- 著者
- Takashi IKEDA Makoto ASANO Naotoshi KUNINAGA Masatsugu SUZUKI
- 出版者
- JAPANESE SOCIETY OF VETERINARY SCIENCE
- 雑誌
- Journal of Veterinary Medical Science (ISSN:09167250)
- 巻号頁・発行日
- pp.20-0083, (Released:2020-05-19)
- 被引用文献数
- 8
Although the first cases of classical swine fever were reported in 2018, no studies have explored this impact on wild boar populations in Japan. Comparing the relative abundance indices and age ratios in the wild boar population before and after the outbreak, we investigated the impact of classical swine fever virus on wild boar population dynamics in August 2017–December 2019. Relative abundance indices declined from 2017 to 2019 drastically, while there were no significant differences in age ratios throughout the study period. Consequently, wildlife managers should consider that wild boars continue to contract classical swine fever virus, and they should intensively implement countermeasures in agricultural lands and in pig farms, in addition to wild boar population management.
- 著者
- Takashi IKEDA Makoto ASANO Masatsugu SUZUKI
- 出版者
- JAPANESE SOCIETY OF VETERINARY SCIENCE
- 雑誌
- Journal of Veterinary Medical Science (ISSN:09167250)
- 巻号頁・発行日
- pp.20-0675, (Released:2021-03-26)
- 被引用文献数
- 3
There is a possibility that classical swine fever virus outbreak has negative impacts on wild boar. To adequately manage native wild boar populations, wildlife managers need to gather the field data on wild boar and implement population management practices. We aimed to report the relative abundance index of wild boar before and after this outbreak. Our results showed that relative abundance index declined from 2017 (8.88 wild boars/100 trap days) to 2019 (2.03 wild boars/100 trap days), because of the negative impact of this virus and continuous culling programs. Although the eradication risk from the synergistic effect is low, wildlife managers need to consider the relationship between the trade-off between the risk of CSF and the conservation ecology risk of native species eradication.
- 著者
- Takuya KATO Yayoi ICHIDA Kazumi TEI Makoto ASANO Shin-ichi HAYAMA
- 出版者
- JAPANESE SOCIETY OF VETERINARY SCIENCE
- 雑誌
- Journal of Veterinary Medical Science (ISSN:09167250)
- 巻号頁・発行日
- vol.71, no.11, pp.1473-1478, 2009 (Released:2009-12-04)
- 参考文献数
- 30
- 被引用文献数
- 5 5
In order to examine reproductive characteristics of feral raccoons in Kamakura, 335 raccoons were collected from March 2005 to March 2007. Raccoons were classified into five age classes: Class I, less than 5 months old; Class II, 5-11 months; Class III, 12-17 months; Class IV, 18-23 months; and Class V, over 23 months old. Females were examined for their age specific pregnancy rate and litter size. To determine when raccoon births occur in the region, birth months of fetuses were estimated by the fetal growth rate, and birth months of Class I individuals were examined by tooth eruption. From fetuses of 18 pregnant females and 47 Class I individuals, it was found that the raccoon births occur from February to October. Of 163 females examined, all of Class I-II females were nulliparous. Pregnancy rate was 47.6% in Class III females, which was significantly lower than 75.0% in Class IV and 78.1% in Class V. The litter size of fetuses ranged from 2 to 5, and 3.9 on average; and that of placental scars ranged from 1 to 7, 3.8 on average. Our findings suggest that parturition of raccoons is a bimodal distribution and age at first parturition may occur between 12 and 17 months old. In order to reduce the raccoon population successfully, females of all ages should be captured throughout the year.