Be alert to stagnant ponds
that contain algae bloom

FROM 2005 I discovered this warning to anyone who walks their dog near ponds that are likely to become stagnant in the summer months - it came with a plea for dog owners to let as many people as possible know about the danger:
"Yesterday morning I lost my daughter's Irish setter to toxic algae. It happened within an hour of an exercise run after which I was careful to cool the dogs down. Our 1.5-year-old red setter had jumped in a nearby pond to cool off and drink after a short 10-minute workout. My water spaniel did the same but did not drink much.

"I found the setter dead in a pool of green puke less than an hour later. I researched the cause, tested the water and compared the algae types to the research, and found toxic algae to be the cause.

"The weather here in St Louis has been 95+ degrees with no wind for several weeks now. Perfect conditions for an algae bloom in a standing pond or small lake. Please search for more information and feel free to cross-post this warning so that people are aware of the dangers."

Research from the Montana University extension service has found that out of a large number of algae species to be found in that state and its neighbours there are only three species that are toxic to animals. The common green algae that can be scooped up in the hand and is stringy and sitting just below the surface is not likely to be toxic. But keep dogs well clear of algae that is blue-green in colour or even has a greenish-brown through to red colouring. This type of algae looks more like a surface scum, is not stringy but rather slippery and falls apart when picked up. It is toxic to all birds and animals.

For the toxic species to bloom the pond just needs to heat up in temperatures of around 72-80F and have no fresh water entering the pond. The pond water evaporates in such temperatures and as soon as light reaches the bottom of the pond and nutrients are present, then the conditions are ideal. For the sake of the safety of your dogs, inspect pond water before you let your dog swim in it or drink it. If it has a scum of any type on it, then treat it as a toxic bloom and don't allow dogs to drink or swim.

There is no known antidote for these toxins. There are two types of toxins produced by the pond, lake and reservoir algae - a peptide that causes liver damage but is individually rarely fatal, and an alkaloid, which causes death in a relatively short time. Symptoms include staggering, muscle spasms, laboured breathing and convulsions. Death is from respiratory failure. Humans are just as susceptible to the toxins, especially children who are unaware of the danger, so it is just as essential to keep children away from infected ponds, given their love of playing in water.

As well as in the USA, Australia and New Zealand have large problems with toxic algae in the rivers during the summer months when flow ceases in many rivers. In New Zealand three dogs were killed in one week early this year from drinking water from a North Island river. And toxic bloom is not confined only to fresh water - many of New Zealand's beaches carry warnings in the summer of toxic bloom that is affecting the shellfish. That particular bloom does not require stagnant water to thrive.

Recent reports in UK carry warnings for swimmers and people walking dogs to keep away from named lakes, reservoirs and rivers. Europe has reported the same problems and China has had a recent scare with two of its largest waterways infected. It seems that no country is free of toxic algae and the problem is becoming worse. Unfortunately it seems that there is little publicity about the potential dangers from swimming in the bloom and swallowing water, drinking from the infected waterways, or eating shellfish or fish caught or gathered from infected areas. Please always be aware and inform friends and dog owners, no matter where they live in the world, of the likely dangers. - Liz Peters