RELATIVE IMPORTANCE OF CLEANING BEHAVIOR IN CENTROLABRUS-EXOLETUS ANDOTHER WRASSE AT ARRABIDA, PORTUGAL

Underwater behavioural observations were conducted to evaluate the rel ative importance of cleaning behaviour in three species of common nort h-eastern Atlantic wrasse (Teleostei: Labridae). At the study site, th e only cleaner was Centrolabrus exoletus. A total of 12 species was cl eaned, with the wrasse, Symphodus melops and Labrus bergylta being the species most frequently cleaned. Neither S. melops nor Ctenolabrus ru pestris, known to be cleaners in other sites or in captivity, could be observed cleaning other fishes. Centrolabrus exoletus was found to be a facultative cleaner fish with cleaning acts representing only 7% of the observed feeding acts. In focal observations of host fishes, the incidence of cleaning acts reached a level (11 h(-1) per host) similar to that reported for tropical reef fishes and probably reflects the h igh numbers of cleaners available. Some factors that may affect the or igin of the cleaning interactions are discussed.