Keywords
hawksbill turtle
Eretmochelys imbricata
Costa Rica
entanglement nets
sea grass.
Tortuga carey
Costa Rica
Golfo Dulce
redes de enmalle
pastos marinos.
How to Cite
Abstract
Limited quantitative information is available for hawksbill turtles (Eretmochelys imbricata) at foraging grounds in the Eastern Tropical Pacific (ETP), where the species composes one of the most endangered marine turtle populations on the planet. Between August 2010 and March 2013 we captured individual hawksbill turtles using entanglement nets along the edges of mangroves and seagrasses of the Golfo Dulce, in southwest Pacific Costa Rica. A total of 62 hawksbills were captured, including 14 recaptures, of which 46 (74.19%) were juveniles (CCL<66cm) and 16 (25.81%) were adults. The catch per unit effort (1 unit: 100m of net for 7h) during the study ranged between 0.03 and 0.07. The Golfo Dulce is highly turbid during the rainy season (May-November), particularly at our study area, as high sediment loads due to intensive runoff lead to poor water clarity. The probability of detection of hawksbills was considerably higher in the dry season (December-April) compared to the rainy season, suggesting these turtles may prefer waters with higher clarity. None of the individuals captured had evidence of internal or external tags, making it possible to conclude that they had not been previously marked at other feeding or breeding sites. A total of 28 (45.16%) individuals were found to host the ectoparasitic barnacle Stephanolepas muricata, which in high concentrations can be harmful by limiting the mobility of organs and limbs. Although consistent in-water quantification of hawksbills in the ETP remains scant, this study represents the longest and most robust marine monitoring dataset for hawksbills in the region to date. Our findings highlight the relevance of the Golfo Dulce as an important foraging ground for hawksbill turtles in the ETP and emphasize the need to monitor and protect this habitat to aid efforts to recover this critically endangered marine turtle population.
References
Altamirano, E. J. (2010). Informe Preliminar Proyecto de Conservación de Tortuga Carey (Eretmochelys imbricata) en la RN Estero Padre Ramos, Temporada 2010. Nicaragua: Flora y Fauna Internacional.
Altamirano, E. J. & Torres, P. (2011). Informe del Proyecto de Conservación de tortuga carey (Eretmochelys imbricata) en la RN Estero Padre Ramos, Nicaragua, Temporada 2011. Nicaragua: Fauna y Flora Internacional e ICAPO.
Blumenthal, J. M., Austin, T. J., Bell, C. D. L., Bothwell, J. B., Broderick, A. C., Ebanks-Petrie, G., …Godley, B. J. (2009). Ecology of hawksbill turtles, Eretmochelys imbricata, on a western Caribbean foraging ground. Chelonian Conservation and Biology, 8, 1-10.
Bolker, B. M. (2008). Ecological Models and Data in R. New Jersey: Princeton University Press.
Boulon, R. H. (1994). Growth Rates of Wild Juvenile Hawksbill Turtles, Eretmochelys imbricata, in St. Thomas, United States Virgin Islands. Copeia, 1994, 811-814.
Burnham, K. P., & Anderson, D. R. (2002). Model selection and multimodel inference: a practical information-theoretic approach. New York: Springer-Verlag.
Carranza, A., Domingo, A., & Estrades, A. (2006). Pelagic longlines: A threat to sea turtles in the Equatorial Eastern Atlantic. Biological Conservation, 131, 52-57.
Carrión, J. A. (2010). Área de actividad local, dieta e intensidad de uso del hábitat de forrajeo de la tortuga carey (Eretmochelys imbricata) en el Pacífico Norte de Costa Rica (Tesis de Maestría). Universidad Autónoma de Baja California Sur, La Paz, México.
Carrión-Cortés, J., Canales-Cerro, C., Arauz, R., & Riosmena-Rodríguez, R. (2013). Habitat Use and Diet of Juvenile Eastern Pacific Hawksbill Turtles (Eretmochelys imbricata) in the North Pacific Coast of Costa Rica. Chelonian Conservation and Biology, 12, 235-245.
