RICHNESS AND DIVERSITY OF MACROPARASITE COMMUNITIES IN TROPICAL EELS ANGUILLA-REINHARDTII IN QUEENSLAND, AUSTRALIA

The prediction that richness and diversity of helminth communities would be greater in tropical fish was tested by analysing total and intestinal helminth communities in samples of Anguilla reinhardtii taken from 10 localities in tropical and semi-tropical freshwaters in Queensland, Australia. Comparison of findings with those from A. anguilla in the UK revealed that regional species richness was higher in Queensland and that helminth communities harboured a suite of common species, virtually all eel specialists, that were responsible for the observed higher levels of similarity between component communities. All measures of community richness and diversity adopted indicated that the poorest helminth communities in A. reinhardtii were comparable with the richest ones reported from the northern temperate A. anguilla. The richest communities in A. reinhardtii were more diverse than those reported from any other species of fish, whether marine or freshwater, to date, and were comparable with the communities found in some species of aquatic birds. Both tropical conditions and age and endemism of the host, i.e. the time hypothesis, were considered as explanations for this richness but neither could be favoured. A cautious approach to generalizations based on data from temperate regions only is advocated, and the need for more studies on tropical parasite communities is strongly emphasized.