A study of fishing on the high seas – those marine waters beyond national jurisdiction –says most of these fisheries would be unprofitable at current rates without government subsidies.
The collaborative study published in the journal Science Advances in June was compiled by researchers from the National Geographic Society, the University of California Santa Barbara, Global Fishing Watch, the Sea Around Us project of the University of British Columbia, and the University of Western Australia.
They concluded that the global cost of fishing in the high seas ranged from between $6.2 and $8 billion in US dollars in 2014, while profits ranged from a loss of $364 million and a profit of $1.4 billion.
These fisheries on the high seas, which cover 64 percent of the ocean surface, are dominated by a small number of fishing countries, which reap most of the benefits of fishing in these waters.
The environmental impacts of fishing on the high seas are well studied, researchers said. Still, a high level of secrecy around distant water fishing had previously precluded reliable estimates of the economic costs and benefits of high seas fishing.
Newly compiled satellite data and machine learning have revealed a far more accurate picture of this fishing effort at the level of individual vessels, they said.
According to the lead author of the study, Enric Sala, National Geographic Explorer-in-Residence, these fleets continue to operate in the high seas because they receive government subsidies. “Without subsidies and the forced labor some of them are known for, fishing would be unprofitable in over half of the high seas fishing grounds,” Sala said.
Researchers used automatic identification systems and vessel monitoring systems to track individual behavior, fishing activity and other characteristics of 3,620 vessels in near-real time. They combined that information with global catch data from the University of British Columbia’s Sea Around Us project to determine effort expanded by the vessels, the size of their catch, and how much profit the catch generated.
They estimated that almost 10 million hours of fishing occur annually across 132 million square kilometers, or 57 percent, of the high seas. Fishing hot spots found near Peru, Argentina and Japan were dominated by Chinese, Taiwanese and South Korean squid fishing fleets. The study also found that beyond subsidies, unfair labor compensation or no compensation at all are key cost-reducing factors in long-distance fishing.