Full Site

Marais de la baie de L'Isle-Verte (QC042)


Marais de la baie de L'Isle-Verte (QC042)

Saint-Jean-Baptiste-de-L'Isle-Verte, Québec

Latitude 48.038°N
Longitude 69.344°W
Altitude 0 - 10m
Area 41.33km²

Site Description

Baie de l'Isle-Verte is a cove located beside the town of Saint-Jean-Baptiste de l'Isle-Verte, on the St. Lawrence River estuary, Québec. This town is located approximately 30 km east of Rivière-du-Loup. A National Wildlife Area (NWA) encompassing the marsh (marais) extends along km of shoreline to the west and east of the town, and a smaller Migratory Bird Sanctuary is centred in the middle of the NWA. There is a succession of different habitat types, from the estuarine waters and tidal marshes composed of saltwater cord-grass, to prairies of salt-meadow grass, and finally to coastal alder swamp. Its main feature is a vast marsh dotted with ice extraction pans created by the action of the retreating ice in the spring. This is the site of the largest remaining spartina marsh in southern Quebec. The marshes are continuously fed by the Green River and a few brooks.


Baie de l'Isle-Verte is a significant site for Greater Snow and Canada Geese. During spring and fall migrations, as many as 27,000 geese have been observed at this site. At the same time, greater than 4,000 Black Ducks can be observed here. Other migrant waterbirds include: Green-winged Teal, Northern Pintail, Common Eider, scoters, gulls and cormorants. The variety of habitats found within Baie de L'Isle-Verte attract a large number of bird species throughout the year. Within the National Wildlife Area, more than 260 bird species have been recorded, including some rare species, such as Eurasian Widgeon, King Rail, Laughing Gull, Hawk Owl, Marsh Wren and Wilson's Phalarope.

Nelson's Sharp-tailed Sparrow breeds here while the Short-eared Owl is a probable breeder. The Short-eared Owl is nationally listed as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). These two species are also likely to be designated as threatened or vulnerable in Québec.

Shorebirds that have been recorded include: Whimbrel, Greater Yellowlegs, Black-bellied Plover, Semipalmated Plover, Spotted Sandpiper, Hudsonian Godwit, Common Snipe, Pectoral Sandpiper, Least Sandpiper, and Semipalmated Sandpiper. Older breeding season surveys recorded 501 Black Duck ducklings (1968), 386 ducklings (1969), and 167 broods in 1970.

Conservation Issues

Baie de l'Isle Verte National Wildlife Area was created in 1980 mainly to protect the spartina marshes, an important habitat for the American Black Duck: 13% of this 548 ha National Wildlife Area is occupied by tidal marshes. In 1986, the Isle-Verte Migratory Bird Sanctuary was added to protect staging habitat for geese and ducks. The National Wildlife Area is overlapped partially by this Migratory Bird Sanctuary around the Anse Verte area. Tidal marshes and mudflats outside the protected areas are under provincial jurisdiction. The federal and provincial properties are protected by the RAMSAR Convention status given in 1987. The IBA is now included in the Kiskotuk coastal park created in November 2012. In 2013, Ducks Unlimited together with the Canadian Wildlife Service constructed riprap sills to maintain waterfowl habitat. Although much protection is afforded to this site, it still remains vulnerable to oil spills.

Fish Habitat

The landscape of the are is made out of Spartina marsh, eelgrass beds, rocky shores and gravel or pebbles beaches. Some rivers are hosting rainbow smelt spawning runs (the south shore population of the St. Lawrence middle estuary). At the beginning of the summer, it is possbile to observe capelin rolling on the beaches during spawning. The downstream migration of American eel toward their breeding sites in the Atlantic, which takes place in the fall, allows the capture of migraing adults using fishing weirs. Two other species commercially exploited are also roaming in the open waters of the estuary: the Atlantic sturgeon and Atlantic herring.

Loss of fish habitat remains a major problem in the region. The dikes, for example, reduce the number of spawning habitats, while agricultural along the coast, the residential development and the presence of resorts together with coastal erosion are resulting in the destruction of several riparian ecosystems.

Major species present:
American eel
American shad
Atlantic herring
Atlantic sturgeon
Rainbow smelt (population of south shore of the St. Lawrence middle estuary)


The landscape of the coastal region is punctuated with salt marshes. Plant species that grow are especially well adapted to survive the rigors of the environment. They occupy different parts of the marsh according to their tolerance to salinity and immersion (tides). We found there mainly cordgrass, saltmeadow cordgrass and glasswort. The tight formation of stems and the large roots network of cordgrass promote the deposition and retention of sediments, reducing coastal erosion. In areas with weak currents, eelgrass colonizes silty soils, while seaweeds attach and inhabit rocky substrates.

The destruction and loss of habitats (shoreline fill, draining wetlands, urbanization) are the main threats affecting the ecosystems of the area. Water pollution and risks of oil spills remain issues of concern. The spread of invasive species need to be monitored. It should be noted that the region is home to 18 endemic plant species, including two endangered species in Québec.

Major species present :
Cordgrass – main species
Saltmeadow cordgrass
Marine eelgrass

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status
Snow Goose
Number Year Season
5,000 - 118,0001997Spring
5,000 - 7,0001996Spring
5,000 - 15,0001991Spring
5,000 - 22,2001990Spring
10,000 - 35,0001986Spring
5,000 - 10,0001984Spring
Barrow's Goldeneye
Number Year Season
Number Year Season
Number Year Season
750 - 1,0001978Summer
American Black Duck
Number Year Season
1,200 - 2,0001992Fall