Across the world’s oceans float thousands of rafts, placed there by fishermen to try and increase their catches. Although this technique has been used for centuries, its increasing prevalence and concerns over the impact this could have on fish stocks are driving calls for restrictions on its use. At their most basic, the rafts, known as fish aggregating devices (FADs), can be simply floating tree logs, shelters under which fish tend to congregate. Fishermen have long recognized this behaviour, and have created FADs ranging from wooden rafts with ropes hanging below to steel and foam constructions complete with radio transmitters for signalling their location. By some estimates there may be tens of thousands of these devices now deployed. But there is little regulation or monitoring of them. “The regulation of FADs is something that is a real issue that I don’t think is being addressed,” says Farah Obaidullah, an oceans campaigner at Greenpeace in Amsterdam. The main concerns of campaigners such as Obaidullah are that FADs assist fishing of populations that are already over-fished, such as tuna, and that they can attract endangered animals, such as turtles, which are then taken up along with the targeted species — a consequence known as ‘bycatch’. Researchers are now increasingly trying to quantify the effects of FADs in an argument that has grown increasingly heated, while largely remaining under the public radar. “FADs are a concern,” says Tim Davies, a marine-conservation researcher at Imperial College London. “We need to know how they’re being used and their effects on the ecosystem. Those two things, they are pressing issues.” But Davies does not advocate for a ban on FADs. Although they do have downsides such as bycatch, they can a relatively ‘clean’ form of fishing for tuna compared with methods such as long lines of baited hooks, he says. In a paper published earlier this month in Marine Policy, Davies and his colleagues assess the use of these devices in the Indian Ocean. They conclude that the use of FADs has dramatically improved the ability of the tuna fleet in this area to catch fish But, the authors warn, management of these fishing aids has not kept pace, and there is currently little regulation of when and where they can be used. “Explicit management of the use of FADs is undoubtedly a necessity to ensure future sustainability of the fishery,” Davies and his team write.… More:
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