Tuna fisheries risk most from climate change

An analysis of more than 500 sustainably certified fisheries around the world suggests those targeting migratory species including tunas, bonitos and billfishes are most at risk from the impacts of shifting fish stocks and the reduction in the number of fish in the ecosystem due to climate change.

The research paper ‘Climate change risks to future sustainable fishing using global seafood ecolabel data’  supported by the FAO-led Common Oceans Project and the Ocean Stewardship Fund was led by the Marine Stewardship Council (MSC) and is being published in the journal Cell Reports Sustainability.

It analysed the risks from the impacts of climate change to fisheries around the world that use a range of different fishing gear types and that target 19 different categories of seafood, from krill to lobsters, and from whitefish to tuna.

Behavioural changes

“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.

“We have seen fisheries adapting their approach to remain sustainable, but it is becoming more and more challenging to do so without the support of fisheries management organisations which are responsive to the challenges of climate change.”

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 favour 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. 

Winners and losers

"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."

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.

Other fisheries vulnerable to climate change associated risks to management, were those targeting small pelagic species like herrings followed by those targeting whitefish like cod.

The analysis only looked at data from MSC certified fisheries, but the researchers suggest fisheries unable to meet MSC certification are likely to be more vulnerable to the effects of climate change. Certified fisheries have robust management plans in place and have met requirements on sustainability and responsible management to gain certification, making them potentially more resilient to climate impacts.