Global warming and ocean acidification are causing noticeable declines in some fisheries currently and are expected to cause major ecological and financial damage to the world’s fisheries in the future.
Fisheries around the world could lose an estimated USD 10 billion (EUR 9.2 billion) in annual revenue by 2050 if climate change continues unchecked, according to a recent study published in Scientific Reports.
“We show that global fisheries revenues could drop by 35 percent more than the projected decrease in catches by the 2050s under high carbon dioxide emission scenarios,” wrote the team of scientists from the University of British Columbia.
Countries that are most dependent on fisheries to feed their populations will experience the biggest impacts, they found.
“It is necessary to implement better marine resource management plans to increase stock resilience to climate change,” said Vicky Lam, lead author and a postdoctoral fellow at UBC’s Institute for the Oceans and Fisheries, in a statement.
However, some developed countries such as Greenland and Iceland could see revenue increases as more fish move into cooler waters, they found.
In North America, New England-area fisheries are already feeling the impacts of warmer waters and changes in water acidity – and significant challenges are expected to continue into the future. The amount of cod in the Gulf of Maine, for example, has drastically fallen over the past few years. Over the past 10 years, the Gulf of Maine has warmed 99 percent faster than any other sea in the world, according to the National Oceanic and Atmospheric Administration (NOAA).
Plus, a new study, published in the ICES Journal of Marine Science, found that Maine lobster larvae and postlarvae reared in high temperature treatments (19° C) experienced significantly lower survival, developed twice as fast, and had significantly higher oxygen consumption rates, than those in ambient treatments (16° C).
“Lobster is still doing quite well; the catch goes up every year,” Jake Kritzer, lead senior scientist for the Environmental Defense Fund, told SeafoodSource. “However, the center of mass of the fishery – where the catches are the highest – is moving up the coast. If that trend continues, we are going to see the lobster population more centered in Canadian waters.”
Another major, lucrative fishery in North America – Alaska crab – could also be significantly impacted by ocean acidification and climate change in the future.
In his analysis of several studies on the topic, Terry Johnson, Alaska Sea Grant marine advisory agent, found that stocks of red king crab, Tanner crab and snow crab are in a prolonged period of decline.
“The future of red king crab does not look good, due to the increasing acidity of Bering Sea waters,” he wrote.
In addition to warmer waters, ocean acidification is expected to cause problems in the Alaskan crab fishery. Juvenile king crabs exhibited slower growth and higher mortality when held in water at a pH level “equivalent to what will predominate in crab rearing habitat within a century,” Johnson wrote, referring to a NOAA study.
“For people going into the crab fishery now, by the time they are mid-career or late-career, it will get slower and slower, so it’s not as economically viable,” Johnson told SeafoodSource. “I’m hoping the industry is going to start thinking about these problems and come up with strategies for adaptation.”
