This story originally appeared on the World Ocean Initiative website, it has been reposted here with permission
Tuna tagging helps Pacific islands face uncertain future
An expedition to monitor the health of the world’s largest tuna fishery concluded on October 2nd. It tagged more than 6,000 tuna during a seven-week voyage in the Pacific Ocean, thanks to support from the fishing and technology sectors.
With most international tourism shut down because of covid-19, many Pacific island countries are even more dependent on the region’s tuna fisheries, valued at around US$6bn in 2018. For many of the countries, licence fees for tuna-fishing in the western and central Pacific account for over half of government income. The tuna industry also provides 25,000 jobs across the region, according to the region’s sustainable development body, the Pacific Community (SPC).
Studies such as the UN special report on the impact of climate change on the ocean warn of an eastward redistribution of skipjack and yellowfin tuna away from established fishing areas towards cooler water in the high seas, potentially leading to a loss of revenue for Pacific island countries. Estimates suggest annual losses of US$60m in fishing fees and reductions in government revenue of up to 15% per year by 2050 in the ten Pacific Island countries and territories (PICTs).
“The tuna fishery will be absolutely critical in supporting economic recovery in the Pacific region,” says Pamela Maru, secretary of the Cook Islands’ marine resources ministry. “Tourism has been significantly impacted by covid-19.” However, any economic development has to be sustainable in the long term, she adds.
A report by the Pacific Islands Forum Fisheries Agency and the SPC says that stocks of yellowfin, bigeye, skipjack and albacore tuna are not overfished and are currently in a healthy state. However, the report warns that there is “no room for complacency”, with the biomass of most stocks continuing to decline and a need to address gaps in management measures.
Tag team challenge
In order to manage its tuna resources, the SPC operates a tuna-tagging programme. Tagging is vital to show how fishing demand and climate change affect the health of fisheries. Since 2006 the SPC has tagged almost 500,000 tuna, generating the most comprehensive dataset for tuna management in the world.
“Continued investment and work through the tuna-tagging programme is critical for us so we can then learn how to approach our fisheries-management strategies and provide information to our industry about how they might have to consider their operations,” says Ms Maru. “The interest for us here in the Pacific is ensuring that we have sustainable stocks so that in the future we can continue to benefit from those resources.”
Conventional tagging involves attaching a thin plastic tag that includes a unique code and instructions to anyone who catches the fish to return the tag for a small reward. This type of tagging captures the size and location of a fish at the time of tagging and its location when recaptured. Each month thousands of tags are returned from tuna-processing plants all over the world.
Electronic tags track and record a fish’s movements and the surrounding water temperature, generating a much richer dataset for researchers. Because these tags cannot transmit their data, it is important to recover the tags for analysis. Knowing the time and place of recapture is also beneficial.
Collaboration with the region’s tuna industry increased the recent tagging expedition’s access to schools of bigeye and yellowfin tuna by providing daily real-time positions of fish-aggregating devices—buoys that attract tuna to increase fishing productivity. The industry is also working with the SPC to find more effective ways to encourage fisheries workers to identify and return electronic tags.
“Most of the time our vessels are very reluctant to share this information,” says William Gibbons-Fly, director of the American Tuna Boat Association, whose members operate 24 large tuna-fishing vessels in the Pacific. “Because of our relationship with SPC and the importance of their stock assessments, we’re able to share this information in real time with the tagging expedition.”
This type of collaboration can inspire similar initiatives elsewhere. “It would be great to see this cross-sectoral approach, involving industry, tech providers and the interests of the Pacific island countries, replicated in other oceans around the world,” says Kathryn Gavira O’Neill, a marine biologist from Spanish satellite company Satlink, which works with the Kiribati government to support sustainable fisheries management.
Main image: Release of a tagged Bigeye tuna (credit: SPC)