Eco-Regions of the St. Lawrence
From the pastoral riverbanks just east of Kingston, Ontario, to the rocky shores of the Gaspé Peninsula, where 150 kilometres separate the north and south shores of the river, the St. Lawrence passes through over 1,000 kilometres of changing landscapes and contrasting environments. Researchers typically divide the St. Lawrence into 4 hydrographic regions:

• Fluvial Section - From Kingston, Ontario to Trois Rivières, Quebec, the Fluvial segment is a slow-moving, alkaline freshwater ecosystem with a large flood plain. It is populated by mollusks, crustaceans, bullhead, carp, walleye, sturgeon, pike, muskellunge, perch, trout, char, blue heron, Canada geese, mergansers, goldeneye, snow geese, wood ducks, peregrine falcons, mink, muskrats, otters, beaver and raccoons. The Lac St.-Pierre region of the fluvial segment is characterized by sedimentation from many area tributaries, resulting in marshes and wet meadows.

• Fluvial Estuary - From Trois Rivières to Ile d'Orleans, a deep, narrow section of the St. Lawrence is characterized by turbid freshwater. The tidal ranges reaches its peak (4 - 5 metres) in this segment. Fish species include bass, shad, eel, bullhead, pumpkinseed, smelt, sturgeon, alewife, whitefish, sea lamprey, redhorse and trout. Bird and mammal species of the Fluvial section extend their range through the Fluvial Estuary.

• Upper Estuary - From Ile d'Orleans to Tadoussac, the river is turbid, brackish and narrow, with extensive bulrush marshes. Both fresh and salt water fish are present, including eel, bullhead, bass, carp, sucker, capelin, lumpfish, cod, tomcod, shark and sturgeon. This river segment has the greatest diversity of water birds, including snow geese, black ducks, gadwall, and purple sandpiper. Marine mammals begin to appear, including beluga whales, longfinned pilot whales, minke whales, harbour seals, harbour porpoises, grey seals and harp seals.

• Lower Estuary and Gulf - From Tadoussac to the Gulf of St. Lawrence, a saltwater marine environment sustains urchins, mussels, cod, skate, halibut, dogfish, flounder, Atlantic salmon, mackerel, sunfish, redfish, herring gulls, Atlantic puffins, common eiders, shearwaters, razorbills, whales, dolphins, harp seals, hooded seals and grey seals.

Tadoussac's Arctic Waters
Wham! At the Quebec village of Tadoussac, on the north shore of the St. Lawrence, near the mouth of the Saguenay River, the icy Labrador current, flowing opposite into the St. Lawrence Estuary, suddenly hits a massive underwater wall. The depth of the current decreases abruptly from 300 metres to only 10, causing the upwelling water to draw enormous amounts of organic material from the bottom. Plankton feed on the material, fish feed on plankton, and marine animals, such as beluga whales and seals, feed on the fish. The conditions produced by the current collision mimic those of Arctic waters, creating a marine micro-environment typical of oceans in the far north.

River Otter Revelry
The river otter (Lontra Canadensis) population of the St. Lawrence River valley may be one of the most stable in North America (inhabiting almost all of the rivers' eco-regions), but the sight of this slender, whiskery, snub-nosed aquatic mammal, popping suddenly out of the water like a gopher from its prairie hole, is still a rare and delightful treat. Whether you set off on a deliberate otter quest, scanning banks for burrows, flattened vegetation and telltale scat, or simply cross its path during a shoreline paddle, you will find it hard to turn your gaze away from its captivating face and glistening, rich brown coat.

The otter, on the other hand, may be less impressed with you. Snorting, snarling, almost barking, it will drop soundlessly beneath the surface, only to emerge suddenly to the right, the left, or on the other side of your canoe. With its ability to close off its ears and nose while submerged, the otter can swim underwater, at speeds of up to 10 kilometres per hour, for at least 4 minutes, and dive to up to 18 metres, making it both an efficient predator and an engaging, unpredictable trickster.

Somersaults and Slides: Supremely agile and acrobatic, the otter is markedly more playful than most animals. It can be observed wrestling and somersaulting with other otters, deliberately tossing and diving for rocks or shells, repeatedly capturing and releasing live prey. It is famous for its tendency to slide gleefully down wet banks, or along snow-covered terrain, a behaviour that has as much to do with practical, speedy travel as it does with pleasure and amusement. Otters are also adept at catching and consuming their prey in the water, sometimes floating on their backs while they hold their food in their forepaws.

Mega-Mustelid: Weighing in at a hefty 6 - 15 kilograms, and extending 1 - 1.5 metres in length (including a flattened, narrow, tapered 30 -45 centimetre tail), the river otter is the largest "mustelid" in a family that includes wolverines, martens, muskrats, fishers, weasels, mink, ferrets, skunks and sea otters. Like all mustelids, the river otter has a pair of scent glands, located in its anal area, that emit a strong, pungent odour when it is frightened or excited.

