A simple invention that can save the lives of many sea creatures accidentally caught in nets

For fishermen fishing, a black squid with many tentacles stuck in the net is an undesirable problem. As for sea turtles or diamondback rays, getting caught in a net means death. To tackle unwanted fishing, US ecologists announced a new remedy: attaching green light-emitting diode (LED) lights to fishing nets. 

According to research, this method significantly reduces the capture of unwanted animals (such as sharks, squid) without affecting the quality and quantity of highly profitable seafood species.

The green light emitting diode (LED) light mounted on the fishing net helps prevent the fishing of turtles, sharks, squid.

The study found a reduction in the number of unwanted species caught and no negative impact on total yields, according to San Diego State University conservation ecologist Rebecca Lewison, who was not involved. research.

To catch fish, many coastal fishermen use gill nets, a type of net that hangs on the water like a wire net fence, the rope is fixed on the water surface by buoys. Nets can drift for hours or days, irrespective of the desired and unwanted species; Unintentionally caught creatures will be thrown into the sea with fatal bodily injuries. This type of fishing contributes significantly to the global decline of species such as dolphins and sea turtles, and slows down the daily activities of fishermen.

This type of net with LED lights helps fishermen still catch as many fish as usual.

Previously, marine ecologist John Wang and colleagues at the National Oceanic and Atmospheric Administration (NOAA) in the United States invented lighting nets to tackle turtle catching. Turtles are particularly good at seeing blue light. The researchers found that the lighting nets reduced the rate of unwanted turtle catching by 64%. So they think the net could help other marine animals get the same benefits.

The team collaborated with small-scale grouper and flounder fishers in the waters off Baja California (Mexico), which is teeming with turtles and other large marine animals, according to the conservation ecologist. Arizona State University professor Jesse Senko, lead researcher. To do this, the researchers deployed 28 pairs of grids with each pair having a grid with LED lights on. The team then weighed and identified each organism that was caught in the net overnight.

According to the results, published in the January 22 issue of Current Biology, light nets caught 63% less fish, 51% fewer turtles, and 81% less squid than dark nets. The results were most "satisfactory" for elasmobranch species, which include sharks and rays, says ecologist Lewison. Catching sharks is a "big problem" in the Gulf of California, she said. In the new study, shark catch rates were reduced by up to 95%.

Perhaps, too simply, the target fish cannot see light like other animals, according to ecologist John Wang. Researchers are still figuring out why some animals avoid light better than others. According to them, elasmobranchs have sophisticated eyesight, while Humboldt squid have large eyeballs. So that these animals can easily recognize green light.

This type of net with LED lights helps fishermen still catch as many target fish as before, but only takes half the time to pull and remove the net. The biggest drawback of this solution is that the cost of equipping a net with lights is up to 140 USD, higher than the financial ability of some fishermen. Currently, researchers are testing solar-powered lights that last longer than battery-powered lights. They also looked at producing similar results in Baja California, fishing grounds in Indonesia and the Caribbean with fewer lights. In these projects, the needs of the fishermen are very important. "They are the people who use the nets every day," says ecologist Lewison.