In Ghen v. Rich (remember the whale hunting case from Property), the court notes that killing a fin whale creates roughly 20 barrels of oil.
Fin whales are on average about 90 feet long, and can weigh over 70 tons. By point of comparison, an African elephant weighs roughly 8 tons.
A barrel of crude oil (I could not find the exact weight of an actual barrel of whale oil) weighs roughly 300 pounds. 20 barrels is roughly 6,000 pounds, or 3 tons. Therefore, roughly speaking, 70 tons of whale blubber yielded 6 tons of oil. That’s less than a 10% yield. That is a lot of whale blubber that goes unused.
And how much was the oil worth? $71.05 in 1881 dollars. That is roughy $1,500 today.