The Coast Guard says the exact source of spill in Twillingate Harbour over the weekend may never be known.
Coast Guard were called out over the weekend after a large amount of fuel could be seen on the surface of the water.
Senior Response Officer with DFO, Larry Crann says there are a number of possibilities as to what may have caused the sheen.
He says it could be diesel, bilge containing diesel, hydraulic oil and lubricating oil, or runoff from the land caused by recent heavy rains.
Crann says an absorbent boom was put out to contain the spill and a survey was conducted to make sure it had not spread further.
In the meantime, Crann is encouraging people to report spills to DFO’s emergency line, rather than just resort to social media, which is hard to monitor and may delay response.
He says their response is much more effective when they get a direct call.
DFO’s Environmental Emergencies Line: 1-800-563-9089