Currently, there is no single multilateral environmental agreement that addresses all types of whaling on all types of cetaceans in all parts of the world. Instead, different agreements address different issues, different regions or different species, providing differing levels of protection - with the International Whaling Commission (IWC) the most widely accepted authority to regulate whaling, at least as it concerns the "great whales."
After the widespread unregulated commercial whaling of the 18th, 19th, and early 20th centuries, humankind finally began to recognize the importance of "managing" whaling and whale stocks. The Bureau of International Whaling Statistics was established in 1930, and in 1931 the League of Nations drew up a Convention for the Regulation of Whaling which came into force in 1934. In 1946, in the aftermath of the Second World War, governments approved the International Convention for the Regulation of Whaling (ICRW), recognizing the "interest of the nations of the world in safeguarding for future generations the great natural resources represented by the whale stocks." Under the ICRW, the IWC was founded - initially with 15 member nations - to adopt regulations on catch limits, whaling methods and protected areas, using a 3/4 majority voting system. While this brought some measure of oversight, for the most part whaling continued unchecked, despite efforts to protect humpback and blue whales in the 1960s.
The U.S. was one of the initial signatories, and acts as the depository government for the IWC. The Commission now numbers over 80 nations, many of which have never whaled.
The United Nations Convention on the Law of the Sea (UNCLOS) Article 65 (and Article 120, which extends the provisions of Article 65 to the high seas) states that the IWC is the most appropriate international organization for management of cetacean hunting. Additionally, United Nations' Agenda 21 recognizes the responsibility of the IWC for the conservation and management of whale stocks and the regulation of whaling pursuant to the ICRW, as well as the work of the IWC Scientific Committee in undertaking studies of cetaceans.
Despite this clear dictate, and the preamble to the ICRW that declares a desire to conclude a "convention to provide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry,..." disputes exist within the IWC as to whether its mandate actually extends to the conservation of all cetaceans, not just the "great whales."
While the IWC’s role over management of all cetaceans remains unresolved, regulation of direct removals of small cetaceans has continued to be undertaken at the national level (for instance, in the U.S. through the Marine Mammal Protection Act and the Endangered Species Act). There are also regional agreements which give management advice rather than set quotas for removals. For example, the North Atlantic Marine Mammal Commission (NAMMCO), comprised of Greenland, Norway, the Faroe Islands and Iceland, provides scientific and management advice over small cetacean hunts by those nations. Although the NAMMCO Scientific Committee does recommend quotas (which are often used to challenge more precautionary advice of the IWC), NAMMCO has never actually set quotas for any cetacean species. Similarly, the Joint Commission on the Conservation and Management of Narwhals and Belugas gives advice on those species to its two members, Canada and Greenland, but has no explicit regulatory role and does not set quotas.
In the European Union, all cetaceans are listed in Annex A of the Habitats Directive (Directive 92/43/EEC) which obliges Member States to prohibit all forms of deliberate capture or killing and prohibit the keeping, transport, sale, exchange, and offering for sale or exchange, of specimens taken from the wild. Notably, the Faroe Islands and Greenland are not part of the E.U.
The Convention on Migratory Species (CMS) prohibits Parties from taking a migratory species listed in its Appendix I, with limited exceptions for science that enhances the survival of the affected species, or where the taking is to accommodate the needs of traditional subsistence users of the species; but CMS has no explicit regulatory role.
The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates international trade in live specimens, parts and derivatives of endangered species, including all species of cetaceans. Twelve species of small cetaceans, and all species of great whales, are listed on CITES Appendix I - which prohibits trade, with all others on Appendix II - which allows for regulated trade. CITES explicitly defers to IWC’s specific expertise in cetaceans and the primacy of its management mandate. CITES applies scientific and trade criteria to determine the management status of species threatened by international trade.