An international bottom trawl survey was designed from a European Commission´s initiative to produce biological data on the demersal resources in the Mediterranean Sea. Nine Mediterranean countries are associated in the programme, which covers all the trawlable areas along their coasts from 10 to 800 m depth. From 1994 to 2000, one survey was carried out each year, applying common standardized protocols. Seven yearly surveys have therefore been done, with a total of 7,500 stations prospected. This paper presents the methods adopted to carry out the surveys.

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The distribution and abundance of large marine debris were investigated on the continental slope and bathyal plain of the northwestern Mediterranean Sea during 3 oceanographic cruises undertaken in June 1994, July 1995 and April 1996. Different types of debris were enumerated, particularly pieces of plastic, plastic and glass bottles, metallic objects, glass and diverse materials including flshing gear. The results showed considerable geographical variation, with concentrations ranging from 0 to 78 pieces of debris ha-' In most stations sampled, plastic bags accounted for a very high percentage (more than 70%) of total debrls. In the Gulf of Lions, only small amounts of debris were collected on the continental shelf. Most of the debris was found in canyons descending from the continental slope and in the bathyal plain, with high amounts occurring to a depth of more than 500 m. An additional cruise was undertaken using the manned submersible Cyana (provided by IFREMER). Sixteen dives (46.07 km distance on the floor) conducted in canyons off Marseilles and Nice (France) ranging from 40 to 1448 m in depth, enabled us to locate accumulation areas. All these results are interpreted in terms of hydrological conditions.

We present a method for combining individual indicator results into a comprehensive diagnostic of fishing impacts on fish populations and communities. A conceptual framework for interpreting combined trends in a set of simple indicators is proposed, relying beforehand on qualitative expectations anchored in ecological theory. The initial state of the community is first assessed using published information. Which combinations of trends are acceptable or undesirable is decided, depending on the initial status. The indicators are then calculated from a time-series and their time trends are estimated as the slopes of linear models. Finally, the test results are combined within the predefined framework, providing a diagnostic on the dynamics of fishing impacts on populations and communities. The method is demonstrated for nine coastal and shelf-sea fish communities monitored by French surveys. Most communities were persistently or increasingly impacted by fishing. In addition, climate change seems to have contributed to changes in East Atlantic communities. Cet article propose une méthode utilisant des indicateurs pour élaborer un diagnostic sur les effets de la pêche sur les populations et les peuplements de poissons. Un cadre conceptuel permet d'interpréter les tendances conjointes d'indicateurs à partir de la théorie écologique. L'état initial du peuplement est d'abord évalué sur la base d'informations publiées. En fonction de l'état initial et des objectifs de gestion, les combinaisons des tendances sont qualifiées d'indésirables ou satisfaisantes. Les indicateurs sont ensuite estimés à partir de données de campagnes de pêches scientifiques: abondance et longueur moyenne d'une sélection de populations, nombre, biomasse totale, poids moyen et longueur moyenne dans le peuplement, et la pente du spectre de taille multispécifique. Les tendances temporelles de ces indicateurs sont testées au moyen d'un modèle linéaire, et les résultats des tests sont combinés en un diagnostic final. La méthode est mise en œuvre pour neuf peuplements de poissons côtiers et du plateau continental, suivis par des campagnes françaises. Il en résulte que la plupart de ces peuplements sont affectés par la pêche de manière stationnaire ou croissante. Par ailleurs, les changements climatiques dans l'Atlantique Nord-Est contribuent aussi à des modifications dans les peuplements de poissons de cette région.

We examine the variation in condition of ten exploited fish species as an indicator of large-scale habitat quality in the northwestern Mediterranean. To determine fish condition, we used morphometric (Fulton's K) and physiological (hepatosomatic, HSI; digestivesomatic, DSI; and gonadosomatic, GSI) indices. Generalized linear models (GLMs) were applied to assess the influence of depth, latitude, length, year, sex and reproductive status on condition. The GLMs incorporating all independent variables accounted for between 25 and 74% of the variance in Fulton's K condition factor, 15-77% of the variance in HSI, 14-35% of the variance in DSI, and 77% of the variance in GSI. The mean condition factor of the species studied showed considerable interannual fluctuations along with an increasing trend over the time series (1994-2001). Length is an important explanatory variable in explaining condition of fish species. Condition typically increased with fish length and explained 72% of the deviance in GSI of M. barbatus. For some species, there were differences in condition due to sex and reproductive status, with adults being usually better in condition than juveniles and, among adults, females better than males. The influence of latitude and depth on condition of a given species varied according to the index used to assess condition. When there was a significant effect, fish with the highest condition factor, HSI and/or DSI inhabited the shallowest and northernmost parts of the area of study. Considering that condition influences growth, reproduction and survival of fish, our results support the importance of shallow habitats to productivity of demersal stocks in the Mediterranean Sea.