Loggerhead turtles are struggling to survive in their native waters of the Mediterranean. New research from the University of Exeter found that thousands are killed annually due to small-scale fishing operations in Cyprus, the Middle East and North Africa.
The problem is such fishing practices trap and tangle loggerheads in deadly nets. What's worse is that the turtles are at a heightened risk of being strangled because they migrate and search for food throughout the areas where fishing is particularly common.
Nesting on beaches from Greece and Turkey to Israel and Libya, loggerheads are the most common turtle in the Mediterranean. In the latest study, the researchers tracked female turtles by satellite as they migrated from Cyprus. Rather than returning to the place of their birth to lay their eggs, the research team found many turtles will nest along beaches in a number of countries.
After breeding, adult females then travel to foraging sites extending from the continental shelf of Cyprus to Levant and North Africa, sometimes swimming up to 2,100 kilometers from their nesting sites.
Over the course of the 10-year study, three of the 27 adult female loggerheads tracked from north Cyprus nesting beaches died within a year of being tagged. It is believed that the turtles likely died from bycatch or accidentally being caught in fishing nets.
"The mortality rate and level of bycatch in these countries is very concerning. There is poor understanding of the need for conservation and of the impacts that fishing practices can cause," said Robin Snape, postgraduate research student with the Marine Turtle Research Group. "This is particularly difficult to manage when local people are dependent on fish for their food and livelihood. Wider studies are needed into fishing practices, the exact methods being used and into how we can mitigate bycatch. Although this is difficult at the moment when countries are at war or politically unstable, Cyprus as an EU member state is well situated to address its significant sea turtle bycatch."
The death of three out of 27 tagged turtles represents an 11 percent mortality rate per year, which is much higher than expected for a long-lived species. It follows then that this staggering decline could have cascading impacts, as turtles are unable to live long enough to produce enough offspring to keep the species going.
"Whilst the Mediterranean loggerhead turtle population is dependent on the continuation of decades of intense conservation work at core nesting sites in Greece, Cyprus and in Turkey, we now need to move into the water to secure the future of the species mitigating threats from fisheries and oil and gas related seismic activity," added Professor Brendan Godley, project leader. "Encouragingly, we have been involved in some recent work elsewhere that has shown that the simple and inexpensive measure of putting LED lights on nets can reduce turtle bycatch significantly. Our knowledge of the impacts of seismic activity is embryonic."
The findings were published in the March 29 issue of the journal Diversity and Distributions.
