CAN NEW TECHNOLOGY PROVIDE A SOLUTION TO A SILENT KILLER OF MARINE TURTLES?
Kilometres and kilometres of fishing gear, like nets, trawling our oceans are deadly. Not only do they entrap intended fish species; they also capture other marine animals that unwittingly stray into their path.
This grisly incidental catch, known as bycatch, sees scores of marine turtles, dolphins, dugongs, sharks and seabirds hauled up onto the decks of fishing vessels and then tossed overboard dead or dying. Globally, bycatch is thought to be the leading cause of death for cetaceans (whales and dolphins). Some populations are even likely to become extinct because of their repeated encounters with fishing gear. But many of these deaths and injuries can be avoided.
WWF is calling for the wholescale adoption of Remote Electronic Monitoring (REM) with cameras across fishing fleets. It could mean a massive boost to the monitoring of catches and identifying incidents of wildlife bycatch, so many of which go unrecorded. There’s an additional factor that might reassure those of us on land: REM could give businesses and the public more confidence that their seafood is coming from a sustainable source.
Globally, fleets hunting for species such as swordfish, marlin and tuna send out long fishing lines, each with hundreds or even thousands of baited hooks attached. The traditional J-shaped hooks can have tragic consequences for turtles, which either swallow the hooks and die of internal bleeding or are suffocated when they’re snagged and unable to surface to breathe.
Alternative ‘circle’ hooks, with the hook points turned inwards at a 90° angle, have proved to reduce turtle deaths by as much as 97%. We’re also helping with tests to try out different types of bait to reduce their appeal to turtles.
Some fishers put out gill nets, near invisible curtains of nets that hang in the water. Fish swim into them and are trapped by their gills, hence the name. Fish aren’t the only creatures ensnared, so how do we stop turtles and other marine animals becoming entangled in these nets?
One answer is to make them visible in a way that deters turtles. Internationally, WWF has been working with the US government’s National Oceanic and Atmospheric Administration to develop special lights that reduce the turtle bycatch in gill nets. Lightsticks are attached to the nets, alerting the turtles to the barrier in front of them. The illumination has been shown to reduce mortality by between 60-70%. The aim is to introduce them to fisheries around the world.
Simple solutions such as circle hooks and warning lights, combined with more high-tech initiatives such as REM, can put us on the path to reducing the problem of bycatch, and making seas safer for marine turtles.
