Sea temperatures drive the distribution of European fish

A team of scientists led by the University of Bristol has recently investigated how environmental variation drives the distribution of marine species from Southern Portugal to northern Norway. By analyzing 198 marine fish species from 23 surveys, together with 31,502 samples collected by fisheries scientists between 2005 and 2018, the experts found that temperature is a critical driver of large-scale spatial variation in fish assemblages across Europe’s marine regions.

“This unique study brings together fisheries survey data from across this vitally important marine ecosystem. Using this information, we are able to conclusively demonstrate the broad scale importance of sea temperature in controlling how fish communities assemble,” said senior author Martin Genner, a professor of Evolutionary Ecology at Bristol.

Although temperature proved to be the most critical variable for determining where marine species are found, water depth and salinity were also important factors. In addition, by combining data on the current distribution of marine fish with future climate projections under multiple emissions scenarios, the scientists provided estimates of how fish will respond to climate change over the coming decades. 

The results indicate that, although global warming will lead to shifts in species communities across the entire region, the largest community-level changes are expected at locations with greater warming, with the most pronounced effects most likely at higher latitudes.

 “The study adds to a growing body of evidence indicating that future climate-driven warming will lead to widespread changes in fish communities, potentially resulting in changes to the catches of commercial fisheries across the region,” said co-author Stephen Simpson, a marine biologist and fish ecologist at Bristol.

“With further predicted changes to fish communities, evaluating the effects of temperature on stocks may help to support appropriate management, although this may be challenging, given that precise mechanisms by which temperatures affect stocks are typically not clear. Where species distributions are predicted to change, and potentially move between existing management areas, internationally coherent management approaches will be needed to enable sustainable harvesting and conservation under a changing climate,” the authors concluded.

The study is published in the journal Global Change Biology.

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By Andrei Ionescu, Earth.com Staff Writer

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