Spatiotemporal change in growth of two populations of Asian chum salmon in relation to intraspecific interaction

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概要

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• Spatiotemporal changes in growth patterns of chum salmon Oncorhynchus keta that returned to the Ishikari (Japan) and Namdae (Korea) rivers in 1984-1998 were investigated using scale analysis. Juvenile chum salmon from both populations left coastal marine areas after spring at a size of over 8 cm fork length (FL). In summer, juvenile salmon from the Namdae River entered the Okhotsk Sea at a larger FL than Ishikari River juveniles. There were no significant differences in annual growth between populations of one-, two-, and four-year-old fish. For three-year-old fish, however, Namdae River salmon had significantly higher synchronous and sympatric growth than Ishikari River salmon. Mean FL of adults was also larger in Namdae River salmon than in Ishikari River salmon. ANCOVA results showed (1) negative linear relations between FL and catch, (2) homogeneous slopes of those relations at regional and species levels, and (3) non-homogeneous slopes at the population level, indicating that density dependent effects on growth were most significant at this level. We concluded that growth of chum salmon was concurrently influenced by stronger effects of intrapopulation competition and weaker effects of inter- and intra-specific interactions in the Bering Sea.鱗分析と体サイズのバックカリキュレーション法に基づき，1984-1998 年に北海道石狩川と韓国ナンダエ川へ回帰したシロザケの成長パターンの時空間変動を明らかにした。その結果，石狩川系幼魚が沿岸から小型で直接オホーツク海へ移動するのに対して，ナンダエ川幼魚は日本海を回遊後オホーツク海へ大型で移動することが明らかとなった。シロザケ4 歳魚の体サイズはベーリング海で3 歳時に種内あるいは個体群間より個体群内で強い密度依存効果を受けることが示唆された。

• 2009-07-01

著者

• SEO Hyunju

  Graduate School of Fisheries Sciences, Hokkaido University

• KUDO Hideaki

  Faculty of Fisheries Sciences, Hokkaido University

• KAERIYAMA Masahide

  Faculty of Fisheries Sciences, Hokkaido University

• Seo Hyunju

  Graduate School Of Fisheries Sciences Hokkaido University

• Kudo Hideaki

  Faculty Of Fisheries Sciences Hokkaido University

• Kaeriyama Masahide

  Faculty Of Fisheries Sciences Hokkaido University

関連論文

• Spatiotemporal change in growth of two populations of Asian chum salmon in relation to intraspecific interaction
• Perspectives on wild and hatchery salmon interactions at sea, potential climate effects on Japanese chum salmon, and the need for sustainable salmon fishery management reform in Japan

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