Assessment of Length-weight Relationship, Sex Ratio, Condition Factor and Socioeconomic Values of Nile tilapia in Lake Hawassa

Abstract

The length – weight relationship, condition factor and sex ratio in Lake Hawassa were evaluated over a period of seven weeks from May to June 2019. The growth coefficient ‘b’ obtained for male, female and combined sexes were 3.17, 3.17 and 3.19 respectively. The ‘b’ value differed significantly (p<0.05) from the value of ‘3’ for all the male, female and combined sexes, indicating a positive allometric growth. The condition factors ‘K’ for male, female and combined sex were 0.97, 1 and 0.94 respectively. There was a significant difference in condition factor between the male, female and combined sexes (ANOVA, p< 0.001). The sex ratio of male and female O. niloticus significantly different (χ2 = 5.78, p< 0.05) from the expected 1:1 ratio. The study conducted to reveal the potential of Nile tilapia to produce fishmeal showed that at least 15.12% of Nile tilapia fish which otherwise would have been discarded as a waste product have the potential to become a fishmeal, such that Lake Hawassa has the potential to produce 27.66 tons of fish meal from annual catch of 182.94 tons of Nile tilapia. The impact of socioeconomic values of Nile tilapia both on fishermen and consumers have been shown as the livelihood of 88% of the fishermen respondents is based on fishery activity with no other source of income with nearly two thirds of the respondents have a monthly income between 1000 to 2000 birr and  annual median income of 18,000 birr. This study also revealed that 90% of the fishermen respondents have been given awareness or training that improves their fishing practices. More than three quarter of the fishermen agreed that the long distance of fish markets from residential areas have reduced the accessibility of the fish resource to the consumers. And also there is strong statistical evidence that supports unhygienic fish processing practices contributed more to the problems and constraints of the socioeconomic values of Nile tilapia. On the other hand consumers’ spending capacity depends on their monthly income and also consumers’ consumption habit depends on factors like the cost of fish, proximity of the fish market and buying power. Further research needs to be undertaken to address some of the problems facing the fishery activity such as lack of proper fish processing, storage and marketing facilities.