Maturity, age and growth of Oreochromis karongae (Teleostei: Cichlidae) in Lakes Malawi and Malombe, Malawi

Abstract

Size-at-50% maturity, age and growth, of Oreochromis (Nyasalapia) karongae (‘chambo\') in Lakes Malawi and Malombe were studied. Oreochromis karongae, a major component of the chambo species flock, attained 50% maturity at 225 mm TL in Lake Malawi and at 203 mm in Lake Malombe. The estimated age-at-50% maturity was 2.19 and 1.49 years in Lakes Malawi and Malombe, respectively. Estimated growth parameters for populations at Karonga, Nkhotakota, Salima and Mangochi in Lake Malawi, and for that in Lake Malombe were L_∞ = 328, 319, 308, 388, and 314 mm TL, respectively; and K-values were 0.31, 0.29, 0.34, 0.20 and 0.35, respectively. Similar size-at-50% maturity and growth patterns (age, L_∞ and K-values) were found for O. karongae populations in Lake Malawi, but differences were observed for Lake Malombe populations, suggesting that the current chambo fisheries management regulations, based on findings from the southern part of Lake Malawi, may be applicable to the central and southern parts of that lake, but may not be applicable to Lake Malombe.

Keywords: artisanal fishers, chambo fishery, closed season, fishing effort, management, populations

African Journal of Aquatic Science 2008, 33(1): 69–76