Abstract
Gonadal maturation and annual reproductive cycle of the cultured scallop, Patinopecten yessoensis from eastern waters near of Kangwon-do province, Korea were studied on the basis of monthly variation of gonadosomatic indices (GSI) and histological observations of gonadal tissue. During the experimental period, water temperature at the depth of 20m and sunshine duration per day were ranged from $5.3^{\circ}C\;to\;18.0^{\circ}C$ and 9.4 to 14.6 hours, respectively. GSI values of femal were in a wide range from $2.8\pm0.37(August)\;to\;22.66\pm4.38(April)$. GSI values began to increase in March and reached the maxium in April, then decreased repidly. GSI values of male were in a range from $2.04\pm0.80(August)\;to\;20.46\pm1.49(April)$ and were same tendency with female's. Digestive diverticula indices (DDI) of both sex reached the maximum values in December, then deceased gradually until September. Contrary to GSI, adductor muscle indices (AMI) of both sex were the minium values in April, but began to increase rapidly until July and reached $47.71\pm3.17(female)\;and\;48.70\pm3.55(male)$. In the scallp collected hermaphroditic gonads were found. Monthly changes of oocyte diameter were in a range from 11.3 um(October) to 73.3um (April) and nuclear diameters were in a range from 8.3um (September) to 35.3um (April), similar tendency with each other. The changes in number of ovarian tubules were reciprocal tendency with those of oocyte diameter and monthly number of ovarian tubules per $\textrm{mm}^2$ in the tissue perpatation was in a range from 51 (April) to 175 (August). As the results, the annual reproductive cycle of the cultured scallolp from eastern waters of Korea could be classified into five successive stages : multiplicative (October), growing (November to February), mature (March and April), spawning (April to June) and recovery (July to September) in female ; multiplicative (October and November), growing (December and January), mature (February to April), spawning (April to June) and recovery (July to September) in male.
우리나라 강원연안에서 수하양식중인 2-3년생 참가리비를 재료로 하여 GSI와 조직학적 방법에 의해 생식소의 성숙 및 생식주기를 조사하였다. 양식장의 연간 수온 분포(수심 20 m)는 5.3-$18.0^{\circ}C$였으며, 낮 길이의 월별변화는 9.4-14.6 시간이었다. 암컷의 GSI는 2.84$\pm0.37$ (8월)-20.46$\pm1.49$(4월)로 암컷과 같은 경향이었다. DDI는 암수 각각 12월에 11.14$\pm1.25$와 11.10$\pm1.13$으로 최고값을 보였다가 이후 최저값을 보인 9월까지 서서히 낮아졌다. AMI와 GSI의 월별 변화는 서로 상반된 경향을 보였다. 조사된 참가리비중 자웅동체의 출현빈도는 2.7%였다. 월별 난경의 변화는 11.3 (10월)-73.3(4월) $\mu$m, 핵경은 8.3(9월)-35.3(4월)$\mu$m로 서로 유사한 변화 경향이었으나, 난소의 조직절편 mm 상(2)당 난소소낭수는 난경과 핵경이 최대값을 보인 4월에 51개로 가장 적었다가 이후 증가하여 8월에 175개로 가장 많았다. 생식소의 조직상, GSI 및 월별 난경과 난소의 단위면적당 소낭수의 변화를 종합한 결과, 동해안 양식산 참가리비의 생식주기는 암컷의 경우, 분열증식기 10월, 성장기 11-2월, 성숙기 3-4월, 산란기 4-6월 및 회복기 7-9월, 수컷에서는 분열증식기 10-11월, 성장기 12-1월, 성숙기 2-4월, 방정기 4-6월 및 회복기 7-9월로 판정되었다.
