Relationship Between Cleaning Rates and Ectoparasite Loads in Coral-Reef Fishes

Individuals from 11 fish species were followed and the number of times and duration that fish were inspected by the cleaner wrasse Labroides dimidiatus were recorded around Lizard Island, Great Barrier Reef. The frequency and duration of inspection were positively correlated with the mean parasite load and mean surface area of the 11 fish species. Surface area, however, explained slightly more of the variation in inspection frequency and duration among species than did ectoparasite load. This suggests surface area may be useful for predicting the cleaning rates of fish species. When the frequency and duration of inspection were corrected for mean surface area and mean ectoparasite load, differences among fish species disappeared. Observations of 3 size classes from 1 fish species, Hemi gymnus melapterus, revealed that larger fish, which have more parasites, were inspected more often and for longer periods than smaller fish with fewer parasites. The fact that fish with more parasites are cleaned more suggests that parasites play an important role in fish cleaning interactions