Mayumi Yokoyama

In this study, we clarified the situation of the wild boar population and damage on Futagami Island, Matsuyama City, Ehime Prefecture, 10 years after the wild boars migrated to the island. First, the REST model was used to estimate the population density, which was estimated to be 69.3 wild boars/km²（median value） as of December 2020. The area of possible habitat was estimated to be 1.97 km²（86％ of the entire island）, and the number of animals inhabiting the island during the same period was estimated to be 117.8 animals, which is equivalent to 1.4 times the human population. Under such habitat conditions, wild boars easily invaded peopleʼs houses and farmland, damaging warehouses and causing wild boars to give birth near farmland and agricultural facilities. Capturing wild boars is essential for the safety and security of peopleʼs lives, but we also found that the average annual number of wild boars captured on Futagami Island is only 12-34％ of the estimated population. While it is necessary to increase the number of animals captured, it is extremely difficult to recruit new trappers on Futagami Island, which is currently suffering from depopulation and an aging population. Therefore, it is necessary to increase the number of animals captured by expanding public support from outside the island.

<p>We recorded a Japanese marten biting the neck of a wild boar piglet, using an infrared-triggered camera installed in the forest in Gifu Prefecture, Japan. It is unclear whether Japanese martens actively capture wild boar piglets as a food resource, but we propose that Japanese marten as a potential predator of wild boar piglets.</p>

<title>Abstract</title> The gullet worms, classical <italic>Gongylonema pulchrum</italic> and newly differentiated <italic>Gongylonema nepalensis</italic>, are prevalent in various mammals in Japan and Sardinia, Italy, respectively. The former species is cosmopolitan in distribution, dwelling in the mucosa of the upper digestive tract of a variety of domestic and wild mammals, and also humans. At present, the geographical distribution of <italic>G. nepalensis</italic> is known in Nepal and Sardinia, with the nematode having been recorded from the oesophagus of water buffaloes (Nepal), cattle, sheep, goats and wild mouflon (Sardinia). To clarify their natural transmission cycles among domestic and wild mammals, the present study analysed the ribosomal RNA gene (rDNA) and mitochondrial cytochrome <italic>c</italic> oxidase subunit 1 gene (<italic>cox</italic>1) of worms of various origins: <italic>G. pulchrum</italic> worms from sika deer, wild boars, Japanese macaques, and feral alien Reeves's muntjacs in Japan, and <italic>G. nepalensis</italic> worms from a red fox and a wild boar in Sardinia. Although the internal transcribed spacer (ITS) regions of rDNA and partial <italic>cox</italic>1 nucleotide sequences of <italic>G. pulchrum</italic> from native wild mammals in Japan were distinct from those of the worms in cattle, the worms from feral alien Reeves's muntjacs showed the cattle-type ITS genotype and <italic>cox</italic>1 cattle-I and II haplotypes. The rDNA and <italic>cox</italic>1 nucleotide sequences of <italic>G. nepalensis</italic> from a red fox in Sardinia were almost identical to those of the worms from domestic and wild ruminants on the island. The ecological interaction between domestic and wild mammals and their susceptibility to different <italic>Gongylonema</italic> spp. must be considered when trying to elucidate this spirurid's transmission dynamics in nature.

Tick-borne encephalitis virus (TBEV), a flavivirus that causes severe neurological symptoms in humans, has been found in Hokkaido, Japan. In the present study, we detected sequences from a novel tick-borne flavivirus, designated Yamaguchi virus (YGV), in liver and serum samples obtained from a wild boar in the Yamaguchi prefecture, Japan. Phylogenetic analysis revealed that YGV belongs to the TBEV complex and is closely related to Langat virus (LGTV). YGV was also detected by specific RT-PCR from 20 in 378 pools of ticks (2923 ticks) collected in Yamaguchi and Wakayama prefectures and from seven in 46 wild boar captured in Wakayama. The major ticks infected with YGV belong to the genus Haemaphysalis. Unfortunately, YGV could not be isolated from any samples from the RT-PCR positive wild boar or ticks. Therefore, ELISA for detection of antibodies against YGV was established using LGTV, and surveillance was performed among wild boar in 10 different prefectures on Honshu Island, the main island of Japan. The results showed that the seroprevalence of tick-borne flavivirus infection in the Wakayama and Hyogo prefectures of western Japan was significantly higher than that in the other prefectures, while antibodies against tick-borne flavivirus were not detected in any wild boar in the Tochigi prefecture in the eastern part of Japan. In addition, wild raccoons or masked palm civets in the Hyogo prefecture did not possess detectable antibodies against tick-borne flaviviruses. In conclusion, YGV appears to be maintained primarily among wild boar and ticks in the western part of Japan. YGV is the second flavivirus (after Japanese encephalitis virus) shown to be circulating on Honshu Island in Japan.

