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Earth's Fish Population Falling Due To Warming Oceans

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Sea temperatures are on the rise worldwide, and even fish are experiencing its effects. Evidently, warming water is causing a reduction in fisheries production in the last eight decades.

Fish And Warm Waters

Fish are cold-blooded animals, which means that they mirror the temperature of the water they are living in. Unfortunately, when the waters get too warm, this alters the enzymes they use for digestion and other functions, rendering them less efficient and thereby affecting their reproduction and growth. What’s more, warmer waters also cause stress on fish because it contains less oxygen.

To study just how much climate change has impacted fisheries around the world, researchers created a model of how fish respond to rising temperatures using a database that represents about a third of all fish caught worldwide.

Decrease In Fish Production

Basically, researchers looked at over 200 stocks of fish and found that nine of them actually had an average of 4 percent increase in production. These, however, are in typically frigid waters that are becoming warmer and more suitable for fish. For instance, in Labrador and Newfoundland in Canada, there was a 14 percent increase since 1930, and it might even get better. Further, Greenland halibut productivity might even increase by 51 percent with every degree Celsius of warming.

On the other hand, in places such as Japan and northern Europe, there are 19 stocks that saw an average of 8 percent decrease in production, and are expected to decrease even further by 54 percent with every degree of warming.

Taking the increases and decreases together, the researchers found a 4 percent lower overall maximum sustainable yield in 235 fish stocks compared to 1930. While this may seem like a small number, it represents a 1.4 million ton decrease in fish production that many people rely on for their livelihood.

Underestimated Data

Researchers surmise that this may even be an underestimate because there was little data from the tropics where the effects of rising sea temperature are likely more felt. In addition, the supposed positive effects of increase in fish production in previously frigid waters are not expected to last, given the expected amount of warming in the coming century.

As such, responsible management of fisheries is all the more important in helping the fish to adapt to climate change.

The study is published in the journal Science.

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