08/29/2025
CAUTION: Harmful Algal Bloom at MTRP
A toxic algal bloom (Anatoxin-a) has been detected in the river at Mission Trails Regional Park. The water is at a cautionary level — avoid contact! The results from sampling collected last week at Old Mission Dam detected presence of the cyanotoxin that can be harmful to people and pets. This was detected at the lowest tier of the three tiered levels, but visitors should use caution at the Old Mission Dam site especially and use caution along the river and at Kumeyaay Lake as additional testing is being conducted.
* Avoid touching algae/scum
* Do not drink the water
* Do not let pets enter or drink the water
* Keep children away from algae in the water and shore
* Do not eat shellfish from the water
If you’ve been exposed, watch for symptoms like diarrhea and vomiting, rashes, ear, nose and throat irritation, abdominal cramping, respiratory issues and seizures. Pets may show drooling, tremors, or lethargy, and in severe cases even death. Seek medical help if needed.
Many thanks to our colleagues at the San Diego River Park Foundation and the Regional Water Quality Control Board for detecting the bloom and posting the signs. Stay tuned for updates but in the meantime, avoid the water.
Photo by San Diego River Park Foundation.
