Factors affecting population regulation of salmonid fishes

2009 Fiscal Year Final Research Report

• Project/Area Number: 19780155
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: General fisheries
• Research Institution: Fisheries Research Agency
• Principal Investigator: MORITA Kentaro Fisheries Research Agency, 北海道区水産研究所, 主任研究員 (30373468)
• Project Period (FY): 2007 – 2009
• Keywords: サケ科魚類 / 野生魚 / 個体群動態 / ベーリング海 / 成長 / 生息密度 / 水温 / 自然産卵

Research Abstract

サケ科魚類は川で産卵し稚魚期を過ごした後,海へ下り大きく成長するため,大きく異なる2つの生息環境を利用している.河川では密度依存的な死亡・成長に加えて,密度非依存的な環境変化による死亡(または移出入)が大きく,海洋では密度依存的な成長がおもな個体数制限要因になると考えられた.海洋での密度依存的な成長は,産卵数の低下という現象をして個体群増加率の低下をもたらすと考えられた.このように,サケ科魚類の個体数制限要因を解明するためには,海洋と河川の双方を包括的に理解する必要があると考えられた.

Research Products

• [Journal Article] Size-dependent thermal preferences in a pelagic fish. (2010)
  • Author(s): Morita, K., Fukuwaka, M., Tanimata, N., Yamamura, O.
  • Journal Title: Oikos (In press)
  • Peer Reviewed
• [Journal Article] Habitat fragmentation by damming threatens coexistence of stream-dwelling charr and salmon in the Fuji River, Japan. (2010)
  • Author(s): Tsuboi, J., Endo, S., Morita, K.
  • Journal Title: Hydrobiologia (In press)
  • Peer Reviewed
• [Journal Article] Latitudinal variation in the growth and maturation of masu salmon parr. (2010)
  • Author(s): Morita, K., Nagasawa, T.
  • Journal Title: Canadian Journal of Fisheries and Aquatic Sciences 67 Pages: 955-965
  • Peer Reviewed
• [Journal Article] Offshore Dolly Varden charr (Salvelinus malma) in the North Pacific. (2009)
  • Author(s): Morita, K., Morita, S.H., Fukuwaka, M., Nagasawa, T.
  • Journal Title: Environmental Biology of Fishes 86 Pages: 451-456
  • Peer Reviewed
• [Journal Article] Latitudinal variation in egg size and number in anadromous masu salmon Oncorhynchus masou. (2009)
  • Author(s): Morita, K., Tamate, T., Sugimoto, Y., Tago, Y., Watanabe, T., Konaka, H., Sato, M., Miyauchi, Y., Ohkuma, K., Nagasawa, T.
  • Journal Title: Journal of Fish Biology 74 Pages: 699-705
  • Peer Reviewed
• [Journal Article] 北海道東部中規模河川庶路川における魚類の流程分布と魚類相の変遷 (2009)
  • Author(s): 永沢亨, 森田健太郎, 坪井潤一
  • Journal Title: 魚類学雑誌 56 Pages: 31-45
  • Peer Reviewed
• [Journal Article] Plasticity in probabilistic reaction norms for maturation in a salmonid fish.
  • Author(s): Morita, K., Tsuboi, J., Nagasawa, T.
  • Journal Title: Biology Letters 5 Pages: 628-631
  • Peer Reviewed
• [Presentation] variation in parr growth and maturation in anadromous masu salmon, Oncorhynchus masou. (2009)
  • Author(s): Morita, K., Nagasawa, T.
  • Organizer: International Symposium on Formosa Landlocked Salmon and Masu Salmon
  • Place of Presentation: 台北
  • Year and Date: 2009-10-24
• [Presentation] Seasonal changes in the population densities of stream-dwelling salmonids in two contrasting tributaries of a subarctic river. (2009)
  • Author(s): Morita, K., Morita, S.H., Nagasawa, T.
  • Organizer: International Symposium on Formosa Landlocked Salmon and Masu Salmon
  • Place of Presentation: 台北
  • Year and Date: 2009-10-23
• [Presentation] カラフトマスの周期的な個体数変動 (2009)
  • Author(s): 森田健太郎, 森田晶子, 福若正章, 永沢亨
  • Organizer: 日本生態学会第57回大会
  • Place of Presentation: 東京
  • Year and Date: 2009-03-17
• [Presentation] Size-dependent effect of temperature on growth of chum salmon: Implications of global warming (2008)
  • Author(s): Morita, K., Fukuwaka, M.
  • Organizer: 5th World Fisheries Congress
  • Place of Presentation: 横浜
  • Year and Date: 2008-10-22
• [Presentation] Habitat fragmentation by damming threatens the coexistence of stream-dwelling charr and salmon (2008)
  • Author(s): Tsuboi, J., Endou, S., Morita, K.
  • Organizer: 5th World Fisheries Congress
  • Place of Presentation: 横浜
  • Year and Date: 2008-10-22
• [Presentation] Potential effect of rising temperature on growth performance and its influence on chum salmon (2008)
  • Author(s): Morita, K., Fukuwaka, M.
  • Organizer: International Symposium Effects of Climate Change on the World's Oceans
  • Place of Presentation: ヒホン, スペイン
  • Year and Date: 2008-05-21