The cause of the death of a dozen fish found last month in the Cedar River near Austin's sewage water treatment facility could not be determined, according to the Minnesota Pollution Control Agency.

The site of the dead fish on Jan. 8 is the same spot where a larger fish kill was found in March.

After the Department of Natural Resources inspected the area, no dead fish were found upstream or downstream and live fish were found near the area of the dead fish, said Ralph Pribble, MPCA information officer.

In its monthly report to the MPCA for December, the sewage water treatment facility did not report any upsets or bypasses in its system, Pribble said.

The MPCA has not yet processed the water treatment facility's January report.

"Everything appears normal," Pribble said. "We couldn't determine any cause for it."

By looking at how much the fish had decomposed, they probably died in December, Pribble said.

Steve Klotz, of the DNR in Lanesboro, said the DNR did not do a formal investigation and did not collect water samples in that area.

Jim Samuel, sewage plant supervisor, said he did not know how the fish would have died. The treatment plant has not had any problems, he said. He said the DNR took two of the fish to sample and the PCA also investigated.

"I haven't heard back from them (the DNR) or the PCA about the results," he said.

Pribble said frequently the MPCA is not able to determine how some fish kills happen.

Cari Quam can be reached at 434-2235 or by e-mail at cari.quam@austindailyherald.com