Tracking tagged turtles

From March 2006 to August 2009, we carried out sea turtle mortality census at 13 index sites along the coast of Baja California Sur (BCS) (funded by 1st and 2nd RSG). At the end of this study, we identified one major mortality hotspots at San Ignacio Lagoon (LSI) (260 dead turtles on a 13-km long beach). LSI is a major East Pacific green (EPG) turtle (Chelonia mydas) foraging ground and hosts a great variety of algae and extensive sea grass.

Threats to turtles in the lagoon include fisheries by-catch and poaching. From 2006 to 2008, mortality estimate for incidental by-catch was calculated as being around 962 turtles per year. From interviews carried out at local communities, it resulted that EPG turtles are considered a delicacy and are still consumed. Most of the young interviewed had eaten sea turtle meat at least once in their life, and that was the only “contact” they had ever had with turtles.

Thus, the goals of this project are:

1. Study EPG turtle movements inside the lagoon to reduce interaction with fishery.

2. Involve local people in sea turtle research and thus have possibly an impact on future consumption rate.

Using GPS/VHF tags we pretend to understand

1) what is the extent of sea turtles home ranges within the lagoon.

2) which are sea turtles' main prey items and where is the resource located);

3) how do sea turtles move within foraging grounds (active or passive swimmers).

If we get to know the answer to these questions, we will be able to work with local fishermen and reduce sea turtle by-catch. This would also provide important inputs for local economy as a healthy sea turtle population and an improved knowledge of how and where sea turtles move within the lagoon would help the implementation of sea turtle-watching programs held by fishers (similarly to what is being done with whales). On a broader scale, this project could help understand sea turtle behaviour at coastal tidally dominated feeding grounds. By actively involving and sharing the research work with local people and especially children and adolescents we hope to inspire them protect sea turtles and give them a new perspective on these endangered animals and their natural resources in general.