Occurrence mechanism of strong-year classes in flathead flounder Hippoglossoides dubius by the assessment of transport process and prey abundance for larvae and juveniles

2015 Fiscal Year Final Research Report

• Project/Area Number: 25450269
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Hokkaido University
• Principal Investigator: Takatsu Tetsuya 北海道大学, 水産科学研究科(研究院), 教授 (50241378)
• Co-Investigator(Kenkyū-buntansha): HOSHI NAOKI 北海道大学, 水産学部, 助教 (50604485) ; NAKAYA MITSUHIRO 北海道大学, 水産学部, 特任助教 (80604313)
• Co-Investigator(Renkei-kenkyūsha): ISODA YUTAKA 北海道大学, 大学院水産科学研究院, 准教授 (10193393)
• Research Collaborator: INAGAKI YUTA ; KANO YOTA ; NAKATANI TOSHIKUNI ; SUZUKI KOTA ; TAMURA JUN'ICHI
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: アカガレイ / 仔魚 / 稚魚 / 着底 / 輸送 / 噴火湾

Outline of Final Research Achievements

To clarify the occurrence mechanism of strong-year classes in flathead flounder Hippoglossoides dubius, transport process of pelagic larvae and juveniles and settled area of juveniles were investigated in Funka Bay and its vicinity in 2013-2015 FY. In May 2013, late pelagic stage larvae were collected with MOHT- and FMT-nets around the area off Muroran City located at the north-east end of the bay, but no larva was collected in 2014-2015. It might be important for the recruitment success in the 2013 year-class that the clockwise vortex off Muroran captured the larvae was retained by the predominantly northwesterly winds. In this vortex, suitable water temperature (4.1-5.6 degrees Celsius) and prey abundance were observed for larval growth. In contrast in August-December through 2013-2015, no settled juvenile was collected on the sea floor with an otter trawl net in and out of the bay with <98-m and 95-354-m bottom depths, respectively.

Free Research Field

水圏生産科学