Last month I shared with you the total data for in situ nests, nest predation and false crawls for the month of July, and mentioned that these data were not adjusted for sampling effort. By sampling effort, I mean the amount of time and / or distance that was invested on each beach to get the data. For example, we monitor 2 km of Piro beach and 4.5 km of Pejeperro beach. So, it isn’t the same to walk Piro beach and find two turtles as it is to walk Pejeperro beach and find two turtles – the distances covered are very different. To compare these two values, we must express them in proportion to the distance traveled, i.e. density of turtles per kilometer. In this case, that would be: Piro: 2 / 2 = 1 and Pejeperro: 2 / 4.5 = 0.44.
By calculating the July and August data in this way, taking the sampling effort on each beach into account, we get the results shown in Figure 1. As you can see, Rio Oro is the beach with the highest density of in situ nests, nest predation and false crawls, followed by Pejeperro. From this graph, we can also see that the density of depredated nests on Rio Oro beach is very similar to the density of in situ nests, which is obviously worrying. In the coming days, I will conduct a preliminary analysis of predation in conjunction with Courtney Thomas, one of our assistants, who is using her participation in this project as part of her studies at Evergreen State College.
I would also like to take advantage of this note to thank Mr. Eliecer Villalta and Mr. Geinor Barquero, from MINAET’s Department of Control and Protection, for their support in recent weeks. Their presence, along with other peers in the area, had an immediate effect in reducing poaching of turtle eggs. I hope we can continue to coordinate this type of support throughout the rest of the season.
Remember that you can help us to protect sea turtles that visit the southern part of the Osa Peninsula in several ways: 1) telling others about our project and the importance of protecting sea turtles, 2) participating in our sea turtle volunteer program and 3) by making a donation to help fund the continuation of the Sea Turtle Conservation Program.