Located in eastern Canada, the Gulf of St. Lawrence owes many of its unique characteristics to its geography. Sea water flows into and out of the gulf through only two channels. Currents and tides sweep cold, Arctic seawater through the narrow Strait of Belle Isle in the north. In the south, the wider Cabot Strait admits warmer water from the Atlantic Gulf Stream. With no other outlet to the Atlantic, the Gulf of St. Lawrence is relatively isolated.
The Gulf Stream Current is one of the strongest ocean currents on Earth. This river of water that ferries heat from the tropics far into the North Atlantic pulls away from the coast of the U.S. Southeast around Cape Hatteras, North Carolina. There the current widens and heads northeastward. In this region, the current begins to meander more, forming curves and loops with swirling eddies on both the colder, northwestern side of the stream and the warmer, southeastern side.