A new study performed by researchers from the “Sea Around Us” initiative at the University of Western Australia and the University of British Columbia has shown that subsidized long-distance fishing has increased, even as fleet catches have diminished.
The study, published in Science Advances, indicates that four countries – Taiwan, South Korea, Spain, and China – have rapidly increased their mean distance to fishing grounds by 2,000 to 4,000 kilometers between 1950 and 2014. The fleets, often subsidized, have increased the total fished area of the world’s oceans from 60 to 90 percent.
"While most countries continue to focus their fishing efforts on local waters, Taiwan, South Korea, Spain and China have aggressively subsidized vessel and fuel costs to encourage their fleets to operate thousands of kilometres from their home ports," said lead author David Tickler, a postgraduate student at UWA's School of Biological Sciences, to Phys.org.
According to the study, the expansion of the mean distance fished from port has coincided with less fish-per-kilometer.
“Catches declined from more than 25 metric tons per 1,000 [kilometers] traveled in the early 1950s to approximately seven metric tons per 1,000 km traveled by 2014,” the study states.
The large distances and expansion of fishing, according to the study, indicates that the industry may be close to the limit of what the capture industry can provide.
“The trends in the spatial expansion of industrial fisheries and their overall catch together indicate that we may be approaching the physical limits of expansion in capture fisheries,” the study states. “By our measure, total industrial catch per unit ocean area has declined by 22 percent since 1996, despite spatial expansion having continued, albeit slowly. Further expansion into the remaining accessible areas of the polar seas, even if it were ecologically justifiable, seems unlikely to reverse this trend.”
Continued expansion into new areas is no longer feasible as fishing fleets already access almost every corner of the ocean.
"Essentially no waters other than those at the polar extremes are presently unfished to some degree," said co-author Daniel Pauly, principal investigator of the Sea Around Us initiative at UBC, to Phys.org. "But this continued expansion and concurrent intensification of fishing efforts has only contributed to the depletion of new areas of the ocean."
The only solution, said study co-author Jessica Meeuwig, who leads UWA’s Marine Futures Lab, is to let the ocean recover.
“We have to accept that for fisheries to continue to support humanity into the future, we are going to have to allow the oceans some space and time to recover from over a century of unfettered industrial fishing."
Photo courtesy of Science Advances