The river otter is cylindrical in shape, with a thick, muscular neck, a blunt, diamond-shaped nose, tiny ears and small eyes set near the top of its skull for just-above-the-surface viewing. Its legs are short, stubby, and powerful, with five webbed toes on each foot. Sensitive facial whiskers and a keen sense of smell compensate for poorer sight, allowing the otter to locate prey even in dark and murky water.

Flexible Fur-Bearer: Males are somewhat larger than females, but both genders bear the same rich brown coat and silvery muzzle and throat. Throughout North America, the otter has been heavily harvested for its short, dense, well-oiled, glistening fur.

Otters are most active at night, though a daytime sighting is not uncommon. Look for them in wooded or marshy areas, where brush piles, large tree roots, or soft riverbanks provide ready-made dens. (Hint: Beaver ponds make ideal otter habitats, and crafty otters are not above squatting in an abandoned beaver or muskrat den.) Despite its name, the river otter does not limit its range to major waterways. Streams, marshes, even farmer's ponds can serve its purpose, as long as the water is reasonably clean and prey - fish, crayfish, amphibians, insects, vegetation and the occasional small mammal or bird - is plentiful. Crayfish are an otter's favourite food, sometimes representing 90% of the summertime diet.

Otters are a highly adaptable species, surviving in both salt and fresh water environments, with no need to hibernate or migrate. Although they have few natural predators, and can complete a natural life span of up to 20 years, their position at the top of the food chain makes them vulnerable to industrial pollutants, and their rich, lustrous coats continue to attract the interest of licensed trappers.

The Declining American Eel
With its slimy, snake-like body, long, continuous fin, pointed head, and mouthful of tiny teeth, the bottom-dwelling American eel (Anugilla rostrata) will never win an aquatic beauty contest. But this homely inhabitant of the St. Lawrence River possesses both a complex life history and a significant commercial value (smoked, pickled or jellied, eels are a European and Asian delicacy). Its recent decline in abundance has alarmed both biologists and fishers and prompted renewed investigation of the factors affecting eel populations.

Although American eels are the only freshwater eel found in North America, their geographic range is vast. They can be found in all of the estuaries and coastal freshwaters of the continent, extending as far north as Labrador, as far inland as the Great Lakes and the Mississippi River, and as far south as Gulf of Mexico, the West Indies and even the northern coast of South America. While eels found in the St. Lawrence River are referred to as "St. Lawrence Stock," they are in fact part of a single global population.

Caribbean Cradle to River Residence: All eels begin their lives in the same location, far from the American heartland. Hobby anglers fishing the St. Lawrence river at Trois Riviéres, Quebec, surprised to find a serpentine creature at the other end of their line, may be downright astonished to learn that their slippery catch originated in the spawning grounds of the Sargasso Sea, east of the Bahamas. In a complete reversal of the anadromous life cycle (freshwater to saltwater to freshwater), the American eel is "catadromous." It migrates from the ocean to freshwater for rearing, returning to the ocean to spawn:

• Mature silver eels spawn in early spring in the Sargasso Sea.

• Buoyant eggs float to the surface, hatch and develop into larvae ("leptocephali") that drift with the ocean currents to the coastal areas of North America.

• Larvae grow into leaf-shaped, transparent "glass eels" (55 - 65 millimetres in length) that are attracted to freshwater and brackish estuaries.

• Glass eels adapting to freshwater gradually darken in colour and become "elvers."

• While some elvers remain in estuaries, many migrate hundreds of kilometres inland, overcoming dams and other obstacles, to grow into "yellow eels" and remain in freshwater for 5 - 20 years. Yellow eels can reach weights of up to 4.5 kilograms, and lengths of up to 1.5 metres. Yellow eels feed nocturnally on fish, crabs, worms, clams and frogs, and hibernate in muddy bottoms during the winter.

• Yellow eels mature sexually into "silver eels." During the fall, silver eels descend streams and rivers, sometimes crawling through damp grass in wet weather, to the ocean, returning to spawn and die in the warm Caribbean waters.

Ladies Only: In addition an epic life cycle, American eels also possess the ability to adapt their gender and reproductive capability to environmental conditions. Males are more likely to develop in warm, crowded, poorly productive waterways, while cooler, less populous areas trigger female characteristics. The American eel population of the St. Lawrence River is exclusively female.

Population Puzzle: In 1986, when only 200,000 eels ascended the eel ladder at the hydroelectric dam near Cornwall, Ontario, compared to over a million just a few years earlier, population alarm bells began to ring. When both ladder counts and commercial catches continued to decline, dipping precipitously in 1993, fisheries managers raised the spectre of industry collapse, extinction of the Great Lakes and St. Lawrence River stocks and - with St. Lawrence eels representing 20% of the total female population - a significant species-wide decline.

