Shark populations in Chatham and Wafer bays, Isla del Coco National Park, Costa Rica.
Poblaciones de tiburones en las bahías Chatham y Wafer del Parque Nacional Isla del Coco, Costa Rica
artículo original
Autor
Zanella, Ilena
López Garro, Andrés
Martínez, Frank
Golfín Duarte, Geiner
Morales, Keylor
Metadatos
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At least fourteen species of sharks live in the Marine Protected Area of Isla del Coco National Park (ICNP), some are resident species such as the whitetip reef shark (Triaenodon obesus); others are migratory and visit the National Park throughout the year, e.g. the scalloped hammerhead shark (Sphyrna lewini) and the whale shark (Rhincodon typus). Between March 2010 and August 2012 six expeditions out to the ICNP were carried, during this period 25 night trips (from 18:00 to 22:00 hr) for shark tagging were conducted in the Wafer and Chatham bays. During those trips, 185 sharks were analyzed: 81.1 % were whitetip reef sharks (T. obesus), 16.7 % were blacktip sharks (Carcharhinus limbatus), 1.1 % were blacktip reef sharks (Carcharhinus melanopterus) and 1.1% were silvertip sharks (Carcharhinus albimarginatus). The most common species in Bahía Chatham was T. obesus, while the most common one in Bahía Wafer was C. limbatus, which represented 80.9 % and 80.5 % of the total sharks caught, respectively. Regarding T. obesus, a sex ratio of 1.2 males per female was estimated (X2=0.09; p=0.17); in turn a sex ratio of 1.01 males per female was observed (X2=0.04; p=0.79) for C. limbatus. The average total length for T. obesus and C. limbatus was 103.66±13.91 cm and 76.58±14.56 cm respectively; suggesting that black tip sharks use those bays during immature stages. The results show an interspecific spatial segregation of the most common resident sharks at ICNP, apparently the clear waters and the coral cover of Chatham Bay are preferred by T. obesus; while the turbid waters of the Genio River mouth are preferred by C. limbatus En el Parque Nacional Isla del Coco (PNIC) habitan al menos catorce especies de tiburones, algunas especies son residentes como el tiburón punta blanca de arrecife (Triaenodon obesus), mientras otras son migratorias. Tal es el caso de les tiburones martillo (Sphyrna lewini) quienes son avistados en el PNIC en diferentes meses del año. Entre marzo del 2010 y agosto del 2012 se realizaron seis expediciones al PNIC, durante las cuales se hicieron 25 recorridos nocturnos (entre las 18:00-22:00 hr) para el marcaje de tiburones. Durante los recorridos se analizaron 185 tiburones, de los cuales el 81.1 % fueron tiburones punta blanca de arrecife (T. obesus), 16.7 % tiburones punta negra (Carcharhinus limbatus), 1.1 % tiburones punta negra de arrecife (Carcharhinus melanopterus) y 1.1 % tiburones punta plateada (Carcharhinus albimarginatus). A su vez más el 80.9 % y 80.5 % de los tiburones T. obesus y C. limbatus se capturaron en Bahía Chatham y Bahía Wafer, respectivamente. Las capturas en los recorridos revelan que el 39.2 % de los organismos se analizaron entre las 19:00 y 20:00 hr. Los resultados muestran una segregación espacial interespecífica de las especies más comunes en el PNIC. Se sugiere que las aguas cristalinas y con cobertura coralinas presentes en Bahía Chatham son preferidas por T. obesus, mientras que la desembocadura del Río Genio y las aguas turbias de Bahía Wafer son preferidas por C. limbatus.
Colecciones
- Revista de Biología Tropical [2107]