Food supply falls as fish flee warmer seas
Both jobs and food are at risk as fish evade rising warmth. Image: By Lalo on Unsplash
On the fishing grounds, they already know about global warming. As fish flee warmer seas there are winners – but many more losers.
LONDON, 4 March 2019 – Global warming has already begun to affect fishing worldwide as fish flee warmer seas, a new study says.
In the last 80 years, there has been an estimated drop of more than 4% in sustainable catches for many kinds of fish and shellfish. That is the average. In some regions – the East China Sea, for instance, and Europe’s North Sea– the estimated decline was between 15% and 35%.
In the course of the last century, global average temperatures have crept up by about 1°C above the average for most of human history, as a reaction to the unconstrained burning of fossil fuels. If the world continues to burn ever-greater volumes of coal, oil and natural gas, it could be 3°C warmer or more by the end of the century.
Last year was only the fourth warmest for air surface temperatures, but the warmest since records began for the world’s oceans.
“Fisheries around the world have already responded to global warming. These aren’t hypothetical changes some time in the future”
US researchers report in the journal Science that they looked at the impact of ocean warming in 235 populations of 124 species of fish, crustaceans and molluscs in 38 ecological regions between the years 1930 and 2010.
They then matched the world data on fish catches with ocean temperature maps to estimate what warming has done to the sustainable catch – that is, the biggest haul fishing crews can make without reducing breeding stocks for the seasons to follow.
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