1. Lake Hawassa is one of the major freshwater bodies in Ethiopian country. It supports a lot of organisms ranging from the microalgae (phytoplankton) to different fish species.
Phytoplankton is the primary producer; zooplankton and omnivores fish feed on, zooplankton, in turn, serves as food for carnivorous fishes at the trophic level. If Nile perch (piscivorous fish ) from Lakes Chamo and Abaya introduced to lake Hawassa, What will happen to the trophic status of the lake? (4pt)
The introduction of Nile perch will lead to a decrease in the number of omnivores fish and zooplankton - major organisms that Nile perch feed on. As a result, the amount of phytoplankton in the lake will increase leading to the increased bioproductivity in the lake. As a result, the trophic status may change to eutrophic or even hypereutrophic.