Gem State Roundup

Southwest District Health issues public health advisory for CJ Strike Reservoir

By: - July 19, 2022 3:45 pm
CJ Strike Reservoir

CJ Strike Reservoir near Grandview and Bruneau is one of the most popular fishing reservoirs in Idaho. (Roger Phillips/Idaho Department of Fish and Game)

Idaho public health authorities are warning people to stay out of the CJ Strike Reservoir and avoid exposing children and pets to the water.

Southwest District Health officials issued a public health advisory Tuesday for CJ Strike Reservoir based on Idaho Department of Environmental Quality testing that showed high concentrations of cyanobacteria, Southwest District Health spokeswoman Ashley Anderson said in a press release issued Tuesday. 

CJ Strike Reservoir is located near Grandview and Bruneau in Owyhee and Elmore counties. It is one of the most popular fishing reservoirs in the state because of the variety of bass, trout, catfish and bluegill, according to the Idaho Department of Fish and Game.  

Cyanobacteria are found in Idaho waters, and when temperatures rise, they bloom and can release toxic chemical compounds called cyanotoxins into the water, public health officials said.

Symptoms of exposure to the cyanotoxins can include hives, vomiting, diarrhea, coughing and wheezing. If water is ingested, that can produce more severe symptoms that affect the liver and nervous system, public health officials said. 

Health officials said dogs are often first affected by exposure to cyanotoxins because of drinking or swimming in the water or licking contaminated water off their fur. Officials warned that dogs, other pets and livestock may get sick or even die within minutes of exposure to cyanotoxins.


Until further notice, Southwest District Health and Idaho Department of Environmental Quality officials recommend people take the following precautions:

  • Avoid swimming, wading or other activities in CJ Strike Reservoir.
  • Take extra precautions to ensure children and pets are not exposed to the water there.
  • Do not drink or cook with water containing a bloom, which could look like surface scum, spilled paint, mats or foam and carry a foul odor. If it is not safe to cook or drink such water even after it is boiled or filtered, public health officials said. 
  • If people or pets are exposed to the water, wash and clean skin or exposed pet fur with clean water as soon as possible. 
  • Wash your hands thoroughly with clean water if you catch or handle fish caught from waters experiencing a bloom. If you eat the fish, wash it, clean it, filet it and remove the organs, fat and skin before cooking and eating.
  • Consult a health care provider if a person is experiencing symptoms that persist and contact a veterinarian if pets or livestock appear sick after drinking or going into the water. 

Southwest District Health officials said they would update the public when it is likely there is no longer a reason for concern.


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Clark Corbin
Clark Corbin

Clark Corbin has more than a decade of experience covering Idaho government and politics. He has covered every Idaho legislative session since 2011 gavel-to-gavel. Prior to joining the Idaho Capital Sun he reported for the Idaho Falls Post Register and Idaho Education News. His reporting in Idaho has helped uncover a multimillion-dollar investment scam and exposed inaccurate data that school districts submitted to the state.