Given the great overfishing of the demersal resources in the Northern Adriatic Sea (geographical sub‐area [GSA] 17), along with the fishing pressure in marine habitats, evidence strongly supports the need to evaluate appropriate management approaches. Several fishing activities operate simultaneously in the area, and the need to minimize conflicts among them is also a social concern. We applied a spatially and temporally explicit fish and fisheries model to assess the impact of a suite of spatial plans suggested by practitioners that could reduce the pressure on the four demersal stocks of high commercial interest in the GSA 17 and that could promote space sharing between mutually exclusive activities. We found that excluding trawlers from some areas has lowered the effective fishing effort, resulting in some economic losses but providing benefit to the set netters. Not every simulated fishing vessel is impacted in the same way because some fishing communities experienced different economic opportunities, particularly when a 6‐nautical mile buffer zone from the coast was implemented in the vicinity of important fishing grounds. Along this buffer zone, the four stocks were only slightly benefiting from the protection of the area and from fewer discards. In contrast, assuming a change in the ability of the population to disperse led to a large effect: Some fish became accessible in the coastal waters, therefore increasing the landings for range‐limited fishers, but the discard rate of fish also increased, greatly impairing the long‐term biomass levels. Our evaluation, however, confirmed that no effort is displaced onto vulnerable benthic habitats and to grounds not suitable for the continued operation of fishing. We conclude that the tested spatial management is helpful, but not sufficient to ensure sustainable fishing in the area, and therefore, additional management measures should be taken. Our test platform investigates the interaction between fish and fisheries at a fine geographical scale and simulates data for varying fishing methods and from different harbor communities in a unified framework. We contribute to the development of effective science‐based inputs to facilitate policy improvement and better governance while evaluating trade‐offs in fisheries management and marine spatial planning.

Natural populations of Aurelia aurita scyphopolyps, settled on a wreck in the northern Adriatic Sea, were monitored for 22 months in order to study their seasonal cycle. The trend of Aurelia polyps is strongly dependent on water temperature with a peak of abundance in summer and low densities in winter. The strobilation process occurs only once a year, during the cold season, and the estimated number of released ephyrae is 780,000–2,600,000/m². The species has been recorded only on the iron wreck while it is completely lacking from the close rocky cliff of Conero Promontory, suggesting that the increase of underwater structures of anthropogenic origin could be related to the increases of jellyfish biomass.