象山港放流虾群亲虾的产卵回归和生物学性状

象山港放流对虾主群在浙江岛礁外侧海区越冬后,翌年春随着温度回升逐步向沿岸回归,回归路线大致与浙江海岸线垂直,主群出现在象山港口的六横南部及三门湾口部海域。少量亲虾在港内越冬。亲虾的交配率达99.7%,性腺发育正常,体长组成与黄渤海亲虾一致。为浙江近海自然繁殖提供了优质的亲虾基础。

THE SPAWNING MIGRATION & BIOLOGICAL CHARACTERISTICS OF PARENT SHRIMPS RELEASED IN XIANGSHAN BAY

After wintering in the area beyond the islands along Zhejiang coastal line,most of the shrimps released in Xiangshan Bay,Zhejiang province,were gradually migrating inshore with the rise of temperature in the next spring.The migrating route is approxi- mately perpendicular to the coastal line and they appeared both in the south area of Liuheng island and at the estuary of Sanmen Bay and lied at the estuary of Xiangshan Bay.The special topography and temperature condition there made only a small part of them wintering inside the Bay,The mating rate reached 99.7% and gonads well de- veloped.The body length distribution was in consistent with that of shrimps in the Yellow Sea and Bohai Sea.The migration of parent shrimps and their normal biological characteristics formed excellent conditions to natural breeding.