September 24, 2014

Cyanobacteria poisoning from Willamette River toxic algae threatens Portland dogs

Portland dogs continue to be at risk from toxic algae in the Willamette River. The current harmful algal bloom has reportedly been confirmed as a species of cyanobacteria (often called blue- green algae) known as Microcystis aeruginosa.

In a city that prizes dog parks with access to a large river, that’s a potentially major problem. Multnomah County dog control ordinances generally require that dogs be on leash except in designated areas. It is unlawful to allow a dog to be an animal at large. Under Multnomah County Code § 13.002, a dog must be “physically restrained when on public property, or any public area, by a leash, tether or other physical control device not to exceed eight feet in length and under the physical control of a capable person.”

But a number of Portland parks and Oregon state parks allow dogs access to the Willamette River, although some require that dogs remain on leash while swimming. Beach portions of parks are usually not within off-leash areas either, but leashes can be reattached when dogs come back to dry land. So a Portland dog could easily contact toxic algae and face imminent—and potentially grave—danger.

According to Oregon State University’s Institute for Water and Watersheds, consumption of cyanobacterial harmful algae blooms (“CHABs”) “by animals can cause illness or even death. Blue-green algae have been implicated in the poisoning of wild animals including rodents, amphibians, fish, pelicans, waterfowl, bats, and zooplankton.” But dogs may be especially at risk. Studies show that they may be attracted by the odors produced by cyanobacteria, and repeated exposure to low levels of toxins can have long-term health consequences.

Unfortunately, dogs that come into contact with the bloom might also suffer cyanobacterial poisoning “within 30 minutes to a few hours after exposure, depending on the size of the dog, the type of toxin, the toxin concentration and how much toxin the dog has ingested. In severe cases, dogs can show signs of cyanobacterial poisoning within a few minutes and can die within an hour of toxin exposure.” New York Sea Grant has a helpful free brochure on dogs and harmful algal blooms available at the link below.

OSU notes that CHABs “are naturally occurring and an integral part of the ecosystem. Cyanobacteria form the basis of the food chain and hence, their existence is essential for all life. The goal is to minimize outbreaks and keep populations from out-competing other species of bacteria, plants and animals.” Every responsible dog guardian’s goals should also include keeping his or her canine companion safe.

Related Web Resources
New York Sea Grant, Dogs and Harmful Algal Blooms (HABs).

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