| The effects of several environment factors on feeding, reproduction, respiration and antioxidant enzyme activities of four planktonic copepods Centropages abdominalis, Calanus sinicus, Schmackeria poplesia and Sinocalanus tenellus (Copepoda:Calanoid) were studied.1. The selective grazing and egg production of Centropages abdominalis and Calanus sinicus in the Yellow Sea and East China SeaFeeding strategies of Centropages abdominalis were studied in the North Yellow Sea in April 2007. The aim of this study was to evaluate the effect of mesozooplankton selective grazing on natural phytoplankton assemblage. Therefore, in-situ feeding experiments were carried out and the phytoplankton growth rate, the grazing rate, and selective index of grazing of Centropages abdominalis on phytoplankton were measured. The results show that the selective feeding behavior of C. abdominalis was dependent on food density. In terms of abundance of natural phytoplankton population, if it reached 59.3 cells/ml for Rhizosolenia setigera,44.7 cells/ml for Pseudo-nitzschia pungen,1972.0 cells/ml for Eucampia zodiacus, 149.0 cells/ml for Rhizosolenia alata f. indica and 124.0 cells/ml for Thalassionema nitzschioides. C. abdominalis would change food selectivity from preference to discrimination. The selective grazing of C. abdominalis could also be affected by changes in the phytoplankton species composition. In the different experimental groups, C. abdominalis prefer the phytoplankton species in higher abundance to the phytoplankton species in highest abundance.Data were collected and experiments performed with R V DONGFANGHONG2 in April-May 2009 in the Yellow Sea and East China Sea. Twelve stations, where the ship was not anchored, were chosen to study the copepod selective feeding on natural phytoplankton and egg production in situ. Grazing pressure of Calanus sinicus on phytoplankton standing stock in the Yellow Sea and East China Sea were 4.0%(0.4-9.6%) and 10.7%(1.1-22.8%) respectively. Egg production and hatching success for Calanus sinicus in the Yellow Sea and East China Sea were 0.3～33.9 eggs/(d·♀) and 51.4%～83.3% respectively. Potential recruiment rate of Calanus sinicus in the Yellow Sea and East China Sea were 1.1×104 nauplii /m2·d and 7.3×103 nauplii/m2·d respectively.2. The effects of different temperature, salinity, algal species and concentration on the feeding behavior of calanoid copepod S. poplesia were studied.The results showed that(1)there was a positive correlation between the temperature,salinity and filtering rates (F, ml/(ind·h)), grazing rates (G, cells/(ind·h)) within the proper range for copepods, and beyond the proper temperature and salinity, F and G decreased. (2)Both the grazing rates (G, cells/(ind-h)) and filtering rates (F, ml/(ind·h)) were significantly affected by different algae and their concentrations.The grazing rates (Q cells/(ind-h)) of the copepod are correlated with food. G tended to increase in optimal range of food concentration, above which range, G decreased. But the filtering rates (F, ml/(ind-h)) always decreased with the increase of food concentration. The maximum G of S. poplesia for Isochrysis galbana appeared at 10.0×104 cells/ml. Furthermore, the F and G of S. poplesia for P. triorrutum and I. galbana is always higher than the others at the same concentration. The effects of different temperature and algal species on the reproduction of calanoid copepod S. poplesia were studied.The results showed that (3) The egg production of S. poplesia were always higher than the others at 25℃in the range of 15～25℃. (4) Phaeodactylum triorrutum, Isochrysis galbana and the mixture of them were better to the reproduction of S. poplesia than Platymonas helgolandica Kylin var Tsingtaoensis, Chlorella sp.and Paviova viridis Tseng.3. The effects of NAPH, PCBs and DDT on development, reproduction and feeding of calanoid copepod S. poplesia were studied.The metamorphosis rates of the first generation exposed to each concentration of NAPH were reduced. Survival, egg production and the percentage of gravid females were all reduced at 160μg/L NAPH. No significant effects were observed on sex ratio and body length of S. poplesia exposed to each concentration of NAPH. The metamorphosis rates of the first generation exposed to each concentration of PCBs were reduced. Survival, egg production and the percentage of gravid females were all reduced at 2μg/L PCBs. No significant effects were observed on sex ratio and body length of S. poplesia exposed to each concentration of PCBs. The metamorphosis rates of the first generation exposed to each concentration of DDT were reduced. Survival, egg production and the percentage of gravid females were all reduced at 350 ng/L DDT. No significant effects were observed on sex ratio and body length of S. poplesia exposed to each concentration of DDT.The filtering rates and grazing rates of copepod S. poplesia were reduced along with the elevation of concentration of NAPH, PCBs and DDT.There seems to be little risk that NAPH is harmful to S. poplesia at worst case environmental concentrations. And there seems to be high risk that PCBs and DDT are harmful to S. poplesia at worst case environmental concentrations.4. The effects of NAPH, PCBs and DDT on survival, reproduction, feeding, respiration and antioxidant enzyme activities of calanoid copepod S. tenellus were studied.The hatching ratio and eggs' diameters of S. tenellus exposed to 20μg/L and 200μg/L of NAPH were reduced. No significant effect was observed on egg production of S. tenellus exposed to each concentration of NAPH.Survival of females was reduced at 200μg/L NAPH. The hatching ratio and eggs' diameters of S. tenellus exposed to 0.2μg/L and 2μg/L of PCBs were reduced. No significant effect was observed on egg production of S. tenellus exposed to each concentration of PCBs. Survival of males was reduced at 2μg/L PCBs. The hatching ratio and eggs' diameters of S. tenellus exposed to 25 ng/L and 250 ng/L of DDT were reduced. No significant effect was observed on egg production and survival of S. tenellus exposed to each concentration of DDT.The filtering rates, grazing rates and respiration of copepod S. tenellus were reduced along with the elevation of concentration of NAPH, PCBs and DDT.The activities of SOD and CAT of copepod S. tenellus were reduced along with the elevation of concentration of NAPH, PCBs and DDT. The activities of SOD and CAT in low concentration treatment groups were increased, but the activities of SOD and CAT in high concentration treatment groups were decreased.There seems to be little risk that NAPH is harmful to S. tenellus at worst case environmental concentrations. And there seems to be high risk that PCBs and DDT are harmful to S. tenellus at worst case environmental concentrations.
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