Numbers of fish being hauled out of the ocean have fallen by nearly 5 per cent as stocks are hit by rising sea temperatures.

Cod, herring and various shellfish species are among the creatures already suffering due to climate change, according to a new analysis examining data from around the world.

The decline has been even more pronounced in key fishing regions such as the East China Sea and the North Sea, where climate-induced losses have been as high as 35 per cent.

This devastation is being aggravated by overfishing and threatening the livelihoods of the 56 million people who rely on fisheries for survival.

While soaring ocean temperatures are expected to cause havoc with marine ecosystems in the future, the new findings are a grim reminder that climate change is already a reality.

Endangered sharks being served up in British fish and chip shops Show all 6 1 /6 Endangered sharks being served up in British fish and chip shops Endangered sharks being served up in British fish and chip shops Scalloped hammerhead shark Scalloped hammerhead shark fins were among those found being sold by an Asian food retailer in the UK. These sharks are endangered, and in parts of the Atlantic Ocean, their populations have declined by over 95% in the past 30 years. Istock/Janos Endangered sharks being served up in British fish and chip shops Spiny dogfish In the samples of takeaway fish and chips sampled, spiny dogfish made up 90% of those sold under the names huss, rock salmon and rock eel. Doug Costa, NOAA/SBNMS Endangered sharks being served up in British fish and chip shops Shortfin mako shark Another vulnerable species found in the dried shark fins tested in the British Asian wholefood retailer was the shortfin mako shark. Istock/Alessandro De Maddalena Endangered sharks being served up in British fish and chip shops Blue shark Blue shark was also found on sale in UK shops. This species is not as vulnerable as the others but is still listed as "Near Threatened" by the International Union for Conservation of Nature Istock/Howard Chen Endangered sharks being served up in British fish and chip shops Nursehound Around a quarter of the sharks being sold in UK fishmongers were nursehounds, another relatively safe species that is nevertheless classified as near threatened. Mario Antonio Pena Zapatería Endangered sharks being served up in British fish and chip shops Misleading names in fish shops The scientists behind the study investigating the prevalence of endangered shark meat on sale concluded that shops must stop selling these species under "umbrella terms" that hide their true origin. Istock

“We were stunned to find that fisheries around the world have already responded to ocean warming,” said Dr Malin Pinsky, an ecologist at Rutgers University in New Jersey, who contributed to the research.

“These aren’t hypothetical changes sometime in the future.”

To conduct their ambitious analysis, the scientists examined fishing data on maximum sustainable catches stretching back to 1930, covering 235 populations of 124 marine species, and linked it with changes in ocean temperatures.

In total this represented around a third of the catch from around the world across this period.

Despite the overall devastation inflicted by warming oceans, the team noted that climate change is yielding some winners.

For example, black sea-bass populations in the mid-Atlantic have thrived even as many of their fellow fish have entered a downward spiral. However, the researchers say these positive trends cannot last forever.

“Fish populations can only tolerate so much warming,” said senior author Dr Olaf Jensen, also from Rutgers University.

“Many of the species that have benefited from warming so far are likely to start declining as temperatures continue to rise.”

If serious action is not taken by world governments to cut global greenhouse gas emissions, ocean temperatures are likely to rise by up to 3.2C by the end of the century.

This damage will be compounded by ocean acidification, another impact of higher CO2 levels in the atmosphere, as well as changes in the water’s oxygen content.

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“We recommend that fisheries managers eliminate overfishing, rebuild fisheries and account for climate change in fisheries management decisions,” said Dr Chris Free, a University of California, Santa Barbara scientist who led the research.

“Policymakers can prepare for regional disparities in fish catches by establishing trade agreements and partnerships to share seafood between winning and losing regions.”