INSIGHT INTO THE DIET COMPOSITION AND GASTROINTESTINAL PARASITE COMMUNITY OF THE COMMON SMOOTH-HOUND, MUSTELUS MUSTELUS (CARCHARHINIFORMES: TRIAKIDAE), IN THE NORTHERN ADRIATIC SEA

We examined gastrointestinal tracts from 15 sharks, common smooth-hound (Mustelus mustelus), sampled between December 2005 and April 2007 by bottom trawls operating in the northern Adriatic Sea, and analysed diet composition and infestation levels of gastrointestinal helminth parasites. Decapod malacostracans were the dominant prey group (Index of Relative Importance, %IRI = 84), with Liocarcinus corrugatus, L. depurator and Pilumnus sp. as the most frequent prey (Frequency of occurrence, %F = 20 - 33). The second highest ranked prey group were ray-finned fish (%IRI = 9.5), represented mostly by Engraulis encrasicolus (%F = 13.3), while the third prey group were cephalopods (%IRI = 6.0), consisting mainly of Sepia elegans. Parasitological examination revealed 377 parasite specimens in 13 infected sharks (Prevalence, P = 86.7%), with a mean intensity (I) of 29 helminths per host. Nematode Cucullanus micropapillatus was the most prevalent (P = 60.0%) and dominant parasite (I = 26.9), recorded with 242 specimens. Trematode Ptychogonimus megastomum was recorded in 3 sharks (P = 20.0%) and numbered 89 individuals, while cestodes were represented by genus Eutetrarhynchus and genus Phyllobothrium, although in low prevalence (both P = 13.3%) and with only few individuals (I = 0.3 and 1.1, respectively).