Long‐term variability and density dependence in Hudson River Dreissena populations

We used a 27‐year record of Dreissena populations in the freshwater tidal Hudson River to describe interannual variation in population density, body size, and body condition; estimate long‐term variation in recruitment, survivorship, and shell growth; and assess possible controls on the populations.Dreissena populations in the Hudson have been highly variable, with interannual ranges of c. 100‐fold in abundance and biomass, and 7‐fold in mean body mass. This large interannual variation arises from both long‐term trends and 2–5‐year cycles.Long‐term trends include the 2008 appearance of the quagga mussel (Dreissena rostriformis), which still forms a small part (