Fishery reserves in the Mediterranean Sea: the Gulf of Castellammare case study

The effects of fisheries management based on artificial reefs and on trawl banning are explored in the Gulf of Castellammare fishery reserve by means of biological (from trammel and trawl survey) data collected during several research programs between 1990 and 2001. The artificial reefs have caused an increase of diversity but not of biomass, as suggested by the comparison between the associated fish assemblage and that of nearby sandy bottoms. The associated species however do not have any trophic relation to the boulders, except the twobanded seabream, Diplodus vulgaris. An overall increase of experimental trammel net yields in the artificial reef area was observed from 1990 to 1998, due mainly to pelagic species associated with the boulders. The trawl ban caused a dramatic increase of groundfish biomass in the protected area (+711% after four years, total species). Different species had different increase rates, from 2-fold for the musky octopus, Eledone moschata to 127-fold for the gurnard, Lepidotrigla cavillone. Eight and ten years after the ban started, the yields did not vary significantly in the overall area, but decreased near to (both outside and inside) the protected area, probably due to increased legal and illegal trawling. The mean size did not increase in three studied species, except for the monkfish, Lophius budegassa. In conclusion the Gulf of Castellammare fishery reserve is considered a positive example of marine coastal fisheries management, especially considering the effects of the trawl ban on the abundance of groundfish stocks, although the cooperation between scientists and administrative bodies is still far from optimal.