Canada – June 22nd, 2013
James Bay and Hudson Bay constitute a large, shallow, inland sea connected to the Atlantic Ocean by Hudson Strait and the Labrador Sea, and to the Arctic Ocean by the Foxe Basin, and Fury and Hecla Strait. Currents are strongly affected by influxes of fresh water from rivers and, during the open-water season, by wind stress. Cold saline water enters Hudson Bay and James Bay from the northwest. Less saline surface outflows occur along the eastern shores of James Bay and Hudson Bay north to Hudson Strait.
These two “bays” are the largest bodies of water in the world that seasonally freeze over each winter and become ice-free each summer. In Hudson Bay, the ice cover starts to form in northern areas by late October and continues to grow until a maximum cover is reached at he end of April. Polynya (open water leads in the ice which are known to be important biologically throughout the Arctic) are found predominantly along the north-west and east coasts of Hudson Bay, both coasts of James Bay, and in the vicinity of the Belcher Islands. In James Bay, the ice cover begins to decay in late May, and the area becomes ice-free by the end of July.
The watershed of Hudson Bay and James Bay covers well over one-third of Canada, from southern Alberta to central Ontario to Baffin Island, as well as parts of North Dakota and Minnesota in the United States. The rivers flowing into Hudson Bay and James Bay discharge more than twice the flow of either the Mackenzie or St. Lawrence rivers. The seasonal timing of this freshwater discharge is a major factor governing the productivity and JSC of the region. Hydro developments that change the timing and rate of flow of fresh water may cause changes in the nature and duration of ice-cover; habitats of marine mammals, fish, and migratory birds; currents into and out of Hudson Bay/James Bay; seasonal and annual loads of sediments and nutrients to marine ecosystems (likely leading to lower biological productivity of estuaries and coastal areas); and anadromous fish populations (click here for more information).