Fish cleaning behaviour in Noumea, New Caledonia

Fish cleaning behaviour was quantified at Noumea, New Caledonia, for compar ison with other studies, using a combination of cleaner fish diet analyses, client (host) parasite analyses, and observations of the cleaning rates of cleaners and client fish. Most (91%) of the items in the diet of the clean er wrasse Labroides dimidiatus were parasitic gnathiid isopod larvae (165 /- 22 gnathiids per gut, mean +/- s.e.) which made up most of the biomass ( 12.8 g). Gnathiids were common on the client fish Hemigymnus melapterus and Scolopsis bilineatus with 88% and 55% respectively infested with gnathiids . L. dimidiatus spent 26% of its time inspecting large numbers of fish (59. 5 +/- 5.1 fish per 15 min observation). H. melapterus was regularly cleaned by L. dimidiatus (2.5 +/- 0.5 times for 17.5 +/- 2.5 s per 30 min observat ion period). The cleaning rates of cleaners and clients are comparable to t hose found at Lizard and Heron Islands, Great Barrier Reef, Australia (1000 km apart), whereas the biomass of gnathiids was lower than at Lizard I. bu t higher than at Heron I., suggesting that the role of gnathiids in cleanin g behaviour is widespread but variable.