Mystery and discovery in the economics of fishing on the high seas

Fishing on the high seas may frequently be economically unsustainable, according to an analysis last year by Enric Sala and colleagues in Science Advances.

This comparatively unregulated fishing industry beyond national exclusive economic zones presents grave environmental concerns, so the motivation for continued fishing under unprofitable conditions is somewhat of a mystery. Sala and colleagues mostly argue that the industry is propped up by government subsidies, but they also discuss two other factors. One is substandard wages and working conditions, even sometimes modern slavery. Another is the possibility that some countries cheat on their harvest reporting and are really more profitable than they appear. The study's data source already corrects for standard estimates of catch underreporting, so this last possibility might require especially brazen underreporting on a scale that has not yet been recognized.

Fig. 3 Net economic benefit of high-seas fishing (Sala et al., 2018). 
Range of estimates of fishing profits (US$ millions) before (π) and after (π*) subsidies for (A) major fishing countries and (B) gear types.

The 2018 study is part of a blossoming research literature that takes advantage of modern tracking data to estimate the "fishing effort" of thousands of individual vessels. To get a sense of this remarkable type of data, see the online mapping capability at Global Fishing Watch. It lets you track individual vessels as they criss-cross the ocean in both the national exclusive economic zones and the high seas.

I came across this study after watching a video from Greenpeace featuring one of the authors, Daniel Pauly, a professor of fisheries at the University of British Columbia. He explains that the decline of fisheries has been going on so long that even adults in fishing communities may not fully understand the long-term baseline bounty that could be possible without overfishing. The environmental sustainability of human consumption of smaller fish is less fraught, but, in the video, Pauly argues that "we are chasing the last of the big fish."