Rising ocean temperatures are prompting fish toward cooler waters and changing the menus at seafood restaurants, according to new research from the University of British Columbia in Vancouver.
Findings of the study were published earlier this week in the journal Nature.
The work raises concerns climate change is emptying the warmer tropics of many of the fish populations communities in those areas of the world count on a sources of income as well as nutrition.
On the other hand, statistics show trawlers in higher elevations are catching more warm-water fish, which will notably change the offerings at locavore restaurants --- those who buy their food from local suppliers.
From from Cape Town to Tokyo, "there'll be changes in the kinds of fish that are available to people who would like to follow that kind of strategy [eating local fish]," Michael Fogarty, a fisheries biologist with the National Oceanic and Atmospheric Administration's Northeast Fisheries Science Center, told NBC News. He added the new numbers put the fishing industry and consumers on alert that they'll need to adapt to climate change.
The research for the study used the temperature preference of fish and other marine species as a way to assess the impact of climate change on the world's oceans between 1970 and 2006.
"If the catch composition is having more and more warm-water species present in it, then the mean temperature of the catch will also increase," said William Cheung, a fisheries biologist at the University of British Columbia, who found fishery catches across the earth are increasingly being dominated by warm-water species migrating out of the tropics toward the north or south poles.
For instance, there are currently more tuna and mackerel in the waters off of British Columbia, Canada, than there are indigenous sockeye salmon, which are on the decline.
"If the temperatures continue to warm in the tropics," then even hot-water adapted species "will find it difficult to live in the tropics, so we would expect as a result that the fishery production potential in the tropics will decline," Cheung said.
Climate change is reaching into fish markets and "our dining tables," Mark Payne, a marine scientist at the National Institute for Aquatic Resources in Denmark, wrote in Nature about the recent. "The question now is, how should we respond?"
According to Cheung, policymakers and fisheries managers need to reduce the stresses on marine ecosystems caused by overfishing, habitat destruction and pollution. Then, the fishing industry as well should prepare for the expected changes in species composition.
"Ultimately," said Cheung, in order to keep the plant's oceans as healthy as possible, "it is important to reduce greenhouse gas emissions...because if we reduce that, then we know that the rate of change in sea surface temperature will be reduced and this would actually reduce the level of response in terms of fish stocks to climate change."