In 2014, an outbreak of Getah virus (GETV) infection occurred in Japan in a horse population that was inoculated with a vaccine against GETV. In this study, we investigated the seroprevalence of GETV infection among wild boars in Japan. Interestingly, the highest rate of anti-GETV-positive wild boars was observed in 2013, which gradually decreased during 2014-2016. The results suggested that GETV spread among wild boars around 2012, resulting in the 2014 outbreak.

Japanese black bears (Ursus thibetanus japonicus) in Hyogo Prefecture exhibit abnormal bone morphology with high frequency. Basic knowledge about the bones of the Japanese black bear is necessary for diagnosis, for cause identification, and for evaluation of the influences of these abnormally formed bones on populations. This study analyzed the regular number and morphology of Japanese black bears vertebrae by comparison with those from three areas: Higashi-chugoku, Kita-kinki, and Iwate. The normal number of vertebrae in Japanese black bears is 7 cervical vertebrae, 14 thoracic vertebrae, 6 lumbar vertebrae, and 5 sacral vertebrae. When vertebrae of three kinds other than the sacral vertebrae were analyzed, three irregular patterns of vertebral combinations were observed. Each was found to be regionally idiosyncratic. Vertebral deformation of two types was identified. One type included extension of the transverse process of the first lumbar vertebrae. It was found more frequently in Kita-kinki. Another type included lumbosacral transitional vertebrae. It was found in Higashi-chugoku and Kita-kinki. Numerical variation of the vertebrae and vertebral deformation might be the result of different genetic characteristics of the three populations.

The differences between male and female deer meat were investigated in terms of meat weight and nutritional value in order to promote effective utilization of the meat of wild sika deer (Cervus nippon). The study samples were sika deer captured in Tanba district, Hyogo Prefecture, in September, November, and December, 2010. For male deer, the average body weight was 46.4 kg, the average meat weight was 16.7 kg, and the meat yield was 35.6％. Nutritionally, the meat consisted of 21.2 g of protein and 0.4 g of lipid per 100 g. For female deer, the average body weight was 36.3 kg, the average meat weight was 13.1 kg, and the meat yield was 35.7％. Nutritionally, the meat consisted of 20.5 g of protein and 0.7 g of lipid per 100 g. The female deer was smaller than the male deer, but had a higher amount of lipid. Differences in values according to season were small in both sexes. The meat weight ratio was high for rounds and shanks, and differences in the nutritional features of meat from the various body parts were small.

The questionnaire was sent to 21 users of mammalian pest repelling dogs in three regions in order to present a summary of the use of the dogs. The questions were categorized into the following groups: 1) information about the user, 2) damage caused by pests, 3) characteristics of the dogs, 4) method of utilizing the dogs 5) efficacy of the dogs, 6) users&#039; impressions, and 7) problems associated with using the dogs. Shiba-inu was the most commonly used (50.0%). The dogs chased pests for an average distance of 306.6m (SD=215.3) and for an average time of 32.4 minutes (SD=42.2). The mean defendable distance of one dog was estimated at 494.4m (SD=255.4). This result indicated the possibility that if one dog is allocated about every 500m, it reduces the damage in the entire target area. Eighty-one percent of users answered that the dogs are more effective in repelling pests than the existing methods, such as fireworks and slingshots. Moreover, all the users desired to continue using the dogs.

Although raccoons (Procyon lotor) are susceptible to influenza viruses, highly pathogenic avian influenza virus (H5N1) infection in these animals has not been reported. We performed a serosurvey of apparently healthy feral raccoons in Japan and found specific antibodies to subtype H5N1 viruses. Feral raccoons may pose a risk to farms and public health.

