The study, published in the journal Current Biology, found that the total fisheries bycatch was reduced by 63% when using lighted fishing nets. It acts as good news for marine conservation as well as fisheries because the impressive 95% reduction of catches in sharks, rays and skates as well as 48% reduction of catches in unwanted finfish and a 81% reduction in Humboldt squid when using lighted gillnets, didn’t affect catch rates or the market value of target fish.
Gillnets are extensively used in coastal regions throughout the world but their use has been controversial due to the high number of bycatch (species not targeted by the fishers) entangled in these nets. Common species accidentally caught include endangered, threatened and protected sharks, marine mammals, seabirds and sharks which usually end up dying or getting injured in gillnets.
While the use of LED lights to illuminate gillnets has already been used to deter sea turtles in coastal gillnet fisheries over the past decade, the effects of lighted nets on other species has not been examined until now. By attaching green LED lights to gillnets along the Pacific coast of Mexico’s Baja California Sur peninsula, the study found that lighted nets almost entirely eliminated the accidental entangling of sharks, skates and rays. The technology also helped fishers reduce the time it took to retrieve and disentangle the nets by 57% which might be a great incentive for fishers to continue to use the technology.
John Wang, a co-author on the study and Fisheries Ecologist at NOAA Fisheries’ Pacific Islands Fisheries Science Center in Honolulu, explained: “Making life easier for fishers by reducing the amount of time untangling bycatch is equally essential as reducing the bycatch biomass in nets. It is important for fishers to know that there are tangible benefits for them. This is critical for the adoption of such technologies by the fishing industry.”
“These results demonstrate that the potential benefits of illuminated nets extend well beyond sea turtles, while demonstrating the strong promise for net illumination to mitigate discarded bycatch in similar coastal gillnet fisheries throughout the world’s oceans,” said Jesse Senko, lead author of the study.
If you want to read more about the practical use of lighted nets in a conservation context, click here to find out how a Peruvian marine biologist uses the technology to reduce the accidental catch of leatherback turtles.
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Photography courtesy of Unsplash.