章节大纲

    • Field surveys on salmon and trout to date have suggested that over 90% of the  juvenile fish that descend into the sea are depleted by the first winter of marine life. Achieving a certain size by the time they leave the coast is an important factor in whether the juvenile fish will die or survive. Small-sized fish demonstrate inferior swimming ability and are thus either preyed upon or exhaust their physical strength when they move to the feeding area. Furthermore, the critical period/growth hypothesis states that individual fish who cannot store enough energy will die due to the lack of food in winter.