Dermochelys coriacea: The Leatherback Sea Turtle
a blog exploring the endangerment and recovery plan
chris king
Description and Ecology
The Leatherback Sea Turtle is the largest living sea turtle with a morphology that is specific and unique when compared to other turtles. Its appearance is so particular that it belongs to a different family altogether: Dermochelyidae.
All other sea turtles belong to the cheloniidae family.
The Leatherback's most unique distinction is its shell composition, which trades traditional bony plates for a rubber-like flexible carapace about 4 centimeters thick.
A Leatherback can be easily recognized by the 7 longitudinal ridges that taper to a blunt point which help give it its familiar barrel-like shape. Its front flippers can reach up 270 centimeters or over 8 feet long. Leatherbacks have been recorded to weigh anywhere from 204-696 kg, with the heaviest on record weighing in at a whopping 916 kg!
Leatherbacks do retain the common cartilaginous skeleton found in other sea turtles. Based on stomach samples, Leatherbacks are recorded to prey on jellyfish, siphonophores, and salpae in the pelagic zone of the ocean. They are thought to be the most pelagic sea turtle and migrate great distances in a huge range of temperatures.
Mating behaviors are similar to other sea turtles, with large amount of eggs being laid and buried in a sandy beach through the months of March to July. However, due to the Leatherback's preference for high energy beaches, many of their 100-120 egg nestings can be lost due to the erosion.
Geographic and Population Changes
Migration patterns seen in the Leatherback Turtle are longer and journey through colder water than any other marine reptile. Data shows that Leatherbacks frequently make routine migrations between boreal, temperate, and tropical waters, most likely chasing food items.
The Leatherback Turtle has not shifted their geographical range in response to ecological issues. They return to the same beach every season to reproduce, hardly ever wavering in their methodical routines. The beaches they lay eggs on however, see extreme geographic change as a result of erosion caused by storms and natural behaviors of the ocean. This can lead to the loss of eggs and thus damage the population.
In 1982, an estimate put the population of Leatherbacks at around 115,000. Contrast that with a 1995 estimate of 34,500 and a recent estimate of 34,000-94,000. The reason for the Leatherback's position on the ESA's list of endangered species is due to the massive population loss experienced over a short period of time.
Hunting and poaching for meat and eggs is suspected to the be the greatest detriment to the population.
Migration patterns seen in the Leatherback Turtle are longer and journey through colder water than any other marine reptile. Data shows that Leatherbacks frequently make routine migrations between boreal, temperate, and tropical waters, most likely chasing food items.The Leatherback Turtle has not shifted their geographical range in response to ecological issues. They return to the same beach every season to reproduce, hardly ever wavering in their methodical routines. The beaches they lay eggs on however, see extreme geographic change as a result of erosion caused by storms and natural behaviors of the ocean. This can lead to the loss of eggs and thus damage the population.
In 1982, an estimate put the population of Leatherbacks at around 115,000. Contrast that with a 1995 estimate of 34,500 and a recent estimate of 34,000-94,000. The reason for the Leatherback's position on the ESA's list of endangered species is due to the massive population loss experienced over a short period of time.
Hunting and poaching for meat and eggs is suspected to the be the greatest detriment to the population.
Listing Date and Type of Listing
The leatherback is listed as endangered throughout its entire range. Despite being listed as endangered on June 2, 1970, the recovery plan for the U.S. Pacific population wasn't drafted until January 12, 1998, a whole 28 years later.
Cause of Listing and Main Threats
Severe population decline (about 81,000 individuals in only 13 years) caused the Leatherback to be listed as endangered under the ESA. Interestingly, the U.S. FWS writes that "casual factors" are a main threat to the turtle's continued existence. Operations such as a sea fisheries, egg collections, and accidental take-ins all have contributed to the Leatherback's near-demise.
Important threats to note are the ones that hold a presence on land. Leatherbacks and their eggs are harvested as food items which results in massive population loss. Humans are not the only guilty party either! Domestic animals such as dogs, cats, and even pigs predate Leatherback nests for their eggs.
In broader context, the increase of human presence as a whole threatens the Leatherback population. More people means more light pollution, debris, and activity -- which can all be disruptive to healthy turtle behavior.
Recovery Plan
Due to the Leatherback's largely pelagic lifestyle and far-reaching migration patterns, designing an effective recovery plan has proved difficult. However, stricter and more diligent monitoring of nesting sites has been effective in maintaining and raising the population.
Additional extensive research is being conducted to better learn the migration patterns, hatching success, maturation frequency, and even eggshell composition.
The Recovery Plan outlines steps needed such as eliminating directed take of turtles and eggs, reducing nest predation by domestic and wild predators, and reducing the effects of human development (light pollution, beach erosion, and human activity) on the nesting sites.
By implementing laws that pertain to each recovery action, the impact of human danger can be greatly reduced and the Leatherback population can thrive. This means incriminating turtle take, stricter laws with animals on nesting beaches, and enforcing specific lighting conditions to reduce light pollution.
Get Involved!
Additional extensive research is being conducted to better learn the migration patterns, hatching success, maturation frequency, and even eggshell composition.
The Leatherback Sea Turtle can make a comeback! But only if we take it upon ourselves to aid in its recovery by being mindful of ourselves. Pick up any debris that you see on the beach, and even in the streets! Always follow the rules posted by the U.S. FWS and other conservation agencies. Never encroach on turtle nesting sites or approach turtles in the wild. View them from a safe distance, not for your safety, but for their's!
Get involved directly by volunteering with conservation agencies or by donating to the cause!
https://www.fws.gov/humancapital/ Click this link to see the opportunities offered by the FWS.
Other Resources
https://ecos.fws.gov/docs/recovery_plan/981201d.pdf (this is the full recovery plan for Pacific Leatherbacks)
http://www.iucnredlist.org/details/6494/0 (this is the IUCN red list's page for Leatherbacks)
I am surprised that they are affected by forces besides humans, I would have thought that only trash in the oceans would have affected them. I am glad you brought up that on land other animals are negatively affecting the turtles, like dogs, cats, and pigs. Lastly, I did not know that the turtles return to the same beach every year, and that the problem lies within beach erosion and such. I think beaches should give more awareness on those we share the beach with, and so I really like your last image that keeps people from ruining a nest.
ReplyDeleteAwesome photos, the babies are so cute! It is extremely interesting to me that such intelligent creatures don't adapt and change to the changes in their ecological environment and continually return to the same breeding grounds every year. It makes it so easy for animals, people, and environmental change to have negative effects on the babies. Awesome blog post!
ReplyDeleteI found it interesting that even though it is detrimental to their fitness and population, leatherback turtles will always return to the beach where they were hatched. I would have thought if they got to the beach where they hatched and they saw that it was not ideal hatching conditions, they would look for somewhere else. I'm glad that you pointed out how easy it is for us to make a difference and help them by picking up trash at the beach and to leave nests alone.
ReplyDelete-Michelle Henderson
I love the facts you including about sea turtles, like that they return to the same beaches every year to lay their eggs. And that there are issues with people stealing the eggs and beach erosion. I'm also glad you included more about how not only trash affects these animals. -Rachel Kenison
ReplyDelete