Industrial fishing fleets have doubled the distance they travel to fishing grounds since 1950, but catch just one third of what they did 65 years ago per kilometre travelled, according to a new study.
Scientists from the University of British Columbia and the University of Western Australia (UWA) mapped the growth and spread of industrial fisheries since 1950 and discovered that global trends were dominated by the heavily-subsidized fleets of a handful of countries, increasing the total area fished from 60 per cent to 90 per cent of the world’s oceans.
The report states that Taiwan, China, Spain and South Korea have significantly subsidized vessel and fuel costs to encourage their fleets to operate far beyond their home ports.
Despite this expansion, the catch rates of these fleets – and those of the other top 20 fishing countries – have declined from over 25 tonnes per 1,000 kilometres travelled in the early 1950s to 7 tonnes per 1,000 kilometres travelled in 2014.
"The data seem to indicate that we have reached the physical limits of expansion in capture fisheries,” says the study’s co-author, Dirk Zeller of UWA. “Industrial catches peaked in 1996, when the discovery of new stocks was no longer able to keep up with the declines in existing stocks."
The world’s top 20 fishing countries are responsible for 60 million tonnes, or 80 per cent of the global industrial fishing catch. There are essentially no remaining regions, other than the most remote polar areas, that remain unfished.