Leatherback Sea Turtles

My AP Biology Thoughts

Unit 8 Ecology

EPISODE TITLE: Disappearance of Costa Rican Leatherback Sea Turtles

Welcome to My AP Biology Thoughts podcast, my name is Beth Hooks, Emilie Sawicki, and Nick Bailey, and we are your hosts for episode # called Unit 8 Ecology-Costa Rican Leatherback Sea Turtles. Today we will be discussing the disappearance of Costa Rican Leatherback Sea Turtles and how it relates to the AP Biology Curriculum.

Segment 1: Overview of Costa Rican Leatherback Sea Turtles Disappearing

Leatherback sea turtles are one of the most ancient reptiles, as well as the most endangered sea turtles. Their habitat spans from the North Atlantic to the south pacific. Their lifespan is estimated to be 50 years or more. They feed on open ocean prey such as jellyfish and salps (NOAA.org).
Their nesting beaches are generally located in tropical latitudes, especially in Trinidad and Tobaago, the West-Indies, Gabon, Costa Rica, and on the Pacific coast of Mexico (NOAA.org).
The greatest threats worldwide are incidental capture in fishing gear, hunting of turtles, and collection of eggs for human consumption. Climate change, loss and degradation of nesting and foraging habitat, ocean pollution, and vessel strikes also pose a threat to the population (NOAA.org).
The Leatherback Sea Turtles are listed as endangered under the Endangered Species Act (NOAA.org).

Segment 2: Evidence that supports Costa Rican Leatherback Sea Turtles Disappearing

The turtles have had a 40% mortality rate in the returning adult population over the last 8 years. This data was obtained by fitting turtles with satellite transmitters and following their migration. Many disappear, and it is believed that mostly because they get stuck in fishing lines (World Turtle Trust).
Projects that monitor nesting sites conduct nightly census work and fit nesting turtles with Passive Integrated Transponders. Projects that protect nests from poachers attempt to maximize the number of hatchlings that survive (World Turtle Trust).

Segment 3: Connection to the Course

The jellyfish population is increasing due to rising global temperatures. This suggests that energy sources are not the problem. The population curve of a predator generally follows the population curve of their prey, so if the jellyfish population increases, this means that the turtle population should increase. However, since so much ocean pollution is present in the form of plastic bags and turtles often mistake them for jellyfish, the jellyfish population may be increasing due to less predation (Lamb, 2017).
Climate change has caused new predators to migrate to places where sea turtles are. This has begun to cause a trophic cascade in some environments that affects the phosphorus content of the sea grass (BurkHolder, Heithaus, Fourqurean, Wirsing, Dill, 2013).
Additionally, the migration of these turtles is an innate behavior. An innate behavior is a behavior that's genetically hardwired in an organism and can be performed in response to a cue without prior experience
At this point, the leatherback turtles have great opportunity to increase as a population, but due to density independent factors, which are unrelated to the size of the population, their population is unable to increase and move towards their carrying capacity. Some examples include human interference, climate change, and natural disasters. So, as the population continues to decrease, these factors will continue to be detrimental towards the population and the sea turtles will have a greater risk of becoming extinct.
And finally, the disappearance of the Costa Rican Leatherback Sea Turtles is just another reminder of the detrimental impact that humans have on the earth and the environments on it. Our footprint is impacting so many ecosystems, environments, and species, and causing many of them to become endangered and even extinct.

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