If you went to the beach over the Memorial Day weekend, you may have seen sea turtle nesting areas cordoned off for protection. That's because South Florida is in the midst of sea turtle nesting season, which began in March and ends in October.
South Florida’s coast is home to three nesting species, all of which are endangered and protected by the Florida Fish and Wildlife Conservation Commission. Sea turtle populations have been negatively impacted by pollution, large developments along the shore and natural factors like sharks or other predators. However, through conservation efforts and legislation, the sea turtle populations in South Florida are slowly recuperating.
Marine biologist and Dean of the College of Arts, Science and Education at Florida International University Dr. Michael Heithaus joined Sundial to talk about how beachgoers can help protect these nests and the research he is conducting on sea turtles around the world.
This has been edited lightly for clarity.
WLRN: [Sea turtle] populations are bouncing back.
HEITHAUS: Yeah, it's a great conservation success story in a lot of places in the world -- not everywhere, but we've created things like turtle excluder devices (nets that capture shrimp but let sea turtles escape) so they don't get caught in fishermen's nets. We've stopped egg poaching on beaches and then created programs in Miami-Dade, Broward and throughout Florida where we are monitoring the nests, protecting the nests, changing the lighting on the beach so the hatchlings don't get disoriented. That started to cause these populations to rebound. Now they're still threatened, but sea turtles are taking a step back from the brink of extinction.
As the populations are bouncing back, do you see a day when we no longer need to protect sea turtles?
Well I certainly hope we see the day where we don't need to have them on the protection list. In some places they're getting there but you have to remain vigilant because of development of coasts. Another problem is on the horizon for these sea turtles. One of the ways you determine if a turtle is male or females is by the temperature of the nest when the egg is incubating. If it gets above 29 degrees Celsius they become more female. There's beaches in Australia where now 99% of the eggs that hatch are females. The question is: will turtles adapt or evolve through time to keep up with rising temperatures?
It sounds [like] climate change is playing a role.
Climate change is absolutely playing a role. Sea-level rise can play a role because if those nests get washed out with hurricanes or just rising sea-levels and if beaches are smaller and they can't lay their eggs that's really an existential threat to their population survival.
One of the things that you focus on is about predators, which are sharks. We've seen turtle populations go up, but shark populations are hurting. If there are less predators is the food chain in any way altered?
Unfortunately we tend to think getting rid of predators makes the world safer. But when you remove big predators bad things tend to happen. You get rid of wolves then deer populations can explode. They can eat themselves out of house. We have evidence that may be happening in the oceans. So in areas where turtle populations are really exploding and shark populations have been really degraded you can have these turtles virtually eat out all the sea grass. In Bermuda there used to be a lot of sea grass and now some researchers from FIU think they may have seen the last bites of sea grass basically disappear and that's because the turtle populations have exploded. The balance is really critical.
Watch a green sea turtle, wearing a small camera attached to its shell, feed on sea grass.