Resolutions from the World Heritage Committee regarding Steller Sea Lions in Shiretoko

In 2024, we revised the Basic Management Policy for the Steller Sea Lion (see below), which included the Shiretoko World Heritage Site within the management area. We gained a general understanding of this from the World Heritage Committee (see 47 COM 7B.7). We are very grateful for this. It was important for us to gain an understanding of the concerns of both the local fishers, who suffer damage to their industry due to sea lions, and the World Heritage Committee, who are concerned with the Outstanding Universal Values of Shiretoko. We will continue to strengthen the scientific evidence in order to promote the coexistence of fisheries and sea lions, while striving for both conservation and human activities.

The Basic Policy for the Management of Steller Sea Lions was "partially revised" in 2024 (Fisheries Agency html in Japanese, full text PDF in Japanese). This was a significant revision:

• It established a catch limit not only for the Sea of ​​Japan coast but also for the waters off eastern Hokkaido, including Shiretoko.
• It targeted the breeding population on the Russian coast, rather than the migratory population to Japan.
• It based its targeting on human-caused mortality based on PBR (potential biological removal).
• It separated the Okhotsk and Kuril populations, taking into consideration the conservation of both breeding populations.

When Shiretoko was inscribed as a World Heritage Site in 2005, the catch limit for all of Japan, including Shiretoko, was set based on PBR, and the inscription was approved. This was also explained to the UNESCO and IUCN survey team in 2008. While some points were raised about the Steller Sea Lions, the Scientific Committee's efforts were highly praised as a "model for other World Heritage sites" (pdf p.11). However, since the Basic Policy for the Management of Steller Sea Lions was formulated in 2014 (pdf in Japanese), the Fisheries Agency's management of Steller Sea Lions has been limited to the Sea of ​​Japan, and there is no longer any scientific basis for determining the catch limit in the waters surrounding the Shiretoko. Since then, the World Heritage Committee (WHC) has repeatedly made recommendations*. 

Hiroyuki Matsuda, 'Population Management Model for Overwintering Populations': (virtual) poster presentation at the Annual Meeting of the Ecological Society of Japan on 15 March 2022. (html in Japanese)

Abstract: When managing populations of migratory birds and animals that cause damage to agriculture, forestry, and fisheries in their wintering grounds, the aim is to balance population persistence and protect their breeding grounds. Furthermore, when animals migrate from two breeding populations (A and B) to two wintering grounds (C and D), it may be necessary to exterminate a certain number of animals at C and D to ensure the persistence of populations A and B. In this case, the catch limit of animals will differ depending on whether populations A and B are considered separately or as a single population.

Let x₁ and x₂ represent the number of individuals in populations A and B, and let m₁₁ and m₁₂ represent the migration rates from A to C and D (the numbers of migrations x₁₁ and x₁₂ are x₁₁= m₁₁ x₁ and x₁₂= m₁₂ x₁, and the migration rate from B be m₂₁ and m₂₂. Let y₁ and y₂ represent the numbers of removal at C and D respectively, with captures made according to the ratio of migration rates from A and B.

In other words, the number of removal from population A captured at site C, y₁₁, is y₁x₁₁/(x₁₁ + x₂₁). If the upper limits of the number of removals  in populations A and B are h₁x₁ and h₂x₂, respectively, the conditions under which the numbers captured at C and D (y₁ and y₂) satisfy these limits can be derived from simultaneous inequalities. If m₁₂ = 0, meaning there is no migration from A to D, the solution for obtaining a number of removals that satisfies the upper limit is that the number of removals at C is always positive, but the number of removal at D is 0 when h₁m₂₁ > h₂m₁₁. In other words, if the migration rate from B to C is high, removal at D will be impossible. In this case, it will be necessary to reduce the number of individuals exterminated at the wintering ground C and in population A below the upper limit, or to selectively exterminate individuals from A and B.

Draft Decision: 47 COM 7B.7 

The World Heritage Committee,  ...

4. Also welcomes that the Basic Management Policy for managing Steller sea lions (Eumetopias jubatus) has been revised based on new population dynamics models of the two breeding populations in the Sea of Okhotsk and the Kuril Islands, and that catch levels have been set at limits that are considered to conserve the sea lion population, and also requests the State Party to continue implementing a sustainable fisheries management approach that is precautionary, adaptive and continues to be informed by scientific population data in order to ensure the long-term conservation of the species as an attribute of the OUV, in consultation with the IUCN Species Survival Commission as required;