An empirical study on embryonic diapause occurring in the early developmental stage of sting rays

2016 Fiscal Year Final Research Report

• Project/Area Number: 26660161
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: Nagasaki University
• Principal Investigator: YAMAGUCHI Atsuko 長崎大学, 水産・環境科学総合研究科(水産), 教授 (10310658)
• Research Collaborator: WYFFELS Jennifer
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 胚休眠 / 繁殖 / 板鰓類 / エイ類 / 胎仔

Outline of Final Research Achievements

We conducted field surveys in the East China Sea to collect adult stingrays with embryos. The stages of embryonic development were examined at the cellular level in detail, as well as the nutritional supplies to embryos in the uterus of adult females. Meanwhile, we succeeded in arranging nearly complete data sets of Dasyatis akajei. Previously, it was thought that embryonic diapause does not occur in some species of stingrays such as D. akajei and that the development of the embryos is completed in a very short pregnancy period followed by birth. However, in this study, we observed that embryonic diapause occurred at developmental stage 1, i.e., a very early embryonic stage. After a short-term diapause, the embryos developed to stage 9 very quickly. To the best of our knowledge, this is the first study that revealed the presence of a very short embryonic diapause in sting rays.

Free Research Field

水圏生産科学