Effect of diet on the development, survival, and reproduction of the calanoid copepod Pseudodiaptomus dubia

Pseudodiaptomus dubia is a calanoid copepod abundant in the mariculture ponds of southern China. However, our understanding of the population dynamics of P. dubia in aquaculture ponds is limited. In this study, groups of larval P. dubia were each fed a different microalgal species, and the effects of these different diets on development, survival, and reproduction were assessed. The five microalgae used were species common in aquaculture farms in China, and included two chlorophytes (Chlorella saccharophila and Platymonas subcordiformis), one golden microalga (Isochrysis zhanjiangensis), and two diatoms (Chaetoceros muelleri and Cyclotella meneghiniana). Our results indicated that C. saccharophila was not a suitable food for larval P. dubia, as all larvae fed this microalga died at stage III (as copepodites). The survival rates of P. dubia larvae fed C. muelleri, I. zhanjiangensis, and P. subcordiformis were significantly higher than that of larvae fed C. meneghiniana. In the adult stage, copepods fed C. muelleri, I. zhanjiangensis, and C. meneghiniana produced more nauplii (430-566 nauplii/female), had higher intrinsic growth rates (0.2-0.253/d), and better longevity (59-60 days) than those fed P. subcordiformis. Our results therefore suggest that P. dubia has different nutritional needs and food preferences at different life stages. For example, P. subcordiformis was suitable for developing larvae but not for breeding adults, while C. meneghiniana was suitable for breeding adults but not for developing larvae. Both C. muelleri and I. zhanjiangensis were excellent foods for P. dubia throughout the entire life cycle.