Evaluation of dietary microalgae for culture of the calanoid copepod Pseudodiaptomus pelagicus

A series of five experiments were conducted to evaluate the effects of various dietary microalgae on survival, reproduction, sex ratio, fecundity, time to first maturation, brood interval, brood size, total nauplii production, and population development of the calanoid copepod Pseudodiaptomus pelagicus. Three experiments utilized 10 reproductive pairs of adults cultured in 1 L beakers. In the first experiment, the microalga Isochrysis galbana (T-iso) was fed at five densities to determine the optimal density for production. In the second experiment, five microalgae, T-iso, Thalassiosira weissfloggi (Tw). Chaetoceros gracilis (Ch), Rhodomonas lens (Rh), and Tetraselmis suecica (Tet), were each fed at a carbon equivalency of 80,000 cells/mL of T-iso. In the third experiment, the same five microalgae were fed along with four mixed microalgae diets, consisting of T-iso/Tw and T-iso/Ch at two ratios, 50:50 and 75:25, all were fed at a carbon equivalency of 160,000 cells/mL of T-iso. The fourth experiment cultured individual pairs in 30 mL beakers to determine the effects of dietary microalgae on nauplii production, brood size, and brood interval. The fifth experiment cultured 100 early stage nauplii (N1-N3) until the population reached sexual maturity. The optimal density of T-iso was 160,000 cells/mL. At 80,000 cells/mL, Tw produced a significantly greater number of copepods than the other microalgal diets. In the 160,000 cells/mL experiment, total production with T-iso/Tw at 50:50 ratio was the highest and was significantly higher than all monoalgal diets except Rh. In general, the total number of copepods produced was greater with mixed algal diets than those attained with the monoalgal diets. Results of the nauplii growout experiment showed that the survival of nauplii to adult was highest with Rh and lowest with T-iso. Time to first maturity was significantly affected by dietary microalgae with T-iso being the slowest. The percentage of ovigerous females was significantly different among dietary microalgae, with T-iso and Ch exhibiting the lowest percentage. P. pelagicus can be successfully cultured with various monoalgal diets but results suggest that a mixed algae ration of T-iso and Tw will produce the greatest population growth. (C) 2010 Elsevier B.V. All rights reserved.