IMPACT OF TRAWLING ON DEMERSAL COMMUNITIES AND PRODUCTIVITY OF FISHERY RESOURCES IN SICILIAN WATERS

Abstract

Comparing areas subject to different fishing pressures is one of the approaches used to assess the impact of trawling on demersal communities. The present research was conducted within the ISPRA-IRBIM 2020 Convention aimed at implementing the EU Marine Strategy Directive (2008/56/EC) and related to the study of seabed integrity and epimegabenthic communities in two areas of the Strait of Sicily under bottom trawling disturbance. In particular, new data on richness and biodiversity of demersal communities, and abundance and demography of the main target species exploited by demersal fisheries in two areas similar in bathymetry and substrate, but subject to different trawling effort (area L with low effort, corresponding to the GFCM Fishery Restricted Area of Gela and area H with high effort) were collected. In general, Area L shows greater specific richness and biodiversity than Area H. In terms of fishery resources, red mullet was found to be significantly more abundant in Area L than in Area H, which is characterized, on the other hand, by higher abundances of European hake and deep-water rose shrimp. The sizes of red mullet, Atlantic horse mackerel, and deep-water rose shrimp were significantly higher in area L, while European hake showed no differences between the two areas. The results obtained confirm the impact of trawling on specific richness and biodiversity of communities and, except for European hake, on the bony fish component of demersal resources. A higher numerical abundance in Area H of deep-water rose shrimp, an r-strategy species (rapid growth and early sexual maturity), should be noted. Given the increasing concerns towards the protection of ecologically critical areas, the information here presented contributes to the identification of spatially based management measures for fisheries that balance conservation needs with those of productive use of marine resources.