Publication details
Pelagic freshwater fish parasites in Lake Tanganyika: do the monogeneans mirror host origin?
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| Year of publication | 2016 |
| Type | Conference abstract |
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| Description | Parasites have been mainly overlooked for many decades in the Great African Lakes. Lake Tanganyika is a well-known study area attracting scientists for its remarkable species diversity. For some years, its fish parasite fauna, especially monogeneans, received more attention with 24 described species in the lake to date. While most investigations focused on the diverse littoral zone, information about economically important pelagic hosts is still missing. Lake Tanganyika’s pelagic zone is dominated by two endemic clupeid species (Limnothrissa miodon, Stolothrissa tanganicae) and four endemic latids (Lates angustifrons, L. mariae, L. microlepis, L. stappersii). All species figure as an important component of the food web and form the main part of local fisheries. Surprisingly, almost nothing is known about their parasite fauna. We examined the abovementioned hosts for the presence of parasites to answer the following questions: which parasites infect clupeids and latids in Lake Tanganyika? Is there any seasonality or geographical variation in infection parameters? And do the parasites mirror host origins? Samples originated from several localities in Lake Tanganyika and included historical fish specimens deposited in the collection of the Royal Museum for Central Africa and specimens from fieldwork and specimens from recent field works. Parasite species identification and description was based on the sclerotised structures of the copulatory and attachment organs. Molecular characterisation was conducted using markers with different rates of molecular evolution (nuclear 18S, ITS1, 28S rDNA and COI mtDNA). Morphological as well as molecular identification showed the existence of two different monogenean species of Ancyrocephalus infecting clupeids in Lake Tanganyika. This result indicates adaptation of freshwater parasite species to originally marine fishes during their colonisation of African freshwater. Contrary, latids as representatives of a originally marine taxon are infected by a single species of Diplectanum, a genus reported mostly from marine and brackish waters, closely related to species reported from Lates calcalifer in Asia.Phylogenetic analyses showed the need for revision of both reported parasite genera. Finally, seasonality of parasite prevalence was observed. Further analyses tracking parasite population structure and demographic history linked with host data are planned to reveal the co-evolutionary history of this host-parasite system. |
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