Massachusetts River Herring Daily Counts and Environmental data

The timing of biological events in plants and animals, such as migration and reproduction, is shifting due to climate change. Anadromous fishes are particularly susceptible to these shifts, as they are subject to strong seasonal cycles when transitioning between marine and freshwater habitats to spawn. We used linear models to determine the extent of phenological shifts in adult alewife (Alosa pseudoharengus) as they migrated from ocean to freshwater environments during spring to spawn at 12 sites along the northeast U.S. We also evaluated broad-scale oceanic and atmospheric drivers that trigger their movements from offshore to inland habitats including sea surface temperature (SST), North Atlantic Oscillation index, and Gulf Stream Index.