- Defining and estimating global marine fisheries bycatch [pdf, 372 KB]
Broadbill swordfish (Xiphias gladius) dead in fishing net. The net is used for Bluefin tuna in a Mattanza fishery (ancient fishing ritual). Swordfish are sometimes caught by accident (bycatch). San Pietro, Italy.
© Brian J. Skerry/National Geographic Stock/WWF
15 Apr 2009
Gland, Switzerland - Nearly half of the world’s recorded fish catch is unused, wasted or not accounted for, according to estimates in a new scientific paper co-authored by WWF, the global conservation organization.
The paper, Defining and estimating global marine fisheries bycatch, estimates that each year at least 38 million tonnes of fish, constituting at least 40% of what is taken from our oceans by fishing activities, is unmanaged or unused and should be considered bycatch.
“The health of our oceans cannot be restored and fisheries sustainably managed if 40% of the global fishing catch is unused or unmanaged,” says James P. Leape, Director General, WWF International.
When fishing vessels go to sea, they go after their so called “target” catch, but as most fishing gear is unselective, fishing fleets also catch millions of tonnes of other marine life, commonly known as bycatch. The catch of so called “non-target” fish and marine creatures often occurs with no oversight or management.
In redefining bycatch as anything fishers take from our oceans that is “unused or unmanaged,” the paper’s estimates go well beyond previous global estimates, which focus mainly on catch which is thrown away and vary from 7 to 27 million tonnes a year.
“In many cases, fish and marine animals are thrown back to sea dead or dying and currently even if bycatch is used there is no way to tell whether it was sustainable to remove it in the first place. It is an insidious and invisible form of over-fishing.” says Amanda Nickson, Leader of WWF’s Bycatch Initiative and co-author of the paper.
(C) Brian J. Skerry/National Geographic Stock/WWF
The paper, to be published in an upcoming edition of the leading journal of ocean policy studies, Marine Policy, estimates the proportion of bycatch in 46 fishing countries and two global fisheries, tuna and shark fin.
In the north-east Atlantic, for example, a fifth of that region's total marine catch is tossed overboard. It is likely that the worst case of wasteful fishing is seen in fisheries that target sharks exclusively for their fins where 92% of what is caught is discarded back in the ocean.
“In addition to ensuring that all fishing activities are appropriately managed, simple, proven methods, such as more selective fishing gear and observers on fishing vessels, already exist to reduce bycatch.” adds Ms Nickson. “But they must become the rule, as part of long-term sustainable marine management, and not the exception.”
According to WWF, bycatch costs fishers time and money contributing to overfishing, jeopardizing future revenue, livelihoods, and long-term food security. It’s also a major killer of marine wildlife, putting several species at risk of extinction and drastically altering the sensitive balance of marine ecosystems.
The conservation organization believes that every form of fishing, and the removal of all marine life from our oceans, should be managed for sustainability, and that anything taken from the ocean by fishing activity is considered part of that fishing effort.