A diver works to remove the carcass of a whale impaled on the bow of a cruise ship that docked in Vancouver on Saturday morning. ((CBC))

A fin whale found dead against the bow of a cruise ship in Vancouver on Saturday might have been ill, according to the Department of Fisheries and Oceans.

Paul Cottrell, the department's marine mammal co-ordinator, cited early findings of the forensic analysis of the carcass.

"The blubber layer was a little more thin than typical for that size of animal and the stomach was empty, which indicates the animal hadn't been eating for a while," he said.

The final report will take weeks to complete, but Cottrell added that the whale was middle-aged to older.

The 70-tonne carcass was to be towed out to sea off the west coast of Vancouver Island on Monday or Tuesday and left to sink. The remains will be extremely important to the shore's ecosystem, said Cottrell.

It took two tugs, three slings and several divers to lift the 21-metre carcass off the bow of the Sapphire Princess cruise ship.

With files from The Canadian Press