Utilization of spawning beds Ikashiba for oval squid Sepioteuthis sp.2 using biotelemetry and DNA polymorphism

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06208
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Hiroshima University
• Principal Investigator: Umino Tetsuya 広島大学, 統合生命科学研究科(生), 教授 (70232890)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: アオリイカ / 産卵床 / 回遊 / イカシバ / バイオテレメトリ / 多回交接 / DNA多型

Outline of Final Research Achievements

Oval squid Sepioteuthis sp.2 is a commercially important species in Japan due to high market price. Hence, artificial spawning beds, so call “Ikashiba” are often to set up for resource management. Meanwhile, their actual usage status of Ikashiba as well as migratory ecologies of adult oval squid are still unclear. The objectives of this study are clarifying for utilization of by oval squid using biotelemetry and DNA polymorphism. seven female squids equipped with depth transmitter were tracked for 40 days in Hikimoto bay, Mie prefecture. Five of seven females remained in the bay and frequently approached at Ikashiba during tracking period. To test for multiple paternity of female oval squid, we conducted genotypic assignment of 20 female and their spermatophores using 7 microsatellite DNA loci. All females showed multiple paternity with one or more males prior to capture. Our results may provide some guidance for artificial spawning beds and resource management of oval squid.

Free Research Field

水産増殖学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的価値は高く、我が国で初めて、親アオリイカの産卵回遊や雌の多回交接の実体を明らかにたものである。一方、イカシバ設置は漁業者らが資源管理に関心を持った事例であるが、その普及によって、一般市民への資源保護への関心増と啓蒙・模範活動につながる。また、間伐材を活用したイカシバは、資源循環と資源維持のためのモデル活動となる。さらには、イカシバ設置によってアオリイカ資源が増大すれば、漁業振興のみならず、遊漁やダイビングなどの観光資源として地域振興への貢献が期待できる。