J-STAGE Advance published date: May 6, 2021

IMPACT OF WHALE RESOURCE MANAGEMENT RESEARCH ON SIKA

IMPACT OF WHALE RESOURCE MANAGEMENTRESEARCH ON SIKA DEER MANAGEMENTKoichi KAJI1, 2
Tokyo University of Agriculture and Technology
Wildlife Management Research Center, Hyogo,
940 Aogakicho Sawano, Tamba, Hyogo 669–3842, Japan
Corresponding author: kkaji@cc.tuat.ac.jp
12Abstract
Sika deer population management in Hokkaido has been strongly inﬂuenced by whale resource management research in monitoring frameworks and management approaches. The
whale survey consisted of ﬁve pillars: catch statistics, visual observations, tag-recovery surveys, biological surveys from whaling, and special catch surveys. In references to the whalemonitoring, sika deer monitoring was constructed involving capture information (SPUE,CPUE), visual observations (spotlight census, aircraft survey), radio telemetry surveys, geneticsurveys, and biological surveys from hunting and culling for assessing age structure and thereproductive characteristics of female deer. We adopted the Revised Management Procedure(RMP）for whaling to Hokkaido sika deer population as feedback management because there
was uncertainty in estimating population size. Feedback management incorporated into deer
management in the eastern part of Hokkaido became the pioneer of science-based wildlife
management in Japan. It inﬂuenced the establishment of the Speciﬁed Wildlife Conservationand Management Plan by amending the Wildlife Protection and Hunting Act in 1999. Feedback management is almost synonymous with adaptive management in a broad sense. The
large-scale feedback management of sika deer in Hokkaido is a practical example of adaptive
management of deer ahead of the world.
Key words:

Adaptive management, feedback management, revised management procedure,
sika deer, monitoring, whale.

Introduction
Hokkaido Government established the Hokkaido Institute of Environmental Sciences (HIES) in
1991, when I started to work as a researcher for sika deer (Cervus nippon) management. Until then,monitoring of terrestrial large animals was not carried out except for Japanese serow (Capricorniscrispus), a species designated as a nation’s Special Natural Monument. Sika deer population management in Hokkaido has been strongly inﬂuenced by whale resource management research in monitoring
frameworks and management approaches. As a result, it has played a leading role in science-based
wildlife management in Japan.

ReviewMonitoring
In 1991, when I was planning sika deer monitoring all over Hokkaido, Dr. Hidehiro Kato kindly
sent me a book entitled “Study on Whale Stock Management” (Sakuramoto et al., ed. 1991). This
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book, covering all aspects of whale resource management involving theory and practice, attracted mevery much. The whale resource management research was ideal for researchers on large mammal population dynamics. Dr. Seiji Ohsumi reviewed the method and its system in Chapter 1 (Ohsumi, 1991),
which was particularly useful for constructing the baseline of sika deer monitoring.
The whale survey consisted of ﬁve pillars: catch statistics, visual observations, tag-recovery surveys, biological surveys from whaling, and special catch surveys. The biological surveys were conducted for three purposes: genetic analysis for separation of lineages, estimation of biological parameters, and elucidation of cetaceans’ ecosystems.
In references to the whale monitoring, I constructed sika deer monitoring using capture information(SPUE: Sighting per Unit Eﬀort, CPUE: Catch per Unit Eﬀort) per each 5 km×5 km grid, and visualobservations (spotlight census, aircraft survey) over a wide area to grasp the rough population trend.
To determine the management unit for sika deer, my research team and I conducted radio telemetry
surveys and genetic surveys in Eastern Hokkaido. We also worked on age determination from the individuals captured by hunting and culling and analyzed the reproductive characteristics of female deer.
Seasonal migration, the genetic structure of populations
To determine management units for sika deer population, we examined seasonal migration andhabitat use by installing dozens of VHS radio transmitters in the deer population in eastern Hokkaido(Uno and Kaji, 2000, Igota et al., 2004). We also studied changes in the populations’ genetic structure
in recovering the distribution from near extinction (Nagata et al., 1998) and expanding the distribution
to the saturation period (Ou et al., 2014). These ﬁndings were signiﬁcant for considering the management unit for developing sika populations in Hokkaido.
Population dynamics: its processes and mechanisms
As model survey sites for closed habitats, I chose Nakanoshima Island in Lake Toya, where deer
have been artiﬁcially introduced, and Cape Shiretoko, where deer colonized. I set up two places foran open environment: Onbetsu town and Ashoro town in Eastern Hokkaido. The population survey
method depended on the region; drive count method on Nakanoshima Island, aerial survey at CapeShiretoko, spotlight count at Onbetsu town, and cohort analysis by age determination of a total of
17,549 individuals captured in Ashoro town over 12 years. Then, we analyzed the process and patternof population ﬂuctuation and its mechanism.
These studies revealed that the natural increase rate of sika deer was around 20% without harvesting or predator, that explosive increases occur, even when they are introduced into the island or naturally colonizing, and even in settled populations with original habitat. Large-scale population crashrepeatedly occurred in closed habitat (Nakanoshima Island and Cape Shiretoko) (Kaji, 2018). Thus, inthe absence of predators and harvesting, the populations would not be in equilibrium with plants andsubstantially impacted the vegetation. These clearly showed that aggressive culling for female deer
was necessary to reduce the overabundant sika deer population.
Feedback Management
From the hunting season in 1994, female deer hunting was allowed in Hokkaido for the ﬁrst time in
72 years. However, there were many objections in fear that overharvesting in the Meiji era would leadto extinction. We recognized the increasing trends of the deer population in eastern Hokkaido. However, there was uncertainty in estimating population size, so it was impossible to determine how many
deer we should harvest at that time.
We invited Dr. Hiroyuki Matsuda, an expert in mathematical ecology and ﬁshery resource management, as a lecturer and held a resource management study session for sika deer to consider breakthrough measures. Dr. Matsuda proposed feedback management of sika deer (Matsuda et al., 1999)
following the Revised Management Procedure (RMP) for whaling (Tanaka, 1982). Feedback man-302

