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 Jpn, 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 Jp), 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 goal is to balance the survival of the population, including 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 survival of the populations A and B. In this case, the catch limit of animals to be exterminated will differ depending on whether populations A and B are considered separate or a single population.

Let the number of individuals in populations A and B be x₁ and x₂, the migration rates from A to C and D be m₁₁ and m₁₂ (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 to be exterminated 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 population A individuals captured at C, y₁₁, is y₁ x₁₁/(x₁₁ + x₂₁). If the upper limits of the number of individuals to be exterminated 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 no migration from A to D, the solution to obtaining a number of extinctions that satisfies the upper limit is that the number of extinctions at C is always positive, but the number of extinctions at D is 0 when h₁m₂₁ > h₂m₁₁. In other words, if the migration rate from B to C is high, extirpation at D will be impossible. In this case, techniques such as reducing the number of individuals exterminated at the wintering ground (C) and in population (A) below the upper limit or selectively exterminating individuals from (A) and (B) will be necessary.

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;