Portal de Periódicos da CAPES

The Pelagic Crab Planes Cyaneus (Dana, 1851) (Decapoda, Brachyura, Grapsidae) in the Southwestern Atlantic Ocean in Association with Loggerhead Sea Turtles and Buoys

2011; Brill; Volume: 84; Issue: 4 Linguagem: Inglês

10.1163/001121611x557064

1568-5403

Pons, Verdi, Domingo,

Turtle Biology and Conservation

This study describes the population structure of the crab Planes cyaneus Dana, 1851 associated with loggerhead sea turtles, Caretta caretta (Linnaeus, 1758), and inanimate flotsam in the southwestern Atlantic Ocean. Samples were collected by scientific observers onboard fishing vessels of the Uruguayan tuna fleet operating between 29°-38°S and 30°-56°W, from May 2002 to July 2005. A total of 140 crabs were sampled, with cephalothorax lengths ranging from 5.6 to 22.9 mm. Eighty-eight percent of the crabs found on loggerhead turtles were adult. However, adults represented only 50% of the crabs found on buoys. We detected no relation between the turtles' carapace size and the number of crabs on each turtle. Over 50% of the sampled turtles presented a single crab; the rest presented two to five crabs. Some characteristics observed for P. cyaneus in the southwestern Atlantic Ocean were similar to those found by other authors for its congener, Planes minutus , in the North Atlantic. Results from the present study, also, extend the known geographic distribution of P. cyaneus in the southwestern Atlantic Ocean into offshore waters and suggest that these crabs opportunistically colonize whatever substrates are available in pelagic environments where substrates are scarce. Este estudio describe la estructura poblacional del cangrejo Planes cyaneus Dana, 1851 en asociacion con la tortuga cabezona, Caretta caretta (Linnaeus, 1758), y boyas en el Oceano Atlantico Sur oeste. Las muestras fueron recolectadas por observadores cientificos a bordo de barcos pesqueros de la flota atunera Uruguaya que operaron entre los 29°-38°S y 30°-56°W entre Mayo de 2002 y Julio de 2005. Un total de 140 cangrejos fueron muestreados, con un largo de cefalotorax que vario entre 5,6 y 22,9 mm. Ochenta y ocho por ciento de los cangrejos encontrados en las tortugas cabezonas eran adultos. Sin embargo los adultos solo representaron el 50% de los cangrejos encontrados en boyas. No se detecto relacion entre el tamano del caparazon de las tortugas y el numero de cangrejos presentes en las mismas. Mas del 50% de las tortugas muestreadas presentaron un unico cangrejo; el resto presento una alta heterogeneidad de grupos de dos a cinco individuos. Algunas caracteristicas observadas para P. cyaneus en el Oceano Atlantico Sur oeste fueron similares a las encontradas por otros autores para su congenere, Planes minutus , en el Atlantico Norte. Los resultados del presente estudio, ademas, amplian la distribucion geografica conocida de P. cyaneus en el Oceano Atlantico Sur oeste hacia aguas mas alejadas de la costa y sugieren que este cangrejo tiene habitos oportunistas colonizando diferentes sustratos disponibles, particularmente en el ambiente pelagico donde los mismos son escasos.