Over 100,000 Sea Turtles Nest at the Same Time. How? | National Geographic

My main interest is understanding how, or specifically what the mechanism is for these sea turtles to synchronize their nesting behaviors. We do not know why the sea turtles specifically come to Austin.

Sea turtles are renowned for their ability to travel extremely long distances as young turtles before returning to the same geographic area where they hatched to lay their eggs as adults. This is a behavior called natal homing that exists in all species of sea turtles, but we really don't have a very good idea for how they do it. It's possible that a sea turtle has a pheromone that they secrete into the ocean, and that perhaps this concentration of this chemical reaches some sort of threshold where all of a sudden the turtles know that it's time to nest and come up on the beach.

At that point, if a sea turtle needs to smell a pheromone or be able to perceive it, then they need their sense of smell in order to know that it's time to do this mass nesting. We are taking a boat that we hire with a local fisherman out to the offshore waters of Austin El, and we are about two miles off the shore. Once we reach that area, we're looking over the horizon for aggregations of sea turtles in the water.

Once we find the sea turtles, Roger is helping me and going into the water and safely capturing them and bringing them onto the boat. Some days they're much more likely to swim away and try to escape, but other days they don't seem to.

The experiment that we're focusing on is trying to see whether we take away that sense of smell if a sea turtle is less likely to come up on the beach and participate in a mass nesting event. Once we have the sea turtle on the boat, then we are doing two different treatments that we're applying to the nostrils of the sea turtle.

We are doing one treatment that is seawater, and this is a control. The treatment that we're actually doing, experimental E, is called zinc sulfate, and this is a chemical that temporarily anesthetizes the olfactory bulb of sea turtles so that the sea turtle will temporarily be unable to smell anything in the few days leading up to a mass nesting event that we're expecting.

We have been going out on the boat and capturing as many sea turtles as possible. Before we release the turtle, we've been drying the carapace and using spray paint to mark a line either horizontally or vertically on the carapace, depending on the treatment, and then we release a sea turtle.

During every mass nesting event, we always have people on the beach surveying the beach and conducting surveys to count the number of nesting females. I have these volunteers looking for the females that we have marked to see how many of each type of sea turtle is actually coming up on the beach to nest.

I certainly don't think this is a question that I can answer in the scope of my PhD, so my hope is that I can then move forward and take this as, you know, a career's worth of research that I can keep trying to answer more and more questions for.