| For investigating the possibility of exploitation freshwater Cladoceras that provides the seafood animal with living bait, in this study, the tolerance of three Cladoceras to salinity of seawater has been studied through salinity training, microwave and chemical mutagen etc. physical and chemical method under different experimental ecology of salinity, temperature, food. All these works will provide theoretical basis for increasing tolerance of freshwater Cladoceras to salinity of seawater and large quantity educates from now on.The reproduction and survival of Simocephalus vetulus Straus, Daphnia pulex Straus and Monia macrocopa Straus under salinities of 2, 3, 4, 6, 8, 10 and 15℃, 20℃, 25℃ have been studied. The results show that the alternate effect of salinity and temperature is outstanding. Thedevelopmental rate of water flea goes up with the increase of temperature under a certain salinity, and the total life span reduces with the increase of salinity under a certain temperature. The optimum salinity-temperature combination level is salinity 2 and temp. 20℃ for S. vetulus and D. pulex. The upper salinity limit of reproduction distinguish to 3-4, 4, 6. After short-term training between 15-25 ℃ and at 25℃, the upper salinity limit of reproduction and survival of S. vetulus and D. pulex is 6, is 8 of M. macrocopa.At 25± 1℃ and under three kinds of food, The comparation on seawater taming of three kinds of freshwater cladoceras and the princioal parameters of population growth of Moina macrocopa are studied by establishing the life table and under four concentrations of seawater salinities. The intrinsic rate of increase (rm=0. 725-1. 070d-1) shows no difference in freshwater—salinity 4 and at three kinds of food. The net reproductive rate (Rj is the highest when fed with Chlorella (average 55. 13ind.), and the generation time (T) is the longest when fed with yeast (average 5.38d). The optimum species-food combination level is M.macrocopa and Chlorella sp. for three kinds of freshwater cladoceras.At 25±1℃ and cow dung+rice straw+good soil of food, the reproduction and survival of M. macrocopa under salinities of 8, 10, 12, 15,18, 21 and 5s, 15s, 25s with microwave irradiation, and of D. pulex under salinities of 2, 4, 6, 8,10 and 5s, 10s, 15s with microwave irradiation are studied. The results indicate that the induced effect is significant. After microwave irradiation, the lethal upper salinity limit of reproduction of M. macrocopa and D. pulex are improved from 6 to 10 and 4 to 6. The survival time may reach 2.9 hr for M. macrocopa in salinity 21 and 4 hr for D.pulex in salinity 10. The induced effect of the former is the best at 15s, and the latter is at 10s.At 25±1℃, Chlorella sp. of food and salinities of 8, 10,15,20, 25, the reproduction and survival are examined in M.macrocopa bathed in chemical solutions (MNNG: 1×10-6, 3×10-6, 5×10-6; EMS: 0. 1‰, 0.3‰, 0.5‰) 1hr after bath.The results indicate that the lethal upper salinity limit of reproduction is improved from 6 to 8-10. The induced effect of MNNG is the best at 1×10-6, the second at 3×10-6, the bad at 5×10-6; The EMS is at 0.3‰, 0.1‰ and 0. 5‰. The EMS changes the result of the obvious good to in result MNNG (p <0. 05)...
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