TEMPERATURE TOLERANCE OF LARVA AND JUVENILE OF PORTU NUS TRITUBERCULATUS

The Portunus trituberculatus is a kind of edible economic crab distributing in the north.west of the Pacific.from the north of South China Sea to the Korea Peninsula.The Portunus trituberculatus has been cultured on a large scale in the sea area of North China.The Portunus trituberculatus is the sea crab which culture dimensions is the maximum in the world.For producing the data to larval rearing and Juvenile culture of Portunus trituberculatus，the influence of different temperatures on development of larva，survival and food intake of juvenile Portunus trituberculatus waft investigated.The re.suits showed that，in the 21-27℃，the zoea could be reared to juvenile crab，but at the 21℃，the zoea and megalopa developed quite slowly，It is the optimal temperature during the 24-27℃ of larval rearing.Over the 30℃.the zoea only be reared to Z4，they all died before the megalopa stage.Below the l8℃，the zoea only be reared to 3，they all died before the Z4 stage.It is proved that to rear the larva of Portunus trituberculatus，the 24-27℃ is optimal，the 2l-27℃ is better.the l8-35℃ can，and below the 15℃ and over 35℃can not.Five days after the temperature acute change from 25℃.the survival rates of juvenile Portunus trituberculatus of 80g is 100% in 10-30℃，75% at 35℃；below the 50℃ the survival time is under 4h.’I’lle proper food intake of survivor is in 20-35℃.the daily mean food intake is over 4.649.With the gradual temperature change of 5℃/d from 25℃，the survival rates of Portunus trituberculatus are 100% in lO-35℃.25% at 5 oC，the survival time is under 6h at 40℃.The proper food intake of survivor is in 20-35℃.the daily mean food intake is over 5.1g. The optimal food intake of survivor is at 30℃，the daily mean food intake is 9.8g.The Portunus tritubercula. fits can feet at 10-35℃.But the food intake is very low at 15℃and 10T.the daily mean food intake is 0.5g and 0.1g respectively.This result shows that to culture the juvenih Portunus trituberculatus (The body weight is about 80g)，the 30℃ is the optimal，the 20-35℃ is better，the 15-35℃ can, and the are 5℃ and 40℃ carl not.All the results show that the Portunus trituberculatus is a typical temperature crab which adapts low temperature better than high temperature. Maybe this is the reason why it mostly distributing in the relative low temperature sea area of Bohai Sea，Yellow Sea and East China Sea.But，if the gradual temperature change was below 5℃/d.the Ponunu,trituberculatus can adapt the high tempera. ture of 35℃，and the food intake is the optimal.Maybe this is the reason why some Portunus trituberculatus still can distribute in the tropic sea area of north of the South China Sea.