Waters in the north-west Atlantic have warmed 99% faster than the rest of the world’s oceans in the past decade due to changes in the Gulf Stream and Pacific

This article is more than 4 years old

This article is more than 4 years old

A rapid warming of the Gulf of Maine off the eastern United States has made the water too warm for cod, pushing stocks towards collapse despite deep reductions in the number of fish caught, a US study has shown.



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The Gulf of Maine had warmed faster than 99% of the rest of the world’s oceans in the past decade, influenced by shifts in the Atlantic Gulf Stream, changes in the Pacific Ocean and a wider trend of climate change, it said.

Scientists said the findings showed a need to take more account of changing water temperatures in managing global fish stocks usually based on historical data of catches.

Traditional calculations “consistently over-estimated the abundance of cod”, said Andrew Pershing, chief scientific officer of the Gulf of Maine Research Institute and lead author of the study in the journal Science.

“Rapid changes outpaced our ability to recognise and react to what was happening in the water,” he told an online news conference.

Fisheries managers cut cod quotas in recent years but cod numbers kept falling because the rapidly warming waters were making the Gulf of Maine inhospitable for the fish.

From 2004, temperatures rose by more than 0.23C (0.4 Fahrenheit) a year, culminating in an ocean heat wave in the north-west Atlantic in 2012-13.

And commercial cod landings fell to 1,000 tonnes in the Gulf of Maine in 2013, sliding from a recent high of 6,000 in 2009, according to the US Department of Commerce.

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A United Nations climate report last year said that global warming was pushing many fish stocks towards the poles. Cod are thriving in cooler waters such as off Canada, Norway or Greenland.

“The Gulf of Maine cod is a wake-up call” for better coordination between climate scientists and fisheries management, said Katherine Mills, one of the authors at the Gulf of Maine Research Institute.

She said it was unlikely that cod catches would recover to pre-crisis levels. The experts laid out scenarios that foresaw a recovery to 5,000 tonnes a year by 2030 in a warm scenario or to just 1,800 tonnes in a hot scenario.