Interaction of water hyacinth with biotic and abiotic factor and the biological agents efficiencies in its control in Winam gulf, lake Victoria Kenya

Abstract

Lake Victoria just like many lakes across the world is effected with water hyacinth which resides in several bays for the better part of the year thus affect several economic activities of the locals and denies the government revenue every year from blue economic activities related to the lake. This paper explores the Interaction of water hyacinth with biotic and a biotic factor and the efficiency of the introduced biological agents (Neochetina eichhorniae and N. bruchi) in its control with an aim of advising on the best way to tackle the menace of the weed. Water quality samples were collected and compared from the time of water hyacinth arrival and sinking within winum gulf, this was divided in three phase, the hyacinth was collected and damages resulting from the weevils recorded. Fish samples were also collected using experimental gill nets and number recorded in Ms excel during the presence and absence of the weed. Water quality was analyzed for ammonium, SRP, nitrates and nitrates using SOP. The weevils were counted manually from each hyacinth collected and the data recorded. Data was then analyzed using R-data analysis at P<0.05 and post hock test to determine significance where applicable. Results indicated that the weevils inhibits nutrient uptake by17% within four weeks, hyacinth increase the nutrient levels in the gulf almost three fold after decaying and sinking and a notable interaction with biotic and a biota factor was also recorded. In conclusion water hyacinth impacts both biotic and a biotic factor and the weevils alone can not be depended upon to eradicate the weed.