandalids in fish diets shifted northward during March. Of multiple hypotheses for these shifts, prey migration is most strongly supported. Future efforts can apply this method to address questions regarding temporal patterns or shifts in prey distribution and abundance that may be driven by large-scale stressors such as food-web shifts or climate change