CITES. (2012). Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres. Apéndice I, II y III. Ginebra, Suiza. Retrieved from www.cites.org
Corrales-Gómez, N., & Herrera-Ulloa, A. (2012). First Record of the Turtle Barnacle Stephanolepas muricata from the Pacific Coast of Costa Rica. Marine Turtle Newsletter, 135, 9-10.
Cortés, J. (1992). Los arrecifes coralinos de Golfo Dulce, Costa Rica: aspectos ecológicos. Revista de Biología Tropical, 40, 19-26.
Cortés, J., Jiménez, C. E., Fonseca, A. C., & Alvarado, J. J. (2010). Status and conservation of coral reefs in Costa Rica. Revista de Biología Tropical, 58, 33:50.
Felger, R. S., Cliffton, K., & Regal, P. (1976). Winter dormancy in sea turtles: independent discovery and explotation in the Gulf of California, México by two local cultures. Science, 191, 283-285.
Fonseca, A. C., Dean, H. K., & Cortés, J. (2006). Non-colonial macro-borers as indicators of coral reef status in the south Pacific of Costa Rica. Revista de Biología Tropical, 54, 101-115.
Fonseca, L. G., Murillo, G. A., Guadamúz, L., Spínola, R. M., & Valverde, R. A. (2009). Downward but Stable Trend in the Abundance of Arribada Olive Ridley Sea Turtles (Lepidochelys olivacea) at Nancite Beach, Costa Rica (1971- 2007). Chelonian Conservation and Biology, 8, 19-27.
Frick, M. G., Zardus, J. D., Ross, A., Senko, J., Montano-Valdez, D., Bucio-Pacheco, B., & Sosa-Cornejo, I. (2011). Novel records and observations of the barnacle Stephanolepas muricata (Cirripedia: Balanomorpha: Coronuloidea); including a case for chemical mediation in turtle and whale barnacles. Journal of Natural History, 45, 629-640.
Gaos, A. R., Arauz, R., & Yañez, I. L. (2006). Hawksbill Turtles on the Pacific Coast of Costa Rica. Marine Turtle Newsletter, 112, 14.
Gaos, A. R., Abreu-Grobois, F. A., Alfaro-Shigueto, J., Amorocho, D., Arauz, R., Baquero, A.,…Zárate, P. (2010). Signs of hope in the eastern Pacific: international collaboration reveals encouraging status for a severely depleted population of hawksbill turtles Eretmochelys imbricate. Oryx, 44, 595-601.
Gaos, A. R., Lewison, R. L., Wallace, B. P., Yañez, I. L., Liles, M. J., Nichols, W. J., …Seminoff, J. A. (2012a). Spatial ecology of critically endangered hawksbill turtles Eretmochelys imbricata: implications for management and conservation. Marine Ecology Progress Series, 450, 181-194.
Gaos, A. R., Lewison, R. L., Yañez, I. L., Wallace, B. P., Liles, M. J., Nichols, W. J., … Seminoff, J. A. (2012b). Shifting the life-history paradigm: discovery of novel habitat use by hawksbill turtles. Biology Letters, 8, 54-56.
Instituto Meteorológico Nacional. (2014). Boletín Junio 2014. San José, Costa Rica.
Liles, M. J., Jandres, M. V., López, W. A., Mariona, G. I., Hasbún, C. R., & Seminoff, J. A. (2011). Hawksbill turtles Eretmochelys imbricata in El Salvador: nesting distribution and mortality at the largest remaining nesting aggregation in the eastern Pacific Ocean. Endangered Species Research, 14, 23-30.
Koch, V., Brooks, L. B., & Nichols, W. J. (2007). Population ecology of the green/black turtle (Chelonia mydas) in Bahía Magdalena, Mexico. Marine Biology, 153, 35-46.
Koch, V., Nichols, W. J., Peckham, H., & De la Toba, V. (2008). Estimates of sea turtle mortality from poaching and bycatch in Bahía Magdalena, Baja California Sur, Mexico. Biological Conservation, 128, 327-334.
