09/17/2025 | Press release | Distributed by Public on 09/17/2025 13:32
The Department of Health and Welfare (DHW) is issuing a health advisory for CJ Strike Reservoir after harmful algal blooms were identified, urging caution when recreating in or near the water. CJ Strike Reservoir is about 15 miles southwest of Mountain Home.
Since Aug. 12, the Cottonwood Creek Boat Ramp and adjacent area on the Bruneau Arm of CJ Strike in Owyhee County have been under a health advisory. Recently, another bloom was confirmed on CJ Strike Reservoir, north of CJ Strike Dam. With this new information, the advisory is being expanded to the entire reservoir.
DHW works closely with Southwest District Health and the Idaho Department of Environmental Quality (DEQ) to identify, respond to, and monitor cyanobacteria harmful algal blooms (cyanoHABs).
Recent samples from CJ Strike Reservoir showed high amounts of toxin-producing cyanobacteria. The toxins they produce (cyanotoxins) can be harmful to people, pets, and livestock.
When recreating near CJ Strike Reservoir, take the following precautions while the advisory is in effect:
Cyanobacteria are a natural part of Idaho's water bodies. When temperatures rise, their populations can bloom and toxic chemical compounds, or cyanotoxins, can be released into the water. Blooms don't all look the same. They may look like mats, foam, spilled paint, or surface scum, and have a foul odor.
Mats can be out of sight on the bottom of the water body. Pets, livestock, and wildlife can get sick or die, within minutes to days after cyanotoxin exposure.
Dogs may become sick before humans because they are more likely to swim in or drink contaminated water or lick contaminated water or bloom material off their fur. If your pets or livestock have been in the water, immediately wash them with clean water to keep them from licking cyanobacteria off their bodies. Seek veterinary care immediately if your pets or livestock seem sick after going in or drinking the water.
For more information about cyanoHABs:
The Idaho Department of Health and Welfare is dedicated to strengthening the health, safety, and independence of Idahoans. Learn more at healthandwelfare.idaho.gov.