What’s Behind the Fish Kill in the Belize River? Public Advisory ‘Still in Effect’The Department of the Environment has found extremely low dissolved oxygen levels along a 17.5-mile stretch of the Belize River where significant fish mortality was recorded. The DOE has collected water samples from the Santander Farms drainage system and locations downstream, along with fish and sediment samples, to determine whether contaminants contributed to the event. The precautionary advisory issued on Wednesday remains in effect, including not eating or consuming fish or other aquatic resources from affected areas or using untreated river water for drinking, cooking, food preparation, livestock or pets. “Process water is recovered, managed, cooled where necessary, and reused within the facility,” it said in a statement on Friday.