Warming Oceans Driving 20 Of 22 Global Tuna Stocks Towards The Poles
Climate change is driving stocks of tuna from their typical habitats towards cooler waters, which could impact the fishing industry in the decades to come, a new study says. Researchers from Spain investigated the patterns of six tuna species, including albacore, Atlantic bluefin and yellowfin, between 1958 and 2004 and found that 20 of 22 tuna stocks studied had shifted their ranges towards cooler waters because of climate change.
"On average, tuna habitat distribution limits have shifted poleward 6.5 km (4 miles) per decade in the Northern Hemisphere and 5.5 km (3.1 miles) per decade in the Southern Hemisphere," the researchers wrote. "Larger tuna distribution shifts and changes in abundance are expected in the future, especially by the end of the century." Some tuna stocks have moved away from areas easily accessible for fishing fleets, which places a burden on communities that rely on the tuna industry for their livelihood and in some cases, as their primary source of protein.
“Many fish species [not just tuna] are shifting, moving to colder water and greater depths,” lead study author Maite Erauskin-Extramiana, a Ph.D. student at the Spanish research institute AZTI, told Earther. “Some freshwater fish have moved upstream in rivers, while warm water fish species in the ocean have been reported to be expanding their distribution limits.”
Other tuna stocks are moving into waters that may not be able to sustain large numbers of predatory fish, the researchers noted.
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https://weather.com/science/environment/news/2019-04-04-climate-change-tuna-stocks