Fish discards. (Photo: OCEAN2012EU)
Almost 10 pct of worldwide catches were discarded in the last decade
Wednesday, June 28, 2017, 00:20 (GMT + 9)
Almost 10 per cent of the world's total catches were discarded in the last decade due to poor fishing practices or inadequate management, as it is concluded in a joint study performed by researchers from the University of British Columbia and the University of Western Australia.
The scientists from Sea Around Us project, an initiative of both universities, who carried out the research, explained this percentage is equivalent to throwing back enough fish to fill about 4,500 Olympic sized swimming pools every year.
“In the current era of increasing food insecurity and human nutritional health concerns, these findings are important,” said Dirk Zeller, lead author for the study and senior research partner with the Sea Around Us.
Fishers discard a portion of their catch because fishing practices damage the fish and make them unmarketable, the fish are too small, the species is out of season, only part of the fish needs to be harvested—as with the Alaska pollock roe—or the fishers caught bycatch.
Sometimes discards also happen because of a practice known as high-grading where fishers continue fishing even after they have caught fish that they can sell, adding that if they catch bigger fish, they throw away the smaller ones as they usually cannot keep both loads because they run out of freezer space or go over their quota.
The study examined the amount of discarded fish over time. In the 1950s, about five million tonnes of fish were discarded every year, in the 1980s that figure grew to 18 million tonnes. It decreased to the current levels of nearly 10 million tonnes per year over the past decade.
The decline in discards in recent years could be attributed to improved fisheries management and new technology, but Zeller and his colleagues say it is likely also an indicator of depleted fish stocks.
A 2016 reconstruction of catch data from 1950 to 2010 by researchers with the Sea Around Us revealed that catches have been declining at a rate of 1.2 million tonnes of fish every year since the mid-1990s.
The scientist and his colleagues Tim Cashion, Maria Palomares and Daniel Pauly, say that the study also shows how industrial fleets move to new waters once certain fisheries decline.
“The shift of discards from Atlantic to Pacific waters shows a dangerous trend in fisheries of exporting our fishing needs and fishing problems to new areas,” Cashion said.
The paper was published in Fish & Fisheries.