A survey of the metazoan parasite assemblage of snoek, Thyrsites atun (Euphrasen, 1791), off South Africa with an assessment of host-parasite relationships and potential biological tags

Abstract

Parasites are a ubiquitous but often unseen, unacknowledged and understudied component of biological communities. However, their roles in structuring ecosystems, their influence on the evolutionary history of host species and their potential applications are slowly being uncovered. The snoek, Thyrsites atun, is a nomadic predator native to the cold coastal waters of the southern Hemisphere. Being a major target of the South African inshore line-fishery, the snoek is a socioeconomically important species whose ecological significance in the southern Benguela should not be underestimated. This study aimed to survey the metazoan parasite community of snoek off South Africa, assess host-parasite relationships and evaluate the potential of parasites as biological tags for stock structure studies. Examination of 210 snoek (FL 411 - 1040 mm) revealed them to be host to 16 parasite taxa. These included 9 new host records (Tentacularia coryphaenae, Caligus coryphaenae, Caligus dakari, Corynosoma australe, Nothobomolochus fradei, Hatschekia conifera, Bolbosoma vasculosum, Rhadinorhynchus cadenati, Digenea sp.) and 4 new locality records (Molicola uncinatus, Pseudoterranova sp., C. dakari, B. vasculosum). A further three cosmopolitan taxa (Anisakis sp., Kudoa thyrsites, Hepatoxylon trichiuri) as well as Caligus zei were also recorded.