912 Outer Bay of Fundy
Geology and Seabed Morphology
Tidal currents have formed significant surface features in the Outer Bay of Fundy/Gulf of Maine system, including extensive fields of sand waves, small ripple-like features, and isolated megaripples. The sandwaves are up to 18 m high and 183 m in length. An extensive field of sand waves occurs just east of Grand Manan Island at depths of 60-100 m and in scattered fields to the south and southwest of Lurcher Shoal (60-80 m). Large sand waves (up to 6 m high) with crests perpendicular to the tidal direction occur seaward of Minas Basin in Scots Bay.
The Outer Bay of Fundy lacks the intertidal mud flats and salt marshes of the inner reaches; the bottom consists of exposed bedrock and a coarse sand and gravel substrate winnowed by tidal currents. Rock formations in the Bay of Fundy are extensions of those that make up the shoreline. This area frequently has a range of wave-like bottom features, but often exposed bedrock occurs.
A frontal zone at the south side of the mouth of the Outer Bay leads to high plant productivity, large populations of herbivorous and detritus-feeding animals, and eventually to concentrations of animals of higher trophic levels. The dominant intertidal alga is the rockweed Ascophyllum nodosum.
Tidal mixing at the mouth of the Bay of Fundy is important in the growth, during the summer months, of the dinoflagellates that cause paralytic shellfish poisoning.
Species of bottom animals are similar to those in the Atlantic Unit 911, but the area has several localized concentrations of particular species, probably related to the tidal currents and rock bottom in some places. Dense beds of the Horse Mussel occur across the Outer Bay from inside Digby Neck to inside Saint John Harbour. Horse Mussels are the most important suspension-feeding organisms in the Unit. Concentrations of the brachiopod Terebratulina septentrionalis occur seaward of those areas in the central axis of the Bay of Fundy. The burrowing polychaete Sternaspis scutata and the tube-building amphipod Haploops fundiensis are common in silt-clay bottoms towards the outer portion on the New Brunswick side. The deep-sea Red Crab occurs in deeper parts of the area on mud, sand, or hard bottoms.
The Outer Bay of Fundy has been recognized as a feeding ground for Right Whales during the summer and autumn. The vicinity of Grand Manan Island is visited by a population of about 200 Northern Right Whales in summer, and they can be observed in Head Harbour Passage, Grand Manan Channel, and along the edges of Grand Manan Basin.
Southernmost breeding colonies of Atlantic Puffin and Razorbill occur on Machias Seal Island near Grand Manan Island in the Outer Bay of Fundy.
The highly productive waters of the Outer Bay of Fundy support important fisheries that form the economic basis of many communities. The summer herring fishery, scallops (Digby), and lobsters are most important. Lurcher Shoal is an important area for commercial scallop fishing. Herring are caught from the shore using weirs in some places, adding a distinctive feature to the coastal landscape. Harvesting of dulse, Irish Moss, and the rockweed Ascophyllum nodosum is locally important. Shell fisheries are usually closed in summer because of the danger of paralytic shellfish poisoning. The Annapolis Basin is the site of the first permanent European settlement in Canada (1605), and Digby remains a centre for marine fisheries and transportation. Bay of Fundy tides have been harnessed to generate electricity on the Annapolis River at Annapolis Royal. Tidal marshes have mostly been dyked and drained for farmland. The high productivity of the waters of the Bay of Fundy provide food for seabirds and marine mammals, including the Humpback Whale, which are important tourist attractions.