[Ethology of the Mediterranean blenny Blennius rouxi Cocco 1833].

The Mediterranean blenny Blennius rouxi has been studied mainly in the Banyuls-sur-Mer region. Data on its behaviour have been obtained by skin diving, SCUBA diving and observations in captivity. At Banyuls-sur-Mer Blennius rouxi lives at a depth of 1 to 42m. As an exception among Mediterranean blennies, Bl. rouxi feeds by grazing off the substrate. Algae, sponges and polychaetes (Sedentaria) are the main components of its food (HEYMER and ZANDER, in press). We could not confirm that the colouration, a white body with a conspicuous dark horizontal band, can be regarded as a signal of cleaning activity in statu nascendi. The male male have a spatial territory in which they occupy haptic holes. The female female lead a vagabond life and actively join the male male in their territories during the breeding season. Head nodding is an agonistic behaviour against other female female and has an attractive significance for spawning-motivated female female. The male male threaten with a widely opened mouth (threat yawning). Our data and observations on the ethology of Bl. rouxi are discussed and compared with those known of Bl. sphinx, Bl. incognitus, and Bl. zvonimiri, its nearest relatives.