Numerous Fish Species Expected to Decline Due to Climate Change, says Report

According to a study, the warming of the oceans caused by climate change will result in a decline in productive fish species in the future. The study, published in the journal Proceedings of the Royal Society B, discovered that as temperatures rise, predator-prey interactions will prevent species from adapting to the conditions that would allow them to thrive.

Findings of Research:

The researchers noted that as the climate warms, not only will large species and commercially important fisheries shift out of their historical ranges, but they will also likely be less abundant even in their new geographic ranges.

A cod fisherman in the Atlantic, for example, may still find fish 200 years from now, but in much smaller numbers, they claim.

"What that implies from a fisheries standpoint is that while the species we fish today will be there tomorrow, they will not be in the same abundance," said study co-author Malin Pinsky, an associate professor at Rutgers University in the United States.

"Overfishing becomes easier in this situation because population growth rates are low. Warming combined with food-web dynamics will be like blending marine biodiversity," Pinsky stated.

Previous research on shifting habitat ranges had focused on the direct effects of climate change on individual species, according to the researchers.

While these "one-at-a-time" species projections provide insights into the composition of ocean communities in a warming world, the researchers claim that they have largely failed to consider how food-web interactions will affect the rate of change.

The most recent study examined trophic interactions (the process by which one species is nourished at the expense of another) and other food-web dynamics to determine how climate change affects species ranges.

The researchers discovered that predator-prey interactions cause many species, particularly large predators, to shift their ranges more slowly than climate.

"The model suggests that over the next 200 years of warming, species will continually reshuffle and shift their ranges," said study lead author E W Tekwa, a former Rutgers postdoc who now works at the University of British Columbia in Canada.

Millions of species are shifting poleward as the climate warms, causing a dramatic reorganization of life on Earth. Our understanding of these dynamics, however, has largely ignored a key feature of life: animals and other organisms must eat.

The researchers have filled this knowledge gap by investigating how species' movements are influenced by the basic need for nourishment. They created a "spatially explicit food-web model" that took into account factors like metabolism, body size, and optimal temperature ranges. By taking climate change into account, their model revealed that dynamic trophic interactions limit species' ability to respond quickly to rising temperatures.

They also discovered that larger-bodied top predators stay longer in historical habitats than smaller prey, owing to the arrival of new food sources in their pre-warming ranges. "These dynamics will be felt not just in one location, but all over the world. That does not bode well for marine life, and this is not a widely recognized effect," Pinsky elaborated.