FREDERICTON (GNB) – The Office of the Chief Medical Officer of Health is issuing a blue-green algae advisory for the Saint John River between Woodstock and Fredericton.

“We want all residents to be active and enjoy the outdoors, but we also want them to understand and consider the potential risks of exposure to blue-green algae in the Saint John River,” said Dr. Cristin Muecke, deputy chief medical officer of health. “Due to the presentation of blue-green algae in the form of benthic mats in the river, and a thorough risk assessment, we are adding the Saint John River between Woodstock and Fredericton to the advisory list. This advisory confirms that blue-green algae is known to form blooms or mats in this area.”

Blue-green algae are a natural component of New Brunswick’s aquatic ecosystems but, under certain conditions, can increase in numbers to form surface blooms which can appear blue-green, green, red, brown or yellow in colour. Blooms can also form on the bottom of lakes and rivers; these are known as benthic mats. Sometimes mats will break away from the bottom of the river and can be found floating in the water or washed up along the shoreline, making them accessible to pets and children. The algae mats look like clumps of vegetation, and can appear black, brown or dark green in the water. They can be attached to rocks or aquatic vegetation. On the shoreline, they may appear brown or grey once they have dried.

The government advises pet owners that algae mats along the shore of lakes and rivers can also be toxic and particularly harmful to dogs. Dogs are attracted to their odour and should not be permitted to eat vegetation or floating mats, as they can be lethal if consumed. As a precaution, children should not be allowed to play with them.

“While enjoying any recreational water, there are always things you can do to help protect yourself,” said Muecke. “Algal blooms can be unpredictable, so it is important that people always check the water before entering. If a bloom is present, it is recommended that you avoid swimming or engaging in other activities that may involve contact with the water.”

Other safety advice includes:

  • Always supervise young children and pets in recreational waters.
  • Do not swallow lake or river water.
  • Bathe or shower immediately after swimming.
  • Do not enter the water with open cuts or sores.
  • Always wash your hands before eating.

The government supports various blue-green algae research projects through the Environmental Trust Fund. These projects, which are underway in the Saint John River and several lakes in the province, are intended to build a better understanding of the distribution of blue-green algae and their toxins.

More information about blue-green algae is available online.