A basis for the rational exploitation of the Tilapia esculenta stock of the North Buvuma Island area, Lake Victoria

Abstract

It is a well established feature of biological systemsthat the constituent organisms are in balance with each other.This is true of a fish population which is in balance with theother organisms of its own ecosystem, and within itself insofaras the numbers of fish entering a fish stock are approximatelyequal to those dying by natural causes.It is also true that 9 as fish grow through the population,they reach a particular size where the increase in weight in a year 9 due to the growth of all the fish in the population of that size, is balanced by the loss of weight due to natural death.The maximum yield of a fishery could thus be obtained by removing all fish as they reach this age. In practice it would require an infinite amount of fishing to accomplish this 9 and it is generalpractice in fishery management to begin cropping fish just before they reach this ideal size and age.