The biology of parasites from the genus Argulus and a review of the interactions with its host

During the 20^th century crustacean ectoparasites of fish did not receive the same research focus that other piscine pathogens experienced. This has resulted in a delay in our understanding of these economically important organisms. However, it is now recognized by fin fish producers and researchers alike that parasitic lice can indeed play a significant role in the economic success of aquaculture organizations. Around the globe there are continuous reports on the deleterious effects of these pathogens on fish farm stock (e.g. Bauer, 1959; Costello, 1993; Menezes et al., 1990) and more recently on wild fish populations (e.g. Johnson et al., 1996; Poulin and Fitzgerald, 1987, 1988; Whelan and Poole, 1996). Even parasitic infections in recreational fisheries are under current investigation to evaluate the effects of such infections on fishery economics (Taylor et al., 2003). These reports have led to an increase in the number of researchers concentrating on the study of ectoparasitic crustaceans found on fish but there is still a considerable lack of knowledge in certain areas. This chapter aims to give a review on the current ecological knowledge available for the Branchiuran genus Argulus with a focus upon the general biology and parasite-host interactions.