A Bioeconomic Analysis of Tilapia Fishery in Lake Baringo - Kenya

Abstract

The economic and biological sustainability of the tilapia fishery in Lake Baringo is investigated by determining the optimal harvesting levels at MSY and MEY using five traditional surplus production models i.e. Schaefer, Schnute, Walters and Hilborn, Fox and Clarke, Yoshimoto and Pooley (CYP) models. The CYP model proves to be the most applicable to this fishery by showing a high goodness of fit (R2 = 0.99) and statistically significant for coefficients at 5% level. This model is then applied to the tilapia catch and effort data collected between 1995 and 2014 to determine the population parameters (K, q, r) and optimum harvest levels. The biological MSY for the tilapia fishery is estimated at 1,167.548 tonnes per annum. On introducing economic information on costs and revenue, the sustainable economic yield MEY is estimated to be 1,158.216 tonnes per annum. The optimal effort levels associated with MSY and MEY is estimated to be 183 and 161 gill nets respectively. When fishing the effort is expanded to open access point, the yield drops to 478,043kgs per annum and its associated effort is estimated to be 548 gill nets. These estimated optimal levels are then compared with the actual effort and catch, and it is found evident that there is substantial excess effort on the tilapia fishery. The current fishing effort (379 gill nets) is found responsible for tilapia overfishing. The study finally recommends for a reduction of the number of gill nets by 51% to promote biological sustainability of tilapia. For economical optimization of the inputs, the study recommends for a reduction effort by 57%. Since Lake Baringo is a mixed fishery, the study recommends for introduction of other more selective fishing gears that should deliberately target catfish and lungfish. Reducing the number of fishing nets will lead to an increase in the tilapia spawning stock and consequently recruitment could increase hence recovery of the tilapia fishery being achieved progressively.