Oceans that are warming due to climate change yield fewer fish

[Judi Lynn]

Some areas have seen up to a 35 percent decline in how many fish can be harvested sustainably
BY CAROLYN GRAMLING 2:00PM, FEBRUARY 28, 2019

Finding the fish is going to get harder as climate change continues to heat up the world’s oceans. Increasing ocean temperatures over 80 years have reduced the sustainable catch of 124 fish and shellfish species — the amount that can be harvested without doing long-term damage to the populations — by a global average of 4.1 percent, a new study finds.

Overfishing has exacerbated that decline, the researchers say. In some parts of the world, such as the heavily fished Sea of Japan, the decrease in sustainable catch is as high as 35 percent.

The study, in the March 1 Science, examined changes from 1930 to 2010 in 235 fish and shellfish populations scattered across 38 ocean regions. On average, Earth’s surface ocean temperatures have increased by about half a degree Celsius in that time, although temperature changes vary from location to location.

About 8 percent of the fish and shellfish populations studied saw losses as a result of the ocean warming, while about 4 percent of the populations increased in that time. That’s because certain species, such as black sea bass along the northeastern U.S. coast, have thrived in the warmer waters. But with continued warming those gains are likely to evaporate, as even those fish reach their heat threshold, says Christopher Free, a quantitative ecologist at the University of California, Santa Barbara, who led the work while he was at Rutgers University in New Brunswick, N.J.

https://www.sciencenews.org/article/oceans-are-warming-due-climate-change-yield-fewer-fish?tgt=nr

[democratisphere]

1. What the hell have we done to this planet and by extension ourselves?

Unfortunately we already know the answer, for which there is no effective solution.

[OKIsItJustMe]

2. Food supply falls as fish flee warmer seas

https://climatenewsnetwork.net/food-supply-falls-as-fish-flee-warmer-seas/

Food supply falls as fish flee warmer seas

March 4th, 2019, by Tim Radford

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.

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