Antarctic whaling began on a large scale in 1904 with the building of a whale processing station at Grytviken, South Georgia. A number of shore-based stations were in operation under some kind of regulation on the catches very shortly after this.
In 1925, the first "factory ships" were built so that whaling could take place entirely at sea. This meant that the whalers were not operating within the territory of any one country and so consequently there were no regulations on catch size or species taken nor on the age or sex (nursing mothers with calves for example) of the catch.
The best catch for whalers were initially Humpback whales as they swam slowly and often close to the land so were easy to reach. As whalers became able to operate away from port with faster whaling boats, their attentions turned to the Blue Whale. Blues were always the preferred species even when numbers were declining, but as they became scarcer attention was turned to firstly Fin and then Sei whales, each progressively less profitable than the predecessor.
Today whaling is regulated by the International Whaling Commission (IWC). Every year about 300 whales are still taken by Japan as so called "scientific whaling".
Available online at: http://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/whales/whaling1.htm