Residency of the scalloped hammerhead shark (Sphyrna lewini) at Malpelo Island and evidence of migration to other islands in the Eastern Tropical Pacific

Abstract

Sixty nine hammerhead sharks, Sphyrna lewini, were tagged at Malpelo Island (Colombia) with ultrasonic transmitters during

Trophic inference in two sympatric sharks, Sphyrna lewini and Carcharhinus falciformis (Elasmobranchii: Carcharhiniformes), based on stable isotope analysis at Malpelo Island, Colombia

“…This species is considered as an important consumer of cephalopods in the eastern Pacific C compared with those offshore due to the influence of benthic primary production (France 1995, Tanaka et al 2008 or upwelling (Burton andKoch 1999, Graham et al 2010). The similarity of the results may be due to: (1) the high mobility of S. lewini throughout the ETP (Bessudo et al 2011b); (2) The results of this study support the hypothesis of Bessudo et al (2011aBessudo et al ( , 2011b, who suggest that during the night, Sphyrna lewini leaves Malpelo Island, probably to feed. The negative values of δ 13 C observed in this study for S. lewini tissues (Tables 1 and 2) are characteristic of oceanic zones (Niño-Torres et al 2006, Páez-Rosas et al 2014, where S. lewini would consume epipelagic and mesopelagic cephalopods (e.g., Dosidicus gigas, Histioteuthis spp., Mastigoteuthis spp., and Sthenoteuthis oualaniensis) (Estupiñán-Montaño et al 2009, Galván-Magaña et al 2013.…”

“…This result may be caused by: (1) the trophic specialization of both species, which reduces interspecific competition; or (2) different habitat use, with Sphyrna lewini showing greater horizontal and vertical movements (Bessudo et al 2011a(Bessudo et al , 2011b, and Carcharhinus falciformis being more limited in its movements by its physiological characteristics, which restrict it to narrower niches (Kohin et al 2006, Filmalter et al 2010. * Acevedo G. 1996.…”

“…In the ETP, S. lewini often forms schools around oceanic islands and seamounts (Klimley 1981, Klimley andNelson 1981), particularly in marine protected areas, and makes vertical movements and horizontal migratory movements between Malpelo Island (Colombia), Cocos Island (Costa Rica), and the Galapagos Islands (Ecuador) (Bessudo et al 2011a(Bessudo et al , 2011b. In the ETP, S. lewini consumes a wide variety of prey species, from benthic, neritic, and epipelagic fishes to cephalopods, rays, lobsters, shrimps, and crabs (TorresRojas et al 2006, Estupiñán-Montaño et al 2009, TorresRojas et al 2010, Zanella et al 2010, Galván-Magaña et al 2013, Torres-Rojas et al 2015.…”

First record of the smooth hammerhead shark (Sphyrna zygaena) in Saint Peter and Saint Paul Archipelago: range extension for the equatorial region

“…Nonetheless, according to the author, the record requires confirmation. Smooth hammerhead sharks may seek shelter and food in island ecosystems, such as scalloped hammerhead sharks, which usually form aggregations in these environments (Hearn et al, 2010;Bessudo et al, 2011;Ketchum et al, 2014).…”

Uso de hábitat de Triaenodon obesus (Carcharhiniformes: Carcharhinidae), Rhincodon typus (Orectolobiformes: Rhincodontidae) y Manta birostris (Myliobatiformes: Myliobatidae) en el Parque Nacional Natural Gorgona, Pacífico colombiano

“…Por su parte, en el Pacífico Oriental dichos trabajos se han iniciado recientemente y las publicaciones disponibles se restringen a poblaciones de Manta alfredi y M. birostris en Hawaii (Clark, 2010;Deakos, Bajer & Bedjer, 2011) y Sphyrna lewini en la isla Malpelo (Bessudo et al, 2011).…”