Seasonal estimates of densities and predation rates of cetaceans in the Ligurian Sea, northwestern Mediterranean Sea: an initial examination

The Ligurian Sea is one of the most attractive areas for cetaceans in Mediterranean Sea, and now included a Marine Protected Area, Pelagos Sanctuary. Despite lower species diversity than other parts world, because their abundance, are thought to represent significant consumers this ecosystem. Surveys were conducted within Sanctuary from 2001 2004. Densities five species: striped dolphin (Stenella coeruleoalba); fin whale (Balaenoptera physalus); sperm (Physeter macrocephalus); long-finned pilot (Globicephala melas); Risso’s (Grampus griseus), estimated converted biomass. Total biomass density was as 93kg km-2 (CV=28%) winter (October March) 509kg (CV=16%) summer (April September). Daily predation rates by 2.9kg d-1 winter, increasing 10.4kg summer, corresponding total annual ingestion 2.4t y-1. primary production required be 12.6gC m-2 y-1, 6- 15% net known area. Estimated cetacean on fish similar reported fisheries landings, nevertheless, management artisanal accurate quantification resources they exploit will necessary responsible Area.