The Effect Of Light On Growth And Development Of The Larvae Of The Scylla Paramamosain

In the ecological laboratory and artificial light conditions, this paper study the effects of different sources, light intensity and light time on development and energy budget of the larvae of mud crab , with a view to the breed for the green crab seeding provide the necessary basic theories and technical support. The major results are following:1. The effects of different sources on growth and development of the larvae of mud crabThe effects of the incandescent lamp and the fluorescent lamp on growth and development of the larvae of mud crab in the laboratory. The final metamorphosis survival rate is 18.33 % under the incandescent lamp, but the final metamorphosis survival rate is only 5.00 % under the fluorescent lamp. There is significantly different between each other(P<0.05). So the incandescent lamp is more suitable as light sources indoor.2. The effects of different photoperiod on growth and development of the larvae of mud crabIn the laboratory conditions, the paper study that the effects of different light photoperiod(0L:24D,6L:18D,12L:12D,18L:6D,24L:0D)on the growth and moult of the larvae of mud crab .The results indicate that in the same development phase and different photoperiod, the mean metamorphosis survival rates have no significantly different from Z1-Z5, but have significantly different from Z5-M.There were no megalopa under the 0L:24Dand 24L:0D. But the moulting rate (24.4%) was the highest than others. The inter-moulting time have no significantly different from Z₂-Z₃ and Z₄-Z₅, but other phases have big different. The larvae growth is fastest under 12L:12D.3. The effects of light intensity on growth of the different development larvae of mud crabCompare to the dark condition, the paper study the effects of different light intensity (3000Lux,5000Lux,7000Lux,9000Lux)on growth of the different development larvae of mud crab. The results indicate that the mean metamorphosis survival rates under the 5000Lux condition have significantly different than other light intensity. The mean metamorphosis survival rates under the 5000Lux are respectively 86.67%,76.67%,63.33%,78.00%,78.00% in the Z1-Z₂,Z₂-Z₃,Z₃-Z₄,Z₄-Z₅,Z₅-M phases. The mean metamorphosis survival rates under the 5000Lux condition have significantly different than dark and 9000Lux condition(P<0.05). The mean metamorphosis survival rates under the dark condition is lowest than other light intensity, are respectively 38.33%,41.67%,15.00%,30.00%,46.00%in the Z1-Z₂,Z₂-Z₃,Z₃-Z₄,Z₄-Z₅,Z₅-M phases. From the stage, Z₃-Z₄ is the larger influenced stage.4. The effects of light intensity on growth of the whole development larvae of mud crabThe paper study the effects of five different light intensity on growth and moult of the whole development larvae of mud crab(1000Lux,3000Lux,5000Lux,7000Lux,9000Lux). The results are as follows: The mean metamorphosis survival rates under 1000Lux obviously decline from Z₄,and the megalopa are not found;The final metamorphosis survival rates under 5000Lux is obviously higher10.00%,7.78%,15.56% than 3000Lux,7000Lux,9000Lux,and is significantly different than these groups(P<0.05).(2)The moulting day are different from Z1 to M: 3000Lux, 19.5days; 5000Lux, 15.2days; 7000Lux, 15.7days; 9000Lux, 17.2days. The development of larvae under 5000Lux and 7000Lux are significantly fast than other groups (P<0.05).5. The effects of light intensity on energy budget of the larvae of mud crabThe light intensity(3000Lux,5000Lux and 7000Lux)have significantly affects to the ingestion energy(I)and the growth energy(G), the ingestion energy and the growth energy of the 5000Lux are significantly higher than other groups. G/I,R/I,E/I,Ev/I(R, Respiration energy; E, Exuvial energy; Ev, Fecal energy and Excretion energy)are not significantly affected under three light intensity. This result show that the light intensity can affect the components energy(absolute values),but can not affect the distribution pattern of components.6. The effects of light intensity on digestive enzyme of the larvae of mud crabThe paper study the effects of light intensity(0Lux,3000Lux,5000Lux,7000Lux, 9000Lux) on digestive enzyme(protease enzyme,amylase enzyme,lipase enzyme) of the larvae of mud crab(Z₁,Z₃,Z₅,M). The results are as follows: (1)With the growth of the mud crab, protease enzyme and lipase enzyme are high activity,but the enzyme activity are low. (2)In the same development phase and different light intensity, the digestive enzyme are higher activity under 5000Lux condition than others. And protease enzyme and lipase enzyme activity are the highest under 5000Lux condition than others in the same development phase respectively(P<0.05).In the dark and 9000Lux conditions, three digestive enzymes activity are a little lower than other light intensity.