Food habits of the silky shark Carcharhinus falciformis (Müller & Henle, 1839) off the western coast of Baja California Sur, Mexico

Abstract

Summary The objective of this study was to establish the trophic niche of the silky shark and to determine the ecological role of this predator in the ecosystem close to Baja California. The trophic spectrum was analyzed from samples taken during summer and autumn (2000–2002) from the fishing camps of Punta Lobos and Punta Belcher on the western coast of Baja California Sur. A total of 263 stomach contents were analyzed (143 with food; 120 empty). The index of relative importance (IRI) showed that at Punta Lobos, silky sharks fed mainly on red crabs Pleuroncodes planipes (%IRI = 83%), whereas at Punta Belcher the main food item was the jumbo squid Dosidicus gigas (%IRI = 41%), followed by chub mackerel Scomber japonicus (%IRI = 33%). According to the Levin Index (Bi), the trophic niche breadth in silky sharks is low (Bi = <0.6), which means that silky sharks are specialist predators because they mainly consume three prey types: red crab, chub mackerel, and jumbo squid. The Shannon‐Wiener Index indicated that all trophic categories at Punta Belcher (0.85–1.22) had lower diversity than at Punta Lobos (0.50–1.6), because the silky shark feeds more on tropical prey found close to Punta Lobos. The Morisita‐Horn Index (Cλ) showed an overlap in the diet between the two areas analyzed and between sexes (Cλ = >0.6). The juveniles and adult females did not show any overlap. In the caloric analysis of the main prey, the jumbo squid (D. gigas) contributed the most calories to the silky shark diet (76%).

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

“…The silky shark, Carcharhinus falciformis, feeds mainly on teleosts but also on cephalopods and crustaceans (Cabrera-Chávez et al 2010, Duffy et al 2015, Estupiñán-Montaño et al 2017) and, occasionally, on sea turtles (Estupiñán-Montaño et al 2017, Acevedo unpublished * ). This species is considered to be a selective predator in the ETP, with a preference for the scombrid genus Thunnus (see Duffy et al 2015, Estupiñán-Montaño et al 2017, which normally inhabits oceanic zones and forms schools near seamounts.…”

“…Carcharhinus falciformis feeds on a large number of prey species, from pelagic and coastal fishes (e.g., tunas, mullets, mackerel) to cephalopods, crustaceans, and sea turtles (Cabrera-Chávez-Costa et al 2010, Duffy et al 2015, Estupiñán-Montaño et al 2017). This shark is considered a piscivorous predator, consuming mainly fishes of the Scombridae family (Duffy et al 2015, Estupiñán-Montaño et al 2017.…”

Trophic ecology of common elasmobranchs exploited by artisanal shark fisheries off south‑western Madagascar

“…However, the individuals we sampled were significantly larger than those analysed by Rabehagasoa et al (2012). Therefore, ontogenetic shifts in diets, which have been documented for this species (Compagno 1984, Cabrera-Chávez-Costa et al 2010, Rabehagasoa et al 2012, may also explain the observed differences with C. falciformis feeding on higher trophic level prey at larger sizes. Moreover, higher δ…”

KEBIASAAN MAKAN HIU KEJEN (Carcharinus falciformis): STUDI KASUS PENDARATAN HIU DI PPP MUNCAR JAWA TIMUR (Feeding habit of Silky Shark (Carcharinus falciformis): Case Study of Landing Shark in Muncar Coastal Fishing Port East Java)

“…Sehingga dapat diasumsikan bahwa hiu kejen menyeleksi jenis mangsa dan memakan mangsa dengan kelimpahan tinggi di perairan. Hal tersebut didukung oleh penelitian serupa yang dilakukan oleh Cabrera-Chaves- Costa et al 2010;Torres-Rojas et al 2009;Kamura et al 2004. Maka dapat diketahui pola makan ikan predator seperti hiu sangat kompleks dan dipengaruhi oleh berbagai macam faktor seperti ketersediaan makanan dan mobilitas mangsa, kelimpahan mangsa, ukuran mangsa, dan perubahan musim.…”