Scotian Shelf, a 700 km section of the Continental Shelf off Nova Scotia. Bounded by the Laurentian Channel on the NE, and Northeast Channel and the Gulf of Maine on the SW, it varies in width from 120 to 240 km; the average depth is 90 m. Deep basins and channels, separating shallow offshore banks (dry land during the ice age), characterize its irregular bathymetry. Only SABLE I remains above water today. Circulation over the inner shelf is dominated by a southwesterly longshore current that varies seasonally with freshwater runoff from the Gulf of ST LAWRENCE. Over the banks the circulation is weaker and more variable, under the influence of storms, tides and the Gulf Stream several hundred km S. Strong tidal streams around southwestern NS produce vertical mixing and enrichment of the herring and lobster fisheries; offshore an international fleet annually removes around half a million tonnes of fish and squid. Recent discoveries of natural gas near Sable I have stimulated further hydrocarbon explorations, creating potential conflict between renewable and nonrenewable resources on the shelf.