Common Oceans - A partnership for sustainability and biodiversity in the ABNJ

What are the effects of climate change on tuna fisheries in the Western and Central Pacific Ocean?

8 January 2019

The Pacific Community (SPC), Conservation International (CI), and partners recently completed a series of analyses to assess the impacts of climate change on tropical tuna species and tuna fisheries in Pacific Island waters and high seas areas. The new modelling simulates the response of tropical tuna species, and the ecosystem that supports them, to projected changes in sea surface temperature, ocean currents, dissolved oxygen levels and other ocean variables under the International Panel for Climate Change (IPCC) "business as usual" emissions scenario in 2050 and 2100. The modelling indicates that significant changes in the distribution of skipjack, yellowfin and bigeye tuna and South Pacific albacore are expected to occur by 2050. These changes include:

  • a strong eastward shift in the distribution of skipjack and yellowfin tuna, resulting in reduced abundance of both species in the exclusive economic zones (EEZs) of Pacific Island countries and territories west of 170E in the Western and Central Pacific Ocean;
  • a similar but weaker eastward shift in the distribution of bigeye tuna;
  • a possible increase in the biomass of South Pacific albacore in the EEZs of Pacific Island countries, although the predictions are uncertain due to poor information about likely future levels of dissolved oxygen in oceanic waters; and
  • an increased abundance of tuna in high seas areas, resulting in a larger proportion of the catch of each species being made in international waters.
Click to enlarge Click to enlarge
Projected mean distributions of skipjack and yellowfin tuna biomass
across the tropical Pacific Ocean under a high emissions scenario
(IPCC AR8.5) for 2005 and from the simulation ensembles in the
decades centered on 2045 and 2095 © Conservation International
Map of the exclusive economic zones of Pacific Island countries and
territories, and International Water (IW) high seas areas, for the
tropical Pacific Ocean © Pacific Community

The projected changes in distribution of tuna have implications for management, and monitoring, control and surveillance, of tuna fisheries across the tropical Pacific Ocean, including the possible need for the tuna regional fisheries management organization Western and Central Pacific Fisheries Commission to assume even greater responsibility for management of the region's tuna resources. The redistribution of tuna from EEZs to high seas areas also has implications for the economies of Pacific Island countries. Conservative, preliminary analyses indicate that government revenue derived from tuna fishing license fees will decrease in eight of the ten Pacific Island countries that currently provide 95% of the tuna caught in the region. These eight are the Federated States of Micronesia, Palau, Papua New Guinea, Marshall Islands, Nauru, Solomon Islands, Tokelau and Tuvalu. Adaptations are needed to reduce the effects of projected redistribution of tuna catches on government revenue in these eight countries, and to capitalize on projected increased presence of tuna in the other two countries (Kiribati and Cook Islands). These adaptations should include negotiations to assist these countries to maintain their rights to manage tuna stocks displaced from their waters by climate change. Additionally, investments are essential to gain a better understanding of the effects of climate change on tropical tuna species to guide these adaptions. Such investments should identify the distribution, size and behavior of each tuna stock, and support improved modelling of the response of each tuna stock to climate change.

Access documents associated with these analyses here:

Impact of climate change on tropical tuna species and tuna fisheries in Pacific Island waters and high seas areas (Report and Information Paper)

 Implications of climate-driven redistribution of tuna for Pacific Island economies (Policy Brief)

The modeling and analyses were made possible through the support of the World Bank-implemented Ocean Partnerships for Sustainable Fisheries and Biodiversity Conservation, a sub-project of the Common Oceans ABNJ Program led by the Food and Agriculture Organization and funded by the Global Environment Facility

For more information, please contact:
  • Mr Pablo Obregon, Senior Program Manager, Fisheries - Conservation International | [email protected]g
GEF Common Oceans World Bank CI