The Potential Of heterotis Niloticus (African Bony-Tongue) as Aquaculture Candidate in Ghana

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Two studies were conducted on the African bony-tongue (Heterotisniloticus) a non-traditional farmed species in Ghana. The first study was done to assess indigenous and culture knowledge of fish farmers from the Ashanti and Eastern regions of Ghana on this non-traditional fish species. Subsequently, a nutritional study was conducted to determine the effect of varying dietary protein levels on the growth and feed utilization of the bony-tongue. The indigenous and culture knowledge of farmers on the bony-tongue were assessed by administering structured questionnaires to ten farmers; five from the Ashanti Region and five from the Eastern Region of Ghana. There is a growing interest of fish farmers for the culture of the bony-tongue. Therefore, there is the need for research to be conducted on this farmed fish species to enable research findings to be extended to farmers to enhance efficient farming of the bony tongue. The nutritional study evaluated the effect of four is oenergeticdiets with varying crude protein (CP) levels of 26.2%, 32.1%, 34.6% and 42.8% on growth; feed utilization and whole-body proximate composition of bony-tongue juveniles. Juveniles (initial weight: 32.65±0.03g) of the bony-tongue were stocked in rearing hapas (2x1m2) at5 fish per hapa. Each diet was assigned to triplicate groups of fish in a completely randomized block design and the experiment lasted for ten weeks. An increasing growth trend and better feed utilization was observed as dietary protein levels increased from 26.2% to 42.8%. Fish fed 42.8% protein diet had the best growth performance and nutrient utilization, with a mean weight gain of 202.30±19.6%, feed conversion ratio of 1.20±0.15 and protein efficiency ratio of 1.66±0.2, however this was not significantly different from values of fish fed 32.1% and 34.6% dietary protein. Significantly lower values were recorded for fish fed 26.2% dietary protein. Whole- body nutrient composition of bony-tongue was not affected by the diets. The results of this study suggest that H.niloticus juveniles would grow best when fed diets containing at least 32.1% protein.
Thesis Submitted to the Department of Fisheries and Watershed Management in Partial Fulfillment of the Requirements for the Degree of MASTER OF PHILOSOPHY