북한강 엷은재첩, Corbicula papyracea (Heude) 의 번식생태 (Reproductive Ecology of the Freshwater Marsh Clam, Corbicula papyracea (Heude) in Bukhan River)

서지정보

· 발행기관 : 한국패류학회
· 수록지 정보 : The Korean Journal of Malacology / 30권 / 2호 / 107 ~ 116페이지
· 저자명 : 김대희, 이완옥, 이준상

초록

북한강에 서식하고 있는 엷은재첩의 산란생태를 파악하기위하여, 생식소 발달단계에 따른 생식주기, 군성숙도, 난경의월별변화를 조사하였다. 각장에 대한 각고, 각폭, 전중, 육중간의 상대성장식에서 상관계수 (R2) 는 0.921-0.984로 높은 상관관계를 나타내었다. 엷은재첩은 기수재첩 보다는 소형종이었으며, 동시자웅동체로서 체내에서 수정되어 아가미 보육낭에서부화되어 체외로 방출하는 난태생종이었다. 월별 비만도는0.14-0.21 범위로 동계인 12월-2월에 낮은 값을 보이다가 2월부터 서서히 높아지기 시작하여 5월에 0.21로 정점을 보였다.
월별 육중량비는 25.9-38.7％로 비만도의 월별 변화와 같은경향을 나타내었다. 비만도와 육중량비의 정점이 생식세포의최성숙기와 1-2개월 차이가 있었다. 생식소의 조직상, 비만도및 생식세포의 월별 변화를 종합하면 북한강산 엷은재첩 생식년주기는 분열증식기(12-2월), 성장기(2-5월), 성숙기(6-8월), 완숙 및 발생기(8-11월), 회복기(11-12월) 로 구분되어 하계산란종이었다. 군성숙 각장은 12.6 mm 였으며, 16 mm 이상의개체는 모두 성숙하여 아가미에 보육낭을 형성하였다

영어초록

Gonadal development and maturation mechanism were studied on the freshwater marsh clam Corbicula papyracea (Heude), which is the endangered species in Korea. The specimens were collected in the rearing ponds and waterway of NFRDI in Gapyeong-gun, Gyeonggi-do from January to December 2004, and then investigated by condition factor, relative growth, gonadal development phases and gonad histological characters based on 30-50 individuals every month. Comparing with the freshwater marsh clam, C. papyracea is small, light olive brown shell and violet interior. The hermaphrodite individuals of C. papyracea take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The average water temperature of inhabit area was in range of 1.8-27.0℃ and usually took great effects on the gonad maturation of C. papyracea. The condition factor ranged from 0.14 to 0.21 throughout the year, which was the lowest during winter season (December-February), and gradually increased to the highest value of 0.21 in May. The ratio of meat weight to total weight was 25.9-38.7%, indicating the similar trend with condition factor. The highest values of condition factor and the ratio of meat weight appeared 1-2 months later than gonadosomatic index reached the peak value, it was probably because that the ovoviviparous eggs would spend a long period before hatching from the foster-sack in the gills. To synthesize the characters of meat weight, condition factor and gonad development by histological study, reproductive cycle of C. papyracea could be divided into five successive stages: multiplicative stage (December to February), growing stage (February to May), mature stage (June to August), spawning stage (August to November), recovery stage (November to December). The smallest shell length of matured C. papyracea was 12.6 mm, and individuals, larger than 16 mm, was formed the nursery in the gills.

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