・有害捕獲で忌避条件付けされた個体と、錯誤捕獲で忌避条件付けされていない個体の放獣後の行動を比較した。・放獣個体の性別や放獣時期、放獣した年の堅果類の豊凶などによって、放獣後の行動が異なるかどうかについても、分析を行なった。・有害捕獲で忌避条件付けされた個体は、錯誤捕獲で忌避条件付けされていない個体よりも、人里周辺の利用頻度が高かった。・堅果類が豊作の年の9月と10月に捕獲された個体は、放獣から日数が経つにつれて人里周辺の利用頻度が高くなった。・堅果類が凶作の年の11月に捕獲された個体は、放獣から日数が経つにつれて人里周辺の利用頻度が低くなった。・これらの結果から、ツキノワグマの放獣後の行動は、忌避条件付け放獣の影響より捕獲までの履歴の影響の方が大きいことが示唆された。そのため、ツキノワグマの人里周辺の利用を防ぐためには、被害を継続的に発生させ、人里を利用するのに馴れてしまった個体を作らないことが重要な課題であると考えられた。

To better manage wild boar (Sus scrofa) populations, we analyzed the relationships between sighting per unit effort (SPUE) of wild boar in gun hunting, and environmental factors affecting wild boars and agricultural damages. Path analysis suggested that snow fall and proportion of secondary deciduous forest had positive path coefficients on the SPUE of wild boar, and the SPUE of Sika deer (Cervus nippon) and gun hunting effort had negative path coefficients. Gun hunting effort was lower in areas of heavier snow. Interactions between snow fall and hunting affecting wild boar, and indirect competition between wild boar and Sika deer through vegetation damage by Sika deer, are both possible. SPUE of wild boar was significantly correlated to agricultural damage, and the relationship had different features from that of Sika deer. On the basis of these results, SPUE can be a target index for population management and helpful to select appropriate methods that depend on local conditions.

We conducted a hearing focused on brown bear (Ursus arctos) and Asian black bear (Ursus thibetanus) population management policy in the 35 prefectural governments where bear species occur, to highlight the issues facing population monitoring and management, from July to September 2007. Eleven prefectures have carried out bear population management under the Specified Wildlife Conservation and Management Plans (SWCMP), which is a system under the Wildlife Protection and Hunting Regulation Law, and five prefectures have carried out management plans under their own intentions. Twelve prefectures did not have any written plans or guidelines for bear population management. While nine prefectures out of 24 that had no legal plan were planning to formulate legal management plans for their bear populations, the remaining 15 prefectures have no plan to establish any legal management plan. The current major management goals including legal and non-legal management plans were 1) avoiding the extinction of local bear populations, 2) avoiding human injuries by bears, and 3) reducing economic damage by bears. The most common subject of numerical goals in the plan was the upper limit of kills, which was listed by eight prefectures out of ten carrying out management plans with numerical goals. The major monitoring subjects were investigations of killed individuals, appearance and damage, acorn and nut production, and so forth. Major subjects in management operation were population management, conflict prevention, release of problem individuals, habitat securing, and diffusion and the widespread education of the public regarding bear conservation. Only three prefectures established an inter-prefectural coordinated management plan for the black bear population, and that was in the Western-Chugoku Region. The placement of numerical goals regarding conflict occurrence and monitoring, the establishment of population trend monitoring measures, and the establishment of monitoring systems by local populations are essential to improve scientific population management of bears in Japan.

We reported on the current status and issues involved in the Specified Wildlife Conservation and Management Plans (SWCMP) for the Japanese black bear (Ursus thibetanus) in 2003&ndash;2007 in Hyogo Prefecture, Japan. Two populations of black bear in Hyogo Prefecture are distributed in the east-Chugoku and north-Kinki regions, and each of these populations has been isolated and endangered. However, the numbers of human-bear conflicts in these regions have been increasing. After the SWCMP was implemented, 86% of all bears captured for nuisance control and miss-trapping have been released with aversive conditioning. We fitted 44 bears with transmitters and monitored their subsequent behavior as long as possible. By such careful monitoring, we could avoid unneeded control-killing of bears. And we could euthanize bears in case of aversive-conditioning when captured again in the same or different village according to the guidelines of the SWCMP. These releases may have prevented the local extinction of the bear populations. We still have at least two problems related to bear management. First, we must develop more effective methods to drive away bears, release with aversive conditioning, and educate local people. Another issue to be solved is large scale management of bear populations distributed over multiple prefectures.<br>

