Bay of Fundy

Overview

The Bay of Fundy experiences the highest tides in the world: tidal range exceeds 15 m at the head of the bay. The tides are the result of the interaction of global-scale tidal forces with the shape of the Gulf of Maine and Bay of Fundy. The time it takes the tides to circle the globe is nearly the same as the time it takes for the tide to travel to the head of the bay and back. As a result, the global-scale tide amplifies the effects of the tide within the Gulf of Maine. Each day, the tides move more than 100 km3 in and out of the bay, a volume four times greater than the discharge of the world’s rivers combined. Tidal mixing causes significant suspension of sediments. Suspended sediments cause the water to be cloudy and result in reduced plant growth.2

Surface area

4,946 mi2 (12,810.1 km2)

Depth

The average depth of the bay is 75 m.3

Bathymetry including key features

The floor of the bay slopes gradually away from the coast. Tidal currents have altered the bathymetry of the sea floor through the formation of fields of sand waves and extensive mud flats. The interaction of the tides and the geology of the bay is an ongoing process that has been in effect since the development of extended tidal range at the end of the last ice age, about 8,000 years ago. This interaction has not reached equilibrium; evidence exists that the seabed of the bay is now more dynamic than ever.4

Substrate

Through both erosion and sedimentation, the tides of the Bay of Fundy have a profound impact on the sediments of the bay.5 The intertidal zone of the inner bay is dominated by broad ranges of mud flats. Subtidally, the bay’s sediments are characterized by sand waves, rock outcrops and mud deposits in deeper or sheltered environments.6

Relationship to large-scale circulatory patterns of the Gulf of Maine

Circulation in the bay is a function of tidal currents and the counterclockwise flowing gyre that dominates circulation in the larger Gulf of Maine. This gyre begins as an intrusion of shelf water from the Scotian Shelf; it flows in and out of the Bay of Fundy establishing a subgyre in the bay as it exits along the coast of Maine. Cooler temperatures of the Scotian Shelf water ensure that the outer Bay of Fundy is cooler than surrounding areas.7,8,9 The counterclockwise subgyre within the bay is reinforced by the effect of the earth’s rotation on tidal currents.10

Information on average (seasonal/annual) oceanographic conditions

Except for areas deeper than 100 m, the Bay of Fundy is well mixed by tidal action.11 As a result, the water column is fairly uniform in temperature and salinity and seasonal variations are minimized.12 Currents in the bay flow in a counterclockwise gyre. The inner bay, influenced by freshwater runoff from several rivers, is estuarine in character. It is warmer than the outer bay due to warming as the tides flow over exposed intertidal mudflats. 13

Presence of GoMOOS buoy

Bouy J is found, not in the Bay of Fundy proper, but in the mouth of Cobscook Bay.

Whale abundance, distribution and migratory patterns

The lower Bay of Fundy is frequented by right whales more than any other location in the Gulf of Maine.14 A portion of the mouth of Bay of Fundy is designated as a “critical habitat area” for the right whale, designated as an endangered species by the National Oceanic and Atmospheric Administration. Right whales breed in the Bay of Fundy, and other areas of the eastern Gulf, through the fall.

1 Desplanque and Mossman, 2004
2 Nova Scotia Museum of Natural History, undatedb
3 Swift et al., 1969
4 Desplanque and Mossman, 2004
5 Ibid.
6 Nova Scotia Museum of Natural History, undatedc
7 Xue, et al., 2000
8 Pettigrew, et al., 2005
9 Nova Scotia Museum of Natural History, undatedc
10 Swift et al., 1969
11 Xue, et al., 2000
12 Nova Scotia Museum of Natural History, undatedb
13 Nova Scotia Museum of Natural History, undatedc
14 Baumgartner and Mate, 2005