Quinte Fishing

April 18, 2006

The Grand River Conservation Authority plans to protect the great blue heron population at Luther Marsh from an invasion of double-crested cormorants.

The plan calls for a GRCA staff member, who is a licensed trapper, to shoot and kill adult cormorants in the Luther Marsh Wildlife Management Area before they establish a breeding colony.

The control of cormorants at Luther Marsh is in compliance with the Ontario Fish and Wildlife Conservation Act, which permits landowners to take action to protect their property from damage caused by nuisance wildlife.

The plan was approved by the GRCA’s Planning and Operations Committee on Tuesday. The committee’s recommendation will be on the agenda of the full GRCA board at its meeting on April 28.

The action is necessary because, over the past two years, an increasing number of cormorants have been invading nesting sites historically occupied by great blue herons in the 5,200-hectare Luther Marsh, which is west of Grand Valley, straddling the Dufferin-Wellington county boundary.

GRCA terrestrial resource management staff are concerned that the cormorants may have a harmful impact on the significant heron habitat.

A survey of herons showed about 84 nesting pairs in 2000. Over the past 40 years the GRCA has supported the heronry by erecting artificial nesting platforms and moving fallen tree trunks into areas to create suitable nesting sites for great blue herons.

In the past two years the number of cormorants in the Luther Marsh area has risen rapidly, from four nesting pairs in 2004 to 25 pairs in 2005. A significant increase is foreseen for 2006. The cormorant population is growing so rapidly that failure to act this year would make it difficult to control the cormorant colony in the future.

Cormorants have significantly expanded their range within the Great Lakes region in recent years. In the past they typically colonized major coastlines and islands within site of large bodies of water but have recently started to colonize smaller inland lakes. Cormorants have generally adapted to lakes, ponds, rivers, lagoons, swamps and coastal bays. They will build nests on the ground or in trees in freshwater situations.

Luther Marsh, which was created by the construction of the Luther Dam in 1954, is one of the largest inland wetland complexes in southwestern Ontario and is highly vulnerable to an invasion by cormorants.

Glad it's happening in other places besides Quinte. (a cull that is)