We examined the Specified Wildlife Conservation and Management Plans (SWCMP) for sika deer (Cervus nippon) populations from 2002 to 2006 in 29 prefectures and one other area (Ohdaigahara) by a questionnaire survey, from June to September, 2006. The goals of these management plans were 1) to avoid extinctions of local populations, 2) to reduce conflicts between deer and humans, such as damage to agriculture and forestry, 3) to reduce deer population sizes, and 4) to conserve ecosystems. To implement these plans, population trends were monitored using the following indices: catch and sighting per unit effort, aerial surveys, spotlight surveys, block count method, pellet groups and pellet count methods. In 11 of the 30 areas implementing SWCMPs, deer population sizes were underestimated. Because of either underestimated population size or the expansion of deer distribution, population control via SWCMP has not been attained in most areas. For successful feedback management, it is necessary to establish an organization or system for evaluating the management plan scientifically at the prefectural government level. Cooperation between scientists and managers is also important for wildlife management. Lastly, one further problem to be solved is the large-scale management of deer populations distributed over plural prefectures.

We reported on the current status and issues involved in the Specified Wildlife Conservation and Management Plans (SWCMP) for sika deer (Cervus nippon) during 2000-2006 in Hyogo Prefecture, Japan. One of the goals of the plan, that of the number of captures per year (10,000-15,000 deer), has been attained, but the other goals, including halving the deer population size (from 31,000 to 15,000) and decreasing crop damage to the expected values, have not been achieved. However, population increases were restrained by the reinforced controlling effort of the prefecture based on monitoring. Substantial monitoring methods, such as density indices, crop damage levels in villages, forest damage levels and dissection analysis, have all been implemented. The next issue to be solved is making a system to form an agreement and to decide on measures based on the data that may be easily explainable to most citizens.

We investigated the structures of communities and populations of the component species in four stands of abandoned charcoal secondary forests that differed in the density of sika deer (Cervus nippon), to clarify the effects of herbivory by deer. Densities of stems in the lower height classes were markedly lower in stands affected by deer herbivory than in stands with no herbivory. In stands with herbivory, the effect of herbivory was not evident in Type I species that had a unimodal or flattened distribution in the upper height classes. However, in Type II species that had modes in the lower height classes, the patterns of stem height distributions changed from L-shaped to bell-shaped in the stands. Most late-successional species of tall trees were of Type II, and their saplings were sparse in stands affected by deer herbivory. This suggests that recruitment and regeneration of these species have been prevented in the stands due to herbivory by sika deer. If herbivory by deer continues over a long time in these stands, it may be difficult for the stands to maintain the framework of forest structure. On the other hand, stand regeneration may be attained by late-successional species of Type I. In this case, the future species composition of these stands should be determined through the processes of plagiosere succession, not by general secondary succession.

We investigated fetal development and the estimation of fetal age of 127 Hokkaido sika deer fetuses, categorizing them into three groups according to the nutritional condition of populations. The order and time of the appearance of ossification centers were clarified, and fetal age was determined based on bone length and the appearance of ossification centers. Then we observed the differences in fetal growth among three populations, and discussed the effect of poor nutrition on the fetal growth. The results suggest that fetal diaphysial length of the femur was affected very little by nutritional conditions, whereas conception dates were delayed and fetal weight was restricted as the nutritional condition became poorer. Although it is impossible to know the exact accurate fetal age in wild populations, it was possible to create a standard to estimate fetal age more precisely by the method described in this study. Both the bone length and the appearance of ossification centers are reliable indices to estimate fetal age precisely in measurements available from fetuses of unknown age, and can be applied to estimate the fetal age of other populations of sika deer, whereas estimation of fetal age based on weight is prone to great errors.<br>

This work was designed to observe the dentine incremental lines of the sika deer (Cervus nippon) fawns and to investigate their periodicity using the chronological labeling method with fluorochromes. The incremental lines were observed in decalcified specimens stained by Bodian's silver technique, and the fluorescence-labeled lines were observed in undecalcified and ground specimens. In the silver stained specimens, there were two types of lines, deeply stained thick lines and faintly stained minute regular incremental lines. The intervals and staining intensities of the deeply stained thick lines were very similar to those of the fluorescence-labeled lines in the ground specimens obtained from the same tooth, and hence, it appeared that the both lines were identical. The number of minute incremental lines between the deeply stained thick lines was the same as that of days between the time when each fluorescent labeling injection was made. Therefore, it seemed that each minute incremental line was formed each day. The possibility of age estimation in days using diurnal dentine increments was discussed.