The small island facing Verdun and Lasalle is home to a rare array of birds, trees and flowers.
However, Quebec's Ministry of Wildlife says there is an overpopulation of white tailed deer, which it says is disturbing the island’s fragile ecosystem.
The island is monitored by the Canada Nature Conservatory, which has given permits to 15 bow hunters to kill some of the deer.
This is also the first time hunting has been allowed near an urban area in Quebec.
Ten years ago one male and two female deer arrived on the 0.43 sq. km island.
The ministry says the quality and quantity of available vegetation on the island — combined with the absence of predators — allowed the deer population to grow rapidly in recent years.
An aerial survey in 2012 counted 46 animals on this small territory.
The ministry says the habitat of Heron Island has deteriorated because of grazing.
They say if action is not taken soon, the deer could cause irreversible damage to the ecosystem, including a sensitive heron habitat.
Hunting the deer will be allowed until October 23.
the Nature Conservatory says it is will be observing the hunting and collecting data on to monitor the deer population in the future.
Citizens are invited to report any poaching activities to SOS Poaching at 1-800-463-2191, or online.