The first study to look at how climate change will affect food supplies offshore warns of severe declines in fish stocks in some of the world’s poorest regions.
Fish populations in the tropics could fall by as much as 40% over the next half century because of global warming, jeopardising a vital food source for the developing world, a new study published today has found.
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It did not take into account the effects of ocean acidification – caused by more carbon dioxide dissolving in seawater and which scientists expect will reinforce the effects of warming on the oceans. “We think that our estimates should be considered conservative because adding ocean acidification into the equation would further decrease future fishery potential,” said Cheung. He said a follow-up study would look at the effects of acidification.
The scientists found that the warming seas were driving fish from their current habitats, with for example, tropical mainstays like snapper moving north. Some will successfully migrate to colder waters – reflected in the projected increase in fish populations in more northern waters. But others will not survive the changes. “Not all of them will make it. They can handle it only by shifting more energy to resisting the higher temperatures, which means less growth and less potential for harvesting,” said Pauly.
The study did not focus on individual species. However, scientists said the changes brought by warming seas would see the decline and possible disappearance of familiar fish even in colder waters, like those off Britain. Cod stocks will flee British waters for Iceland, Norway and Greenland.
Suzanne Goldenberg, The Guardian, 8 October 2009. Full article.
