Dr. George-Nascimento-Failla, Mario

A new species, Hemipera cribbi sp. nov., is described. This trematode was found in three intertidal fish species: Scartichthys viridis (Valenciennes) (Blenniidae), Gobiesox marmoratus Jenyns (Gobiesocidae) and Myxodes viridis Valenciennes (Clinidae) from the central and southern coast of Chile. Of 233 individuals of S. viridis from the central coast examined, 19 were infected. From the southern coast, nine individuals of S. viridis (one infected), five individuals of G. marmoratus (four infected), and 16 individuals of M. viridis (one fish infected) were examined. Hemipera cribbi sp. nov. is distinguished from the five other congeneric species mainly in the body size, being the smallest and narrowest species in the genus, reaching five times longer than wide. This is the first species of the genus described for the South Pacific Ocean off South America. ITS2 rDNA sequences of Hemipera cribbi sp. nov. from each host and locality were identified.

Research using parasites infish population studies in the South Eastern Pacific (SEP) is summarized. There are 27 suchstudies (snapshots mainly) in single host species sampled at different geographic localities and at somewhat similar times.They have been devoted mainly to economically important species, though others on coastal and intertidalfish or on less- ornon-commercial species provide insights on scales of temporal and spatial variation of parasite infracommunities. Later, weassess whether the probability of harbouring parasites depends on the host species body size. Our results indicate that astronger tool forfish population studies may be developed under regular (long term) scrutiny of parasite communities,especially of smallfish host species, due to their larger variability in richness, abundance and total biomass, than in largefishspecies. Finally, it might also be necessary to consider the effects offishing on parasite communities as well as the naturaloscillations (coupled or not) of host and parasite populations.