Beware of toxic algae if your dog goes swimming

N.H. Sunday News - Dog Tracks Column - 6/6/10
By: Gail T. Fisher


Possibly because ice-out was earlier this year, with a warmer-than-usual spring, the reported outbreaks of algae and other bacteria in lakes and ponds is occurring earlier than usual, too. I originally wrote about this topic three years ago when it came to my attention that toxic algae can be fatal to dogs, other animals, and people. This is a good time to reprise that column:
An email alert from the “Whole Dog Journal” read: “Freshwater ponds, lakes and streams could be deadly to your water dog if they contain toxins borne by blue-green algae [Cyanobacteria].

“If the water where your dog swims looks cloudy, with a green or blue-green cast, you should suspect a dangerous overgrowth of blue-green algae, and prevent your dog from ingesting the water.
“Whole Dog Journal has confirmed a report from a Michigan dog owner whose nine-month-old Border Collie died shortly after swimming in a pond near Fenton, Missouri.”

The article went on to say, “The emergency vet told the dog’s owner that he had recently seen other dogs die of blue-green algae toxicity – a condition that can kill pets, livestock, and people who drink the contaminated water. ‘Had I ever heard of the danger of blue-green algae, I never would have allowed my dogs to swim in that or any other pond; I would have bought a pool,’ the owner told Whole Dog Journal.

“However, when the man whose dog died this week in Michigan contacted his state’s Department of Natural Resources, looking for more information about the dangerous algae, he says he was told that the toxic blooms rarely occur except in late summer, and not to either panic or panic other people. ‘Had someone else panicked, we wouldn’t be having this conversation right now,’ the grieving owner told the state representative.

“Dog owners should be aware that toxic algae blooms usually occur in late summer or early fall, but can occur at any time. They can occur in marine, estuarine, and (especially) fresh water. The latter are of the greatest concern to dog owners, as dogs are commonly taken to ponds, lakes, and reservoirs in the summer for recreation, exercise, and cooling -- and they routinely drink the water. Some of these algae blooms look like foam, scum, or mats on the surface of the water. The blooms can be blue, bright green, brown, or red (‘red tide’ is perhaps the best-known so-called ‘harmful algal bloom’) – but some blooms may not affect the appearance of the water. The water may or may not smell bad. As a further difficulty to dog owners trying to protect their dogs, not all algal blooms are toxic!”

After reading this, I contacted the NH Department of Environmental Services (DES), and spoke with Jody Connor, Limnology Center Director to ask if this is something New Hampshire dog owners need to be aware of.

We sure do! A few years ago, a horse died after drinking toxic water from a Pond in Pittsfield. In fact, New Hampshire was the first state in the nation to issue public beach advisories. This is a world-wide problem. In 1998, the World Health Organization published a drinking water guideline value for one cyanotoxin.

Quoting from an article Jody wrote, “Severe blooms impact the tourism industry as people avoid lakes with unsightly pea soup or bluish green colored scums and foul odors. In some cases, the blooms may cover the entire water body but in most cases, you will find them congregated as large scums on the windward shoreline. In severe cases, the high cell count leads to low dissolved oxygen, increased ammonia which cause fish kills.

Even without seeing the “severe case”, the bottom line is that we need to be extremely cautious when taking our dogs swimming. Contact the DES Limnology Center at (603) 271-3414 or the cyanobacteria hotline at 603-419-9229 immediately to report any suspicious algae blooms at your lake or pond, and collect a sample (if possible) for the DES to examine. And before you take your dog (or children) swimming, you can check for updates on current advisories that may be in effect, on the Department of Environmental Services website

Copyright © Gail T. Fisher, 2010. All rights reserved. For permission to reprint this article or suggestions for future topics, please contact us.