The 1937 International Whaling Conference and Convention marked an expanded attempt to regulate industrial whaling as governments warned that the largest whales could be driven to extinction. The agreement established broad seasonal and species protections, but its hoped-for reach exceeded its actual participation: Japan did not join, and its Antarctic whaling operation continued to grow.

Background and Aims

An international agreement drafted in 1935 under the auspices of the League of Nations had proved insufficient. At a conference in Oslo in May 1936, Britain and Norway agreed on a closed season and limits on the number of catcher boats working with a factory ship. The proposed season ran from December to March, but the narrow participation and limited scope left the larger problem unresolved.

Britain then placed itself at the forefront of renewed control efforts while acknowledging its own interests in the industry. In May 1937, an expanded conference brought representatives from South Africa, America, Argentina, Australia, Germany, Ireland, New Zealand, Norway, and Britain together. The warning was stark: Britain’s Minister of Agriculture and Fisheries, W. S. Morrison, said that continued hunting would exterminate the blue whale and soon end Antarctic whaling.

The Convention’s Protections

The conference announced a convention that prohibited pelagic whaling for nine months of the year. It also provided for complete protection in some areas and absolute protection for certain whale species, calves, and females accompanied by calves. Whales below a specified size were protected as well. Whaling from land stations, including stations in the southern hemisphere, was subject to a six-month closed season.

These provisions addressed several pressures at once: the scale of open-sea hunting, the vulnerability of young whales and mothers with calves, and the capture of undersized animals. The convention thus moved beyond a general appeal for restraint to specify seasons, places, and classes of whale. It nevertheless relied on national adherence and did not place every expanding whaling operation under the same rules.

The Limits of Participation

The conference hoped that other countries, particularly Japan, would adhere to the convention. Japan had learned modern whaling techniques from Norway and, by 1934, had begun voyages into the Southern Ocean. It declined to join the international agreements; within five years, six Japanese factory ships were operating in Antarctic waters. The gap between the convention’s protective aims and the reach of its membership was therefore visible almost immediately.

The following years showed that regulation and large-scale killing could coexist. In May 1939, a Norwegian captain was prosecuted for killing a fifty-nine-foot female blue whale, below the seventy-foot limit. Yet Britain and Norway together remained responsible for 95 percent of an annual toll of 30,000 whales. The convention established concrete protections and helped make population decline an explicit international concern, but it did not end the industrial chase or secure uniform participation.