Legal Opinion Concerning Japan’s Duty to Cooperate with the International Whaling Commission with Respect to Any Resumption of Commercial Whaling

32 Pages Posted: 28 Jun 2019

See all articles by Chris Wold

Chris Wold

Lewis & Clark College Paul L Boley Library

Date Written: April 26, 2019


Japan has formally indicated its intent to withdraw from the International Convention for the Regulation of Whaling (ICRW) and the International Whaling Commission (IWC) and signaled its intent to resume commercial whaling for minke, sei, and Bryde’s whales within its territorial seas and exclusive economic zones. Even if Japan withdraws from the ICRW and IWC, however, Japan is still bound by customary international law and other treaty law, including the UN Convention on the Law of the Sea (UNCLOS), to which it is a party. Both customary international law and UNCLOS impose on States a duty to cooperate. Customary international law also includes a duty to conduct a transboundary environmental impact assessment (EIA) prior to conducting any activity that may adversely affect the territory of another State or areas beyond national jurisdiction. Thus, if Japan resumes commercial whaling after withdrawing from the ICRW, it would still be bound by the duty to cooperate and, because it intends to allow hunting of whales shared with other States, it would be required to prepare a transboundary EIA.

The International Court of Justice (ICJ), the International Tribunal for the Law of the Sea (ITLOS), and other international tribunals have all declared that the duty to cooperate, whether as customary international law or as a fundamental principle of UNCLOS, requires States to give “due regard” to the rights of other States, as well as exchange information and consult regarding activities that engage those rights. In particular, UNCLOS requires Japan to cooperate through the IWC because UNCLOS requires Parties to cooperate through the “appropriate international organizations.” The IWC is the “appropriate international organization” regardless of whether Japan whales in its exclusive economic zone or the high seas and regardless of the presence of any other organization because the IWC has a global mandate to conserve, manage, and study whales and it has actively embraced that mandate, including with respect to the stocks that Japan intends to hunt. To fulfill its UNCLOS duty to cooperate, Japan must participate meaningfully in meetings of the IWC and the IWC Scientific Committee, submit data on whales struck and lost as well as whales caught as bycatch, and implement the Revised Management Procedure (RMP) because the RMP represents the scientifically-vetted method for calculating sustainable catch limits. Moreover, to ensure its whaling is sustainable, Japan must prohibit whaling, at least until significant data gaps are filled in relation to the stocks that Japan intends to hunt. IWC members that are also UNCLOS Parties may vindicate their rights using the binding and compulsory dispute settlement provisions of UNCLOS.

Keywords: duty to cooperate, transboundary environmental assessment, Japan, whaling

JEL Classification: K32, K33

Suggested Citation

Wold, Chris, Legal Opinion Concerning Japan’s Duty to Cooperate with the International Whaling Commission with Respect to Any Resumption of Commercial Whaling (April 26, 2019). Available at SSRN: or

Chris Wold (Contact Author)

Lewis & Clark College Paul L Boley Library ( email )

10015 S.W. Terwilliger Blvd.
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United States

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