03/04/2015 10:07 EST | Updated 05/04/2015 05:59 EDT

Franklin expedition's HMS Erebus to be examined by dive teams in April

Prime Minister Stephen Harper says the next step in the expedition to examine and document HMS Erebus will begin in April, when teams of navy divers and Parks Canada underwater archeologists will plunge beneath the Arctic ice to investigate the sunken ship.

HMS Erebus, part of Sir John Franklin’s doomed Arctic expedition, was located in September 2014. Another ship, HMS Terror, has not yet been found — though Harper said he believes the second missing ship can be located.

Speaking Wednesday at an event at Toronto’s Royal Ontario Museum celebrating the discovery of the historic shipwreck last year, Harper said the search is not just about solving a mystery, but also about mapping, research and demonstrating Canada's sovereignty in the North. 

Franklin's expedition to find the Northwest Passage began in England in 1845. The ships crossed the ocean but eventually became stuck in thick sea ice. 

Discovery of the Erebus followed a long series of searches for the lost Franklin ships, including six Parks Canada-led efforts since 2008.

The ship was located by the 2014 Victoria Strait Expedition team using a Parks Canada remotely operated underwater vehicle. Traditional Inuit oral testimony, which told of a shipwreck south of King William Island, also played a major role in the search.