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IMPACT OF WHALE RESOURCE MANAGEMENT RESEARCH ON SIKA

agement incorporated into deer management in the eastern part of Hokkaido became the pioneer ofscience-based wildlife management in Japan. It inﬂuenced the establishment of the Speciﬁed Wildlife
Conservation and Management Plan by amending the Wildlife Protection and Hunting Act in 1999.
The Ministry of the Environment adopted a Feedback management approach in the deer management
manual.
Towards adaptive management
Adaptive management is suitable for managing wildlife populations and natural resources thatobtain insuﬃcient and uncertain data and continuously improves management policies and practices
through adaptive learning and feedback management (Walters, 1986). On the other hand, feedback
management is a management policy for sustainable use at the optimum level based on uncertain
information on natural resources (Tanaka, 1982), which is almost synonymous with adaptive management in a broad sense.
Adaptive management is considered the best way to solve the biological and policy dilemma of
deer management in US national parks; however, there are limited cases in practice (Porter and Underwood, 1999). In France, adaptive management using indicators of ecological change is adopted for themanagement of small scale and well-deﬁned population of roe deer (Morellet et al., 2007). Therefore,
the large-scale feedback management of sika deer in Hokkaido is a practical example of adaptive management of deer ahead of the world.

Conclusion
On October 25, 2001, I had the opportunity to report on the feedback management of sika deer in
Hokkaido at the Institute of Cetacean Research seminar. Dr. Shoichi Tanaka, who advocated feedback
management, and Dr. Ohsumi, the Institute of Cetacean Research director, attended the venue.
In the seminar, I explained that the deer management goal in Europe and the United States wasmaintaining maximum sustain yield (MSY) by managing the population around K/2 of the MSY
curve. However, K/2 was too high to prevent damages to agriculture and forestry and ecosystem of
cervid populations with weak density dependence like sika deer (Kaji et al., 2010). Avoiding severe
deer damages, maintaining the population considerably lower than the carrying capacity was required.
The sika deer management goals of our program were: (1) to keep the population at moderate densitylevels preventing population irruption, (2) to reduce damage to crops and forests, and (3) to sustain areasonable yield of hunting without endangering the population. We developed a threshold harvesting
approach as feedback management involving three threshold levels of relative population size, fourlevels of hunting pressure, with a choice of four corresponding management actions by sex-speciﬁchunting, based on the estimates of relative population size (Matsuda et al., 1999).
I concluded that harvesting was the only operational experiment, essential for population abundance
estimation and density dependency detection. Hunting was a large-scale ecological experiment since
it was impossible to conduct repetitive experiments in nature and manipulate the natural environment.
Drs. Ohsumi and Tanaka were pleased to listen to my presentation, which encouraged me to progressscience-based wildlife management for sika deer.

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Received: January 13, 2021
Accepted: February 15, 2021
Published online: May 6, 2021

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