Development of a noninvasive sexing method for marine fish by high-res ultrasonography

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22328
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: Ryosuke Yazawa 東京海洋大学, 学術研究院, 准教授 (70625863)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 性判定 / マサバ / 超音波 / 性特異的SNPs / 養殖親魚

Outline of Final Research Achievements

For an efficient and stable aquaculture production of mackerels, which have become important aquaculture target species in Japan, it is desirable to work with a female-biased broodstock and thus to be able to manage precisely their sex ratio. In the present research project, we developed a noninvasive sexing method for marine fish by high-res ultrasonography. By analysis of ultrasound images of gonads, it was possible to identify their sex in more than 95% accuracy. We have also developed PCR-based molecular sex identification method for both chub and blue mackerels using sex-specific single-nucleotide variations identified by pool-sequencing analyses. Results demonstrated by this method were robust and accurate in assessing the genotypic sex of both blue and chub mackerels. We therefore conclude that these methods could be applied for the efficient management of sex-ratios in both mackerel aquaculture populations and wild-caught animals for fisheries management.

Free Research Field

海産魚の繁殖生理学および発生工学

Academic Significance and Societal Importance of the Research Achievements

本研究において開発された技術により、生殖腺の形態の性的二型およびその発達度合いを指標に超音波画像診断が可能となった。さらに、成熟度合いに依存しない分子情報を用いた性判定についても可能となり、当初の目的であった親魚集団中のメス親魚の割合を自由に制御することを実現した。将来的には、これらの技術を複合的に用いることで、メス親魚の成熟度の判定について情報を蓄積し、良質な卵を産む親魚を判別する技術の開発についても期待される。近年サバの養殖が日本各地で盛んになっており、本研究の成果はただちに養殖現場で利用可能な技術であり、より高度なサバ養殖技術の発展に寄与するものである。