Reduced growth, body condition and foot length of the bivalve Austrovenus stutchburyi in response to parasite infection

Abstract

Parasites often have direct impacts on their host physiology or function, which can in turn have indirect effects on interspecific interactions and ecosystem structure. The present study investigates the effect of trematode parasite infection on the ecologically and commercially important venerid clam Austrovenus stutchburyi. Although the indirect impacts of clam infection on the broader benthic community, mediated by impaired burrowing of parasitized clams, have been well documented before, the more direct impacts on the clam itself remain poorly studied. The consequence of parasite infection on clam growth rate, mortality, body condition and foot length was quantified in a three-month laboratory experiment, in which juvenile clams were infected with varying levels of the echinostome trematode Curtuteria australis. Although mortality was unaffected by parasite infection, greater numbers of parasites deleteriously affected the growth rate, body condition and foot length of clams. This may result in delayed maturity and a lower filtration rate for infected individuals, as well as a reduced ability to bury into the sediment. Consequently, increased parasite infection not only has subsequent broader impacts on the surrounding ecological community, but can also affect the clam host directly and lower its value as a harvested species.