Diet Composition and Feeding Behavior of Larval American Shad, Alosa sapidissima (Wilson), after the Introduction of the Invasive Zebra Mussel, Dreissena polymorpha (Pallas), in the Hudson River Estuary, NY.

The invasive Dreissena polymorpha (Zebra Mussel) has greatly altered the zooplankton community of the Hudson River by reducing the abundance of native zooplankton and inundating the system with its free-swimming veliger larvae. Since the invasion, there has been a reduction in pelagic fishes, including Alosa sapidissima (American Shad), which is thought to be, in part, a result of the decreases in zooplankton populations. To better understand the complex interaction between this mussel species and American Shad, it is important to describe the fish’s current larval diet. Although American Shad larvae readily consumed veligers and this food source may contribute to year-class strength, the importance of veligers as a diet item greatly depends on larval–veliger temporal overlap and yearly shifts in veliger abundance, digestibility, and nutrition. [ABSTRACT FROM AUTHOR]