Modelling the trophic roles of the demersal Chondrichthyes in the Northern Ionian Sea (Central Mediterranean Sea)

摘要: Abstract The maintenance of natural capital and the stability regulation services marine ecosystems has proved to be linked conservation key species supporting function. Chondrichthyes are top-predators their removal from due fishing exploitation could lead changes in interactions biomass that can negatively influence provision services. ecological role demersal living food web Calabrian area Northern Ionian Sea (Central Mediterranean Sea) was analysed by means indicators derived Ecopath mass-balance models estimated stationary states during periods 1995–1997, 2003–2005 2013–2015. trophic model described 57 functional groups (7 which representing Chondrichthyes), were Biomass (t/km2), Production Consumption rate, Diet, Landings (t/km2) e Discards (t/km2). Remarkable recorded for shark rays, as a consequence patterns oceanographic regime shift named Bimodal Oscillating Systems (BiOS). Demersal occupy high positions Calabria showing levels higher than 4.1, with D. licha identified main apex predators, while E. spinax G. melastomus meso‑predators. pattern consumption flows highlighted potential sensitivity deep waters circulation caused BiOS acting on entire ecosystem Sea. keystone predators all investigated periods. analysis indirect direct impacts shows beneficial positive effects several preys. Results also showed Shelf Elasmobranchs group (e.g. Raja asterias, Mustelus mustelus, etc.…) overexploited 1995 sharks rays underwent decrease rate over time. medium-low values overlap gears (