Fishing nets illuminated with LED lights avoid entanglement of marine turtles and other marine species
- Nesting abundance in the most important beaches from Mexico and Costa Rica has been reduced in 97% since the 1980s.
- Annually, it is estimated that between 300 and 600, and even up to 1000 leatherback marine turtles are captured incidentally in Peru, Chile and Ecuador.
- LED lights helps to reduce marine turtle bycatch by almost 60%.
Marine turtles shared the Earth with dinosaurs over 100 million years ago and, they play an important role in marine ecosystems helping to maintain the ocean health. Among the species of marine turtles that we can find in Peru we have: the green turtle, loggerhead turtle, hawksbill turtle, leatherback turtle and Kemp´s ridley turtle. These 5 species are endangered because of the threats that they deal during their life cycle and their migratory routes.
Victims of climatic change, pollution by plastic, and specially, bycatch
Climatic change is one of the major threats that marine turtles deal, since it is affecting their natural habitat and the place where they reproduce. These species must face the loss of their reproductive habitat on beaches, due to the rise of the sea level. Likewise, temperature rising produces an alteration of sex ratios, generating the absence of male turtles because this factor is determined by incubation temperature in the sand.
Additionally, pollution by plastic, the non-controlled urban development on beaches and irresponsible tourism, are some threats that marine turtles deal daily. It is known that these species can confuse the floating plastic on the sea with food and they suffocate trying to eat them. A scientific study estimated at about 50% the probability of mortality of marine turtles when they have had 14 plastic pieces in their digestive tract, pieces between 0.01-10.41 g.
However, the main threat for these marine animals is fisheries bycatch. This is a problem that occurs globally and affects hundreds of thousands of organisms per year, in all their range of distribution. Only in Peru, an important feeding area for these species, marine turtle bycatch rate has been estimated that it would reach tens of thousands of marine turtles per year. Peru is one of the countries with the major bycatch of marine turtles, mammals and sea birds.
“The steep decline of leatherback turtles along the Eastern Pacific during the past two decades has made them one of the most endangered populations in the world,” says Aimée Leslie, director of the WWF Peru Marine Program. “Nesting abundance in the most important beaches from Mexico and Costa Rica has been reduced in 97% since the 1980s. These zones comprise almost 90% of all the nesting of leatherback turtles in the region. And it is precisely in Peru where it is presumed that these ancient animals are dying due to the entanglement in fishing gears”.
In 2013, a group of experts convened by the National Fish and Wildlife Foundation (NFWF) established that the most serious threat to leatherback turtles from the Eastern Pacific remains bycatch interactions with fishing gear, particularly in South American waters where leatherback turtles feed, as in Peru. Worldwide, it is estimated that annually between 1000 and 2000 leatherback turtles are caught in nets and longlines, of which 30-50% die as a result of these interactions. Therefore, bycatch mortality is estimated between 300 and 600, and up to 1000 leatherback marine turtles annually in Peru, Chile and Ecuador. These estimations are especially worrisome, considering that the total abundance of nesting females of this species is estimated at less than 1000 organisms.
Conservation measures: training and technology
WWF Peru has been working on the reduction of marine turtle bycatch, through training of fishers, non-governmental organizations and government institutions in the proper handling and release of marine turtles that will ensure their survival. In that sense, we participated in the creation of the guide for the marine turtle release and the National Network of Instructors for the Management and Release of Marine Turtles, which has trained at least 1659 fishers in 2018 along the Peruvian coast.
Studies in Baja California, Mexico showed that implementing LED lights in fishing nets could reduce marine turtle bycatch by up to 60%. These positive results were confirmed through experiments carried out in Peru by ProDelphinus. Since 2016 WWF joined these efforts and promoting the implementation of this technology in various ports of the country.
“The efforts of our organizations are important, but punctual. We need that the Peruvian government approves and implement the Marine Turtle Conservation National Plan which has been under discussion since 2014,” says Aimée Leslie. “Government support is required to facilitate access and development of devices in local industry, such as LED lights, which have been shown to reduce bycatch without harming the target catch of fishers.