Abstract
M.Sc.
Representatives of the genus Argulus (Crustacea: Branchiura) are ectoparasites
of marine, brackish and freshwater fish. A survey of the literature revealed that more than 20 species of the genus are endemic to the African continent. Information on some of the species is extremely meager. Because of a need for a single reference that would present the basic data on the African argulids in a concise and systematic manner, a
compendium was compiled of the taxonomic characteristics of all the endemic as well as one alien Argulus species which occur in Africa. The occurrence and distribution of these species are also given. Some discrepancy in terminology was found e.g. in the designation of cephalic appendages, the armature of the carapace, the thoracopods and, in the accessory appendages that are used in copulation. Subsequently, a
glossary of technical terms were compiled for the genus Argulus in order that uniform descriptions of morphological structures can be given. Argulid ectoparasites were collected in various impoundments in the Transvaal. All the specimens collected were identified as Argulus japonicus Thiele, 1900. Argulus japonicus affected a broad spectrum of fish hosts. A survey was carried out in Lake Barberspan and Bloemhof Dam in which site selection on hosts was studied and infestation statistics were compiled. The fishlouse A. japonicus is an opportunistic ectoparasite which was
probably introduced by introductions of exotic fish. This alien fish parasite was associated with mortalities of rainbow trout, Salmo gairdneri, in an aquaculture system in the Transvaal. A morphological study was carried out on adult, male and female, specimens collected from the Transvaal. This study, the first scanning electron
microscopy investigation on any argulid specie as yet, elucidated morphological structures as well as ultrastructures not previously reported.