Artificial Reproduction and Description of the Embryonic, Larval, and Juvenile Development of Sea Cucumber (holothuria Inornata Semper 1868) with Three Different Microalgae Diets

The sea cucumber Holothuria inornata is a species whose populations are at risk. This study aims to investigate its reproduction, embryonic and larval development, and the settlement of H. inornata under an algae-based diet. Twenty breeders were utilized, which underwent a 1.5-h desiccation followed by a thermal shock (27 to 32 °C). Embryonic development stage was recorded, and from the auricularia larval stage, three treatments were evaluated: A: Chaetoceros muelleri and Isochrysis galbana (1:1 ratio); B: C. muelleri, I. galbana, Tetraselmis suecica, and Pavlova lutheri (1:1:1:1 ratio); and C: Chaetoceros muelleri, I. galbana, T. suecica, P. lutheri, Navicula sp. (LPU-6) (1:1:1:1:1 ratio), with a larval density of 100 larvae L−1 in triplicate. The embryonic development in H. inornata lasts for 3 days, five larval stages were recorded: (1) Auricularia (days 3–8, 300 to 520 μm), (2) late auricularia (days 8–11, 520 to 670 μm), (3) doliolaria (days 11–13, 460 to 550 μm), (4) late doliolaria (days 13–16, 400 to 440 μm), and (5) pentacula (days 15–19, 650 to 900 μm). The post-settlement survival rate was 0