The International Whaling Commission set limits on the number, species and size of whales that could be taken, for example a quota of 16,000 blue whale units could be taken in a season which usually lasted from December to April . The daily catches were reported to the IWC and they would issue instructions when this quota was reached. However 16,000 blue whale units is only a measure. But many more than this could be caught because one blue whale equaled two fin whales or one blue whale equaled six sei whales. So really 16,000 blue whales was just a yardstick.

Unfortunately for whales in the Southern Oceans due to a worldwide shortage of oil and animal fat approximately 30-40 pelagic whaling factory ships were now operating in the hunt for whales and each factory ship had 10-14 catcher vessels working for them, so in hindsight it was obvious that the whales depletion was rapid. By the mid sixties a complete moratorium was introduced on commercial whaling, apart from this moratorium it was no longer viable to send an expedition to the South for the purposes of whaling as there were very few of the species of whales that made it viable available to be caught.