ABSTRACT
El objetivo de esta investigación fue conocer aspectos poblacionales, biológicos y ecológicos de las tortugas carey (Eretmochelys imbricata) presentes en el Pacífico sur de Colombia (Departamento del Cauca), para esto se tomó información de morfometría, se revisó el estado de salud de los individuos y se tomaron muestras de sangre para valoración de química sanguínea. Durante siete meses de muestreo se capturaron 25 tortugas carey (16 individuos diferentes) en los arrecifes del Parque Nacional Natural Gorgona, con un porcentaje de recaptura del 46 %. Aunque no se notaron problemas evidentes de salud, la mayoría de animales presentaron gran parte del caparazón cubierto de algas filamentosas y algunos epibiontes sobre el plastrón y el caparazón. La Longitud Curva Caparazón (LCC) mostró una mayor proporción de individuos con tallas entre 37 y 45 cm de longitud (prom. 42,3 cm; min. 37,5 cm; max. 58 cm). Por medio de la prueba de Mann Whitney U, se comparó la LCC de los 16 individuos diferentes capturados en el PNN Gorgona, con 11 individuos capturados en la zona del litoral del Departamento del Cauca, encontrándose diferencias significativas entre estos dos grupos, donde los animales presentes en el PNN Gorgona fueron de mayor talla que los presentes en el continente (Z = -2,59; p = 0,007). Los valores de ácido úrico se encontraron por encima de los valores de referencia.
The objective of this research was to determine biological and ecological population characteristics of the hawksbill turtle (Eretmochelys imbricata) found in the southern Colombian Pacific department of Cauca. Morphometric measurements were recorded, the health status of individuals was reviewed, and blood samples were taken for a biochemistry assessment. During the seven months of the investigation, 25 hawksbill turtles were caught (16 different individuals) on the reefs of Gorgona Natural National Park. Forty-six percent of the total numbers of turtles assessed were recaptured during the study period. While no obvious health problems were noted, most animals possessed epibionts and filamentous algae covering the carapace, some parts of the limbs, as well as on their neck. Curved carapace length (CCL) showed the highest proportion of individuals were between 37 and 45 cm. Sixteen individuals captured in Gorgona Natural National Park were compared with 11 individuals captured in the coastal zone of the department of Cauca. Using the Mann-Whitney U test, a significant difference in CCL was found between these two groups; the animals from Gorgona National Park were larger than those present on the coast of the mainland (Z = -2.59, p = 0.007). Uric acid concentrations were found to be higher than previously referenced values.
ABSTRACT
The ecotouristic approach to sharks and rays has developed rapidly in the last 20 years. We studied three species in Gorgona Island from 427 dives ( 2004-2011), including 866 photographs and videos. There was at least one sighting in 34.4% of the dives, and 25.0% of the photos and videos were useful for identification of individuals. T. obesus was seen in all months of the year, and its presence was correlated with depths of 20-30m (66.9%), sandy-rocky bottoms (79.8%), and western (61.2%) and south (52.9%) areas of the island. The southern area had groups of up to 9 individuals but abundance was not correlated with zone, depth, bottom type or temperature. R. typus and M. birostris were mainly seen at 28- 33oC, in the north, where plankton was more abundant. We identified individually five whale sharks, 15 manta rays and 38 whitetip sharks, 9 of which (one ray and 8 whitetip sharks) were recaptured in different months and years. Most of recaptured whitetip sharks were alone (63.06%), resting (49.37%) and on the bottom (82.91%) in the same area of the photographic capture, suggesting a high philopatry of this species on the island; however, the recapture of three individuals in different zones indicate connectivity between of this species in the west, south and north zones. The Gorgona Island is an important area for breeding and growth of T. obesus, with presence of gravid females and births. It is also a seasonal passage area for R. typus and M. birostris, which occur most frequently between March and September, but do not form aggregations around the island. Rev. Biol. Trop. 62 (Suppl. 1): 329-342. Epub 2014 February 01.
Se evaluó el uso de hábitat del aletiblanco Triaenodon obesus, la mantaraya Manta birostris y el tiburón ballena Rhincodon typus en la Isla Gorgona, a partir de 427 inmersiones de buceo y del análisis de 866 fotografías y videos. T. obesus se observó a lo largo del año, y su presencia se correlacionó con profundidades entre 20 y 30m (66.9%), fondos areno-rocosos (79.8%) y las zonas occidental (61.2%) y sur (52.9%), con mayores congregaciones en esta última zona. R. typus y M. birostris se avistaron entre 28 y 33oC y su presencia se correlacionó con la zona norte de la isla, área de mayor abundancia de zoo e ictioplancton. Se identificaron 5 tiburones ballena, 15 mantarrayas y 38 aletiblancos, 9 de los cuales fueron recapturados en años diferentes. La mayoría de los aletiblancos recapturados fueron observados solos, en reposo y sobre el fondo y en la misma zona, sugiriendo alta filopatría; sin embargo, la recaptura de tres individuos en zonas diferentes, indican conectividad de la especie en la isla. Gorgona es un área importante para la reproducción y crecimiento del aletiblanco, y un área de paso para el tiburón ballena y la mantarraya, los cuales se observan con mayor frecuencia entre marzo y septiembre, pero no forman agregaciones.