First description for ovarian maturation induction of female Harpiosquilla raphidea broodstock in individual containers within a recirculating aquaculture system

This research aimed to use individual containers within a recirculating aquaculture system to induce ovarian maturation in female mantis shrimp (Harpiosquilla raphidea) broodstock. Forty-one female H. raphidea were cultured in individual containers at a density of one mantis shrimp/0.2 m2/container for 60 days. Seawater in the circulating system was replaced at a rate of 10% per day. The survival rate of female H. raphidea was 63% with an absolute growth rate of 0.210 ± 0.15 g day−1. Ovarian development was classified into six stages by monitoring changes in the external appearance (i.e., telson color and semen appearance), the color of the ovaries, the pattern of oocytes, and the gonadosomatic index (GSI). Stage 1 was classified by white ovaries (32.32 ± 7.72 µm in diameter; N = 11); stage 2 was classified by ovaries that appeared a cloudy white color (99.29 ± 21.01 µm in diameter; N = 6). Stage 3 was classified by light-yellow ovaries (105.23 ± 22.09 µm in diameter; N = 4). Stage 4 ovaries were a yellow/orange color (106.50 ± 27.70 µm in diameter; N = 11). Stage 5 had orange ovaries (162.11 ± 50.39 µm of diameter; N = 5) and stage 6 had dark orange ovaries (179.89 ± 27.41 µm of diameter; N = 4). Histological analysis also revealed six staged of oocyte developmental in H. raphidea, including early previtellogenic, late previtellogenic, early vitellogenic, late vitellogenic, maturation, and pre-spawn stages. The Lightness values (L*) of the ventral telson with the fused ovary were significantly higher in female H. raphidea broodstock in stages V and VI of ovarian development (p