ERI and Partners Conduct Baseline Study of Sea Turtle Distribution and Abundance at the Turneffe Ato
Three species of sea turtles have been documented to inhabit coastal waters and nest Belizean beaches. These include: Hawksbill (Eretmochelys imbricata), Loggerhead (Caretta caretta) and Green (Chelonia mydas) sea turtles. In Belize, sea turtle research is limited especially when looking at factors such as abundance, habitat use, connectivity, threats and impacts.
The Turneffe Atoll is the largest of 3 offshore atolls and the most recent of Belize’s marine protected areas, declared in November 2012. Spanning some 52 km long and 18 km wide, it is a haven for marine life being comprised of numerous mangrove cayes, beaches, sea grass beds and reef ecosystems. The hawksbill, green and loggerhead sea turtles have all been recorded to nest on the atoll. To achieve effective management of the newly declared marine reserve, it is necessary to have greater understanding of the life that it hosts, including sea turtles.
In order to fill the gaps in sea turtle research, the ERI through partnership with Oceanic Society, financial support from the Mohamed Bin Zayed Species Conservation Fund along with University of Belize students, conducted the first baseline study of sea turtle distribution and abundance around the Turneffe Atoll. The objectives of the study were to:
Execute a circum-atoll visualization survey using trained and supervised volunteer snorkelers to assess abundance and behaviors of turtles in different habitat types,
Capture turtles by hand when possible to collect biometric information and tag individual turtles to establish a long-term capture-mark-recapture program, and
Create maps and a report of sea turtle distribution and abundance at Turneffe Atoll for national and local resource managers.
The team conducted in-water surveys June 9-13, 2013 and employed the distance sampling methodology developed by the Wildlife Conservation Society (WCS). This method allows comparison and joint analysis of sea turtle data between the different sites. ERI’s marine team had previosuly worked with this method through participation in WCS’s turtle survey at the Glovers Reef Atoll in April.
In-water surveys provide the opportunity to estimate population size along with chances to capture, measure and tag individuals, providing morphometric data of the population. All this and collection of skin samples for genetic analysis was done for captured turtles.
Surveys came up with a total of 87 turtles from` 18 sites distributed around the atoll - 61 hawksbills, 17 green and 9 loggerheads. Of those recorded, 17 were captured, measured, tagged and released. All captured hawksbill and green turtles were juveniles. Only a single adult female loggerhead was captured. It seems that hawksbill and green turtles use the atoll as a juvenile foraging and developmental area.
Apart from providing baseline data of the sea turtle population at Turneffe Atoll, the survey adds to the in-country work being carried out by other organizations such as The Wildlife Conservation Society, ECOMAR and the Belize Fisheries Department.
All data collected is being housed at the Environmental Research Institute, to be published via an online database later in the year.