Abstract This study examined the effectiveness of recombinant gonadotropins derived from Japanese eel Anguilla japonica for inducing oocyte maturation and ovulation in female whitespotted conger Conger myriaster . Recombinant follicle-stimulating hormone (rFSH, 500 µg/kg body weight, BW) was administered weekly to females at the pre-vitellogenic and early vitellogenic stages to promote vitellogenesis. At the migratory nucleus stage, as indicated by cytoplasmic clearing in the oocytes, recombinant luteinizing hormone (rLH, 500 µg/kg BW) was administered to induce final oocyte maturation and ovulation. In Experiment 1, seven of eight females (87.5%) ovulated, with a mean hatching rate of 35.1% (range: 1–75%). In Experiment 2, 10 of 11 females (90.9%) ovulated, with a mean hatching rate of 44.5% (range: 0–83%). These results show that rFSH and rLH derived from Japanese eel are effective for inducing vitellogenesis, final oocyte maturation, and ovulation in whitespotted conger.
Nakamura et al. (2026) studied this question.