Cod's decline traced to warming Gulf of Maine // NY Times
by Erica Goode
Rapid warming in the Gulf of Maine contributed to the collapse of cod fishing in New England, and might help explain why the cod population has failed to recover, even though fishing has largely ceased, according to a new study.
Fisheries managers have tried to reverse the cod’s decline in the gulf by imposing increasingly severe limits on fishing since 2010, reducing quotas to the point that recreational cod fishing has been effectively closed and few commercial fishermen now set out intending to catch cod.A team of marine scientists found that rising temperatures in the gulf decreased reproduction and increased mortality among the once-plentiful Atlantic cod, adding to the toll of many decades of overfishing.
But the quotas, the study’s authors say, were based on population estimates that did not take into account the temperature changes and therefore were set too high. Even when fishermen stayed within the quotas, they were in effect overfishing, the researchers write in their report, which appears in the Oct. 30 issue of the journal Science.
“The failure to consider temperature impacts on Gulf of Maine cod recruitment created unrealistic expectations for how large this stock can be and how quickly it can rebuild,” the researchers write.
The study uses data about water surface temperatures to look at warming trends in the gulf since 1982 and compares the rate of increase to ocean waters in other parts of the world. From 2004 to 2013, the scientists found, temperatures rose faster in the Gulf of Maine than in 99.9 percent of the global ocean.