Historical and Projected Changes in Spawning Phenologies of American Shad and Striped Bass in the Hudson River Estuary

Predicted increases in temperatures over the next century have raised many concerns about changes in the life history traits and geographical distributions of anadromous fishes. Anadromous fishes are particularly vulnerable to human activities due to the diverse array of habitats needed to complete their life cycle and the proximity of essential habitats to large human population centers. To understand the potential changes in spawning phenology of American Shad Alosa sapidissima and Striped Bass Morone saxatilis in the Hudson River estuary, a model was developed to estimate the onset, cessation, and duration of the spawning season through the 21st century, corresponding to projected water temperatures. Water temperatures for the Hudson River estuary were determined using recent models accepted by the Intergovernmental Panel on Climate Change. Model results indicate that by the 2090s, the spawning season of both species will initiate, on average, approximately 15 d earlier in the year, with spawning duration reduced by 4 d compared to the average spawning season in the 2010s.