Warming oceans will scramble fish species diversity, Rutgers study finds

April 19, 2022

A school of menhaden. NOAA Photo/Jerry Prezioso.

The effects of climate change in the ocean are already shifting fish populations, and a new study by scientists at Rutgers University predicts changes in the food web could prevent these species from thriving in their new geographic ranges. .

The study, published April 13 in the journal Royal Proceedings Company B, highlights how climate-induced changes in food web relationships might change over time.

Using computer modeling of hundreds of fish populations over 200 years of warming, the researchers showed that species-by-species predictions of fish movements likely overestimate their ability to adapt to changing conditions.

The effect will be more pronounced for larger predator species, which could increase the risk of overfishing, the paper notes.

“What this suggests from a fisheries perspective is that while the species we catch today will be there tomorrow, they won’t be there in the same abundance. In such a setting, overfishing becomes easier because population growth rates are low,” said study co-author Malin Pinsky, an associate professor in the Department of Ecology, Evolution and Natural Resources at Rutgers in a statement describing the results.

“Warming coupled with food web dynamics will be like putting marine biodiversity in a blender,” Pinsky said.

“We found that dynamic trophic interactions impeded species range shifts over 450 simulated food webs with up to 200 species each over 200 years of warming,” the authors write in an abstract. “All species experiencing dynamic trophic interactions moved more slowly than single-species models predict. Additionally, the trailing edges of larger species ranges moved particularly slowly due to the ecological subsidies of small moving prey.

“Current predictions ignoring dynamic interactions between food webs and allometry may overestimate the tendency of species to follow climate change.”

“The model suggests that over the next 200 years of warming, species will continually reshuffle and be shifting their ranges,” said lead author EW Tekwa, a former Rutgers postdoctoral fellow in ecology, evolution and natural resources, now at the University of British Columbia. “Even after 200 years, marine species will still lag behind temperature changes, and this is especially true for those at the top of the food chain.”

The researchers’ “spatially explicit food web model” included factors such as metabolism, body size and optimal temperature ranges. Taking climate change into account, the model demonstrated that dynamic changes in predator-prey interactions will hamper the ability of fish species to respond quickly to warming temperatures.

Major predator species may also linger longer in their historic ranges, even though their usual prey moves away, when historic habitats new food species arrive.

“That dynamic won’t just be in one place but on a global scale,” Pinsky said. “That doesn’t bode well for marine life, and it’s not a widely recognized effect.”

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