Abundancia, reproducción y tallas del tiburón martillo Sphyrna lewini (Carcharhiniformes: Sphyrnidae) en la pesca artesanal de Golfo Dulce, Pacífico de Costa Rica

Abstract

En Golfo Dulce, Costa Rica, se han reportado capturas incidentales de S. lewini por pescadores artesanales. Debido a esto, este estudio tiene como objetivo caracterizar las capturas del tiburón martillo en Golfo Dulce, y recomendar pautas de manejo. Entre mayo 2010 y mayo 2011 se recopiló información biológica-pesquera de tiburones capturados durante faenas artesanales en Golfo Dulce. Se estimó la captura por unidad de esfuerzo a lo largo del año. Se analizaron un total de 315 tiburones, todos juveniles, con una longitud total media de 74.3±17.4cm. Las longitudes totales y la abundancia relativa tuvieron tendencias opuestas: en julio-agosto cuando las longitudes totales medias fueron menores, las capturas por unidad de esfuerzo fueron mayores. Debido a esto, se recomienda implementar vedas temporales durante el periodo de nacimiento de las crías de tiburón martillo (junio-agosto) en sitios donde se reportaron las mayores capturas.

Reproductive biology of the scalloped hammerhead (Sphyrna lewini) in the central-eastern Pacific Ocean

“…This also coincides with the observations reported by Torres-Huerta et al (2008) in the Gulf of California, Mexico, where embryos of 41-59 cm TL were detected in July, suggesting a gestation period of about 11 months in which the birth occurred during the latter month. The high similarity in terms of the period of the gestation and birth may be explained by the genetic relationship among small populations of S. lewini along the eastern Pacific Ocean (Nance et al, 2011), as well as the presence of neonates in the Pacific coast of Costa Rica during July-August (Zanella & López-Garro, 2015) and in Panama during March-June (Robles et al, 2015). In spite of the similarities between our results and those from other studies, our results should be interpreted with caution due to the low number of gravid females analysed (N = 12); hence, more studies are needed to support these findings.…”

Nursery habitat use patterns of the scalloped hammerhead shark, Sphyrna lewini, in coastal areas of the central Mexican Pacific

“…The peak of catches observed in these studies coincides with the greater presence of neonates, and the subsequent sharp decline in catches was attributed to emigration (Duncan & Holland, 2006) and mainly mortality from starvation (Duncan & Holland, 2006;Lowe, 2002) Schettini et al, 1998). Different authors have reported the preference of YOY SPL for the river mouths or mangroves, with turbid water and sandy or muddy bottoms (Clarke, 1971;Castro, 1993;Simpfendorfer & Milward, 1993;Duncan & Holland, 2006;Zanella et al, 2009;Yates et al 2015;Zanella & L opez-Garro, 2015;Marie et al, 2017). During 5-6 months inland water discharges provide food and refuge to juveniles, allowing fast growth rates in the study area.…”

“…A total of 41 prey items were found in the stomach of YOY SPL caught in the study area, and teleost fishes were the most important in their diet (Rosende-Pereiro et al, 2019). Among SPL main prey are the same ones that were captured in the fishery's independent samplings (Lutjanidae, Haemulidae, Ariidae, Carangidae, Sciaenidae), as well as others that are also associated with soft bottoms in river mouths the Golfo Dulce (Zanella & L opez-Garro, 2015) and Golfo de Nicoya (Zanella et al, 2009) on the Pacific coast of Costa Rica. In our study area, no catches of juveniles larger than 100 cm were reported, as Duncan and Holland (2006) found in the Kane'ohe Bay, which has a maximum depth of 19 m (Clarke, 1971).…”

Movements of scalloped hammerhead sharks (Sphyrna lewini) at Cocos Island, Costa Rica and between oceanic islands in the Eastern Tropical Pacific

“…lewini are landed by artisanal fisheries [ 28 , 65 , 66 , 67 , 68 ]. Some of the larger coastal lagoons in this region have been identified as nursery habitat [ 28 , 69 , 70 ]. Although neonate S .…”