Reproductive biology and some aspects of production of the African lungfish (Protopterus Aethiopicus) in lake Victoria, Mwanza Gulf

The catch population of lungfish (P. aethiopicus) was sampled by bottom trawling for twelve months (June 1984 - May 1985). A total number of 576 fish were investigated. Total length distribution in the catch ranged from 36.8 to 54 cm, and dominated (60%) by length group 96 to 116 cm. Length frequency distribution is symmetrical and unimodal. There was no shift of the monthly length frequency modes with time to indicate any growth rate. The sex ratio was found to be 1:1.98 in favour of females. Log/log length-weight relationship was found to be significantly different between the sexes. Males of the lungfish were found to have algometric growth while females have isometric growth. Minimum size at maturity was found to be 96.0 cm. T.L. It was not possible to establish spawning season and maturation trend neither from the variations in monthly length/weight relationships, nor gonad somatic index (G.S.I.). Fat deposited along the gonads was found to be a better basis for assessing maturation and spawning in lungfish. Spawning season was found to be from September to May. Fecundity was found to range from 705 (in 84 cm T.L. fish) to 14,922 eggs (in 130 cm T.L. fish). The principal diet of the lungfish was found to be Gastropods - Bellamyaspps. (98% occurrence) throughout the year. No relationship was found between fish size and prey size. By weight lungfish contributes 12% of total catch in artisanal fisheries and 44% in commercial trawling fisheries in Lake Victoria - Mwanza gulf.