The predicted increase in greenhouse gases in the atmosphere will reduce oxygen in the world's oceans and lead to smaller fish, especially bottom feeders like halibut and cod, says a study by U.S. and Canadian scientists. But fish populations might shift northward as tropical waters get warmer. From Reuters:
Average maximum body weights for 600 types of marine fish, such as cod, plaice, halibut and flounder, would contract by 14 to 24 per cent by 2050 from 2000 under a scenario of a quick rise in greenhouse-gas emissions, [the study] said.
"The reductions in body size will affect whole ecosystems," lead author William Cheung of the University of British Columbia told Reuters of the findings in the journal Nature Climate Change. His team of scientists said a trend toward smaller sizes was "expected to have large implications" for ocean food webs and for human "fisheries and global protein supply."