This study investigates the conservation benefits on the demersal resources of the Maltese 25 Nautical Mile Fisheries Management Zone (FMZ) that had been established as an exclusive fisheries zone in 1971 and then as a FMZ after EU accession in 2004. First the relationships between the demersal communities, by-catch species and infauna were examined. Then the study looked at the demersal communities inside and outside the FMZ, at populations and communities within the FMZ under different intensities of trawling pressure and at the fishers' perception of the FMZ.
The commercial demersal assemblages and by-catch within the FMZ were largely
influenced by geographic location, depth and sediment characteristics. Certain areas, which had similar commercial assemblages, had different by-catch assemblages and this may imply a different feeding regime for the commercial species but these results need to be confirmed by studying the feeding habits of selected commercial species. The infauna was spatially very variable and this may be due to the low abundance of infauna ca. 64 ind/m² and the low number of replicates. The demersal fishery resources on the muddy bottoms of Maltese trawling grounds inside and outside the FMZ are stratified in four main depth ranges: 83-166 m (continental shelf), 140-230 m (shelf break), 270- 440 m (shallow slope), and 466-701 m (deep slope). For the continental shelf significant differences were detected between the inside and outside stations of the FMZ
with the inside stations having twice as much biomass and larger individuals of some species (e.g. elasmobranchs) than those outside. The depth strata identified also do not coincide with those sampled in the existing trawl survey programme MEDITS in the Mediterranean, which were set up without reference to demersal assemblage structure and its relation to depth and that survey design must take this into consideration.
The ecosystem effects of fishing in the Mediterranean deep sea red shrimp trawl fishery (500 - 800 m) were also investigated at the population and community level by sampling in trawled and non-trawled areas within the FMZ as determined by the Vessel Monitoring System (VMS) fishing effort data for the year 2006 and 2007. At the population level, Aristaeomorpha foliacea and Etmopterux spinax did not show any differences in biomass while the biomass of Plesionika martia, Nephrops norvegicus, Helicolenus dactylopterus dactylopterus, and Galeus melastomus was four, sixteen, six and twice respectively as much higher in the non-trawled areas. At the community level higher biomass, density and diversity indices were recorded at the non-trawled areas together with differences in community structure.
The last part of the study examined fishers' perception of the FMZ and investigated if the perceptions depend on fishers' demographic, economic, social characteristics and fishing activity of the fishers using a questionnaire survey. The perception of the commercial fishers was that the establishment of the FMZ has had an overall negative impact on their fishing activity and that the zone is not important for the protection of local fish stocks. However recreational fishers had opposing perceptions. The results suggest that the proportion of individual income derived from fishing was the strongest factor that influenced attitudinal differences. The heterogeneity among fishers' attitudes revealed by the study indicated that the implementation of spatial closures may gain inherent acceptance from some sectors of the industry, while others may require
additional incentives to accept such schemes.