Hecate Strait is a body of water 48-140 km wide, underlain by a shallow basin (less than 45 m at the north end) separating Haida Gwaii from mainland British Columbia. Marine weather conditions are severe: winter storms originating in the Gulf of Alaska bring high waves through the strait and winds persistently higher than 40 km/h off the south end of Moresby Island. The open strait and numerous sheltered inlets are rich in marine life.
Halibut, groundfish, herring, shellfish and salmon fisheries are centered around Prince Rupert. Hecate Strait was navigated for trade and plunder by the Haida, whose water-based settlements on the east coast of Haida Gwaii date from 6000-8000 years ago. Spanish explorer Jacinto Caamano (1792) was the first European into the waters of the strait, although its name is that of a British paddlewheel sloop that surveyed the North Pacific coast from 1860 to 1863. Offshore oil drilling under the southern strait began in the 1950s but was halted in 1972.