Book Review "A Family Tree of Blakiston's Fish Owls: The author’s Lifework" (Yuko Hayashi 2026)

 

Book Review Yuko Hayashi (2026). “Blakiston’s Fish Owl: Called Kamui in Hokkaido” 「カムイのフクロウ－シマフクロウを追う」. University of Tokyo Press, 192 pp. ISBN: 978-4-13-063968-2. price: 3,520 yen.

I wrote a book review, and here is a summary of the English translation.

The centerpiece of the book is likely the family tree on page 96, which traces the lineage of Blakiston's fish owls. Its complexity rivals that of the Egyptian pharaohs, whose dynasties were marked by frequent inbreeding.

The author spent 37 years creating this diagram—from undergraduate to the president of Japanese Society of Ornithology, including her long tenure as a postdoctoral researcher—to track the breeding records of this specific lineage. One realizes that such dedication underpins the Ministry of the Environment’s conservation and propagation program for the Blakiston’s fish owl, conducted under the Act on Conservation of Endangered Species of Wild Fauna and Flora.

This book is also a compelling read as a collection of essays. The writing never feels preachy; instead, the author’s hardships and failures are glimpsed through understated descriptions, fostering a sense of empathy. I also appreciate that the author writes candidly about both the successes and the challenges of conservation efforts.

The author’s words carry significant weight, given his long-standing involvement in Blakiston's fish owl conservation—dating back to before 1990, when the population was likely at its lowest ebb. The book reveals many details that official government documents cannot convey, such as the nature of relationships with the Ministry of the Environment and the Forestry Agency, interactions with specific officials, and the dedication of citizen researchers.

Furthermore, I would like to see consideration given to publishing an English translation. This work holds value comparable to the stories found in Wild Animals I Have Known by Ernest Thompson Seton.

Comments on the IUCN Red List 2025 Reclassification of the Green Sea Turtle

 The IUCN Red List classification of the Green Sea Turtle, which was listed as Endangered (EN) as recently as 2023, was downgraded to Least Concern (LC) in late 2025 [1]. I welcome the final conclusion of LC, but disagreeing with several methodological points in the assessment process.

1. The Logical Contradiction in Omitting Criterion E

The handling of Criterion E (extinction risk assessment) is logically unfair. The IUCN asserts that a species can be listed under threatened categories if it meets other criteria, even if it fails to meet Criterion E (although I disagree with it [2]). However, by choosing not to run or apply Criterion E simply because the species already failed to meet Criteria A through D, the committee creates a catch-22: Criterion E becomes effectively obsolete.

While it is highly improbable that the global Green Sea Turtle population would trigger Criterion E, individual subpopulations might exhibit different results from Criteria A–D; some may be higher or lower. To maintain scientific integrity across the Red List framework, Criterion E should be evaluated independently of the other metrics.

2. Methodological Underestimation of Population Trends

The assessment report states:

"In the absence of long-term data, we assumed that population abundance three generations ago (~135 years), was similar to the first observed abundance rather than assuming that the population has always been in a decline (or increase)."

This flatline assumption mathematically underestimates the true rate of change. By drawing a static line backward to a historical era (~135 years ago), the model effectively erases the historical context.

A more rigorous approach would be to extrapolate the known trend. Since we have reliable data spanning the 54 years between 1970 and 2024, we should calculate the observed rate of change R for this period and apply it over the full three generations as R^(135/54). In the case of the Green Sea Turtle, because the recent population has been increasing, the final conclusion of "Least Concern" would remain unchanged. 

3. Misdefining the "Shifting Baseline" Problem

The report conflates data gaps with a well-known ecological concept. The committee frames the use of 1970s data (due to the lack of numbers from 2–3 generations ago) as an unavoidable "Shifting Baseline" problem.

