Complex sentence: Hudson Strait links the northern seaports of Manitoba and Ontario with the Atlantic Ocean this means that it could be an eastern entrance to the Northwest Passage if it were not for ice in the Fury and Hecla Strait south of western Baffin Island.
Split into simpler sentences: Hudson Strait links the northern seaports of Manitoba and Ontario with the Atlantic Ocean. It could be an eastern entrance to the Northwest Passage were it not for ice in the Fury and Hecla Strait south of western Baffin Island.