On September 23, 2013, I observed a fish kill in the Central Welland River located in the town of Wellandport, ON. Species included common carp and channel catfish. There were many dead and dozens more appeared to be gasping for air at or near surface of the water.
Local Conservation Authority contacted the Ministry of Environment to investigate. Testing revealed very low dissolved oxygen and toxic concentrations of ammonia. The Ministry of Environment investigation revealed an over-application of biosolids upstream.