The role of fisheries and the environment in driving the decline of elasmobranchs in the northern Adriatic Sea

Elasmobranch populations are declining worldwide, calling for urgent assessment of fishery exploitation and application of effective conservation\udstrategies. Here, we applied a novel approach, integrating long-term time-series of landings (1945–2012) and extensive surveys at\udthe fishmarket of Chioggia, Italy, home of themajor fishing fleet of the northern Adriatic Sea, to evaluate the status of elasmobranch populations\udand fisheries in the one of the most fished Mediterranean basins. The time-series highlight a dramatic decline in elasmobranch landings,\udparticularly for skates and catsharks (Scyliorhinus spp.), whose current catch rates are 2.4 and 10.6% of the average 1940s levels,\udrespectively. These data likely reflect similar large reductions in abundance, as indicated by the analysis of catch-per unit-effort timeseries.\udThe biomass of landed skates and catsharks showed regular fluctuations that disappeared after the collapse of the landings.\udElasmobranch market composition, assessed through the sampling of 11 900 specimens from 2006 to 2013, included 14 species, but\udwas dominated by just two: Mustelus mustelus and M. punctulatus, which represented more than 60% of the catch. The proportion of sexually\udimmature individuals was generally very high, up to 83%of landed females and 71% of landed males, depending on the species. Although\udsome correlations were detected between landings and local hydrography or climatic indices, the analyses of landings and surveys at the fish\udmarket identified fishery exploitation as the main driver of the striking, long-term elasmobranch decline in the northern Adriatic Sea, calling\udfor urgent management actions to improve the conservation status of these fish