Poissons et invertébrés au large des côtes de France. Indicateurs issus des pêches scientifiques. Bilan 2004

The integration of fishing management into the ecosystemic approach has been recommended for many years by international consultative bodies; it is also written into international conventions and agreements. The implementation of the ecosystemic approach involves the development of programmes for monitoring exploited ecosystems in order to measure the effects of management steps. Plotting the results of these observations for operational reasons requires formalizing summary performance indicators. IFREMER has carried out halieutic observation campaigns for some twenty years along the coasts of France from oceanographic ships and chartered ships. The objective of these campaigns is to produce abundance indices of species that are of halieutic interest. These campaigns constitute a first knowledge base for characterising and monitoring the status of exploited fish and invertebrate communities. A work group, bringing together the biologists in charge of the campaign series, biostatisticians and ecologists from IFREMER's department of Ecology and Models for Fisheries Management (EMH), developed common tools of analysis and performance indicators on the sampled populations and communities. This bulletin uses indicators of explicit interpretation and that are widely validated; it deals with the demersal biocoenoses from the plateaus of the southern North Sea to the eastern coasts of Corsica, with estuarine nursery zones of the Channel and of the Gulf of Gascony and the area around the Cape of Flamanville (Manche). It aims to give an account of the status and evolution of these ecosystems from dynamic indicators based on data from the halieutic observation campaigns guided by IFREMER. These indicators are calculated for a set of species proper to each zone. The bulletin is composed of two parts. In the first part of the document, the results obtained are presented in the form of a summarised chart by zone. These charts describe the trends of average abundance, size and weight of the monitored populations and communities. One species is presented in a more detailed way for each zone. The indices chosen were selected from among the demographic indicators known to be particularly sensitive to the impact of fishing. Interpretation of the trends that they describe must also take into account the environmental context in which the populations in question live. The second part responds to this need and presents reference points on the biogeography of the zones covered by the observation system. After a first instalment that presented the results obtained from data collected until 2002, this bulletin, "Assessment 2004", has been greatly improved by further analysis both of the species presented in a detailed and of the communities. It is thus written into the project to pursue the periodic updating of the assessment of the populations and communities that are of halieutic interest all along the coasts of France; the data from the last available campaigns are used and enriched by the use of the latest methodological development on developing indicators, validated by the scientific community.