MADISON, Wis. — A manure spill from a northeastern Wisconsin farm is thinning as it flows downstream toward the bay of Green Bay, state environmental officials said Thursday.

Oxygen levels in the Little Suamico River are improving and Department of Natural Resources investigators have seen fish, minnows and crayfish in various locations, DNR spokeswoman Sarah Hoye said, although some parts of the river remain cloudy.

Clean-up efforts along the river have ceases with work now focused on containment efforts at the farm, she added.

Rain during the night of July 9-10 in Oconto County sent manure running off the Betley Farms' fields into an unnamed Little Suamico tributary, causing a fish kill and water quality problems.