Demographic and tumour prevalence data for juvenile green turtles at the Coastal-Marine Protected Area of Cerro Verde, Uruguay

ABSTRACT

Marine Protected Areas are increasingly considered in coastal areas as an instrument to preserve threatened fauna and fragile habitats from the detrimental effects of human activities. For this reason baseline data are of utmost importance for the evaluation of the outcomes of ongoing conservation efforts. Along the Uruguayan coast, the area of Cerro Verde (declared protected since 2011) represents the most important foraging and development area for green turtles (Chelonia mydas). Between 2002 and 2009, a long-term capture-mark-recapture programme for green turtles was developed to gather data on demography, ecology and status of the species in the area. Turtles captured were juveniles ranging from 28.8 to 64.3 cm in length over the curve of the carapace (n = 514), and results indicated a size-based habitat segregation. Tumour prevalence was 5.3% (n = 27) and was positively correlated with carapace length. The mean body condition index was 1.25 ± 0.14 (n = 494). From the total number of tagged turtles 10.6% were recaptured during the study period. Green turtles showed high site fidelity; 81% of the turtles were recaptured within the same season and 76% were recaptured in different seasons but were found at the original capture spot. Mean annual growth rate was 1.6 ± 0.9 cm year⁻¹. The catch per unit effort of 2008 differed from 2009, higher in 2009, but also significantly different between capture spots. The present study constitutes a baseline dataset for future monitoring of green turtles in the area and provides valuable information for wider analyses of population dynamics in the Southwestern Atlantic Ocean.

RESPONSIBLE EDITOR:

• Leandro Bugoni

KEYWORDS:

• Southwest Atlantic
• protected areas
• site fidelity
• size distribution
• health condition

Acknowledgements

We would like to thank all Karumbé members, volunteers and our families. Especially we thank Carlos Romero (fisherman) for his unconditional support throughout these years. Thanks to the Army Park Service (Ministry of Defence) for lodging us during the first years of monitoring. We are very grateful to Coronilla's people who have supported Karumbé since the beginning of its activities in the area. We also thank Luciana Alonso who provided valuable assistance in the field, laboratory and data analysis. Thanks to Alvar Carranza for his comments on the previous versions of the manuscript. This research was conducted under license (No. 200/04, 073/08 and 323/11) from the Fauna Department – Ministry of Cattle, Agriculture and Fishing of Uruguay.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Conservation Leadership Programme (Future Conservationist, Follow-up and Leadership Awards) under grant no. 001404F; National Fish and Wildlife Foundation; Peoples Trust for Endangered Species; Rufford Small Grants; Idea Wild; PADI Foundation; International Fund for Animal Welfare; Green Grants; and Project Aware Foundation.