The Influence of Predator-prey Interactions on Climate-induced Range Shifts in Marine Communities

Trawl surveys conducted over the last 40 years have provided evidence of widespread shifts in the distribution of marine species in the coastal United States. For many species, the shift in their distribution matched the shift in their preferred temperatures. However, some species, notably American lobster, Homarus americanus, shifted poleward substantially faster than would be predicted from climate alone, while others lagged significantly behind. We investigated the degree to which ecological interactions could alter climate-induced range shifts in marine communities, focusing specifically on American lobster and its key predators. Parallel analysis of the changes in distribution and abundance of lobster, cod, and black sea bass revealed that the increase in lobster abundance and northeastern shift in the center of its range occurred in conjunction with a decline in cod biomass in the northern part of its range. The contraction of the southern lobster range limit was tracked by the northward expansion of its southern predator, black sea bass. These results suggest that predator release in the Gulf of Maine in conjunction with predator invasion at the southern limit may have contributed to the accelerated response of lobster to ocean warming.