[NEW YORK] Tuna, the economic mainstay of the Pacific Small Island Developing States (SIDS), are being driven out of the exclusive economic zones (EEZ) of these vulnerable countries by ocean warming, says a new study.

The SIDS are among parties to the UN Framework Convention on Climate Change that are least responsible for changing climate but are most vulnerable, especially to sea levels rising from global warming.

Tuna stocks earn the Pacific SIDS access fees paid by foreign fleets that catch 1.4 million tonnes of tuna from the combined EEZs of the Federated States of Micronesia, Kiribati, Marshall Islands, Nauru, Palau, Papua New Guinea, Solomon Islands, and Tuvalu.

According to the study, published late July in Nature Sustainability, by 2050, under a high greenhouse gas emissions scenario, the total biomass of three tuna species in the waters of the Pacific SIDS could decline by an average of 13 per cent as fish move into international waters.

The sustainable management of the world’s largest tuna fishery located in the Pacific SIDS will also be affected as the fish move into international waters, the researchers say.

According to the researchers, sustainable development of tuna-dependent economies in the Pacific Island region is likely to be at substantial risk from continued high greenhouse gas emissions. Their models indicate that it is not a question of ‘if’ tuna biomass will shift from the combined EEZs of the 10 Pacific SIDS but ‘when, how quickly and to what extent’.

Johann Bell, lead author of the study and senior director of Pacific Tuna Fisheries at Conservation International’s Center for Oceans, says the study’s findings demonstrate that the effects of climate change on the redistribution of tuna in the Pacific Ocean is expected to be stronger than reported previously.

Earlier studies, Bell explains, indicated that the “eastward movement of tuna in response to a warming ocean would result in some countries in the west of the Pacific Island region losing tuna, and those in the east gaining tuna. The latest modelling indicates that the effects of climate change on the redistribution of tuna will result in all of the Pacific (SIDS) that depend heavily on tuna for economic development losing some of these fish from their waters by 2050”.

“It is now evident that if high greenhouse gas emissions continue, a greater percentage of the region’s tuna resources will occur in the high seas (international waters).”

“It is now evident that if high greenhouse gas emissions continue, a greater percentage of the region’s tuna resources will occur in the high seas”

Johann Bell, Conservation International

In some of the Pacific SIDS, the lower tuna catch from their EEZ could reduce total government revenue by eight to 17 per cent per year since foreign fleets that pay access fees to catch tuna within the zone will take a greater proportion of their catches from international waters.

Pascal Bach, researcher at the French National Research Institute for Sustainable Development, in Marseilles, France, says that 90 per cent of the tuna caught in the EEZs of the 10 Pacific SIDS is exported to canneries in Indonesia, the Philippines and Thailand. The remaining 10 per cent is processed in Papua New Guinea, Solomon Islands, Fiji, and Samoa at factories that employ some 15,000 people.

Hugh Walton, chief technical advisor at the Pacific Islands Forum Fisheries Agency, says the study “is very important to vulnerable Pacific SIDS that already are facing serious change issues from global warming and sea level rise, especially for the atoll nations”.

“A change in the abundance and habitat of tuna species with decreasing in-zone fishing and associated reductions in access and licence income and possible food security risks is a major issue for Pacific SIDS,” says Walton. “Clearly understanding the issues now through this type of research allows us to look more specifically at mitigation strategies.”

Climate justice is at issue here, believes Walton, adding: “Pacific SIDS are not contributing to global warming, but they are increasingly carrying the impact burden.

“From this study and other related work, we can see that committing to the emissions reduction targets of the Paris Agreement could potentially return us to a pathway to sustainability for tuna-dependent Pacific Island economies.”

This piece was produced by SciDev.Net’s Asia & Pacific desk.