Effects Of Four Environmental Factors On The Feeding, Reproduction And Development Of Pseudodiaptomidae Inopinus

As a key component of marine zooplankton, copepods play a critical role in material recycling and energy transformation of the marine ecosystem. Therefore, it has a high profile in marine ecology study. In order to obtain the optimal conditions of multi-generation continuous culture in the lab, we had researched the effects of four environmental factors on the feeding, reproduction and development of P. inopinus. As follows are the research results.1. Different algae had significant effect on the grazing rate, filtering rate and feces production of P. inopinus (p<0.05). Isochrysis galbana and Chlorella sp. were better than Platymonas hellgolandica, Chaetoceros muelleri and Thalassiosira weissflogii.The curve of temperature, salinity and pH effect on the grazing rate, filtering rate and feces production present inverted bell shaped structure. Under optimum conditions they had positive relationships; beyond the confines, they had negative relationships. The optimal temperature, salinity and pH were 20℃,10～20, 7.5～9.5, respectively.2. Different algae had no significant effect on the hatching rate and hatching time of P. inopinus (p>0.05). In contrast, temperature had significant effect on it (p<0.05), hatching rate increased firstly and then decreased, hatching time rapidly decreased with increasing temperature. Optimal temperature was 10～20 ℃. Between the optimum salinity range 10～20, the hatching rate and hatching time had no significant differences between each other (p>0.05). But they become significantly different when the salinity beyond the critical value. Hatching rate and hatching time had’nt been effected by pH value.3. Different algae had no significant effect on the egg production and spawning interval of P. inopinus (p<0.05). But the egg production of the groups feeding on T. weissflogii was lower than the others. The egg production slowly decreased and spawning interval rapidly increased as the temperature rise. Optimal temperature was 10～20℃. Egg production decreased and spawning interval increased with increasing salinity. Optimal salinity was 10～20. Optimal pH was 6.5～9.5. Egg production and spawning interval hadn’t been significantly effected by the pH.4. The development time of P. inopinus from nauplius to adults was decreased obviously with increasing temperature (p<0.05), the survival rate of different groups had no significant diversity within the optimal temperature. But all individuals had died before maturation above 25℃, optimal temperature was 10～20℃. Development period extended and survival rate decreased with increasing salinity. Before adultness, all individuals had died when the salinity was beyond 25. Optimal salinity is 10～20. Optimal pH is 6.5～8.5. Development period extended and survival rate increased firstly, then decreased except the group of pH5.5.