Parasites and Other Associates of Whale Sharks

There is very little known about the parasites and pathogens of the world’s biggest fish; there are no publications about viruses, bacteria, fungi or protistan parasites that live in association with whale sharks and only a handful about their metazoan parasites. These include three copepods, one isopod, one digenean flatworm, one rather dubious record of a tapeworm, and an opportunistic leech infection. These certainly do not constitute the entire parasite fauna, but, rather, they reflect the drastic under-sampling of whale sharks. That situation is unlikely to be rectified due to the lethal nature of sampling for many of these organisms, which is not generally possible for an endangered species and so requires opportunistic sampling of stranded animals. There are also other animals, primarily bony fishes, that associate with whale sharks but are neither their predator nor their prey. Many of these appear to use the massive bodies of whale sharks for protection, to travel efficiently or to facilitate their own foraging and feeding behaviors. The precise nature of these relationships deserves dedicated study because some of them seem to be quite complex and nuanced. This chapter reviews published studies on parasites, pathogens and facultative associates of whale sharks.