Fish species could shrink in size by as much as 30 percent thanks to climate change, says a study in the journal Global Change Biology.
“Fish, as cold-blooded animals, cannot regulate their own body temperatures. When ocean waters become warmer, a fish’s metabolism accelerates, and it needs more oxygen to sustain its body functions,” says Nexus Media. “The problem is that the gills’ surface area does not grow at the same pace as the rest of the fish’s body — and warm water contains less oxygen than cooler water.” Essentially, fish can’t keep up with their metabolic demands.
The effect is especially pronounced in larger species like tuna, which would see a 30 percent drop in size, compared to brown trout, which because they aren’t as active as tuna, are predicted to shrink by 8 percent.
“Some parts of the world, such as in the topics, are going to see even larger decreases,” said William Cheung, director of science for the Nippon Foundation — University of British Columbia Nereus Program and a co-author of the study. “This will have substantial impacts on the availability of fishes for people.”