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Setting Nets On More Tuna, ISSF’s Solution To FAD By-catch?

ISSF sponsored research has made a connection between school size, by-catch and FADs when fishing for tuna. A study published in the Canadian Journal of Fisheries and Aquatic Scientists found that while the amount of tuna around a FAD can vary from a few tons to several thousand tons, the amount of non-tuna species is much less variable. From this, ISSF concluded: “The bigger the school, the better the catch.”

Researchers found that fishing both small and large tuna aggregations around FADs (Fish Aggregating Devices) would result in a similar amount of by-catch of non-tuna species. As a result, they outlined that the total annual by-catch per vessel has a direct relation to the number of sets made and not the volume of tuna caught.

As much as 50 percent of the world’s canned tuna is caught using FADs and, since the boom of operation of this device in 1980, by-catch of juvenile bigeye tuna has rocketed from less than 5,000 tons per year to just under 80,000 tons in 2010. FADs can attract between 5 and 15 species of marine life and when setting a net around any floating object, a purse seine net encircles everything surrounding it.

ISSF is now advocating that one easy solution for reducing by-catch from tuna fishing is to avoid setting on small aggregations. Data collected by observers determined that avoiding sets on schools of tuna less than 10 tons could reduce the amount of by-catch by as much as 23-43 percent, dependent on the ocean region. Total tuna catch would be expected to only reduce by 3-10 percent.

Despite this, recorded by-catch figures over the last 50 years show that the introduction of FADs has had a dramatic impact on non-targeted species and, before 1980, numbers were bordering on zero. Environmental initiative, Pew Charitable Trusts describes the FAD situation as “out of control” stating that 100,000 new FADs are estimated to be thrown into the world’s tropical oceans every year. Pew urges consumers to “choose canned tuna that is labeled FAD-free or pole-and-line-caught.” Its FAD factsheets stress: “It’s time to rein in the widespread use of this indiscriminate tuna fishing gear.”

The ISSF research findings and other studies might be the start of a future way of tuna fishing, by which FAD fishing continues to be allowed by under a stricter set of rules, at a reduced frequency, and with less FADs in the water. It remains to be seen how a policy of larger catches per FAD set would work out for smaller tonnage artisanal vessel, compared to the larger industrial purse seiners.