Researchers say they’ve come to a startling discovery about why Maine’s once-thriving population of cod has all but vanished. Marine scientists have traditionally blamed decades of overfishing, but because fishing for cod in the Gulf of Maine has largely come to a halt under restrictive limits, one group decided to see if rising sea temperatures had anything to do with it.
The study, which appears in the latest issue of Science, found that climate change “decreased reproduction and increased mortality among the once-plentiful Atlantic cod.” They speculate that warmer water is killing off cod’s food while, conversely, exposing baby cod to more predators as they flee to cooler, deeper waters. The fishing quotas that were set years ago might’ve worked, too, the researchers venture, if regulators had thought to take the toll of rising ocean temperatures into account. That failure, they write, “created unrealistic expectations for how large this stock can be and how quickly it can rebuild.” They predict it could take nearly double the previously estimated time to rebuild the collapsed population around Maine.
That’s some bad news for Americans’ fish-and-chips consumption, but the scariest part is the severity of the rise: Researchers compared Gulf of Maine temperatures to sea temperatures everywhere else, and they found that from 2004 to 2013 water in the gulf warmed faster than it did in 99.9 percent of the world’s oceans.