How Do Changes in Species-Specific Habitat Affect Predator-Prey Overlap?

Temperature is a key driver of animal distributions and abundances globally. Species-specific spatio-temporal responses to environmental changes may result in potential mismatch between predator and prey species as well as new community compositions. Recent declines in Northwest Atlantic herring recruitment have driven dramatic cuts in fishery quotas. The mechanisms of this decline are not certain but one hypothesis is that a potential mismatch between the thermal habitat of herring and preferred prey species during larval and/or adult life stages. We tested this hypothesis using thermal habitat models for herring adults and larvae and their preferred zooplankton prey species. Metrics of annual predator-prey overlaps in time and space were modelled using high-resolution simulated bottom temperatures. We found that the overlap of the thermal habitat of Atlantic herring with their prey at both the larval and adult stage is decreasing in the spring and increasing in the fall. Favorable predator-prey overlap during the fall season may explain the transition to more summer and fall spawning in western Atlantic herring populations and/or low recent low recruitment. Models using additional parameters (surface temperature and bottom salinity) are also explored.