Lacking competition, the remaining salmon grow less vigorous with each generation, and lose their resistance to disease. They are "fish out of water," unable to build up their defenses against modern civilization.
缺乏競爭，鮭魚生機衰竭，族群奄奄一息，對外來病疫，毫無招架之力，就像一群對現代文明毫無抵抗力的「原住魚」。