A tropical assemblage of ectoparasites: gill and head parasites of Lethrinus miniatus (Teleostei, Lethrinidae).

Aspects of the community ecology of metazoan ectoparasites of Lethrinus miniatus (Teleostei. Lethrinidae) from 3 localities on the Great Barrier Reef were examined. Twelve species of Monogenea, 6 of Copepoda, 2 species of adult and several larval Isopoda and 1 leech were found. Total parasite numbers reach 3500 per host, and prevalence of infection with a particular parasite species reached 100% in some species. Numbers of parasite species per fish varied from 5 to 11. Four parasite species were most dominant on different fish if intensities of infection were used to calculate dominance, one species representing about 80% of all parasite individuals on a particular fish at 2 localities and about 50% at the third locality. Ten parasite species were most dominant on different fish, if volume (biomass) was used for calculating dominance, one species representing about 55% at one and 80% of total parasite volume at 2 localities. Parasites included at least 12 congeneric species of 4 or more genera, and those (of 2 genera) occurring on the gills showed much overlap in their distribution. Congeneric Monogenea of the families Dactylogyridae and Diplectanidae occurring in the same sites differ markedly in the size and structure of their copulatory sclerites. Positive associations between species were much more common than negative ones. The bony parts of the gills (gill arches) were never found to be infected, indicating the availability of empty niches.