Department of Mathematics, Idaho State University, 921 S. 8th Ave., Stop 8085, Pocatello, ID 83209, USA.
J Biol Dyn. 2010 Mar;4(2):158-75. doi: 10.1080/17513750902962608.
Native salmonid fish have been displaced worldwide by nonnatives through hybridization, competition, and predation, but the dynamics of these factors are poorly understood. We apply stochastic Lotka-Volterra models to the displacement of cutthroat trout by rainbow/hybrid trout in the Snake River, Idaho, USA. Cutthroat trout are susceptible to hybridization in the river but are reproductively isolated in tributaries via removal of migratory rainbow/hybrid spawners at weirs. Based on information-theoretic analysis, population data provide evidence that hybridization was the primary mechanism for cutthroat trout displacement in the first 17 years of the invasion. However, under some parameter values, the data provide evidence for a model in which interaction occurs among fish from both river and tributary subpopulations. This situation is likely to occur when tributary-spawned cutthroat trout out-migrate to the river as fry. The resulting competition with rainbow/hybrid trout can result in the extinction of cutthroat trout even when reproductive segregation is maintained.
本地鲑鱼已被世界各地的非本地鱼类通过杂交、竞争和捕食而取代，但这些因素的动态变化却知之甚少。我们应用随机洛特卡-沃尔泰拉模型来研究美国爱达荷州蛇河流域虹鳟/杂交鳟鱼对大口黑鲈的取代。大口黑鲈在河流中易发生杂交，但在支流中通过在堰坝处移除洄游的虹鳟/杂交鳟鱼的鱼卵来实现生殖隔离。基于信息理论分析，种群数据表明，在入侵的头 17 年，杂交是大口黑鲈被取代的主要机制。然而，在某些参数值下，数据表明存在一个模型，其中来自河流和支流亚种群的鱼类之间存在相互作用。当作为幼鱼洄游到河流的支流产卵的大口黑鲈与虹鳟/杂交鳟鱼发生竞争时，就可能出现这种情况。即使保持生殖隔离，这种竞争也可能导致大口黑鲈灭绝。
