Preliminary studies to accelerate deep-sea fish research

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K19335
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
• Research Institution: Mie University
• Principal Investigator: Miyazaki Taeko 三重大学, 生物資源学研究科, 准教授 (60346004)
• Co-Investigator(Kenkyū-buntansha): 中村 亨 三重大学, 生物資源学研究科, 助教 (00402694)
• Project Period (FY): 2018-06-29 – 2023-03-31
• Keywords: 深海魚 / ヨコエソ / 成熟 / 生殖腺

Outline of Final Research Achievements

The body length composition of the Sigmops gracilis collected was dominated by 50 and 60 mm, with larger sizes rapidly declining in numbers. As for the relationship between body length and sex, females were found above 80 mm, males below 50 mm, and intersex was mixed between 50 mm and 80 mm. Therefore, the size of the sex change of this species was estimated to be 50-80 mm. The Gonadal somatic index (GSI) ranged from 0.63 to 1.96 for spermatozoa-bearing males and was positively correlated with body length and weight. On the other hand, the GSI of females at ovarian maturity ranged from 1.06 to 14.26 and correlated with body weight. These results suggest that males should be around 50 mm and females 80 mm or more and weighing 10 g or more are appropriate for artificial insemination.

Free Research Field

Fish physiology

Academic Significance and Societal Importance of the Research Achievements

深海魚の人工授精による飼育を実現するには、船上で成熟した雌雄を開腹し、新鮮な精子と卵を入手する必要があるが、深海魚の成熟サイズについては未知である。本研究ではヨコエソを対象に生殖腺を組織学的に解析し、本種の体サイズと性、ならびに成熟度の関係を明らかにした。本結果により採集直後の膨大な数の生物標本から成熟した雌雄の選別が可能となり、人工授精を好条件で実施することにより深海魚の卵発生や個体発生に関する研究の展開が期待される。