On the limnology of Lake Tanganyika
2008
Langenberg, V.T.
The fluctuations in Tanganyikan fish catches defy standard fisheries planning, management and development practice. For long the available knowledge seemed not adequate to elucidate the Lake’s ecosystem functioning and productivity. This project synthesised new insights in the dynamics of the main hydrodynamical, limnological and ecological variables that are crucial to further understand the mechanisms securing the biological basis for fish production. Across the lake we now describe how the seasonal meteorological and hydrodynamical patterns affect the thermal and chemical gradients that in turn, depending on their position and strength, seem crucial for the timing and magnitude of internal nutrient fluxes and algal production, and may regionally determine zooplankton abundance and community assembly. A first comprehensive study on the external nutrient sources showed them also to be significant for the lake’s annual primary production. The carbon sources for pelagic fish production were scrutinized, and a new view of Tanganyika’s trophic structure emerged. New production and biomass figures of key organisms combined with transfer efficiencies between the main trophic levels of Tanganyika’s pelagic foodweb showed no special mechanism needs to be invoked to explain its flourishing fisheries.
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