Content area
Full text
Helgol Mar Res (2012) 66:295306 DOI 10.1007/s10152-011-0270-3
ORIGINAL ARTICLE
Pelagic cephalopods of the central Mediterranean Sea determined by the analysis of the stomach content of large sh predators
Teresa Romeo Pietro Battaglia Cristina Ped
Patrizia Perzia Pierpaolo Consoli
Valentina Esposito Franco Andaloro
Received: 14 March 2011 / Revised: 26 July 2011 / Accepted: 28 July 2011 / Published online: 10 August 2011 Springer-Verlag and AWI 2011
Abstract The pelagic cephalopod fauna of the central Mediterranean Sea was investigated through stomach content analyses of large sh predators. A total of 124 Xiphias gladius, 22 Thunnus thynnus, 100 Thunnus alalunga, and 25 Tetrapturus belone were analyzed. Overall, 3,096 cephalopods belonging to 23 species and 16 families were identied. The cephalopod fauna in the study area is dominated by Sepiolidae, Ommastrephidae, and Onychoteuthidae. The sepiolid Heteroteuthis dispar was the most abundant species (n = 1,402) while the ommastrephid Todarodes sagittatus showed the highest biomass. They can be considered key-species in the pelagic food web of the study area. The neutrally buoyant Histioteuthis bonnellii, H. reversa, and Chiroteuthis veranyi seem to characterize the deeper water layers. Given the difculty in sampling pelagic cephalopods, the presence of cephalopod beaks in the stomach of predators represents a fundamental tool to assess the biodiversity and the ecological importance of these taxa in the marine ecosystem.
Keywords Pelagic cephalopods Beaks Large pelagic
predators Mediterranean Sea
Introduction
Knowledge of the pelagic cephalopod community has increased over the last decades thanks to improved techniques. However, there is still a signicant lack of information on these animals biology, distribution, and importance in the food web. This is mainly due to the difculties associated with sampling, as conventional gears used in monitoring of the pelagic environment usually collect juvenile cephalopods, while adult specimens generally avoid being captured (Clarke 1996a).
Despite the difculties in sampling, the ecological importance of cephalopods in the marine ecosystem has already been emphasized by several authors (Clarke 1996b; Bustamante et al. 1998; Piatkowski et al. 2001; Velasco et al. 2001). In particular, muscular squids are able to quickly convert their food into biomass and to grow rapidly. They, therefore, represent a signicant source of energy for predators. Moreover, while most mid-water shes do not grow bigger than 200 mm in length, many pelagic...