Along with Kanmuri-jima Island, it is designated as the Kanmurijima and Kutsujima islands game reserve (collective breeding place) by Kyoto Prefecture (the total area of both islands is 471 hectares, including 44 hectares of special protection area), and is an uninhabited island, with visits largely banned in order to protect breeding sea birds.
冠島とともに京都府指定冠島沓島鳥獣保護区（集団繁殖地）に指定されており（面積は両島で471ヘクタール、うち特別保護地区44ha）、無人島で海鳥の繁殖保護のため原則として上陸が禁止されている。