Wood Chris C, Foote Chris J
Department of Fisheries and Oceans, Biological Sciences Branch, Pacific Biological Station, Nanaimo, British Columbia, V9R 5K6, Canada.
Evolution. 1996 Jun;50(3):1265-1279. doi: 10.1111/j.1558-5646.1996.tb02367.x.
Anadromous and nonanadromous morphs of the Pacific salmon Oncorhynchus nerka spawn in close physical proximity in tributaries to Takla Lake, British Columbia, yet differ in morphology, gill raker number, allozyme allele frequencies, and reproductive traits. Both morphs are semelparous typically maturing at age four, the anadromous morph (sockeye) at fork lengths of 38-65 cm and the nonanadromous morph (kokanee) at 17-22 cm. When reared together, pure and hybrid morphs also exhibited different growth rates and maturity schedules. Collectively, these large differences between the morphs confirm that sockeye and kokanee exist as reproductively isolated populations. Average gene flow (m) was estimated to be 0.1-0.8% between morphs, 1.7-3.7% among tributaries for kokanee, and 0.3-5.6% among tributaries for sockeye. We conclude that divergence has occurred in sympatry and examine potential isolating mechanisms.
太平洋红大麻哈鱼（Oncorhynchus nerka）的溯河洄游型和非溯河洄游型在不列颠哥伦比亚省塔克拉湖的支流中近距离产卵，但在形态、鳃耙数量、等位酶等位基因频率和繁殖特征方面存在差异。两种形态均为一次性产卵，通常在四岁时成熟，溯河洄游型（红大马哈鱼）叉长为38 - 65厘米，非溯河洄游型（红大麻哈鱼陆封型）叉长为17 - 22厘米。当一起饲养时，纯种和杂种形态也表现出不同的生长速度和成熟时间表。总体而言，这些形态之间的巨大差异证实了红大马哈鱼和红大麻哈鱼陆封型作为生殖隔离种群而存在。形态之间的平均基因流（m）估计为0.1 - 0.8%，红大麻哈鱼陆封型在支流间为1.7 - 3.7%，红大马哈鱼在支流间为0.3 - 5.6%。我们得出结论，分化已在同域中发生，并研究了潜在的隔离机制。
