Response of endemic Clarias species’ life-history biometrics to land use around the papyrus-dominated Mpologoma riverine wetland, Uganda

Abstract

The Mpologoma River wetland is highly negatively impacted by rice growing and yet it provides habitat to endemic Clarias species that are important to the wetland fishery. Variations in life-history biometrics of small Clarias species at various wetland sites in relation to land-use changes within the wetland were studied in 2012. Four sites exposed to different land uses were sampled for vegetation, water quality and small Clarias species’ life-history biometrics. Water conductivity was significantly higher at the highly disturbed site, ranging from 140 to 480 µS cm⁻¹. Limiting nutrient levels, particularly phosphorus, were higher at the least disturbed sites. Two small Clarias species were identified. Mean total length and weight of Clarias liocephalus, the most abundant species (66%), were 16.81 cm (SD 4.03) and 33.77 g (SD 19.63), respectively, whilst those for Clarias alluaudi (34%) were 17.83 cm (SD 4.49) and 39.94 g (SD 22.99), respectively. Mean total length, weight and fecundity of both species were significantly higher at the highly disturbed sites than at the least disturbed sites. Habitat disturbance intensities due to land use conferred population-level benefits such as higher values of life-history biometrics of Clarias species at the highly disturbed sites in the wetland.