Fishing in the Pacific Ocean for Purseine Tuna. Credit: ISSF, Jeff MuirA major international study found that climate change-driven redistribution key commercial tuna species could cause economic damage to small islands states in the Western and Central Pacific, and threaten the sustainability and viability of the largest tuna fishery in the world.This study integrates climate science, economic modeling, and climate science to give a complete analysis of the effects of climate change on Pacific tuna stocks as well as the small island states dependent on them. The study is published in Nature Sustainability today.The research was conducted by a consortium of institutions and organisations from North America, Europe, and the Pacific. These included Conservation International, Conservation International, University of Wollongong and the Pacific Community (SPC), Conservation International and the Pacific Islands Forum Fisheries Agency.The 10 islands states of the Western PacificCook Islands and Federated States of Micronesia, Kiribati and Marshall Islands, Nauru and Palau, Papua New Guinea Solomon Islands, Tokelau, Tuvalu, and Kiribati are so dependent on their tuna fisheries to ensure economic development and food security, they are "tuna dependent".Over the past decades, the management of most Islands' tuna fisheries by a cooperative agreement has been a success story in sustainable development. It has provided reliable and needed revenue for development, while also preventing overfishing from destroying fish stocks.The waters of the Western Pacific and Central Pacific account for approximately half the world's tuna catch. For those 10 small islands states, fishing fees paid by industrial fishing fleets to access their waters make up an average 37 percent of all government revenues. This ranges from 4 percent to 84 percent in Tokelau for Papua New Guinea's relatively large economy to Papua New Guinea's 4 percent.Johann Bell, Senior Director of Pacific Tuna Fisheries Conservation International Center for Oceans and Visiting Professorial Fellow, UOW's Australian National Centre for Ocean Resources and Security, (ANCORS), was the study lead author. He said that the major species of bigeye, skipjack and yellowfin were highly migratory and could move across large swathes of the ocean depending on oceanographic conditions."Currently, these tuna stock are found mostly within the waters off the 10 islands states. Dr. Bell stated that they will shift eastward due to climate change and move out of sovereign waters into the high seas.A school for tuna. Credit: ISSF, David Itano"By 2050, the total biomass for skipjack, yellowfin and bigeye tuna could decrease by an average 13 percent under a high level of greenhouse gas emissions as more fish move into high seas."Potential implications for Pacific Island economies include a 20 percent decline in purse-seine capture, a loss of regional tuna-fishing access fees up to US$140million, and a reduction in government revenue up to 17% for individual Pacific Island states.Lower greenhouse gas emissions would mean that the future of the Pacific Island States looks brighter, leading to smaller losses. The Paris Agreement's reductions in greenhouse gas emissions would be a step towards sustainability for the tuna-dependent Pacific Island economies.Dr. Bell stated that "the greenhouse gas emissions from these small island countries are negligible, but they are amongst the most vulnerable to the effects of climate change.""Many island states have very limited opportunities to earn income, other than their tuna resources which are expected to leave their jurisdictions due the ocean warming. This is a climate justice matter that should be brought up at the United Nations Climate Change Conference, Glasgow, later in the year.Associate Professor Quentin Hanich from UOW, a Pacific Ocean governance and fisheries management expert and marine conservation specialist, was a co-author.He said that "Pacific Island states can negotiate with the regional fisheries organization to keep the benefits they get from tuna," regardless of future distribution.As a co-author of the study, Assistant Professor Katherine Seto from the University of California Santa Cruz, and a Research Fellow at ANCORS noted that tuna become more vulnerable to overfishing as they move into high seas beyond national jurisdiction.She stated that "Preventing overfishing and ensuring compliance fisheries management measures is more difficult than in the exclusive economic zones on the islands because compliance rests solely with the states that flag fishing vessels, which often leads to self-regulation."Nature Sustainability published "Pathways for sustaining tuna-dependent Pacific Island economies during Climate Change" by Johann D. Bell and colleagues.Further Tuna Showdown at Samoa ConferenceFurther information: Johann D. Bell and others, Pathways for sustaining tuna-dependent Pacific Island economies under climate change, Nature Sustainability (2021). Information from Nature Sustainability Johann D. Bell and colleagues, Pathways for sustaining tuna-dependent Pacific Island economy during climate change. (2021). DOI: 10.1038/s41893-021-00745-z
