Aquatic invasive species found for first time in Canada at Hillman Marsh

The aquatic invasive plant, hydrilla. (Source: ERCA)

The aquatic invasive plant, hydrilla, has been detected for the first time in Canada at a marsh in Leamington.

It was located in the West Cell at Hillman Marsh Conservation Area.

The Essex Region Conservation Authority (ERCA) is working closely with the Ministry of Natural Resources, the Invasive Species Centre, the Ontario Federation of Anglers and Hunters and many other partners to evaluate the extent of the infestation, contain the spread, and develop plans to control this invasive species. To date, surveys have shown the infestation to be limited to the contained wetland area of the West Cell of Hillman Marsh that is not directly connected to Lake Erie.

Hydrilla (Hydrilla verticillata) can grow up to 2.5 centimetres per day and to lengths of 7.5 meters. This rapid growing invasive species can choke out native species and clog water intake pipes, boat motors and impede other recreational activities like swimming and paddling.

Hydrilla is a prohibited invasive species under Ontario’s Invasive Species Act 2015.

In a pro-active effort to contain the spread of this invasive plant, ERCA will be immediately closing the West Cell of Hillman Marsh, including the trail and boardwalk, to boating, walking and hunting. Hydrilla is easily spread when boat propellers, kayaks, canoes, trailers, fishing and hunting gear, pets or people inadvertently carry attached plant fragments to new areas.

ERCA is asking the public for assistance in refraining from accessing this area.A drone image shows the Hillman Marsh and the dyke that protects the farmland to the south. (Image coutesy: Ian Duckworth)

“Ontario recognizes the importance of the prevention, early detection and management of invasive species that pose a threat to Ontario’s native species and ecosystems. If left unchecked, hydrilla – an aggressive aquatic plant – has the potential to severely impact navigation, recreation, and aquatic life,” said Graydon Smith, Minister of Natural Resources. “That’s why we’re working diligently with our partners to develop plans for its control.”

ERCA’s director of conservation services Kevin Money said the detection of this highly aggressive water plant is alarming.

“Most concerning is its ability to significantly disrupt, alter and outcompete the natural ecosystem. We take its detection within our wetland with the utmost seriousness and are proactively taking all steps we can to contain it, including, unfortunately, halting recreational activities within the cell and its surrounding area.”