This is a misapplication of the term. A true Shifting Baseline Syndrome occurs when a historical population (or the biological carrying capacity) undergoes a catastrophic collapse, stabilizes at a severely depleted level for three generations, and then—because it is no longer declining—gets removed from the threatened list due to human amnesia regarding past abundance. Substituting a known data gap (1970) for an unknown historical value (1900) is a data-mangling compromise, not a true shifting baseline issue.

In CITES, the EU should have 1 vote, not 27.

 At CITES COP20, the proposal to list eels in the Appendix was rejected by a vote of 35 to 100. Of those 35 votes, 27 are believed to have come from the EU, which proposed the listing. However, these weren't cast by individual member states; instead, a single EU representative pushed one button to vote on behalf of all 27 countries. Furthermore, even with an Appendix listing, free trade would remain legal within the EU. In practice, the EU operates as a single entity under CITES.

If each EU country voted independently and voluntarily, there would be no issue with the legitimacy of the outcome. However, I believe that using a 'single button' to represent 27 nations is an unacceptable stance for democratic societies.

How would these leaders feel if the same lopsided system were used in their children’s school elections? Would they not feel ashamed to explain such a process to the next generation?

It is disappointing that the EU appears to feel no such conflict. This is especially glaring given that, excluding the EU's block vote, the proposal was rejected by a staggering margin of 100 to 8 among the rest of the world.

Supplementary comments from newspaper interviews about Japanese eels

Supplementary comments on the interview in the Mainichi Shimbun (reported on October 29, 2025 "Are Japanese eel populations increasing? Two conflicting papers, third-party assessment") Japanese blog of 8 Nov. 2025

• Kaifu et al. (2025)'s criticisms of Tanaka (2014, 2025) are based on three main points:

1. The CPUE data for glass eels includes both under-reporting and over-reporting.
2. The data includes a mixture of information on eel fishing and bycatch, meaning that effort is not limited to eels.
3. The catch, including releases, cannot be said to reflect the resource abundance.　However, Tanaka (2025) conducted a sensitivity analysis that took into account unreported data (Figure 6b).

• On the other hand, Tanaka (2025, p. 8, left column, below Figure 7) criticized Kaifu & Yokouchi (2019) for failing to ensure representativeness of the resource status due to the lack of a sampling plan and the small scale of the survey.
• These criticisms are valid for both (and also for Kaifu et al. 2025). This is unavoidable, as the assessment is based on incomplete information.
• Regarding the criticism of Tanaka (2025), the question is whether the stock assessment would qualitatively change if these factors were corrected. If the unreported rate has remained constant both in the past and now, the absolute stock abundance would actually be higher (Tanaka Figure 6b). If the unreported rate was much higher in the past, it is unlikely that the stock has recovered (although it is questionable whether it continues to decline sharply). (2) If dependence on eel fishing has been lower in recent years, using total effort as the denominator of CPUE would actually underestimate the stock recovery rate. If dependence has been higher in recent years, the opposite would be true. (3) If the glass eel catch rate is lower now, an analysis including releases would not necessarily underestimate the true rate of decline. If it is higher now, the opposite would be true.
• I don't mind Kaifu et al. using unpublished data, but to maintain anonymity, the catch amount data are not shown. Unfortunately, we are unable to confirm their regression model (though Kaifu can replicate Tanaka 2025 to some extent). It's likely that the reviewers also pointed this out. Furthermore, Kaifu et al. (2025, Table 3) treat each fishing ground as an independent population and provide point estimates of the decline rate for each fishing ground. However, the Japanese eel stock is actually a single entity, and parent and offspring likely do not migrate upstream to the same location. A single overall decline rate should be estimated as an interval estimate. Including Chiba, where the population increased 4.5-fold (this could be adjusted, for example, by limiting the overall population to the October-December period), would result in a value with a reasonable range. To begin with, CPUE is not suitable for quantitatively assessing the true decline rate of stock abundance (R. Myers's infamous 90% decline in tuna species was later criticized, and it's now said to be at most 30-50%). However, Kaifu's analysis is also valuable. The fact that it can only be published anonymously is "abnormal." He persisted in his analysis. 
• The results for glass eels are consistent in both cases, suggesting a flat population (or no significant increase or decrease, as stated in the abstract of Kaifu et al. 2025). However, Kaifu et al. 2025 includes the results for glass eels, excluding as many unreported cases as possible, in Figure 4 and Table 4. Table 4 does not specify the estimates and SEs, but the likely growth rates are -0.021 and +0.101 (per year?). Simply applying SE (whether this is appropriate or not is unclear, but the paper lacks the data necessary for further analysis) would suggest a 0.17 increase and a 0.09 decrease (unclear increase or decrease). This is probably the most reliable conclusion. If this is the case, we cannot deny the possibility of continued decline (a decrease of more than 80% over 24 years [or, at the same rate, a decrease of more than 60% over 14 years] is likely less than 5%), but there is also a possibility of recovery. 
• This alone may not be sufficient evidence for listing species under CITES. There is no doubt that the decline has been significant compared to half a century ago. However, it is unclear whether the decline has continued since 2010. If the proposal had been made at the same time as the European eel, there would have been little opposition to listing it on CITES Appendix II, but it would be better to wait a little longer to see the results of subsequent conservation efforts. It's unclear why it's being proposed now.
• The international treaty could be throwing cold water on the issue without waiting for the results of Asian countries' efforts since around 2015, but perhaps that's their raison d'être. Like the IWC, CITES is a "fossilized" treaty based on a dichotomy.
• The Red List is determined based on past decline rates, so it likely met the numerical standards of the IUCN (criteria A) and the Japan Ministry of the Environment at the time (criteria E). The Red List is not based on extinction risk itself, so even with a CR rating, fishing is still possible, as with bluefin tuna, and some species are recovering through exploitation. I have been criticizing the Red List criteria for about 30 years (Matsuda et al. 1997), saying they are strange, but the IUCN criteria (ver. 3.1) has been clearly stated that "species that meet the numerical criteria will be included even if they are known to have a low risk of extinction".

