Les estuaires de la partie supérieure de la Baie des Chaleurs

Malgré ses dimensions, la baie des Chaleurs est relativement dépourvue de traits géographiques significatifs. L'Île du Héron est la seule grande île de la baie et il n'y a que quelques rivières qui s'y déversent. Ces rivières incluent : la Jacquet, la Benjamin, la Charlo, et la Restigouche. Ces rivières forment des petits estuaires écologiquement intéressants avant de se jeter dans la baie. La Restigouche est beaucoup plus grande et plus diverse sur le plan écologique que tous les petits estuaires réunis.

En juin de l'an 2000, l'estuaire de la Restigouche a été désigné réserve ornithologique de portée internationale (la première au Nouveau-Brunswick) parce qu'il est le plus vaste territoire dans l'est de l'Amérique du Nord pour la macreuse à bec jaune.





Estuaries in the
Upper Bay of Chaleur

Mike Lushington
Restigouche Naturalists Club
June 2004

lthough the Bay of Chaleur appears small on the map in comparison to the Bay of Fundy, it is an impressive body of water in its own right. It stretches for approximately 120 kilometres across the northeastern corner of New Brunswick and for that distance also embraces the southeastern shoreline of the Gaspe Peninsula of Quebec. It is nearly fifty kilometres wide between Bathurst and New Carlisle and is over twenty-five kilometres wide for most of its length.

The Restigouche Estuary
taken from the writer's home

(photo: Mike Lushington)

Despite its size, the Bay of Chaleur is relatively devoid of significant geographical features. Heron Island is the only large island in the Bay and there are only a few rivers that empty into it, especially on the New Brunswick side. The writer is reasonably familiar with several of them in the upper bay; the Jacquet and Benjamin Rivers form small but ecologically interesting estuaries before joining the bay.

The Jacquet River remains one of the most productive small salmon rivers in the area and also has a significant sea trout run each spring and early summer. The Benjamin River is one of only two in the entire Maritime Provinces known to host nesting Harlequin duck, at least on an occasional basis. Its estuary, adjacent small rocky islets and nearby Heron Island provide nesting sites for a significant colony of Common eider, as well as Double crested cormorant, several species of gull, and a small rookery of Harbour seals.

The Charlo River enters the upper bay a few kilometres to the west of the Benjamin River. Its two branches form a considerable estuary that attracts good numbers of waterfowl and shorebirds, particularly in fall. The Charlo River is the second of the two upper Bay of Chaleur rivers to host Harlequin duck. In late summer, it is a dependable staging area for post-nesting Bonaparte gulls, and the waters of the Bay just off the mouth of the estuary attract large numbers of Canada geese, Common eiders and more than twenty other species of waterfowl during migrations.

(photo: Mike Lushington)

At the extreme western end of the Bay of Chaleur, one finds another estuary, that of the Restigouche River, that is far larger and more ecologically diverse than all of the smaller estuaries considered together.

The Restigouche estuary extends almost 25 kilometres from its mouth in Dalhousie to where it narrows into the river proper at Campbellton. At its widest, between Pt. La Nim, New Brunswick, and Escuminac Cove on the Quebec shore, it is nearly eight kilometres across. It is, in its own right, an impressive body of water and tidal flats. There are several small rivers that flow into it from the Quebec side that form small estuaries of their own, and that contribute to the overall richness of the ecosystem. (The Restigouche River itself, together with its principal tributaries, the Matapedia, the Patapedia and the Kedgwick Rivers, remains one of the most famous and productive Atlantic Salmon fishing rivers in this part of the world.)

In June of 2000, The Restigouche Estuary was designated an Important Bird Area of International Significance (the first in New Brunswick) because it is the largest staging area in eastern North America for Black scoter. As many as 100 000 of these birds have been discovered to use the area in late April and early May. They rest, they refuel on the abundant Soft-shell clam and Blue mussel populations present, and they conduct courtships to form pairs prior to their final flights into northern Quebec and eastern Manitoba nesting areas.

Each spring since 1998, the Restigouche estuary has been the site of research programs on the Black scoter. Several have been captured and outfitted with telemeters that have enabled scientists to track the birds' movements into their northern nesting areas as well as their migration patterns. Studies have also been conducted on their food sources and possible contaminants of those sources. Population monitoring has been done each spring since then and scientists and field observers are currently estimating sex ratios in the flocks, as well as movement patterns.

(photo: Mike Lushington)

The work on the Black scoter has led to the realization that the Restigouche estuary is also a very important area for other species of sea bird and waterfowl, particularly in spring but extending into summer and fall. Several hundred immature and nonbreeding Common loon frequent these waters from early May until late October. As many as 3 000 Northern gannets have been counted in spring flights up the Bay into the estuary from their colony on Isle Bonaventure whenever there is a strong run of spring herring. Double crested cormorants, Common eider, Common goldeneye, Common and Red-breasted merganser, Surf scoter and increasingly large numbers of Snow geese appear each spring. There are at least eight active Osprey nests in the hills adjacent to the estuary on the New Brunswick side and at least that many again on the Quebec shore.

The estuary is large, but its waters are shallow. As a result, it warms up quickly once the ice breaks up in mid April. With the strong outflow from the river, up-swellings of tidal and river currents, and the configuration of the rocky ledges, the estuary teems with the nutrients necessary for an abundant supply of clams, mussels, shrimp, rock crabs and small fish. These creatures, in turn, attract larger fish and the birds.

In short, then, this is a most impressive and beautiful estuary.