LEDs are Helping Shrimpers to Avoid Catching Endangered Species of Fish in Their Nets

For the past four years, trawlers on the West Coast have been hauling in vast amounts of pink shrimp, much of it destined for dainty salads and shrimp cocktails across the country. But though these have been boom times for shrimpers, many are uneasy.Along with pink shrimp, their nets often scoop up a threatened smelt called eulachon. Many shrimpers worry that the species’ vulnerability could lead to new federal restrictions on their industry.

Now scientists in Oregon seem to have hit upon an effective and low-cost solution, reports Ingfei Chen in The New York Times: light up the nets.

Last July, fisheries biologists Robert Hannah and Stephen Jones of the Oregon Department of Fish and Wildlife and Mark Lomeli of the Pacific States Marine Fisheries Commission chartered a shrimp trawler for an unusual experiment.

The double-rigged boat drags a pair of socklike nets a foot or two above the dark seafloor. The researchers placed 10 battery-powered green LEDs at the mouth of one net, tying them to the “footrope” on its bottom side. The other net was unlit.

The crew made one trawling tow, dumped the catch from each net into a divided hopper.On one side of the hopper, the haul from the unlit net held lots of silvery eulachon, flatfishes and other so-called bycatch mixed in among bright pink shrimp. On the other side, the catch from the LED-lit net was virtually nothing but shrimp.

“We couldn’t believe what we were looking at,” Mr. Hannah said. Illuminating the net’s opening helped the eulachon dodge it. “They’re taking advantage of a little more light to see escape routes,” Mr. Jones said.

Results of the Oregon researchers’ experiment, funded by a grant from the National Oceanic and Atmospheric Administration, will be published in a fisheries research journal. But already, the news has spread quickly through the state’s shrimping industry.“Within two months, virtually the entire fleet was using these lights,” Mr. Hannah said.

Read the full article: http://www.nytimes.com/2015/04/14/science/easy-solution-for-shrimpers-and-smelt-alike.html?hpw&rref=science&action=click&pgtype=Homepage&module=well-region&region=bottom-well&WT.nav=bottom-well&_r=3.