Det ser illa ut för fisken. Haven har blivit varmare, surare och syrefattigare.
Fish are in trouble with the climate crisis, IPCC report finds
(CNN)Since the 1970s, the climate crisis has made our oceans warmer and more acidic, reducing the number of fish we rely on for our food and putting the future of fish in peril, according to a major UN report out Wednesday.
Rising temperatures mean oceans will have less oxygen, and this, along with more heatwaves and increased acidification, will make fish move further away from the coast and create larger deadzones, where life cannot survive.
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Ocean warming this century has contributed to an "overall decrease in maximum catch potential." Overfishing makes the issue worse, the Intergovernmental Panel on Climate Change (IPCC) report said.
Scientists are "virtually certain" that the ocean has warmed between 1970 and 2017.
Marine heatwaves, periods of extremely high ocean surface temperatures, have "very likely" doubled in frequency from 1982 to 2016, according to the report, lasting longer and becoming more intense due to the climate crisis.
Warmer waters hold less oxygen, and fish need that oxygen to survive. Warmer waters also lead to algae blooms, red tides that further decrease oxygen, and kill sea life. A ride tide triggered a state of emergency in Florida in 2018, killing thousands of animals and costing the state millions. The toxin created by the algal blooms can also make shellfish poisonous to humans.
Warmer waters endanger coral reefs that are homes to many fish. Foundation species, meaning fish food, also decline.
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It's "virtually certain" that the ocean has taken up between 20-30% of the total human produced carbon since the 1980s, changing the very chemistry of the ocean, making it more acidic, the IPCC report found.
Acidification eats away at the shells of some mollusks. The change in the ocean's pH makes carbonate ions less abundant. Oysters, mussels, clams, and other animals need these ions to build up their shells. The acidification also hurts creatures like calcareous plankton that many fish rely on for food
Ocean acidification has already caused massive die-offs of oysters in the Pacific Northwest.
https://edition.cnn.com/2019/09/25/health/fish-climate-crisis-ipcc/index.html