Lake Victoria Cichlids and Nile Perch Impact
What is the impact of the introduction of Nile perch to Lake Victoria on the cichlid species?
a. The cichlid species in Lake Victoria thrived and increased in population.
b. The number of cichlid species decreased due to predation by the Nile perch.
c. The Nile perch and cichlid species coexisted peacefully in Lake Victoria.
d. The Nile perch population decreased while the cichlid species increased.
Answer:
b. The number of cichlid species decreased due to predation by the Nile perch.
The introduction of the predatory Nile perch to Lake Victoria had a significant impact on the cichlid species in the lake. By the mid-1980s, the Nile perch became the dominant fish species in the lake, leading to a decrease in the number of cichlid species. The Nile perch preyed heavily on the cichlid species, particularly those that fed on algae and debris on the lake's bottom.
This predation caused a decrease in the cichlid population and had further consequences on the lake's ecosystem. With the decrease in cichlid species, algae levels in the lake increased, leading to a decrease in oxygen levels. This shift in the ecosystem had ripple effects on the remaining cichlid species, forcing some to adapt in order to survive.
One visible adaptation observed in some cichlid species in Lake Victoria was the increase in gill surface area over just a 20-year period. This adaptation likely enabled the cichlids to extract more oxygen from the water, compensating for the decreased oxygen levels in the lake due to the presence of the Nile perch.