Parasite community similarity between four Irish lakes

A total of 140 trout were examined from four lakes in north west Ireland, L oughs Craghy, Waskel, Meela and Owennamarve. Eleven species of metazoan par asite were recorded, ten of which were of freshwater origin and Anisakissp. was the only marine species. No acanthocephalan species were found. Diphyl lobothrium ditremum, D. dendriticum and Anisakissp. were the only allogenic species. Lough Owennamarve had the largest component community with nine s pecies recorded. Lough Meela, the only brackish water lake had the smallest component community with six species recorded. Lough Waskel and Craghy had intermediate component community values. Lough Meela showed the lowest lev els of similarity to any of the other lakes. Values for the Shannon-Wiener diversity index were highest for Lough Owennamarve and lowest for Lough Mee la and intermediate for the other two lakes. Lough Meela had the highest va lues for the Simpson's dominance index and the Berger-Parker index. Lough O wennamarve had the highest Brillouin's index and Lough Meela had the lowest . The use of multiple regression techniques to control for the potentially confounding effect of geographical distance as a predictor of community sim ilarity was discussed. No parasite species found could be considered as reg ionally and locally abundant and therefore described as a core species. The helminth community appears to have some degree of predictability, but chan ce colonization events are also important.