Toxic Algae in Rivers and Lakes: A Guide for Dog Owners
Posted in: Companion Animals
Toxic algae (cyanobacteria) forms dark, musty-smelling mats on riverbeds and can be deadly to dogs in very small amounts. It’s most common over summer in South Canterbury’s rivers and lakes. If your dog licks or eats it, this is an emergency – some dogs can become seriously unwell within 30 minutes.
When you’re out exercising your dogs near ponds, lakes or rivers keep an eye out for toxic algae blooms and keep an eye on the ecan website. I have included a link below.
Dogs that come into contact with algal blooms (swim in the water, drink from the water and/or lick/consume the blooms) can become sick and sometimes die from the effects of toxic algal poisoning.
If you suspect your dog has come into contact with toxic algae blooms get veterinary help immediately.
Symptoms can include vomiting, diarrhea, blood in stool or black tarry motions, salivation, difficulty breathing, pale gums or jaundice (yellowing of gums), shock, disorientation, neurological symptoms (e.g. muscle tremors, rigidity).
Frequently Asked Questions
What does toxic algae look like?
It often appears as dark brown, black, or greenish slimy mats on rocks or riverbanks, sometimes with a strong musty smell that dogs find attractive.
How much toxic algae is dangerous to a dog?
Even a small piece can be enough to be fatal, so any suspected contact or ingestion should be treated as an emergency.
How fast do symptoms appear?
Very fast – in severe cases, symptoms can develop within 30 minutes of ingestion.
What should I do if my dog has been near toxic algae?
If you think your dog has licked or eaten it, treat it as an emergency and get to a vet immediately, even before symptoms appear.
Where in Canterbury should I be extra cautious?
Rivers known to experience blooms include the Opihi, Otaio, Pareora, Temuka, and Waihao – check Environment Canterbury’s alerts before visiting swimming spots in summer.