Thursday May 29, 2025
Oregon Public Broadcasting —
Following the deaths of two dogs last year, Clark County is alerting the public to a new form of cyanobacteria found in the Columbia River: benthic algae mats.
The county first learned of this new bacteria in October 2024, when a dog’s death was attributed to cyanotoxin poisoning. The dog had previously spent time on Ackerman Island in the Columbia River. Another dog also died from the same bacteria in August 2024 near St. Helens, Oregon, Clark County later learned.
But there was no visible algae bloom at the Port of Camas-Washougal, Columbia River or Ackerman Island – at least, not the kind the general public is aware of.
Outbreaks of cyanobacteria and other forms of life in waterways can “bloom” in large numbers and produce toxins that make people and animals sick. In recent years, the Columbia River has become increasingly prone to blooms of cyanobacteria, more commonly known as blue-green algae.