Đặc điểm sinh học và ảnh hưởng của thức ăn vi tảo đến sinh trưởng và sinh sản của loài copepoda <i>Apocyclops royi</i> (Lindberg, 1940)

Abstract

Apocyclops royi is an important Copepoda species widely utilized as live feed in marine fish larval rearing at commercial hatcheries. This study was conducted with two experiments to elucidate key biological characteristics of A. royi under laboratory conditions. In the first experiment, A. royi was cultured in glass containers (1 L) at an initial density of 50 females per container to monitor development, life cycle, reproduction, and longevity. In the second experiment, A. royi was cultured with three microalgal feeding regimes: Isochrysis galbana, Chaetoceros muelleri, and a mixture of I. galbana + C. muelleri (1:1 ratio) at an initial density of 500 nauplii per container to evaluate culture performance. Each treatment was replicated five times over 33 and 10 days, respectively. Parameters assessed included size at each developmental stage, reproductive lifespan, longevity. Results showed that A. royi developed well under experimental conditions, with nauplii measuring approximately 101 µm initially reaching adult size (485–586 µm in length) after 8 days. Mean lifespan was approximately 32 days. Lifetime fecundity reached 251.7 ± 31.65 eggs per female. Microalgal feeding trials revealed no significant differences in basic biological parameters, including survival rate, eggs per female, nauplii per female, hatching rate, and adult body size among treatments, indicating that A. royi can efficiently utilize the tested microalgae. These findings provide insights into the biological characteristics of A. royi, which are crucial for developing and optimizing mass culture protocols for live feed production in marine fish larval rearing, thereby enhancing hatchery production efficiency.

Keywords: Apocyclops royi, Chaetoceros muelleri, development, Isochrysis galbana, reproduction.