1 ICES CM 2005/BB:11 Comparison between trophic models of protected and fishing areas for an ecosystem approach to fisheries in Adriatic Sea Simone Libralato 1,* , Marta Coll 2 , Alberto Santojanni 3 , Cosimo Solidoro 1 , Enrico Arneri 3 and Isabel Palomera 2 1 Istituto Nazionale di Oceanografia e di Geofisica Sperimentale  OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico (TS), Italy 2 Institut de CiLnces del Mar, CMIMA-CSIC, Passeig Martim de la Barceloneta, 37-49, 08003 Barcelona, Spain 3 Istituto di Scienze Marine (CNR), Sezione Pesca Marittima, Largo Fiera della pesca, 2 - 60125 Ancona, Italia Italy Abstract The Adriatic Sea is one of the most productive areas in the Mediterranean basin. Because of this, an ecosystem based approach to fisheries management seems particularly appropriate, since it allows to account for the effects of both fishing and environmental pressures, along with their indirect and cascading effects on the trophic web. Mass-balance models, although static pictures of the ecosystem, can be a valuable tool in giving information on structure and functioning of the ecosystem, in evidencing effects of fishing and in allowing inference on management options at ecosystem scale. Comparison between models of exploited and non-exploited sub-systems can offer valuable insight, too. Here we compare two ecological models describing a protected and a non protected area for the same ecosystem, i.e., the Adriatic Sea. The former represents the MPA of Miramare (Gulf of Trieste, Italy). The latter represents the fished North and Central Adriatic Sea. The study is the first example of this kind of comparison in the Mediterranean Sea. In order to have meaningful result, model first were standardized and then compared on the basis of biomass and flows of production and consumptions aggregated into integer trophic levels and analyzed in terms of their trophic spectra. The comparison evidences similarities between the two food webs and differences due to intrinsic features of both areas. However, differences in the functional role of analogous trophic groups and in ecosystem structure are also highlighted, thus indicating functional changes that fisheries might have induced. Analyses applied to the exploited ecosystem model highlights the effects of fishing on target and non target species, and results are discussed in relation with the observations on the MPA model. Keywords: ecosystem approach to fisheries; fisheries impact; fisheries management; ecological models; marine protected area; Adriatic Sea. * Contact author: Simone Libralato: Dept. Oceanography, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale – OGS, Borgo Grotta Gigante 42/. 34010 Sgonico (TS), Italy [tel: +39 040 2140376, fax: +39 040 2140266, e-mail: slibralato@ogs.trieste.it ]