ECOLOGICAL INDICATORS BASED ON FISHERIES LANDING TIME-SERIES DATA: AN APPLICATION TO THREE COASTAL LAGOONS IN AMVRAKIKOS GULF (E. MEDITERRANEAN, GREECE)

kThe landing time-series in Logarou, Rodia-Tsoukalio and Tsopeli lagoons (Amvrakikos Gulf, NW Greece) were analyzed for the time period 1980-2004 in order to estimate fisheries production in relation to the environmental quality and the anthropogenic pressures imposed on the lagoons. According to the findings, the fishing yields in the studied systems showed a decreasing trend. In Logarou lagoon, a decreasing trend was noticed in the mean trophic level ecological index (mTL) as well as tendency changes in the trophic structure according to the initial sigmoid shape of the relative biomass trophic level spectra (BTLS). Moreover, a 'Fishing down food web (FDFW)' effect for the period 1994-1997 was identified. Rodia-Tsoukalio lagoon complex is characterized by a constant trend of the mTL index as a result of changes in the productivity of the lagoon. In Tsopeli lagoon, the collapse of the eel production and the environmental status of the adjacent coastal area seem to predominate as a driver for the ecological index trend as no obvious source of pollution or significant trophic level composition alterations occurred in the system.