In 1930, Right Whales are the first to be protected from commercial whaling.
And in 1931 the Blue Whale Unit was introduced to measure and ultimately regulate nations’ quotas for whaling. One blue whale unit can be expressed in terms of: one blue whale, two fin whales, two and a half humpback whale, or six sei whales. The ratios are roughly based on the relative amounts of oil that each species yields.