Reproductive biology, growth and mortality of tylochromis Bangwelensis (Regan, 1920) in Bangweulu lakes and swamps complex fishery.

Thumbnail Image
Kabundula, Kahilu
Journal Title
Journal ISSN
Volume Title
The University of Zambia
This study investigates selected aspects of the population biology of Tylochromis bangwelensis that included: reproductive biology, growth and mortality in Bangweulu Lakes and Swamps Complex Fishery. The main objective was to determine if stocks of the species are under or over exploited in the fishery. A sampling area (S 11o 19’ 24.6” and E 029o 34’ 16.9”) that represented the main landing sites was selected. The fish samples were procured from the local fisher’s catches for seven months from March 2019 to September 2019. Length measurements were taken from each fish specimen using a fish measuring board. Weight was measured using an electronic balance to the nearest one gramme. The reproductive biology were investigated by examining fish sex and maturity stages of the gonads. Length frequency histograms were also used to determine spawning seasonality. Growth parameters L∞ and k of the species were determined using the Ford-Walford plot. Mean lengths representing each peak from peaks of length frequency histograms plotted for all the specimens were collected. Analysis of Variance was performed on all quantitative data using GenStat software, 2019. It was found that this species of fish is a seasonal breeder, different peaks were observed on the length frequency histogram graphs plotted from specimens collected during each month an indication of the presence of breeding seasonality in this species. The asymptotic length, L∞ was estimated at 348mm and k was found to be 0.837. Total mortality coefficient (Z) was found to be 1.87, natural mortality coefficient (M) was estimated at 0.03, fishing mortality coefficient (F) was 1.84 and exploitation rate was 0.98. T. bangwelensis in the fishery is being exploited beyond optimum level since exploitation rate is above 0.50. Therefore, the study recommended that fisheries management plan should not aim at increasing the catch of T. bangwelensis stock from the fishery since it is already diminishing.
Thesis of Master of Science in Tropical Ecology and Biodiversity.