Body condition metrics and reproductive aspects of three spiny eels (Teleostei: Mastacembelidae) from littoral habitats in southern Lake Tanganyika

Abstract

The body condition metrics and reproductive aspects of three spiny eel species (Mastacembelus moorii, M. ellipsifer and M. cunningtoni) inhabiting littoral habitats in southern Lake Tanganyika were evaluated. As Mastacembelids are important in artisanal fisheries, the study aimed to provide essential baseline data (growth, condition, fecundity) for understanding the ecological roles and conservation needs of Mastacembelids in Lake Tanganyika, to mitigate the risks of recruitment overfishing and aid in their long-term viability. Data were collected between November 2023 and March 2024. Biometric parameters (total length, weight and organ weights) were analysed for condition factors and organosomatic indices. Results revealed length–weight relationships indicating isometric growth across all species, with slight species-specific differences in Fulton’s condition factor and the hepatosomatic and cardiosomatic indices. Female sexual maturity was assessed in relation to the gonadosomatic index; a 1% gonadosomatic index threshold could effectively discriminate between mature and immature individuals. Fecundity curves predicted egg number from maternal total length. Mature M. cunningtoni females showed the highest fecundity for maternal body-size. Notably, M. moorii showed indications of asynchronous egg release, warranting further investigation. Mastacembelids face numerous anthropogenic pressures and these results contribute information relevant to the incorporation of these species in sustainable fisheries management plans.