ABSTRACT
The body of an elasmobranch offers a diversity of sites that can be, and often are, occupied by other animals. Indeed, essentially no organ system of elasmobranchs has escaped the attention of one or more groups of parasites (Figure 18.1). That is not to say that all sites of the body of an elasmobranch are equally parasitized. Certain organs and organ systems, such as the skin, digestive system, and gills, for example, tend to host particularly diverse faunas of parasites. Caira (1990), Cheung (1993), and Benz and Bullard (2004) have all treated the parasites of these hosts to various degrees within the last two or so decades. Although all three of these works provided overviews of the taxonomic diversity of the metazoan parasites, each emphasized a different aspect of the host-parasite relationship. Caira (1990) focused on the life cycles and utility of metazoan parasites as indicators of elasmobranch biology, Cheung (1993) included an extensive list of many of the parasite species reported from elasmobranchs, and Benz and Bullard (2004) concentrated on the pathology caused by, and treatment of, parasites, with emphasis on those harmful, or at least potentially harmful, to captive chondrichthyans. In this chapter, we have taken a slightly different approach and have treated the various parasites based on the sites they occupy within their hosts. We have concentrated on the parasitic metazoans, or multicellular parasites, because we did not feel we could do justice to the diversity of protistan (i.e., unicellular) taxa parasitizing elasmobranchs at this time. Readers interested in the protists are directed to Cheung (1993) for a list of the approximately 30 species reported from elasmobranchs. Also omitted from discussion here are the vertebrate associates of elasmobranchs such as hag-sh, lampreys, eels, etc. (e.g., Caira et al., 1997a). For comparative purposes, the metazoans of holocephalans are briey treated in the nal section of this chapter.
