Anthropogenic Change on the Distribution of Marine Megafauna and Their Prey

Anthropogenic change is impacting the distribution and survival of marine megafauna and their prey. Humans are changing every aspect of the marine environment, with effects reaching as large as changing the composition of marine environments to directly overexploiting species through the fishing industry. The role that marine megafauna play in balancing ecosystems, including as top apex predators, leads to detrimental results in the absences and population declines of these species. Migrations and declines due to threats on marine apex predator species will alter their environments by causing mesopredator release and changes in community structure, which is often associated with reduced productivity. If such human activities persist unchecked, the collapse of many marine megafauna and their prey, which contribute to biodiversity and ecosystem services, will be inevitable. This review assesses the impacts of anthropogenic effects on marine megafauna by examining (1) how changing abiotic conditions in the ocean alters the distributions of the prey species used by marine megafauna, (2) how climate warming and unsustainable fishing practices have caused dramatic population declines in these prey species, and (3) how direct human interactions with marine megafauna cause top-down effects. These alterations to marine trophic interactions will be interpreted with respect to how they ultimately affect marine biodiversity and ecosystem function