Hecate Strait (; Haida language: K̲andaliig̲wii, also siigaay which means simply "ocean")<!--the Tsimshian and other native-language names should be included; Hecate Strait is not purely "Haida teritory"--> is a wide but shallow strait between Haida Gwaii and the mainland of British Columbia, Canada. It merges with Queen Charlotte Sound to the south and Dixon Entrance to the north. About wide at its southern end, Hecate Strait narrows in the north to about . It is about in length.
Definition
According to the BCGNIS, the southern boundary of Hecate Strait is defined as a line running from the southernmost point of Price Island to Cape St James on Kunghit Island, the southernmost point of Haida Gwaii. The northern boundary is a line from Rose Point, the northeastern tip of Graham Island, to Hooper Point at the north end of Stephens Island off the mainland.
The Strait was first explored for the Europeans in 1792 by the Spanish Armada explorer Jacinto Caamaño. Hecate Strait was named by Captain George Henry Richards in 1861 or 1862 after his surveying vessel, HMS Hecate. The depth of the strait varies from 200 metres in the south to 25 metres east of Rose Spit.
Flora and fauna
The strait once contained strong salmon and halibut fisheries.
Hecate Strait is one of the few locations in the world with species from the glass sponge class of fauna. Regions with these sponge are currently protected from damage by commercial fishing.
The Hecate Strait and Queen Charlotte Sound Glass Sponge Reefs Marine Protected Area was designated by the Fisheries and Oceans Canada in February 2017. The MPA is located in the Northern Shelf bioregion of the Pacific Region, southeast of Haida Gwaii, North and South of the entrance to the Douglas Channel. The MPA is composed of three individual areas known as the Northern Reef, the Central Reefs, and the Southern Reef. Together these three areas cover approximately 2,410 square kilometers. The four reef complexes in the Hecate Strait and Queen Charlotte Sound discontinuously cover an area of about 1,000 km<sup>2</sup>, and are located in glacial troughs between 140 m and 240 m deep.
Hazards and restrictions
Environment Canada comments that “it has been said that the Hecate Strait is the fourth most dangerous body of water in the world”. It is noted for strong winds, seasonal fog, powerful tidal currents, frequent southeast gales and shallow waters. During winter storms, swells commonly reach 8 to 10 metres in the southern part of the Strait.
There is a moratorium on large oil tankers in a large zone that includes the Hecate Strait.