Quantitative Assessment of the Reproductive Effort of Tresus keenae (Kuroda and Habae 1950 ) on the South Coast of Korea Using Egg Specific Polyclonal Antibody

Abstract

Reproductive cycle and reproductive effort of Tresus keenae in Yeosu, South coast of Korea was determined using immune assay techniques combine with the histology. The polyclonal antibody developed against the egg proteins of T. keenae, only detected the egg proteins with a high sensitivity (0.64-10.24µg/ml) was used to quantification of the eggs using indirect ELISA. T. keenae in Yeosu spawned in late autumn (October and November) and ready to spawn female and spawning male observed in late winter (March) while first clam with oogonial mitosis also observed in March. The mean GSI of ready to spawn clam in October was 5.7±2.2 and March was 2.4±0.3. Condition Index (CI) from October to November was declined, however during March CI was not scaled down and potential fecundity of the T. keenae in Yeosu estimated to be varied from 121.92×106 to 22.07×106 (average 53.40×106 ) eggs per clam in October while it was ranged from 69.19×106 to 29.07×106 with average of 44.91×106 eggs per clam in March. The dry weight of siphon and carbohydrate of the siphon declined during the early development of the gametes suggesting that the carbohydrate stored in the siphon exploited for gametogenesis. A noticeable reduction of total carbohydrate in adductor muscle, siphon and body was observed during the spawning period suggesting that the carbohydrate fulfilled the energy demand during the spawning. The egg specific antibody developed in this study is sensitive enough to quantify the reproductive effort of the clam which is difficult to measure using the conventional methods and using developed antibody reproductive effort of T. keenae was successfully determined.