Ischua Creek fish die-off in New York under investigation

Franklinville, N.Y. — As a result of an ongoing investigation, the New York State Department of Environmental Conservation on Aug. 31 directed Great Lakes Cheese facility in Franklinville, Cattaraugus County, to take immediate actions to address ongoing impacts related to the discharge of organic waste to Ischua Creek.

The facility, in response, is pausing the operations of its discharge outfall to Ischua Creek.

The actions follow reports involving visible effluent discharge and odors from the facility’s outfall to the creek and a significant die-off under ongoing DEC investigation that is affecting tens of thousands of fish and many aquatic species.

A press release said DEC is requiring Great Lakes Cheese to implement a suite of operational improvements and enhanced monitoring to immediately address effluent exceedances from its wastewater treatment process, improve the quality of the facility’s digester operations, and continue data collection to fully assess impacts to the creek.

DEC has documented tens of thousands of fish, amphibians, reptiles, and other species impacted in the recent die-off. The investigation is ongoing, and more details will be provided as information becomes available.

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On Sept. 6, DEC completed a preliminary review of laboratory results from in-stream water quality sampling of Ishua and Olean creeks. The data suggests the creek downstream of the Great Lakes Cheese facility had low dissolved oxygen and high levels of nutrients in exceedance of state standards. This includes levels of nitrite and ammonia in the water that are toxic to fish and other aquatic life. Other water quality parameters which exceeded standards include manganese and total dissolved solids.

Water quality upstream of the facility’s discharge was compliant with state standards and aquatic life in the upstream reaches remains healthy. Based on the current evaluation by DEC’s water quality experts, the impacts on water quality are limited to Ischua Creek and did not impact other waterbodies.

On Aug. 26, 2025, DEC responded to reports of a large fish kill in Ischua Creek in Franklinville. DEC field teams immediately responded to investigate and are closely monitoring water quality, tracking downstream of Franklinville, and assessing impacts to aquatic life. Staff observed multiple types of dead aquatic species in the area.

Out of an abundance of caution, the public is advised to avoid all contact with Ischua Creek downstream of Franklinville, including recreational uses such as fishing/fish consumption, boating, and swimming, until further notice.

“DEC and our partners at the Department of Health will continue to coordinate assessing any potential public health impacts and encourage the community to follow the recreational use advisory that remains in place at this time,” DEC Commissioner Amanda Lefton said in the news release.

The public is encouraged to report unusual fish and wildlife observations in the region by calling 716-851-7201. For more information about animal health, visit here.

Editor’s Note: At press time, DEC was still providing almost regular updates regarding Ischua Creek water quality.