Project 95 / 19 IFREMER - CE
Project 95 / 54 IEO - CE
Project 95 / 65 SIBM - CE
Project 95 / 27 NCMR - CE

The Medits programme is an international bottom trawl survey in the Mediterranean. It has been designed from a European Commission’s initiative to produce biological data on the demersal resources along the coasts of the four Mediterranean countries of the European Union (Spain, France, Italy and Greece). The main objective was to obtain independent knowledges useful for the fishery management, in an area where it is difficult to follow in detail the exploitation patterns of the fishing fleets. The programme began in 1993 and, for now, four annual surveys have been conducted. Since 1996, the programme covers almost all the Adriatic sea owing to the participation of scientists from the Balkan countries (Albania, Croatia and Slovenia). Involving about twenty institutes and laboratories from the seven participating countries, the programme is the first one which produces such common data at this scale in the Mediterranean, covering all the trawlable areas on the shelves and the upper slopes (at depths from 10 to 800 m) and using the same standardized protocol. During each survey, about one thousand hauls are carried out. At the end of each survey, all the data are combined and a working group produces standardized analyses on the abundance and the length distribution of around thirty reference species. The development of further data analyses from the first four surveys (1994 to 1997) will be incited through a symposium which will be held in 1998.

This report presents the works done inside the programme during the years 1996 and 1997. It contains all the available information linked with the conditions whereby each of the surveys have been carried out and the first general biological results obtained by that way. To make easier the consulting of the information, the documents are divided into two reports for each survey: one Technical report and one Biological report.

During the last two years (1996 and 1997), the contribution of each of the partners continued to strengthen due to the development of their experience in this common work. As the first objective of the programme was to produce a common data bank, efforts have been conducted to maintain and develop the quality of this data bank. Therefore, routine checking procedures have been introduced for the verification of the data. Furthermore, the common annual analysis of the biological data organized each year during a working group strongly contributes to the validation of the data.

The results obtained during the last two years confirm the general trends identified during the previous years on the geographical and bathymetric distribution of the thirty-one reference species. In addition, as a series of four years is now available for the main areas covered by the surveys, first indications have been obtained on the year to year variations in the abundance of these species. So for some important species like Merluccius merluccius , very big changes may occur between the areas and the years, illustrating the very wide diversity of the situations between the different places. Furthermore, it appears that those variations are very different from one species to another one, not permitting to identify in such a short period a general trend on the condition of the demersal resources in the Mediterranean.

The present data bank has to be considered as a first step to promote the development of local and general analysis of those fishery resources in the future. To progress in that direction, the partners of the programme have prepared an important contribution to the symposium on Assessment of demersal resources in the Mediterranean and the adjacent Seas which will be held in Pisa (Italy) in March 1998.

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