Tens of thousands of endangered sea turtles are being caught and killed in fishing nets off South America’s Pacific coast, new research warned.
Small fishing boats using gillnets are trapping the marine creatures including critically endangered leatherbacks and hawksbills.
A survey of just 43 harbours in Ecuador, Peru and Chile revealed gillnet fisheries catch more than 46,000 sea turtles a year, with more than 16,000 killed in the process.
However University of Exeter researchers warned the true figures are likely to be higher, as not all ports in each country were surveyed.
Professor Brendan Godley, of the Centre for Ecology and Conservation at the university’s Cornwall campus said: “Incidental catch in fisheries, or bycatch is thought to pose a major threat to marine vertebrates at a global level.
“This has been confirmed in detail for sea turtles, where many populations face large impacts due to bycatch in industrial fisheries.
“People worry about industrial fisheries but a real concern that people are waking up to is small-scale fisheries.
“These are small vessels but they exist in such huge numbers that they can have a massive impact on ecosystems.”
He added: “There is a growing interest in marine turtle bycatch in gillnets and small-scale fisheries.
“Our study was designed to fill a major data gap in the southeastern Pacific by using a rapid assessment protocol to estimate regional turtle bycatch in small-scale gillnet fisheries.
“To further contextualise our data, it is important to note that we estimate that the vessels in the surveyed harbours constituted 16.4 per cent, 41 per cent, and 22 per cent of the small-scale gillnet fishing fleet in Ecuador, Peru, and Chile, respectively
“Our results offer insights in the extent of marine mammal and seabird bycatch and indicate that the annual mortality from bycatch of five species of turtles is likely in the low tens of thousands, making turtle bycatch in gillnets in this region among the highest in the world.
“For example, the turtle bycatch we report here is of similar magnitude to that of the entire Mediterranean, a major bycatch hotspot, where 23,000 turtles were estimated as the incidental catch in small-scale fisheries using set nets.
“A recent study using surveys in Italy reported 52,000 bycatch events, of which 10,000 were fatal.”
Dr Joanna Alfaro, who obtained her PhD at Exeter and is now director of ProDelphinus, a conservation organisation in Peru, said: “This work highlights the importance and the benefits of our approach of engaging with fishers.
“We are actively working with fishers in this region to develop and implement solutions to bycatch – not just to improve the situation for turtles but for the health of fisheries and fish stocks.
“Our goal is to develop fisheries that are sustainable for small-scale fishing communities and the species with which they interact.”
Prof Godley said: “Due to their simplicity and relatively low cost, gillnets are one of the most widely used fishing gears in small-scale fisheries.
“This is particularly true for Ecuador and Peru, where the magnitude of net fisheries is large, and is also partly due to the open access nature of small-scale fisheries.
“As a result, the number of gillnet vessels in these two countries surpasses, by two orders of magnitude, the Chilean gillnet fleet.
“Moreover, Chilean fisheries are firmly regulated by specific, resource-based management measures.”
He added poor fisher families often rely on turtles as “marine bushmeat.”
But he said: “However, from the total estimated turtle bycatch, a greater percentagewere reported released back to sea, which highlights an opportunity for the use of bycatch mitigation measures in net fisheries such as increasing net visibility, reducing net profiles, using buoyless float lines, tiedown modifications or promoting the use of tools and guidelines to safely release animals
“Apart from reducing negative impacts to sea turtles, the use of these mitigation measures can also impart practical benefits to fishermen in the form of cost and time
savings resulting from reduced entanglements and net damage.
“Multiple marine turtle populations that occur in the eastern Pacific have been assessed as high-risk and high-threat, particularly from fisheries bycatch, thus making this region a conservation priority for turtles.
“Our results support this high priority designation given the high turtle mortality from fisheries and the presence of highly threatened populations of loggerhead, leatherback and hawksbill turtles in particular.
“Small-scale fisheries are the main protein provider for one billion people and also support the livelihoods of about 200 million people.
“In the eastern Pacific, these fisheries are key for one million small-scale fishermen and their families and there is, therefore a clear need to identify conservation opportunities that promote their long-term sustainability, both for the communities they serve and the marine fauna with which they interact.”
The study was published in the journal Fisheries Research.