Résumé
The Marine Reserve of Cerbère-Banyuls, like the whole of the Marine Protected Areas (MPA) from the Western Mediterranean, represents a refuge for dusky grouper populations. Since the installation of the moratorium prohibiting its fishing in 1993, the density of population increase regularly (7 in 1985, 50 in 1998 and 193 in 2001). For a few years, the interest of scientists has been growing (observations of reproductive behaviours, density surveys) (Culioli and Quignard, 1999 ; Garcia-Rubies et al., 1999 ; Harmelin et al., 2002 ; Lenfant et al., 2003). However, a lack of knowledge is evident on the behaviour of the dusky grouper, in particular during the winter period. We carried out a survey by acoustic telemetry on 6 groupers between September 2005 and June 2006. This method, which allows the data acquisition of continuous detections over a long period (several months), showed (i) a strong sedentary behaviour of largest individuals and (ii) a high sensitivity to variations of environmental conditions (storms). In term of patrimonial species management like for the dusky grouper, a sedentary behaviour consolidates and encourages the conservation and the protection of the essential habitat of this species. However, it seems that a part of the population does not adopt this sedentary behaviour throughout the year. They begin to colonise sites outside the marine reserve.