TRICHODINIDS (CILIOPHORA, PERITRICHIA) FROM A CALANOID COPEPOD AND CATFISH FROM SOUTH-AFRICA WITH NOTES ON HOST SPECIFICITY

A case study is presented in which a trichodinid infestation was found on Clarias gariepinus (Burchell, 1822) larvae in a hatchery. Upon examination of copepods in the water system, it was found that they too hosted this trichodinid species. After following the infestation for some time it was found that the trichodinids on the catfish disappeared, whilst the infestation on the calanoid copepods persisted. It was concluded that the trichodinid originated from the copepods and could not establish a viable infestation on the catfish larvae. Specimens of catfish fry from the same farm, however, hosted a different trichodinid which is described as a new species. After analysis of published information, it was concluded that the trichodinid from these calanoid copepods belongs to the same species as described by different authors from various localities from Eurasia. In order to provide a specific identification of this trichodinid, a literature review is presented. In a discussion of host specificity, it is concluded that the trichodinid involved is specific to planktonic copepods and cannot establish an infestation on fish.