Dangerous shoals in the area were a hazard to ships entering the Bay of Fundy en route to the port of Saint John, New Brunswick.

Other improvements, both made in 1840, were the provision of a signal gun and the digging of a chute in the rock to allow the lighthouse keeper to lower and raise his boat.

[6] Pressurized petroleum vapour was burned in the lamp, producing a light with an intensity of 85,000 candlepower, reputedly second only to that of the Eddystone Lighthouse.

[6] In 1906 a new keeper's residence was built of brick, and in 1931 this was in turn replaced by a 2+1⁄2-storey reinforced concrete dwelling attached to the lighthouse tower.

There it is the centrepiece of the Walter B. McLaughlin Marine Gallery, whose name honours Gannet Rock's longest serving (1853–1880) head lighthouse keeper.

At that time the Coast Guard planned to "completely restore and maintain the exterior of this historic structure that continues to be an essential aid to navigation in the Bay of Fundy".

[11] However, the site continued to deteriorate and by late 2010 the Coast Guard deemed Gannet Rock "no longer safe for maintenance crews to visit".

The Department of Fisheries and Oceans, which is responsible for the Canadian Coast Guard, then declared all of its 976 active and inactive lighthouses, including Gannet Rock, "surplus to requirements".

This is likely to be beyond the means of the small community of Grand Manan, which has already purchased the Swallowtail Lighthouse on the island and is in the process of restoring it at a cost of "hundreds of thousands of dollars".