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Reisverslag Preparing research on sea turtle nesting
17 juli 2012
Dit reisverslag is ook geplaatst in de wnf community.
Preparing research on sea turtle nesting
Sticking to plans is somehow challenging in a tropical country like Cuba. Sometimes you believe everything has been set for a task and ready to go on, when suddenly you realise that some key factors unexpectedly change the course of things.
At times, the key factor is one person that changes his/her mind or declares that she/he was not properly informed about an important issue. In other occasions it is simply the weather; which can be as unpredictable as some people’s minds.
This week I was supposed to be in the field, overseeing the starting of the marine turtle nesting season in San Felipe. This National Park is composed by a chain of cays located in South Western Cuba, where WWF and its local partners Flora y Fauna, the Centre for Fisheries Research and the Centre for Marine Research of the University of Havana are also carrying out a joint research about the possible impacts of global warming on the reproduction of marine turtles.
As in other “cold blood” reptiles, sex of offspring is determined by incubation temperature rather than genetically. Above a temperature of around 29ºC the embryo turns female.
Thus, global warming is threatening marine turtles with bigger female populations and less males available to fertilise their eggs. This would accelerate the extinction process of these already threatened species.
Several months ago we deployed eight temperature loggers buried in the sands of the beach of El Sijú cay, and one logger under the shadow of the trees to measure air temperature. We hope this measurement will help us understand the relationship between air temperature and sand temperature at the average depth of marine turtle nest in the beach (50 cm).
During this week we were supposed to deploy ten additional loggers, but this time we would collocate them in the middle of nests. This would help us understand the relationship between air temperature, sand temperature and nest temperature: as the embryos develop inside the eggs, the metabolism produces additional heat that also accounts for the sex determination.