Saint Lawrence Seaway - Ecology

Ecology

To create a navigable channel through the Long Sault rapids and to allow hydroelectric stations to be established immediately upriver from Cornwall, Ontario and Massena, New York, Lake St. Lawrence was created through the flooding on 1 July 1958 of six villages and three hamlets in Ontario, now collectively known as "The Lost Villages." There was also inundation on the New York side, but no communities were affected. The creation of the seaway also led to the introduction of invasive species of aquatic animals, most notably the zebra mussel into the Great Lakes Basin.

The seaway provides significant entertainment and recreation such as boating, camping, fishing, and scuba diving. Of note, The Old Power House near Lock 23 (near Morrisburg, ON) became an attractive site for scuba divers, the submerged stone building covered with barnacles and home to an abundance of underwater life.

The Seaway also provides a number of divable shipwrecks within recreational scuba limits (shallower than 130 ft (40 m)) The region also offers technical diving with some wrecks lying at 240 ft (73 m). Surprisingly, the water temperature can be as warm as 75 °F (24 °C) during the mid to late summer months. The first 10 ft (3 m) of Lake Ontario is warmed and enters the St. Lawrence river as the fast moving water body has no thermocline circulation.

On 12 July 2010, Richelieu (owned by Canada Steamship Lines) ran aground after losing power near the Côte-Sainte-Catherine lock. The grounding punctured a fuel tank, spilling an estimated 200 tonnes of diesel fuel, covering approximately 500 m2. The seaway and the lock were shut down to help contain the spill.