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Global Warming Is Depleting World’s Fish Stocks, Study Says – The Weather Channel

Climate Change is Killing Fish and That's Bad News
  • Global warming is having a devastating impact on the world’s fish stocks.
  • Between 1930 and 2010, there was a 4.1 percent decline in the amount of sustainable fish catch worldwide.
  • Some of the largest fish-producing eco-regions experienced losses of up to 35 percent.

Global warming is depleting much of the world’s sustainable fish stocks and is making it more difficult to rebuild overfished populations, a new study says.

Between 1930 and 2010, there was a 4.1 percent decline in the amount of sustainable catches worldwide, according to the study published Thursday in the journal Science. Some of the largest fish-producing eco-regions, like those off the coasts of China and Japan, experienced losses of up to 35 percent.

“A four percent decline might sound small, but’s it’s a loss of 1.4 million metric tons of fish since 1930,” lead author Chris Free, a post-doctoral scientist at the University of California, Santa Barbara, told weather.com. “That’s 1.4 million tons of fish no longer available for food and no longer able to support the livelihoods of fishermen.”

Using global data on fisheries and ocean temperature maps, the researchers analyzed the impact of ocean warming on 235 populations of 124 species, including fish, crustaceans and mollusks, in 38 ecological regions around the world.

“We were stunned to find that fisheries around the world have already responded to ocean warming,” Malin Pinsky, study co-author and associate professor in Rutgers’ Department of Ecology, Evolution, and Natural Resources, said in a press release. “These aren’t hypothetical changes sometime in the future.”

The researchers noted that while some species have responded negatively to ocean warming, other species like black sea bass have benefited, although that may only be temporary and the overall losses far outweigh the fleeting benefits.

“Fish populations can only tolerate so much warming, though,” said senior author Olaf Jensen, an associate professor in Rutgers’ Department of Marine and Coastal Sciences. “Many of the species that have benefited from warming so far are likely to start declining as temperatures continue to rise.”

The North Sea and East Asian ecosystems were the regions hardest hit by historical ocean warming with losses in sustainable catches of 8 to 35 percent, Free told weather.com.

“We suspect that these losses are due to cascading impacts of warming on the food web,” he added. “Declines in the productivity of zooplankton, small animals at the bottom of the food web, means declines in the productivity of fish, which depend on these animals for food.”

The greatest gains were in the Labrador-Newfoundland, Baltic Sea, Indian Ocean and Northeast U.S. Shelf regions, according to the study.

(MORE: Plastic Has Been Found in the Guts of Creatures Living in the Deepest Parts of the Oceans)

According to the Food and Agriculture Organization (FAO) of the United Nations, fish provide 17 percent of the world’s intake of protein. In some coastal and island countries, the amount can surpass 70 percent. FAO also estimates that fishing and aquaculture support the livelihoods of 10 to 12 percent of the world’s population, or around 50 million people.

Overfishing is also playing a major role in the decline in global sustainable catch. The study points out that while overfishing makes fisheries more vulnerable to ocean warming, continued warming will hinder efforts to rebuild overfished populations.

Free said preventing overfishing and rebuilding overfished populations is essential to building resilience to climate change.

“Overfishing is a one-two punch: it makes populations more vulnerable to ocean warming and rebuilding overfished populations is hindered by warming,” he said.

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