St. Lawrence River Ecosystem

The Upper St. Lawrence River has a wonderfully complex ecosystem and is home to the Thousand Islands region, a globally unique archipelago.

Linking Great Lakes to the Ocean

The St. Lawrence River is one of the largest Rivers in the world, linking the Great Lakes to the Atlantic Ocean. The Great Lakes hold nearly 20% of the world's freshwater, placing the St. Lawrence River in a unique position. As the only natural outflow to the Great Lakes, the health of the St. Lawrence is forever directly tied to the health of one of the world's greatest freshwater ecosystems.

Thousand Islands

Flowing over ancient glaciated rock, the upper St. Lawrence River has formed a unique island paradise known as the Thousand Islands, consisting of 1,864 islands. The islands provide a variety of habitats supporting all kinds of plants and wildlife.

Wildlife

The St. Lawrence River valley is teeming with wildlife throughout the year.

The River is home to several species of concern including threatened and endangered species such as Blanding's turtle, bald eagles, osprey, black tern, and the Indiana bat.

Numerous north woods mammal species find their home on the shores and islands of the River including muskrat, beaver, flying squirrels, mink, deer, porcupine, and many others. Winter ice cover on the River provides important passage for animals from the shoreline and to/from many of the islands.

Known as one of the great freshwater sport fishing grounds in the northeast, anglers travel from around the country to fish for pike, bass (particularly smallmouth bass), and muskellunge on the River.

The St. Lawrence River Valley is a key part of the Atlantic Migratory Fly-Way - the main pathway for seasonal migration of many bird species. The region has also been listed as an Important Bird Area by Audubon New York.

Bald eagles, which have not been seen in the River valley for many years, are making a comeback and can be seen frequently on the River in the winter. Visit our bald eagle page to learn more.

Wetlands

The St. Lawrence River is home to extensive coastal wetlands which provide filtration for runoff, flood retention, and provide wildlife with food and shelter. Wetlands also act as a nursery for the species of the River including waterfowl, numerous fish species as well as amphibians and reptiles.

For more information about the River's ecosystem visit the following:

• Frontenac Arch Biosphere Reserve - The Canadian portion of the Thousand Islands region has been designated a United Nations Biosphere Reserve in recognition of the area's globally unique ecosystem.
• The Algonquin to Adirondack Conservation Association - Learn about the critical wildlife corridor that connects Ontario, Canada to the Adirondak mountains via the St. Lawrence River valley.
• Thousand Islands Land Trust - The Thousand Islands Land Trust is a not-for-profit land trust dedicated to the conservation and enhancement of the scenic, recreational, natural and historic character of the Thousand Islands Region.
• Great Lakes Information Network - A wealth of information about all things Great Lakes.