Anse de Saint-Vallier is a small bay on the south shore of the St. Lawrence River by the village of St. Vallier, Québec. It consists primarily of a mudflat and a Scirpus marsh; the area's boundaries are delineated by the high and low tide levels. The Boyer River, which flows into the bay, is a spawning site for three species of fish at risk.
Anse de Saint-Vallier is noteworthy for its flocks of migrating waterfowl. The most prominent of these is the Greater Snow Goose (subspecies atlanticus), which can be present in globally significant numbers in the spring. In 1995, a flock of 50,000 were spotted, accounting for over 1% of the global population of this subspecies.
Numerous other waterfowl species, including Canada Goose, are common at the site, especially in fall when hunting pressures elsewhere bring them here for shelter. At this time, surveys have recorded both species of scaup, with maximum counts of 2,510 for Greater (1975) and 4,000 for Lesser (1988).
This site also hosts flocks of migrant shorebirds in spring and fall. The most common species are Killdeer, Black-bellied Plover, Spotted Sandpiper, Greater and Lesser yellowlegs, and White-rumped, Least and Semipalmated sandpiper. The highest numbers are found in early August. For instance, in August 1989, a peak of 4,000 Semipalmated Sandpiper were recorded.
The St. Lawrence Seaway is a heavily travelled route, making the risk of oil spills constant. Toxic substances found in the area come from three major sources: the waters of the river and its tributaries, industrial waste, and municipally-used waters. Two industrial plants situated upstream from Saint-Vallier have been designated as major sources of pollutants by the Priority Intervention Zone committee. Heavy metals are the main known toxins and attach to suspended material in the river but, since sediments don't stay long in the Orléans Island channel, the contamination level is not known. There are agricultural fields along the Boyer River that, in turn, could be another pollution source. The presence of invasive exotic species is also of concern: the Japanese knotweed is spreading in the vicinity of the main observation site and zebra mussel shells are now found on the shores, a sign that this species reached this part of the St. Lawrence. Finally, the high tides of December 2010 led to increased coastal erosion. This IBA is designated a Migratory Bird Sanctuary and is also included in the Priority Intervention Zone of the Québec and Chaudière-Appalaches region. The site is also designated as a Periodically Flooded Area.
The bulrush marsh is the typical coastal habitat in the region. While the water has in this region a low salinity, tides are still present and reshape continuously the river landscape. Several species, such as the rainbow smelt (population of south shore of the St. Lawrence middle estuary) and Atlantic tomcod exploit the shallow waters of the area. Many migratory species (anadromous and catadromous) are also found in the area. In addition to the two species mentioned above, we found also the American shad, the Atlantic sturgeon and the American eel, all three species being prized for their tasteful flesh.
However, several sources of pressures are threatening both the quality and the availability of aquatic habitats. The expansion of agriculture, the residential development, the creation of new resorts and artificialization of the shoreline represent significant habitat losses. The presence of major obstacles may impede the movement of fish toward their breeding site. Finally, the maintenance of the Seaway for commercial navigation (dredging and the discharge of sediments) reduces the water quality and may cause the destruction of spawning sites. The decrease of the Atlantic sturgeon population of in the St. Lawrence can be assign to this aspect. Because of habitat alteration, high exploitation of commercial and recreational fisheries and non-compliance, the population of striped bass in the estuary of the St. Lawrence disappeared around 1968. In 2002, Quebec government has established an important reintroduction program to rehabilitate the specie. Between 2002 and 2007, more than 6 300 striped bass and 6,5 millions larvae were introduced into the St. Lawrence river. A network monitoring incidental captures has been implemented in 2004, allowing to document the evolution of the population.
30,000 fry and more than a thousand individual larger than 35 cm were introduced into the St. Lawrence. In early summer 2006, over one million . From 2008, up to 50 000 fry are introduced annually over a period of 10 years. The objective of this program is to rehabilitate the striped bass population of the St. Lawrence.
Major species present:
Rainbow smelt (population of south shore of the St. Lawrence middle estuary)
|70,000 - 75,000||2016||Fall|
|26,000 - 45,000||2013||Fall|
|17,000 - 53,000||2012||Fall|
|18,000 - 20,000||2012||Spring|
|5,000 - 20,000||1996||Fall|
|5,000 - 7,000||1996||Spring|
|5,000 - 50,000||1995||Spring|
|10,000 - 20,000||1994||Spring|
|15,000 - 20,000||1990||Spring|