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Battures aux Loups Marins (QC100)


Battures aux Loups Marins (QC100)

L'Islet-sur-Mer, Québec

Latitude 47.245°N
Longitude 70.418°W
Altitude 0 - 10m
Area 14.87km²

Site Description

The three small Îles aux Loups Marins (Loups Marins Islands) and the large rocky flats (battures) that surrounds these islands are found approximately 8 km off the south shore of the St. Lawrence estuary, Québec. L'Islet-sur-mer, the closest town, is situated 23 km east of Montmagny. The large rocky flats are interspersed with muddy depressions. The small shale reef islands support mainly herbaceous vegetation. A large stand of Reed-Grass (Phragmites communis) occurs on the largest islets, as do alder and rose plants. Large willow trees are found near an uninhabited cottage on the largest islet.


The Battures aux Loups Marins have the largest concentration of Semipalmated Sandpipers along the St. Lawrence. In excess of 30,000 birds, about 1% of the estimated global population of this species, has been recorded at this site during fall migration. Other shorebird species occurring in large numbers at this site during fall migration include Semipalmated Plovers (770 or 1.5% of the global population) and Ruddy Turnstone (250). Black-crowned Night-Herons occur in nationally significant numbers at this site. A total of 135 nests have been recorded, representing almost 3% of the estimated Canadian population. The other heron at this site, the Great Blue Heron occurs in much smaller numbers (8 nests).

Common Eiders have gradually increased in numbers since 1971 when only 24 nests were recorded. By the early 1990s, an average of 273 pairs were counted at this site. American Black Duck and Northern Pintail nest in small numbers on the islands and the "battures" are used as a staging area for the Greater Snow Goose in spring and fall. Although no recent surveys have reconfirmed the breeding presence of gulls, in 1971, 20 nests of Great Black-backed and 60 nests of Herring Gulls were recorded at this site.

Conservation Issues

Oil spills are a constant threat to the islands of the St. Lawrence estuary, as a result of the steady flow of large ocean freighters. Oil spills and illegal discharges from these boats occur fairly frequently. The oil from these releases occasionally has devastating results on local seabird populations and other marine wildlife. Concerns at this site include the disturbance of birds from tourists, naturalists and yachters who sometimes approach the colonies too closely.

Fish Habitat

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:
American eel
American shad
Atlantic sturgeon
Atlantic tomcod
Lake sturgeon
Rainbow smelt (population of south shore of the St. Lawrence middle estuary)
Striped bass


Coastal habitats of this area are soaked by generally turbid and lightly salted water. We found mostly brackish marshes, dominated by American bulrush, sessilefruit arrowhead and broad-leafed arrowhead. With there large root system, theses plants retain the soil in place, helping to protect the banks against coastal erosion. In addition, the underground parts are used as a food source by the snow geese during their migrations.

The destruction and loss of habitat (shoreline fill, draining wetlands, urbanization) are the main threats affecting this ecosystem. Water pollution and the risks of oil spills are issues of concern. The spread of invasive species is to be monitored. This region is hosting 18 endemic plant species, including three endangered species in Québec.

Major species present :
American bulrush
Broad-leafed arrowhead
Sessilefruit arrowhead

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status
Semipalmated Sandpiper
Number Year Season