Dogs & Harmful Algal Blooms

Protect your dog from hidden dangers around the water.

The Green Menace in the Chesapeake Bay

Harmful Algal Blooms (HABs) are rapid overgrowths of toxic blue-green algae (cyanobacteria). Fueled by fertilizer runoff and septic systems draining into our creeks and rivers, these blooms poison local waterways.

What They Look Like
They typically appear as a thick green or blue-green paint-like scum, foam, or discoloration on the surface of the water.
The Danger
Cyanobacteria produce powerful toxins that target the liver. They can be fatal to dogs and wildlife and even make humans incredibly sick.

How Dogs Can Be Exposed

Dogs are especially vulnerable because they naturally explore their surroundings. Exposure can happen when they:

Drink contaminated water.
Swim or wade in affected areas.
Lick algae-contaminated water from their fur.
Eat shoreline debris, shellfish, or mussels that may contain toxins.

Even small amounts of toxin exposure can cause serious illness, making prevention essential.

Signs of Algal Toxin Poisoning

Repeated Vomiting (Green Liquid)
Diarrhea or Tarry (Bloody) Stool
Loss of Appetite
Jaundice (Yellowing of Eye Whites, Gums)
Abdominal Swelling That May Be Tender to the Touch
Cyanosis (Bluish Coloration of the Skin)
Dark Urine or Reduced/No Urine Output

How to Reduce Your Dog's Risk

Keep your dog on a leash near shorelines.
Prevent your dog from drinking untreated water.
Avoid areas with visible algae or water discoloration.
Don't allow your dog to eat shellfish, mussels, or beach debris.
Rinse your dog's coat with clean water after swimming.

Helpful Resources

Before visiting local waterways, check for reports of harmful algal blooms in your area through local environmental agencies. Staying informed can help you make safer choices for your pet.

You can also download an educational Dogs & Harmful Algal Blooms flyer for quick safety tips before your next outdoor adventure.