Aquatic Invasive Species

Like their terrestrial counterparts, aquatic invasive species (plants and animals) have been entering Canadian waters for centuries but never as rapidly as today. Fisheries and Oceans Canada states that aquatic invasive species have already been responsible for significant devastation of some native fish species and fisheries in Canada. Annually, the problem is responsible for billions of dollars in lost revenue and control measures.

Water-based recreational activities such as angling, boating and diving can spread aquatic invasive species to new locations. Plants, animals, and microscopic creatures can cling to clothing, equipment and boats. If not cleaned, these species can be introduced into new bodies of water.

In the Okanagan Valley, there has been little attention on invasive aquatic species, with the exception of Eurasian Water Milfoil. Invasive plants like milfoil can form thick mats on the surface of the water, which can impede light penetration to underwater plants and animals, hinder boat traffic, clog intake pipes of boats, foul fishing lines and nets and cause a danger to swimmers. Once established, these species are extremely difficult, if not impossible, to eradicate. Economically, the impacts of aquatic invasive plants can be devastating. Many of these species can cause increased boat repair and maintenance costs when they become tangled in motors. Real estate values can become depressed on waterbodies with aquatic plant infestations like milfoil. Water intake structures on dams can be damaged from mats of invasive plant materials. Management strategies to address infestations are extremely costly.

Unfortunately, the concerns do not end with plants. In fact, aquatic invasive animals pose a far greater threat to our waterways. Of immediate concern are two freshwater mussel species, Zebra and Quagga Mussels; there are no known occurrences of these mussels in British Columbia. These invertebrates rapidly colonize hard surfaces and can subsequently clog water-intake structures, impact recreation, alter food webs and affect water quality. Invasive mussels can affect entire ecosystems. Recent research has determined there is a high risk of invasive mussels not only surviving in some parts of Okanagan Lake, but there is a high potential for massive infestations.

When it comes to aquatic invasive species, the ecological balance of our lakes and rivers is at risk, and so is our drinking water. Prevention of harmful new invasions is the first priority, as it is the most cost-effective way to deal with the problem. Once species are established, the task becomes far more complex and costly.

Since 2013, OASISS has worked cooperatively with the Okanagan Basin Water Board (OBWB) local government, marinas and yacht clubs, and the provincial government on a valley wide campaign to stop the spread of aquatic invasive species. 

Summer students Matt (South Okanagan), Connor (North Okanagan) and Sierra (Central Okanagan) are helping to protect our waters in 2019.


Report possible sightings of Zebra and Quagga Mussels to the B.C. Conservation Officer Service at 1-877-952-7277 (RAPP)


Preventing Zebra and Quagga Mussels from invading the Okanagan is a high priority.


Eurasian milfoil is a commonly recognized invasive aquatic plant in the Okanagan Valley.


Zebra Mussels attach to any hard surface that is submerged, including rocks, native species, boats and equipment, pilings and water-intake pipes.

Photo: Jacquie Rasmussen