Keywords: Demersal fisheries - Indicators - stock assessment - Fishery management - Models - Adriatic Sea - Mediterranean Sea

Abstract

This paper analyses the state of trawl fisheries in the Southern Adriatic Sea (FAO Geographical Sub Area 18) from a biological, economic and social point of view. The analysis was performed using a set of forty-six indicators, twenty-one of which belong to the category of biological (population and community) indicators to be obtained from fishery-independent data and the remaining twenty-five are of socio-economic nature and of fishery-dependent origin. Biological indicators and relative estimators were classified for the single species (population level: Eledone cirrhosa, Eledone moschata, Illex coindetti, Merluccius merluccius, Mullus barbatus, Nephrops norvegicus, Parapenaeus longirostris, Raja clavata, and Zeus faber) as well as for the multispecies approach (community level). Economic indicators include six indicators on economic performance, eight on productivity, four on costs and prices, and one general indicator summarising economic sustainability. From the social point of view, five indicators plus one general indicator summarising social sustainability are defined. Particular attention was devoted to the selection and analysis of sustainability indicators. The standard distinction among biological, economic, and social sustainability has been held in this paper. Trends of these indicators were analysed using the so-called Traffic light system. Reference values were set according to their percentile value in the following series: > 66th percentile, 66th-33rd, and < 33rd percentile. Based on each specific indicator, the three standard colours, green, yellow, and red, were assigned to the three areas defined by the reference values at 33rd and 66th percentiles. The analysis was performed by using data available from the MEDITS surveys project and from IREPA monitoring system in the basin concerned. The period under consideration goes from 1996 to 2003. The inclusive discussion of the results from both fishery-independent and fishery-dependent data analysis underlines some common features. In fact, an apparent and progressive deterioration seems to affect the trawl fishery system in the GSA 18 during the investigated period, according mainly to the variation in catch composition (increasing of r-strategist species and decreasing of k-strategist ones) and to the trajectories of some socio-economic indicators.