The IWC was set up under the International Convention for the Regulation of Whaling which was signed in Washington DC on 2nd December 1946. The preamble to the Convention states that its purpose is to provide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry.
An integral part of the Convention is its legally binding 'Schedule.' The Schedule sets out specific measures that the IWC has collectively decided are necessary in order to regulate whaling and conserve whale stocks.
These measures include catch limits (which may be zero as it the case for commercial whaling) by species and area, designating specified areas as whale sanctuaries, protection of calves and females accompanied by calves, and restrictions on hunting methods. Unlike the Convention, the Schedule can be amended and updated when the Commission meets (a change requires at least three quarters majority agreement). There are a number of reasons why changes to the Schedule may be necessary. These include new information from the Scientific Committee, and variations in the requirements of aboriginal subsistence whalers.