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Issue Aquat. Living Resour. Volume 11, Number 2, March 1998 Page(s) 75 - 85 DOI 10.1016/S0990-7440(98)80063-6

Aquat. Living Resour. 11 (1998) 75-85
DOI: 10.1016/S0990-7440(98)80063-6

Stability of spatial structures of demersal assemblages: a multitable approach

Jean-Claude Gaertner¹, Daniel Chessel² and Jacques Bertrand<sup>3

1</sup>  IFREMER, Laboratoire d'Ecologie halieutique, 1 rue Jean Vilar, BP 171 34203 Sète cedex France
²  Laboratoire d'Ecologie des eaux douces et des grands fleuves, URA CNRS 1451, Université Lyon 1 69622 Villeurbanne cedex France
³  IFREMER, Laboratoire Ressources halieutiques, 1 rue Jean Vilar, BP 171 34203 Sète cedex France

(Received 10 October 1997; accepted 16 February 1998. Available online 11 November 1999.)

Abstract
The present work is based on a set of bottom trawl surveys performed in the Gulf of Lions between 1983 and 1992. A new method which couples the STATIS multitable approach with the logic of correspondence analysis (CoA) is proposed to study the stability of spatial organization of demersal assemblages in terms of species composition. This CoA version of STATIS has provided a clear representation of the stable part of the spatial structure of the assemblages. In addition, it gave an insight into the interannual variations of the distribution of each population around the reference structure. Our results showed that the demersal assemblages of the Gulf of Lions exhibited bold spatial structuring, mainly orientated along a bathymetric gradient. This gradient is structured around three major regions: the coast, the continental shelf and the continental slope. Despite sampling variations that occurred during the course of the study, the analysis showed a high degree of reproducibility for this spatial pattern. With the exception of Mullus surmuletus, the species considered in this investigation exhibit limited variations in their spatial distribution. Finally, in the absence of log-books covering the activities of commercial fishing vessels, these findings constitute a base of reference for the analysis of the dynamics of fishing fleets exploiting the demersal resources of the Gulf of Lions.

Key words: Fish assemblage / trawl surveys / multitable analysis / correspondence analysis / Mediterranean sea / stability / spatial structure


© Elsevier, IRD, Inra, Ifremer, Cemagref, CNRS 1998

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