Fish migrating to cooler waters, study says

CLIMATE CHANGE

February 12, 2009|By Azadeh Ansari CNN
Red areas on this map show regions that are expected to have the greatest increase in fish populations by 2050.

Climate-driven environmental changes could drastically affect the distribution of more than 1,000 species of commercial fish and shellfish around the world, scientists say.

For the first time, researchers using computer models have been able to predict the effect that warming oceans, fed by greenhouse-gas emissions, could have on marine biodiversity on a global scale.

A new study predicts that by 2050, large numbers of marine species will migrate from tropical seas toward cooler waters -- specifically the Arctic and Southern Ocean -- at an average rate of 40 to 45 kilometers (about 25 to 28 miles) per decade.

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These migrations could lead to "numerous extinctions" of marine species outside the Arctic and Antarctic, especially in tropical waters, according to the study's projections.

"These are major impacts that we are going to see within our lifetime and our children's lifetime," said William Cheung, lead author of the study, set to be published this week in the journal Fish and Fisheries.

"Climate change provides us with a kick in the pants," added Cheung, a marine biologist and lecturer at the University of East Anglia in the United Kingdom. "We can't think about climate change and biodiversity without thinking about the impact it will have on people."

Researchers from the University of East Anglia, Princeton University and the Sea Around Us Project at the University of British Columbia participated in the study.

Using a combination of data from fisheries and computer models that can project the potential effects of climate change on biodiversity, researchers were able to make predictions on the migration patterns of different fish species under varying climate-change scenarios.

The study predicts that within 41 years, the global distribution of marine species will shift 60 percent as more fish move toward cooler waters near the Earth's poles.

"Even if we completely stop fishing, we will still see a big difference in 10 years," said Emily Pidgeon, senior technical adviser with the Regional Marine Strategies Department at Conservation International.

The study suggests that conservationists will have to adapt their approach to a shifting marine environment. Added Pidgeon, "The goal posts are changing, so we need to re-think and re-tool the way we look at fishery management."

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