Leatherback Turtles And Conservation Hotspots
Leatherback turtles are of great conservation importance as they represent reptiles that have existed on Earth for over 100 million years.
They also provide ecosystem regulation through the consumption of jellyfish, keeping populations in check, and provide vital income for coastal communities by attracting ecotourists.
They are the largest sea turtle species and also one of the most migratory. Able to grow up to 2metres long and weigh as much as 900 kilograms; the largest ever recorded was a massive 2.6 metres long and weighed in at 916 kilograms.
They also have the ability to dive deeper than any other turtle reaching depths of 1,280 metres for up to 85 minutes. With a wide distribution they can be found in the Atlantic, Pacific and Indian Oceans as well as the Mediterranean Sea.
Despite this wide distribution their future is uncertain.
Leatherback Turtles Threatened
Leatherback turtles are under pressure from numerous threats.
Eggs are regularly taken from nests by humans for consumption and nesting turtles can be killed for meat. Hatchling success can be reduced by coastal development.
Turtles require dark, quiet beaches to lay eggs and development means they are in competition with tourist and residents to use beaches. Artificial lighting will also discourage the use of beaches and as such females may choose a less appropriate beach, reducing the chance of hatchling survival. This lighting can also disorientate hatchlings.
Moving away from the ocean hatchlings may die from dehydration or predation. Individuals can also die as a result of ingesting floating plastic debris mistaken for jellyfish, a main component of their diet.
The fishing industry has been major contributor to the decline of turtle populations with individuals being caught as by-catch by shrimp fisheries. This can cause them to become injured, drown or crushed by machinery.
Despite this there have been some developments and the introduction of the TED (turtle excluder device), now mandatory for shrimp boats, has improved the situation. These devices allow turtles to safely exit the net. Other commercial fisheries are still causing high levels of turtle mortality.
One such practice is long lining, which can cause turtles to become caught or entangled and drown. Boat strikes are another common cause of death caused by the fishing industry. Turtles are extremely vulnerable to this due to the fact they come to the surface to breathe and occasionally bask.
Recent studies hold the potential to reduce the impacts of the fishing industry. Researchers have been able to identify potential hotspots where turtles were most likely to come into contact with vessels using GPS technology. 135 adult turtles were tagged and tracked via satellite to determine distributions.
By comparing this data with that of the distribution of longline fishing efforts they have been able to predict areas at risk of by-catch. This information could potentially lead to seasonal and area closures for the fishing industry, protecting turtles.
The paper appears in the Proceedings of the Royal Society B journal.
Research revealed several areas of particularly high risk. Such areas have been highlighted for western Pacific populations in the north and central Pacific Ocean and adjacent to the nesting beaches in tropical seas of Indo-Pacific islands. For eastern Pacific populations the migration corridor between Costa Rica and the Galapagos Islands has been identified. This information will allow these areas to be regulated both to maintain the health of the fishing industries utilising these waters and to protect turtle populations.
These findings will allow future efforts to be concentrated on targeted management of the Leatherback Turtles and conservation hotspots, enabling fishing efforts to be adjusted accordingly, especially in areas where management is currently lacking.
Such management will significantly enhance conservation efforts and help to sustain turtle populations.
About the Author Megan Smith
Megan Smith is a third year student studying Ecology and Wildlife Conservation in Bournemouth. She has completed work placements with the Research Institute for Nature and Forestry and the UmPhafa Reserve in South Africa, owned by Colchester Zoo. She plans to go on to do a masters degree once she graduates.