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.

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How to Build Matrix Population Models from Process Components

 Literature Introduction of "Notes on Building Matrix Population Models: Insights From Combining Distinct Matrices for Survival, Reproduction, and Growth" (Matsuda H & Taper ML 2025, Population Ecology POPE70005, doi.org/10.1002/1438-390x.70005) (full manuscript) (See html for lecture pdf & video).

Abstract

We propose a unified method for formulating matrix population models in wildlife and fisheries management, adaptable to variations in population measurement timing and natural and human-induced mortality. For populations with a common and short breeding season, this approach applies to age-, size-, and stage-structured populations. The process is considered separately as three: survival, reproduction, and age increment or growth, with the respective matrices designated as S, B, and G. In the age-structured model, reproduction and age increment occurs simultaneously, and are expressed as a matrix model of S(BG) if the population census is taken immediately before the parturition, and (BG)S if it is taken immediately after the parturition. In the size- or stage-structured model, growth and survival proceed in parallel, and are expressed as a matrix model of (GS)B if the population census is taken just before the parturition, and B(GS) if it is taken just after the parturition. When the population census is taken at any other time, the survival rate from the parturition to the census and the survival rate from the census to the parturition can be considered separately. Furthermore, even when capture mortality is given as the number of individuals rather than a rate, a unified formulation by capture time is possible by expressing the number of captures as a vector. 

Inaugural Address by the New Chair of Earthwatch Institute Japan

In recent years, the fusion of traditional knowledge and scientific knowledge has progressed beyond the conventional scientific framework. The role of citizens in advancing science has also become increasingly important. Since its founding in 1971, Earthwatch has been a leader in citizen science, sending citizen volunteers into the field to advance research activities with corporate support. In the future, environmental issues will become increasingly important and urgent, and we are entering an era that will require a new "relationship between people and nature”. We would like to work hard to further develop citizen science by respecting diverse values and positions and providing a forum for free and lively exchange of opinions. We sincerely appreciate your participation and cooperation.

(Original Message in Japanese)