Using eel ladder recruitment data and records of commercial catches from eel-fishing areas such as the Bay of Quinte in Lake Ontario, researchers are examining possible causes of population decline, including St. Lawrence Seaway obstructions, overfishing, water pollution and changes in the ocean climate.

Even when stocks are numerous and healthy, eel fishery management is challenging, due to the complexity and lingering mystery of its lengthy and complex life cycle. Environmental contaminants are an ongoing concern, since the fatty flesh of the eel makes it very vulnerable to toxins such as PCBs and organochlorous pesticides.

Greater Numbers of Greater Snow Geese

By mid-October of each year, the 10 kilometre stretch of St. Lawrence River shoreline in the Cap Tourmente National Wildlife Area, downstream from Quebec City, is chock-a-block with Greater Snow Geese feasting on the rhizomes of the American bulrush. By first frost, up to 80,000 of the large (2.8 - 4 kilogram), sharp-beaked, herbivorous, snow-white birds will have stripped the ground bare, in gluttonous preparation for the final leg of their 4,000 kilometre journey from Baffin Island to their New England seaboard wintering grounds.

While Cap Tourmente's tidal marsh has always attracted high numbers of Greater Snow Geese, the central (Quebec City) St. Lawrence River region as a whole acts as a seasonal staging area for virtually all of the world's Snow Geese population. Their spring and fall arrivals are an ever-increasing spectacle, as their total numbers have grown from a near-extinct level of 3,000 in 1900 to almost 1 million at the turn of the 21st century. The dramatic rise in the Great Snow Goose population can be attributed to several factors:

• Historical Hunting Restrictions: In 1916, a Canada-U.S. treaty banned the hunting of migratory birds, including spring hunting of Greater Snow Geese. (Based on the current strength of the species, a stringently-controlled spring hunt has recently been re-introduced.)

• Protected Areas: The establishment of National Wildlife Areas such as Cap Tourmente, and of Migratory Bird Sanctuaries such as Saint-Vallier, Montmagny and Cap-Saint-Ignace have provided flyway refuge to migrating geese. The species' main nesting colony, on Bylot Island off the northeast coast of Baffin Island, has also been designated as a federal Migratory Bird Sanctuary.

• Plentiful Food: As agricultural lands have replaced the wilderness of North America, food supplies for migrating Snow Geese have increased. For the geese, farmers' fields have become a favoured feeding ground, but for some farmers, growing numbers of geese have become a nuisance.

• Climate Change: A trend toward milder temperatures in the Arctic have created more favourable reproductive conditions for the geese and contributed to higher rates of survival for their young

St. Lawrence Vision 2000: An Action Plan
Since the 17th century, the St. Lawrence River has provided the resources for the most intensive process of urbanization and industrial development in Canada. But it was well into the 20th century before questions arose about the river itself: How clean was the water? How healthy were the fish and wildlife? What did shipping and navigation do to the river's shoreline? Just how diverse - and how sensitive - was the ecosystem of "Le Fleuve"?

Community Partnerships: Following the Canadian federal government's first St. Lawrence water quality study in 1970, and a 1978 Province of Quebec River Water Quality wastewater treatment initiative, the two jurisdictions joined forces in 1988 to launch the "St. Lawrence Action Plan." Known today as "St. Lawrence Vision 2000" (SLV 2000), the umbrella organization now coordinates research and information in cooperation with bodies such as Strategies Saint-Laurent, the Biosphere-Ecowatch program, the St. Lawrence Observatory, and a number of community-based "ZIP" committees that identify priorities for local action.

With its partners, St. Lawrence Vision 2000 has addressed issues of industrial, urban and agricultural pollution, human health, navigation and biodiversity. Treatment of municipal wastewater, and identification and treatment of industrial effluents, including those of the pulp and paper industry, have been paramount. Studies have been carried out regarding endangered species, toxic levels and effects of sport and commercial fish, water level fluctuations and disturbance of wildlife.

Shoreline Conservation and Species Biodiversity: Now in its third phase, St. Lawrence Vision 2000 has recently studied the wave action created by shipping and recreational boating on shoreline erosion of the upper Cornwall to Montmagny section of the river, and has made recommendations concerning reduced speeds.

In addition, a major inventory and assessment of St. Lawrence River biodiversity, "Biodiversity Portrait of the St. Lawrence," compiled by a multidisciplinary team of 40 scientists over 5 years, has provided an exhaustive, online compendium of current knowledge about the flora and fauna of the river. The initiative has led to the identification of new conservation sites based on evidence of their species richness.