Stock Assessment and Estimation of Optimum Yield for Tilapia Stock (Oreochromis niloticus) in Lake Hawassa, Ethiopia

The basic purpose of stock assessment is to provide decision makers with the information necessary to make rational choices on the optimum level of exploitation of aquatic living resources such as fish. Aquatic living resources are limited butrenewable, and fish stock assessment may be described as the search for the exploitation level, which in the long run gives the maximum sustainable bio-economic yield in weight from fishery.

Fish resource utilization is the primary and an important economic activity. Its purpose is to provide a flow of benefits to human society; it serves as a food because ofits rich nutritional value in provision of protein. The global capture fisheries production in 2008 was reported by FAO, Fisheries and Aquaculture Department, as 90 million tones, with an estimated first-sale value of US$93.9 billion, comprising about 80 million tons from marine waters and 10 million tons from inland waters.