Nile Perch

The Nile Perch: Friend or Foe for Lake Victoria
INTRODUCTION:
An alien species is a species introduced outside its normal distribution. It is clear that alien species can be both beneficial, for example the honey bee, pollinating many of the countries important crops and fruit. However it is more frequently seen that alien species have a negative effect on the habitat. The alien species under discussion in this essay is the Nile Perch. The Nile Perch is seen throughout much of the Afrotropic ecozone, as well as being native to the Nile, Senegal, Congo, Volta, Niger, Lake Turkana, and Lake Chad. The Nile Perch was introduced manually into Lake Victoria in the late 1950s and early 1960s. Lake Victoria covers a total of 69,000 square kilometres,

In the 1970s it began to colonise the rich, fertile, multispecies fishing areas of the Nyanza Gulf in Kenya, it was here that in the next 10 years the Nile Perch became a major component of the fish population. Until the late 1970s the biomass composition of the lake remained relatively constant, but in the middle 1980s, a survey of the lake revealed a sudden and unexpected change, a total reverse in biomass compositions. Cichlid numbers had decreased dramatically and only consisted of 1% of the total fish weight in the lake, while the Nile Perch had suddenly increased to constitute 80%. This large increase in numbers of the Nile Perch may have been caused due to the advantages it may have had over other fish in the lake. The Nile perch is a dominating predatory fish within the Lake. The Nile Perch can inhibit both tropical and fresh water. They become sexually mature at the age of three years and reproduce in large numbers (they can produce 16 million eggs at one time) with juveniles requiring no parental

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