its intermediate bird hosts (Smit et al. 2017). The low specificity of S. acheilognathi
for intermediate or definitive hosts resulted in its rapid naturalisation and spread to
fish populations throughout the country, where it now infects at least ten native fish
hosts (Smit et al. 2017).
6.2.3 Cnidaria
The Freshwater Jellyfish Craspedacusta sowerbiyi, most likely introduced into
South Africa as a stowaway with aquatic plants, was first reported from Midmar
Dam in KwaZulu-Natal in the late 1970s (Rayner 1988). This species is now
widespread in South Africa, occurring in large impoundments and ponds in KwaZulu-Natal and the Western Cape (Griffiths et al. 2015). Although no impacts have
been documented, freshwater jellyfish are predators on other zooplankton, and so
Fig. 6.2 Micrographs of the co-invasive (a) Apiosoma psicicola (Blanchard, 1885), (b)
Chilodinella piscicola (Zacharias, 1894), (c) Chilodonella hexasticha (Kiernik, 1909), (d)
Schyzocotyle acheilognathi (Yamaguti, 1934), (e) Lernaea cyprinacea Linnaeus, 1758 and (f)
Argulus japonicus Thiele, 1900 found from various native fish species in South Africa. Photographs
courtesy of Linda Basson (a–c) and Nico Smit (d–f)
6 Alien Freshwater Fauna in South Africa
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