2025-06-26 北海道大学
クロソイ全雌仔魚
＜関連情報＞
- https://www.hokudai.ac.jp/news/2025/06/post-1945.html
- https://www.hokudai.ac.jp/news/pdf/250626_pr.pdf
- https://www.sciencedirect.com/science/article/abs/pii/S0044848625007045?via%3Dihub
間接 的な雌化手法を用いた全雌単一性クロソイ個体群の作出 Establishment of an all-female monosex population in black rockfish (Sebastes schlegelii) through an indirect feminization method
Mutea Fridah Gacheri, Yo Yamaguchi, Takuma Kawasaki, Takashi Todo, Naoshi Hiramatsu
Aquaculture Available online: 7 June 2025
DOI:https://doi.org/10.1016/j.aquaculture.2025.742818
Highlights
- Sex reversal of black rockfish larvae using 17α-methyltestosterone was successful.
- Pseudomales exhibited normal testicular differentiation similar to control males.
- Artificial insemination of the females led to offspring production.
- The first all-female monosex population in black rockfish was achieved.
- Gonadal development of the all-female progeny was similar to the control group.
Abstract
Monosex production is crucial for enhancing the productivity of black rockfish (Sebastes schlegelii) aquaculture. This study aimed to produce an all-female monosex population (AFMSP) of this species. The larvae were fed a diet containing the synthetic androgen 17α-methyltestosterone (MT) at a dose of 10 mg MT/kg diet (MT group) or ethanol vehicle alone (control group) for 50 days followed by a commercial diet. The experimental fish were sampled at 290, 371, and 745 days post parturition (dpp) for growth monitoring and genetic and phenotypic sexing. Significant differences were observed in the body weight and total length between males and females in the control group at 745 dpp. Control fish exhibited nearly 1:1 sex ratios with aligned genetic and phenotypic ratios. The MT group also showed a 1:1 genetic sex ratio and 100 % normal testicular differentiation, indicating successful pseudo-male production (i.e., genetic females with testes). Control males and pseudo-males were separately crossed with genetic females; the former produced larvae of both genotypes in nearly 1:1 sex ratio, whereas the latter resulted in the production of 100 % genetic female larvae. Histological results confirmed that all offspring from pseudo-males developed ovaries, whereas those from control genetic males had a nearly 1:1 phenotypic sex ratio, with identical genetic and phenotypic ratios throughout sampling. This is the first report on AFMSP production in black rockfish using sperm from MT-treated pseudo-males through artificial insemination via an indirect feminization method; an approach that can significantly boost growth, ensure size uniformity, and enhance the sustainability of aquaculture productivity.
