VICTORIA -- Federal officials say emergency response crews will work through the holidays to try to contain an oil spill from a historic shipwreck off the west coast of Vancouver Island. 

The coast guard says it is still working to confirm just how much fuel oil was on board the Holland America freighter when it ran aground in Nootka Sound and sank in January 1968.

The 150-metre MV Schiedyk was carrying thousands of tonnes of wood pulp and barley bound for Portland, Ore. when it went down near Bligh Island. All 34 sailors aboard the ship survived the wreck.

Mariners and aviators in the remote area say small slicks of bubbling oil have long been apparent on the water’s surface, but last month those trickles turned into a plume of oil stretching upwards of two kilometres.

The coast guard says it first received reports of an oil sheen near the island in September but investigators couldn’t locate its source until early this month.

On Tuesday, officials said there are approximately 30 to 50 litres of oil on the water’s surface at any given time.

Six pollution response vessels and 40 personnel are currently on scene, with two more expected to arrive over the coming weeks. Crews have deployed two oil skimmers and nearly 5,000 metres of containment booms around the site to contain what DFO officials say is a “continuous but slow discharge of oil pollution.”

More than 40 additional pollution response workers from federal, provincial and local governments are managing the spill response on shore.

Federal officials said Tuesday they don’t know how much oil has been collected to date. Samples of the oil have been sent to a lab for identification and officials say both bunker fuel and diesel were on board when the vessel sank.

“Photo and video documentation from the ROV (remotely operated underwater vehicle) shows that the ship sustained significant damage when it sank in 1968,” said wreck co-ordination spokesperson Kiri Westnedge. “The upwell of oil is coming from several locations in the vessel.”

Westnedge says a dead sea otter was found near the spill site and a necropsy will determine whether it died due to exposure to the oil.

Another sea otter was found alive but covered in oil. Crews were attempting to capture the otter Tuesday to transport it to the Vancouver Aquarium’s Marine Mammal Rescue Centre. A blue heron was also found coated in oil.

“There is potential for more wildlife to be impacted,” Westnedge said. “We have a team of wildlife and marine mammal experts who are focused on keeping wildlife away from the shipwreck site, and capturing and rehabilitating any impacted animals.”

Officials don’t have a cost estimate on the cleanup yet. Transport Canada says that while Holland America still technically owns the vessel, the company will not be liable for cleanup costs through a federal ship-source pollution fund due to the statute of limitations set out under the Maritime Liability Act.

“Under international maritime law, the ownership of a vessel, even if sunk, remains unchanged,” said Transport Canada spokesperson Cybelle Morin. “In this case, the ship-source oil pollution fund cannot be used to cover the cost as it falls outside the time frame.”

Holland America did not respond to multiple requests for comment on this story.