Survey of Aquatic Weed Infestation and Its Effects on Fish Production in Ponds in Taraba State

Aquatic weed infestation is a persistent management challenge in fish ponds across North East Nigeria, reducing dissolved oxygen, shading ponds, and interfering with feeding and harvesting operations. This study surveys the types, extent, and management of aquatic weeds in 40 fish ponds across Jalingo and Ardo-Kola Local Government Areas in Taraba State. Farm visits and structured interviews with pond owners were conducted over three months. Weed species were identified using standard botanical keys, and percentage surface coverage was estimated visually for each pond. Fish farmers were interviewed on the economic impact of weeds and management strategies employed. Results identified 14 aquatic weed species, with Pistia stratiotes, Eichhornia crassipes, and Lemna spp. as the most prevalent, occurring in 72%, 58%, and 45% of surveyed ponds respectively. Ponds with greater than 50% weed coverage recorded significantly lower dissolved oxygen concentrations and reduced feeding responses in stocked fish. Farmers reported yield reductions of 15 to 30% in heavily infested ponds. Manual removal was the primary control method used by 89% of farmers, though it was described as labour-intensive and unsustainable. Herbicide use was reported by 12% of farmers without apparent awareness of regulatory restrictions. The study recommends integrated weed management protocols tailored to the resource capacity of smallholder fish farmers in Taraba State, including the promotion of herbivorous fish species as biological control agents.

Keywords: aquatic weeds, fish pond management, Pistia stratiotes, Taraba State, weed control