EFFECT OF DUCKWEED (Lemna minor) ON SOME WATER QUALITY PARAMETERS IN THE CULTURE OF NILE TILAPIA (Oreochromis niloticus) FRY OVERTIME

ABSTRACT

There are several claims that macrophytes such as duckweed (Lemna minor) help in the management of water quality in fish culture. This study investigated the effect of culturing duckweed (Lemna minor) along with Nile tilapia (Oreochromis niloticus) on water quality parameters. Nile tilapia fingerlings were stocked in outdoor plastic tanks under four treatment conditions: T₀(Control) fish culture alone, (T₁) fish + duckweed co-culture all through,(T₂) fish + duckweed co-culture for the first three weeks and (T₃) fish + duckweed co-culture for the last three weeks. Each treatment had three replicates. Water quality parameters including dissolved oxygen, pH, ammonia, and Temperature  were monitored weekly for 6 weeks.

The result of this study shows that the presence of duckweed significantly improved dissolved oxygen levels in T₁(5.717mg/l),T₂(5.344mg/l) and T₃(5.783mg/l)  compared to the Control T₀(3.606mg/l) without duckweed. The highest level of ammonia was recorded in the Control T₀(3.404mg/l) and lowest in T₁(0.181mg/l). T₃(7.846) recorded the highest level of pH while T₀(6.602) had the lowest pH.

 The results demonstrate that duckweed can effectively maintain optimal water quality when integrated into Nile tilapia culture systems by oxygenating the water, and absorbing nutrients. Therefore, it is recommended that culturing duckweed along side Nile tilapia  should be adopted to enhance water quality and sustainability in aquaculture.