Fisheries targeting migratory species including tunas, bonitos and billfishes are most at risk from climate change because of the impacts of shifting fish stocks and the reduction in the number of fish in the ecosystem. This was the conclusion of a new report led by the Marine Stewardship Council that analyzed more than 500 sustainably certified fisheries around the world.
The paper, Climate change risks to future sustainable fishing using global seafood ecolabel data was supported by the United Nations Food and Agriculture Organization (FAO)-led Common Oceans Project and MSC’s Ocean Stewardship Fund. It is being published in the journal Cell Reports Sustainability.
The research only analyzed MSC fisheries for climate change impact risks. It examined fisheries that use various gear types and that target 19 different categories of seafood, from krill to lobsters, and from whitefish to tuna.
The analysis found that fisheries targeting highly migratory species, like tuna, were most at risk. As ocean temperatures change, migratory species change their routes in favor of cooler waters. For example, Atlantic bluefin tuna have returned to waters around the UK having disappeared decades ago. In the Pacific, there are growing signs tuna are moving away from the west of the region to the east. As tuna appear in new jurisdictions, or in the high seas, they move into areas of the ocean governed by different countries and subject to different regulations. This is likely to increase disagreements between governments over how much of each stock they are allowed to catch, potentially leading to overfishing.
“The effects of climate change are causing all types of species to alter their behaviour. Fish are moving to new and different locations and as a result existing fishing quota agreements quickly become obsolete because the fish stocks have moved,” said MSC data science manager Lauren Koerner, lead author of the report.
The research suggests that to mitigate these risks, greater international cooperation is needed, for example by implementing adaptive allocations, where countries’ fishing quotas are adjusted in response to shifting fish populations. Governments also need to further reduce greenhouse gas emissions if they want to continue to sustainably harvest some species and ensure stocks for future generations.
“With climate change there will be winners and losers in tuna fisheries but for some developing small island states, the impact on their economies could be devastating,” said Joe Zelasney, Common Oceans Tuna Project Manager. “It is important for governments and the five tuna regional fisheries management organisations that manage tuna fisheries on the high seas to work closely together to stay ahead of the changes to protect livelihoods and regional food security.”
