New Publication shows Dutch Caribbean turtles migrate into risky waters

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New publication shows Dutch Caribbean turtles migrate into risky waters

Gepubliceerd op
19 mei 2016

Lisa Becking (Wageningen University and IMARES) and Marjolijn Christianen (Rijksuniversiteit Groningen and IMARES) together with Mabel Nava, Sue Willis and their team at Sea Turtle Conservation Bonaire (STCB) have shown in a recent publication that sea turtles who breed in Bonaire, Caribbean Netherlands, migrate to foraging grounds in 10 different countries across the Caribbean. The turtles migrate great distances of up to 3500km. This study identifies 2 important foraging grounds for turtles from Bonaire, namely in Venezuela and in shallow banks off the East coast of Nicaragua and Honduras. Their journey is risky, because they cross waters of countries where sea turtle harvest is legal or where they are in high risk of ending up as unwanted bycatch.

What is the geographic scope of sea turtles??

The Dutch Caribbean island Bonaire is home to small nesting beaches of three sea turtle species: Hawksbill turtles (Eretmochelys embricata), Green turtles (Chelonia mydas) and Loggerheads (Caretta caretta). To elucidate the geographic scope of the populations of sea turtles breeding at Bonaire and Klein Bonaire (Caribbean Netherlands) STCB's team tracked turtles for 11 years. The team examined 5 female loggerheads, 4 female green turtles, and 2 male and 13 female hawksbill turtles. Researchers Lisa Becking (Wageningen University and IMARES) and Marjolijn Christianen (Rijksuniversiteit Groningen and IMARES) collaborated with Mabel Nava and Sue Willis (Sea Turtle Conservation Bonaire). A long journey to their rookery on Bonaire

Sea turtles are long-lived migratory reptiles with a complex life cycle. Mature sea turtles breed in the vicinity of the beach beach where they were born (called a rookery) and at the onset of the reproductive season, adults migrate from their resident foraging area to their natal rookery region to breed. Sea turtles who breed in Bonaire, migrate great distances of up to 3500km to reach their foraging grounds across the Caribbean.

Loggerhead female in the south of Bonaire returning to sea after being tagged in 2007 (Photo by Mabel Nava)
Loggerhead female in the south of Bonaire returning to sea after being tagged in 2007 (Photo by Mabel Nava)

More knowledge is needed of sea turtle migratory behaviour

For small rookeries, such as those utilizing the islands of the Caribbean Netherlands, knowledge of turtle migratory behavior remains scarce. Knowledge of such linkages is valuable for conservation efforts, as foraging aggregations are not homogeneously distributed across the Caribbean Sea and migration routes can vary among individuals of the same nesting colony. Understanding turtle spatial ecology and identifying critical foraging habitats and movements is integral to effective sea turtle conservation.

Risks for sea turtles in the Caribbean

Nesting sea turtles are a key tourist attraction in Bonaire, and they are at risk of harvest in the waters they frequent. Given the wide dispersal, these turtles are at risk of legal or illegal harvest, which impacts conservation efforts and threatens turtle populations far removed from those territories. The breeding turtles from Bonaire face particular threats in the countries of Nicaragua, Panama, Venezuela, Colombia and Haiti.

Fig. 1. Post-breeding tracks and foraging locations from Bonaire and Klein Bonaire, Caribbean Netherlands.(A) Post-breeding tracks across the Caribbean; (B) detail of Rosalind Bank, Serranilla Bank, and Banco Gorda; and (C) detail of Los Roques, Venezuela.
Fig. 1. Post-breeding tracks and foraging locations from Bonaire and Klein Bonaire, Caribbean Netherlands.(A) Post-breeding tracks across the Caribbean; (B) detail of Rosalind Bank, Serranilla Bank, and Banco Gorda; and (C) detail of Los Roques, Venezuela.

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