Every year, bycatch—unwanted fish or other marine species accidentally caught by fisher’s nets—makes up 25 percent of the fishing industry’s hauls. These fish either are too small or too young or are of an undesired species, and, as the World Wildlife Fund describes it, “very year fishermen throw back into the ocean some 30 million metric tons of dead fish caught as bycatch.”
In an attempt to drive down bycatch rates, Dan Watson, an engineer from Scotland, has designed an illuminated ring which can be installed in trawler nets to hold sections open and allow small animals to flee. Though bycatch can involve species that are larger or smaller than the desired fish, Watson’s device could help cut down on the number of young fish being caught. The BBC:
Because the devices are rigid they keep the surrounding net meshes open, preventing the gaps from closing when the equipment is under tension. Fish are often injured when this happens using standard equipment.
Watson’s device is also packed with lights, which are meant to draw fish towards the gaps, acting “as an emergency exit sign.”
Using submerged lights is a long-standing technique for attracting fish. Some species are attracted directly to the lights; others are drawn to the microscopic plankton, tiny organisms on which fish feed, that gather around the light.
More from Smithsonian.com:
Going “Bycatch Neutral”
50 Years of Longline Fishermen Throwing Out the Endangered Half of Their Catch