The Studies On Ingestion, Reproduction And Development Of Three Marine Copepods

The effects of several ecology factors on ingestion, reproduction, survival and development of two planktonic copepods Sinocalanus tenellus and Pseudo-diaptomus marinus (Copepoda: Calanoida) were studied in this paper, as well as the preliminary studies on the cultivation of a benthic copepod Nitocra sp. (Copepod: Harpacticoida) were carried out.The results from ingestion experiment of S. tenellus and P. marinus showed that: (1) There is a positive correlation between the water temperature and filtering rates (F, ml.ind-1h-1), grazing rates (G, cells-ind-1'-h-1) within the proper temperature range for copepods, and beyond the proper temperature, F and G decreased. (2) The grazing rates of the two copepods are closed correlated with food. F tended to increase in optimal food concentration range, above this range, F decreased. But G always decreased with the increase of food concentration. What else, the two copepods are able to select optimal algae from mixed food. The alga with highest F must not be the most optimal one. (3) The F between male copepods and female copepods were compared. The results indicated that F and G of females are higher than that of males.The results from reproduction and survival experiment of S. tenellus indicated that: (1) S. tenellus lay eggs into water directly, and the egg-laying often happened in dusk and night. Its long-term egg-laying pattern is erratically interval. (2) Within proper temperature, the higher temperature induced to higher egg production and hatching rates for S.tenellus, as well as hatching become more quickly; The egg production increased with the increase of food concentration within 15. 104~25. 104 cells/ml, but there is no obvious variation of hatching rate. Among different food, the Isochrysis galbana Parke 8701 and mixed food are better. (3) Within proper temperature, S. tenellus develops faster as well as survival rates higher at higher temperature. On the other hand, the survival rate is higher at low salinity( 10-20) than that in high salinity (25 -30), while, the effect of salinity on nauplii survival is greaterthan on copepodites and adults; food quality can affect the survival ofS.tenellus , but the effect of food quality on the survival of nauplii and copepodites is different. Isochrysis galbana Parke 8701, Nitzschia clostertum and their mixed food are more optimal to the survival of S.tenellus.The results from reproduction and development experiment of P.marinus show that: (1) The reproductive rate and developing rate increase with the rise of temperature in the range of 15~25. At 15, it need about 15 days to finish nauplii stages development; And duration from Nil to adult is about 18 days at 20, about 11 days at 25. Furthermore, at the same condition, the developmental time of naplii inclined to be isochronal, and is obvious shorter than that of copepodites. And the growth rates of P.marinus increase in higher temperature. (2) Isochrysis galbana Parke 8701, Phaeodactylum triorrutum and the mixture of them are better to the development and growth rate of P.marinus than Chlorella sp, Chaetoceros calciterans, Heterosigma akashiwo, Platymonas helgolandica, Paviova viridis and N. clostertum. But there are no significant difference among the developmental time and growth rates when P.marinus were fed on these three kinds of food respectively. It indicates that there are complicated affects of food on P.marinus.The preliminary studies on the cultivation of Nitocra sp. showed that the optimal condition to culture Nitocra sp. is: salinity 20, temperature 25, mixture of Isochrysis galbana Parke 8701, Phaeodactylum triorrutum and yeast, concentration about 10~20104 cells/ml. Moreover, a kind of l00L-intensive copepod mass culture system is designed independently and applied to culture Nitocra sp. in this study . The work procedure of this culture system was described in detail. The results indicate that the harvest of Nitocra sp. is closed positive correlation with initial females density. And the results also indicated that the system is suitable for c...