Authors

Discussion

The current trend in marine parasitology, particularly in South Africa, is to focus on a specific parasite taxon and not on the total parasite community of a specific fish host. These surveys are often sporadic collections scattered along the coast and in different seasons, focusing more on parasite taxonomy and not ecology. Therefore, these records do not provide information on parasite community structures within a specific host fish and cannot be related to the ecological role of the parasites in the system. The present study aimed to compile more comprehensive data on all metazoan parasites of a single host fish, the endemic intertidal klipfish, Clinus superciliosus, and gain more inclusive information on which abiotic and biotic factors influence parasite community composition and structure within this species. Metazoan parasites were sampled at four localities over six surveys from March 2019 to October 2020. The sampling localities include two commercial harbours on the west coast (Langebaan marina and Cape Town harbour) and two relatively pristine localities along the south coast (Tsitsikamma in the Garden Route National Park and a small coastal town, Chintsa) of South Africa. A total of 75 klipfish were examined, where 27 different parasite taxa representing all major taxonomic groups were found, including: nematodes (5 species); monogeneans (1 species); crustaceans (3 species); hirudinean (1 species); cestodes (2 species); acanthocephalans (3 species); and digeneans (12 species). Data were subjected to various biodiversity indices and multivariate statistical analyses were done to identify the drivers of parasite community structure. Based on the Brillouin diversity index, a higher diversity was found at Chintsa 2019 (1.884), Tsitsikamma 2019 (1.668), Tsitsikamma 2020 (1.661) and Chintsa 2020 (1.379), while the lowest diversity values were calculated for Langebaan marina 2019 (0.324) and Cape Town harbour 2019 (< 0.0001). Considering various biotic and abiotic factors as drivers of diversity (location, survey period, habitat type, parasite lifecycle, fish host size, sex and condition factors), an ANOSIM analysis indicated differences between localities (R = 0.861) with a significance level of sample statistics at 0.1%. Furthermore, redundancy analysis indicated that the parasite life cycle, habitat type and water temperature were considered to significantly influence the community structure. The south coast has higher water temperatures than the west coast localities, and in combination with known upwelling events, results in nutrient rich water. These eutrophic conditions correlate positively with overall parasite species richness. Even with this high parasite diversity in a single fish species, the rarefaction curve extrapolated from the parasite data indicated that a greater sampling effort might reveal even more parasite species. The results from this study again emphasised the importance of parasitological surveys including all parasite taxa on hosts from various localities and seasons, in order to better establish the full ecological role of parasites in marine ecosystems.