과거 연안 오염과 환경 훼손으로 거머리말 군락이 급격히 줄었으나, 지난 2008년 남해 완도군 소안도 일대에서 군락지가 되살아난 것이 발견됐다.
In the past, the colony of leeches was drastically reduced due to coastal pollution and environmental damage, but a colony was found to have been revived in the area of Soan Island in Wando County of the southern sea in 2008.