Along with Kutsu-jima Island, the islands have been designated by Kyoto Prefecture as the Kanmurijima and Kutsujima islands game reserve (collective breeding place) (the total area of both islands is 471 hectares, with 44 hectares being set aside as a special protection area).
また沓島とともに京都府指定冠島沓島鳥獣保護区（集団繁殖地）に指定されている（面積は両島合わせて471ヘクタール、うち特別保護地区44ha）。