Effect of monoalgal and mixed marine microalgal diets on pearl oyster larval growth (Pinctada imbricata radiata)

Abstract

The pearl farming industry plays an important role in pearl production, and the production of larvae is a crucial part of this whole process. Our aim was to determine the appropriate microalgae species and concentrations for pearl oyster, Pinctada imbricata radiata, larval feeding. We evaluated the suitability of six microalgae species (Isochrysis galbana, Pavlova lutheri, Tetraselmis suecica, Porphyridium cruentum, Nannochloropsis oculata, and Chlorella vulgaris), as well as two mixed diet, as a food source for pearl oyster larvae (15 mL⁻¹), investigating the effects of different concentrations (5000 cells mL⁻¹ and 10,000 cells mL⁻¹) of monoalgae and mixed algae on larval growth. The results showed that mixed algal diets, especially diet Mix1 (1:1:1 ratio of I. galbana, T. suecica, and P. lutheri), were more effective in promoting larval growth. Larvae fed with diet Mix1 at a concentration of 5000 cells mL⁻¹ showed the highest specific growth rates (SGR) and the lowest mortality rates, demonstrating the importance of algal composition for larval nutrition. Furthermore, larvae fed with P. lutheri at a concentration of 10,000 cells mL⁻¹ showed remarkable growth along with low mortality, emphasizing the importance of an appropriate algal concentration. This study not only contributes to the development of protocols for commercial production of P. imbricata radiata but also provides valuable insights into bivalve aquaculture and the larval nutrition. The results underline the potential of specific microalgae feeds such as diet Mix1 and P. lutheri to increase the efficiency and success of pearl oyster larvae rearing.