Warming changes the life history composition of marine fish communities at high latitudes

Abstract

Across marine ecosystems, species are redistributing as a response to increased sea temperatures. In the Arctic, rapid warming causes poleward shifts of boreal species. Which species are redistributing and the drivers of their movements can be related to their life history traits. Here, we aimed to characterize and analyze the spatio-temporal changes in the life history strategy (LHS) composition of fish communities in the Barents Sea (2004-2017). We performed an archetype analysis to characterize species’ LHS based on their life history traits and related it to the equilibrium-periodic-opportunistic framework. Fish species in temperate ecosystems were documented to be largely distributed along the opportunistic-periodic continuum, whereas many fish species in the Barents Sea are distributed along the opportunistic-equilibrium continuum, illustrating the specificity of Arctic fish LHS. During the study period, boreal periodic species showed an increase in the central Barents Sea, a zoogeographic transition area. Simultaneously, Arctic opportunistic species retracted to cold waters, and the abundance of equilibrium strategists increased in the eastern Barents Sea. The expansion of periodic species may be explained by the configuration of their traits. This includes a high reproductive potential, broader diet, and migratory behavior. These traits might increase their tolerance and adaptive capacity to a changing environment. Fish LHS play a crucial role in fisheries management, particularly in promoting better fishing practices for vulnerable populations. By understanding the various LHS adopted by different fish species and their environmental preferences, fisheries managers can develop informed fishing strategies on a broader scale.