Limpus, C. J. (1992). The hawksbill turtle, Eretmochelys imbrlcata, in Queensland: population structure within a southern Great Barrier Reef feeding ground. Wildlife Research, 19, 489-506.
Meylan, A. B. (1988). Spongivory in hawksbill turtles: A diet of glass. Science, 239, 393-395.
Meylan, A. B. & Donnelly, M. (1999). Status Justification for Listing the Hawksbill Turtle (Eretmochelys imbricata) as Critically Endangered on the 1996 IUCN Red List of Threatened Animals. Chelonian Conservation and Biology, 3, 200-224.
Quesada-Alpízar, M. A., & Morales-Ramírez, A. (2004). Comportamiento de las masas de agua en el Golfo Dulce, Costa Rica durante El Niño (1997 - 1998). Revista de Biología Tropical, 52, 95-103.
Quiñones, J., González-Carman, V., Zeballos, J., Purca, S., & Mianzan, H. (2010). Effects of El Niño-driven environmental variability on black turtle migration to Peruvian foraging grounds. Hydrobiologia, 645, 69-79.
R Development Core Team. (2013). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0.
Saltidrián-Tomillo, P., Saba, V. S., Piedra, R., Paladino, F. V., & Spotila, J. R. (2008). Effects of Illegal Harvest of Eggs on the Population Decline of Leatherback Turtles in Las Baulas Marine National Park, Costa Rica. Conservation Biology, 22, 1216-1224.
Seminoff, J. A., Nichols, W. J., Resendiz, A., & Brooks, L. (2003). Occurrence of Hawksbill Turtles, Eretmochelys imbricata (Reptilia: Cheloniidae), near the Baja California Peninsula, Mexico. Pacific Science, 57, 9-16.
Sosa-Cornejo, I., Montaño-Valdez, D. I., Bucio-Pacheco, M., Enciso-Saracho, F., Sanchez-Zazueta, J. G., & Fierros-Pérez, E. (2012). Determination of Epibionts of the Marine Turtle Lepidochelys Olivacea (Eschscholtz, 1829) Nesting in Ceuta Beach, Sinaloa, Mexico. Journal of Agricultural Science and Technology, B2, 1190-1194.
Torres, P. & Altamirano, E. (2012). Informe de proyecto de conservación de tortuga carey (Eretmochelys imbricata) en la Reserva Natural Estero Padre Ramos, Nicaragua. Temporada 2012. Nicarargua: Fauna y Flora Internacional e ICAPO.
UICN. (2012). IUCN Red List of Threatened Species. IUCN Global Species Programme. Red List Unit: Cambridge, UK. Retrieved from www.iucnredlist.org
van Dam, R. P., & Diez, C. E. (1997). Diving behavior of immature hawksbill turtles (Eretmochelys imbricata) in a Caribbean reef habitat. Coral Reefs, 16, 133-138.
Wallace, B. P., DiMatteo, A. D., Bolten, A. B., Chaloupka, M. Y., Hutchinson, B. J., Abreu-Grobois, A., … Mast, R. (2011). Global Conservation Priorities for Marine Turtles. PLoS ONE, 6(9), e24510.
Ward, M. W., Elkins, C., & Ward, R. J. (2010). Punta Pargos Green Turtle Monitoring and Protection Program of Costa Rica. 2011 (Technical Report). Costa Rica: Sea Turtles Forever.
Wenger, S. J. & Freeman, M. C. (2008). Estimating species occurrence, abundance, and detection probability using zero-inflated distributions. Ecology, 89, 2953-2959.
Zardus, J. D. & Balazs, G. H. (2007). Two previously unreported barnacles commensal with the green sea turtle, Chelonia mydas (Linnaeus, 1758), in Hawaii and a comparison of their attachment modes. Crustaceana, 80, 1303-1315.
Comments
This work is licensed under a Creative Commons Attribution 4.0 International License.
Copyright (c) 2015 Revista de Biología Tropical