Live fast and die young: Cumulative impacts of rapid climate velocities and fishing on marine species
Climate and hunting/fishing are two of the dominant anthropogenic impacts affecting many species on land and in the ocean, and yet our understanding for the interaction and cumulative impacts of these two processes remains limited. Climate impacts are often expressed as past and future shifts in species distributions, a process that can be effectively predicted from the rate and direction of climate velocities across the landscape. Hunting or fishing can also affect the extent and location of species distributions, but these impacts depend on details of human behavior that can be difficult to generalize. Here, a variety of approaches are used to examine the cumulative impacts of climate and fishing on marine fish and invertebrates, including simulations from a spatial population dynamics model, a metaanalysis across 325 species in North America, and case studies where the details of historical fishing locations are known.
Fishing appears to have one of two opposing impacts on species ability to keep up with climate velocities. On the one hand, fishing can substantially impede the ability of species to colonize new territory, a process that predictably decreases the maximum climate velocity that a species can survive. On the other, fishing can also cause species to shift their distributions even faster than climate velocities. Which effect is realized depends on the location of fishing: harvest from the leading edge of a species range impedes colonization, while harvest from the trailing edge speeds species along. Regulatory, economic, and social constraints appear to favor the latter process in real systems by causing fisheries to lag behind the species that they target.