ニホンイシガメ生息域外保全活動
Ex-Situ conservation activities of the Japanese pond turtle,
Mauremys japonica in Adachi Park of Living Things
辻井聖武*1,*2,*3、角山綾香*1,*2 、大山裕樹*1,*2*1足立区生物園、 *2(株)自然教育研究センター、*3千葉県ニホンイシガメ保護対策協議会
Masamu Tsujii *1,*2,*3, Ayaka Kakuyama *1,*2, Yūki Ōyama *1,*2*1Adachi Park of Living Things, *2Center for Environmental Studies, *3Conservation Activity Council of the native freshwater turtles in Chiba Prefecture

はじめに：日本固有の淡水棲カメ類のニホンイシガメは，千葉県において北米原産のアライグマによる捕食，クサガメとの交雑などにより急激に個体数が減少している．これ
らの減少要因から効果的なニホンイシガメの保全策をとるため，これまで長期的に調査をしていた個人の有志や大学機関の研究者が集まり千葉県ニホンイシガメ保護対策協議会が設立された．

Introduction: In Chiba Prefecture, the Japanese pond turtle, Mauremys japonica has
rapidly been decreasing due to severe predation by the introduced North American
raccoon, Procyon rotor, and hybridization with the Chinese pond turtle, Mauremys
reevesii. To take effective conservation measures to protect this species, the interested
persons and groups who have been engaged in long-term ecological research on
freshwater turtles have established the Conservation Activity Council for the nativefreshwater turtles in Chiba Prefecture.

Over exploitation

Physical factor

Habitat loss

Biological factor

Competition for invasive turtles

Predation by Procyon lotor

Habitat fragmentation

River alteration

ニホンイシガメMauremys japonica•日本固有種Endemic to Japan•千葉県が分布域の北限Northern limit of distribution is Chiba pref.

Rapid decrease in Mauremys japonica

Hybridization withMauremys reevesii

Farmland consolidation
Water pollution

Resource alteration

Abandonment of cultivation

協議会の設立（2013年） The Council established

生息域外保全活動 Ex-situ conservation activities

保護復興計画

1．緊急活動計画

1．アライグマの根絶

Conservation andRecovery plan

Emergency Action Plan

Eradication of the invasive raccoons

2．中期活動計画

2．緊急避難・飼育

Mid-term Action Plan

Emergency evacuation and keeping

鴨川シ―ワールド Kamogawa Sea World
千葉市動物公園 Chiba Zoological Park
足立区生物園 Adachi Park of Living Things

足立区生物園Adachi Park of Living Things

・緊急収容・保護Purpose: Reintroduction
目的：野生復帰
活動：保護・増殖事業 Action: Protection & breeding project・Emergency reception and protection

2015年：2個体（♂1，♀1）受取普及啓発として飼育展示

In 2015, one mature male and one mature female received from the Council.
These individuals are keeping and displaying for public awareness.

・増殖・Breeding
2016年：1蔵卵個体（♀1）受取In 2016, one gravid female received from the Council.
繁殖を試みたが，水中産卵し失敗
We tried reproduction, but failed due to that female laid eggs underwater.
・Progress・進捗
協議会はメス個体の捕獲を試みた
Although the Council tried to capture gravid females to perform theが，現地の個体群密度が低かったた protect and breeding project in Adachi Park of Living Things, no individuals
め，期間中での捕獲はできなかった． caught because indigenous population density was greatly low.
FuturePlans:We
revealedthatdensityofthelocal
populationtopreserve
今後の活動：ニホンイシガメを保全する局所個体群では密度がかなり低

Mauremysjaponicawasgreatlylow.
Therefore
reinforcementofproliferating
いことが明らかとなった．現地での捕獲調査がより必要であると同時に，水techniques such as to prevent laying eggs underwater as well as more investigation
中産卵を防ぐなどの繁殖技術の強化が必要である．
to capture in indigenous is needed.

謝辞：本研究を行うにあたり，千葉県ニホンイシガメ保護対策協議会の皆様には個体の捕獲 Acknowledgements: We thank Conservation Activity Council of the native freshwater turtles inや保全事業の助言を頂いた．また，本研究の活動は2016年度日本動物園水族館協会野生生物 Chiba Prefecture for helping capture turtles and giving to advice this conservation project. This study wasfunded by the Wildlife Protection Foundation of the Japanese Association of Zoos and Aquariums in 2016.
保護募金による助成を受けました．ここに感謝の意を表します．