The purpose of this study was to provide basic data for evaluating the reproductive health of bivalves using intersexuality. We analyzed purplish bifurcate mussel Mytilisepta virgata (n = 67, shell height 37.1±8.3 mm), Manila clam Ruditapes philippinarum (n = 288, shell length 28.6±4.2 mm) collected from coastal water near Yeosu, Korea. The sex ratio (female:male) of M. virgata and R. philippinarum were 1:1.5 and 1:0.8, respectively, and showed differences depending on the collection area. The total intersexuality of M. virgata was 20.9%. The intersexuality in female (33.3%) was higher than in male (12.5%), and the regional intersexuality was 72.7% in Sogyeongdo, 20.0% in Oesamdo and 5.6% in Jungsamdo with the highest in Sogyeongdo. The total intersexuality of R. philippinarum was 11.8%. The intersexuality in female (17.5%) was higher than in male (4.7%), and regional intersexuality was 20.0% in Neungchodo, 13.0% in Dokdo, 2.8% in Samdo, 5.9% in Orando, 19.6% in Oesamdo with the highest in Neungchodo. The incidence of intersexuality according to distance from cities and ports each sampling area showed no clear tendency. Intersex specimens were showed histological structure changes of digestive gland, such as digestive tubule disruption and necrosis of epithelial cells, accumulation of eosinophilic granules in lumen of tubule, necrosis of connective tissue. These results suggest that not only the histological structure of the digestive gland but also intersexuality should be used as important biomarker for toxicity assessment of pollutants.
본 연구는 여수 인근 13개 무인도 주변 해역의 굴 Crassostrea gigas (n=410, SH 43.3±11.4 mm) 에서 확인된 인터섹스 현상을 보고하고자 하였다. 전체 성비(암:수)는 1:1.1이었으나 채집 정점 별로 성비의 차이를 보였다. 가장도, 소경도, 중삼도에서는 암컷이 65% 이상의 높은 비율을 보 였으며, 송도, 초도, 부서도에서는 수컷이 65% 이상의 높은 비율을 나타냈다. 전체 intersexuality 는 약 12.8%로 암컷에서 약 34.7%, 수컷에서 약 64.3%로 수컷에서 높았다. Intersexuality는 가막만의 초도에서 약 43.8%로 가장 높았다. 조직학적으로 인터섹스는 intrafollicular type, interfollicular type, mixed type의 세 가지 형태로 나눌 수 있었다. 이들 세 가지 형태 가운데 intrafollicular type이 약 81.6%로 가장 우세하였다. 본 연구에서 보고된 굴의 인터섹스 원인에 관해서는 추후 세부적인 연구가 필요할 것으로 생각된다.