Climate change to cause dark night of the shoal
PARIS — Climate change will cause key species of fish to migrate towards the poles, badly depleting many commercial fisheries, scientists said in a study published on Thursday.
“The impact of climate change on marine biodiversity and fisheries is going to be huge,” said its lead author, William Cheung, of the School of Environmental Sciences at the University of East Anglia, eastern England.
Cheung’s team used a high-powered computer model, based on knowledge of 1,066 species of fish, their habitat and climate change, to predict what might happen by 2050 according to three scenarios for global warming.
Warmer water will lead to “large-scale redistribution” of these species, with most of them moving towards the poles, shifting on average by more than 40 kilometers (25 miles) per decade, they said.
Arctic Norway will benefit from an increased catch, but in sub-polar regions, the tropics and semi-enclosed seas, “climate change may lead to numerous local extinction,” hitting developing countries most of all, the paper warned.
Part of this trend will be offset by colder-water species that venture into a warmer habitat.
In the North Sea, for instance, stocks of Atlantic cod may fall by more than a fifth as the species heads towards chillier waters.
On the other hand, the European plaice, a more southerly fish, could increase in the North Sea by more than 10 percent.
In the United States, there would be a fall of up to 50 percent in today’s cod fisheries on the east coast.
Some species will face a high risk of extinction, including the striped rock cod in the Antarctic and the St. Paul rock lobster in the Southern Ocean.
The paper, appearing in a British journal, Fish and Fisheries, says the turnover of species will be “dramatic,” affecting 60 percent of present biodiversity, and with repercussions for the entire food chain.