Waters of Île Patte de Lièvre (QC151)

Waters of Île Patte de Lièvre (QC151)

Forestville, Québec

Site Description

This site is on the north shore of the St. Lawrence River, and covers the open water from the towns of Point-au-Boisvert on the west, to Forestville on the east. The area is approximately 20 kilometres long, and extends 5 kilometres offshore. West of Forestville there is a large underwater plateau around Île Patte de Lièvre, creating shallower waters within the river.

Birds

Extensive aerial surveys were conducted in the spring and summer of 1994 and 1995 along the north and south shores of the St. Lawrence River. Results of these surveys showed that the underwater plateaus of the river within this site were important staging and moulting areas for scoters, particularly Black and Surf scoter. On May 2, 1995, 9,720 scoters were present in this site. Within one week, this number had increased to a peak of 20,732 scoters, which is a globally significant number of waterfowl. Although the exact species composition was not determined, it is likely that both Black and Surf Scoters were present in globally significant numbers. After mid-May, the birds quickly dispersed to their breeding grounds, as seen by the quick decline in numbers within the study site: only 228 scoters were surveyed two weeks later, on May 23, 1995. The distribution of the scoters in spring appears to be influenced, in part, by the spawning locations and timing of Atlantic Herring.

Another undated report, records an impressive 100,000 to 200,000 scoters and eiders in the waters in the Forestville – Ste-Anne-de-Portneuf area.

Scoters are known to travel thousands of kilometres to reach favoured moulting sites and, by late July, many moulting scoters are back in the area: 5,000 were recorded on July 27, 1994. The majority of these moulting scoters were Surf Scoters, probably due to their more southerly nesting grounds, but a few Black Scoters were also present. The majority of Black Scoters moult in James Bay, explaining their low numbers here in summer.

As well as Surf and Black scoters, White-winged Scoters are also present, although in much lower numbers. During the three surveys in May of 1995, fewer than 1,000 birds of this species were ever identified. They were also detected in small numbers during moult in July, 1994. Only small numbers of Common Eiders were surveyed, since most birds at this time of year tend to be clumped around breeding islands, of which there are none in the study site. A total of 28, 349 and 93 birds were detected in three days in May, 1995.

Conservation Issues

The St. Lawrence Seaway is a very busy shipping lane so the risk of oil spills is always present. Seaducks are very vulnerable to oil spills, especially when moulting. Scoters tend to use traditional staging and moulting sites each year, thus ideally shellfish aquaculture farms should not be located in these regions, as sea ducks can have a significant impact on their productivity. Also, the harvesting of shellfish in these areas should be regulated since it may affect the availability of food to the scoters. Boat traffic, either recreational and commercial, could cause disturbance to the scoters in spring and summer.

Fish Habitat

The landscape of the area is typified by salt marshes, intertidal rocky shore, mudflats, river's estuaries and long sandy beaches. The mixing of the cold and well-oxygenated waters with the warmer waters of the St. Lawrence favors an unusual marine biodiversity. Several marine species are commercially exploited, such as the common whelk, the soft-shell clam, the green sea urchins, the Stimpson's surf clams, the snow crab and the Atlantic herring. Moreover, the harvest of soft-shell clam at low tide is a popular recreational activity throughout the region of Lower North Shore. The north shore of the estuary is also hosting a variety of pelagic species occupying an important role in the food chain, such as the capelin and the rainbow smelt are also targeted by the sport fishermen.

The fish habitat is affected by coastal erosion, residential development, harnessing of rivers and the creation of resorts. In addition, the presence of industries discharging pollutants in the system does impacts the water quality. The Atlantic salmon is sensible to aluminum contamination through bioaccumulation of the residues present in the system.


Major species present:
Atlantic herring
Atlantic salmon
Capelin
Green sea urchin
Snow crab
Soft-shell clam
Stimpson's surf clam

Plants

The salinity of the St. Lawrence water has a strong influence on the flora of the coastal habitats. Salt marshes are dominated by saltmeadow cordgrass, tall cordgrass, red fescue and chaffy paleacea. Present in a variable proportion, a variety of plants typical of estuarine environments: sea pea, Scotch lovage, American searocket, sea milkwort, etc. In areas submerged where substrate is thin, and water velocity is small, eelgrass grows. Eelgrass beds are home to an amazing biodiversity: shellfish, crustacean, fish, etc. which attract many predators. Several fish-eating birds such as the great blue heron come to take a meal. The Brant goose is closely linked with this habitat since the underground parts of the eelgrass are at the basis of its diet.

Habitat loss, whether caused by human interventions (wetland drainage, road construction, urban spread, etc.) or through natural phenomena (coastal erosion) severely impact the flora. Similarly, water pollution and risks of oil spills are issues of special concern for the flora and fauna of these areas.

Major species present :
American searocket
Chaffy paleacea
Marine eelgrass
Red fescue
Saltmeadow cordgrass
Scotch lovage
Sea milkwort
Sea pea / Beach pea
Tall cordgrass

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status

• Surf Scoter50,000 (max.)
• Black Scoter5,000 (max.)
• White-winged Scoter6,500 (max.)
• Red-throated Loon500 (max.)
• Little Gull2 (max.)
• Common Eider10,000 (max.)