Diet composition of smooth-hound shark,Mustelus mustelus(Linnaeus, 1758), in the Gulf of Gabès, southern Tunisia

Abstract

The diet of the smooth-hound shark, Mustelus mustelus, from the Gulf of Gabe`s (southern Tunisia, central Mediterranean Sea) was investigated with respect to fish size and season. Stomach contents were analyzed from 540 specimens with total lengths ranging from 34 to 158.5 cm. Of the total number of stomachs examined, 63 were empty (11.67%). Smooth-hound shark fed mainly on crustaceans, fishes and cephalopods. Sipunculids, polychaetes and echinoderms were occasional preys. No differences were found between the diets of males and females. Ontogenetic changes in diet of M. mustelus were apparent, with crustaceans forming a greater proportion of the diet of smaller sharks. Both teleosts and molluscs increased in importance with increasing shark size. Consumptions of polycheates, sipunculids and echinoderms were not related to predator size. Prey diversity also increased with size, with large and mobile prey species found more commonly in the diet of larger sharks. The limited overlap in the dietary compositions of juveniles, subadults and adults suggests the possibility of resource partitioning. Seasonality in food habits was in accordance with the dynamics of the predator and the prey species.

Feeding habits of Mustelus henlei on the western coast of Baja California Sur, México

“…For M. henlei a small number of empty stomachs was found, as it has been reported in other studies where the percentage of empty stomachs in the species of the genus Mustelus is very low in general: 3.1% in M. griseus (Kamura & Hashimoto 2004); 0.8% in M. palumbes (Smale & Compagno 1997); 2.47% in M. schmitti (Belleggia et al 2012); 8.7-11.7% in M. mustelus (Smale & Compagno 1997, Saïdi et al 2009a; 8% in M. antarticus (Yick et al 2012);13.7-14.28% in M. punculatus (Jardas et al 2007, Saïdi et al 2009b, Lipej et al 2011; 6% in M. californicus (Talent 1982) and M. lunulatus (Navia et al 2006);5.5-14% in M. henlei (Talent 1982, Haesker & Czech 1993.…”

Preliminary study on age, growth and reproduction of Mustelus mustelus (Elasmobranchii: Carcharhiniformes: Triakidae) inhabiting the Gulf of Iskenderun, north-eastern Mediterranean Sea

“…The maximum lengths of the same species were reported as 165 cm for female off South Africa (Smale and Compagno 1997); 164 cm in Mossel Bay, South Africa (Goosen and Smale 1997); 165 cm in the Adriatic Sea, Mediterranean (Maddalena et al 2001); 148.3 cm in the Adriatic (Pallaoro et al 2005); 123 cm in the Gulf of Gabès (Saïdi et al 2008); 122 cm in the Gulf of Gabès again (Saïdi et al 2009). The maximum lengths reported around the Turkish coasts are given Table 3.…”

Food habits of the rough rayRaja radula(Chondrichthyes: Rajidae) from the Gulf of Gabès (central Mediterranean Sea)

“…However, Beretovski (1989 concluded that skates could not feed in the water column because of their morphology and suggested that pelagic fish traumatized by trawls in the fishing grounds were subsequently preyed upon by skates. The occurrence of pelagic preys in the diet of demersal elasmobranch species may derive from scavenging off the discard of commercial fisheries (Simpfendorfer et al 2001;Saidi et al 2009). …”