The Missisquoi River is scheduled to be treated today with chemicals to kill sea lamprey, a parasitic fish that preys on certain species of sport fish.
The treatment was postponed on Wednesday because of high water levels, which have since receded.
The Fish and Wildlife Department says a water use advisory will go into effect at 7 a.m. for the Missisquoi River downstream from the Swanton dam and at 7 p.m. for the eastern half of Missisquoi Bay in Highgate.
The department advises against using river or lake water for household, agricultural and recreational purposes until the advisories are lifted.