Warming ocean temperatures resulting from climate change are endangering fish stocks around the world, shrinking some populations by as much as 35 percent, according to a new study, reported by CNN.
The study shows that rising ocean temperatures over the past 80 years have led to declining sustainable catches in 124 fish and shellfish species. This figure represents the amount that can be fished without causing long-term damage to the populations. Overall, the study found a decline of 4 percent as a result of rising temperatures.
The researchers, from Rutgers University in New Jersey, analyzed data on fisheries and ocean temperatures to evaluate changes in sustainable catches from 1930 to 2010.
The most dramatic declines were in regions along Asia’s Pacific coast, such as the East China Sea and Japan’s Kuroshi Current, where seafood stocks declined between 15 and 35 percent over the past 80 years. Many of the world’s fastest growing populations rely on fish stocks in these regions.
“Ecosystems in East Asia have seen enormous declines in productivity. These areas have particularly rapid warming [and] also have historically high levels of overfishing,” according to the study’s lead author, University of California Santa Barbara quantitative ecologist Chris Free.
These effects have been exacerbated by overfishing, Free says. Reducing the reproductive capacity makes the populations more vulnerable to the longer-term effects of climate change.
Some species, such as black sea bass on the US Atlantic coast, have actually benefited from the warmer temperatures. But if warming continues, scientists say those species are likely to decline as well once they reach their own temperature thresholds.
The researchers said they were “stunned” by the results, which could have grave repercussions for much of the world. Over 56 million people work in the fishing industry around the world. A total of 3.2 billion people rely on seafood as a protein source, and in developing countries, seafood accounts for half of all animal protein consumed.
Free says governments can help address the problem by enforcing rules against overfishing, and using trade agreements to share supplies between areas with populations that have been hurt, and those that have boosted, by warming oceans.
The study was published in the March 1st edition of the journal Science.