Consuegra Sofia, Phillips Nia, Gajardo Gonzalo, de Leaniz Carlos Garcia
IBERS, Aberystwyth University, Penglais Campus Aberystwyth SY23 3DA, UK.
Laboratorio de Genética, Biodiversidad & Acuicultura, Universidad de Los Lagos Osorno, Chile.
Evol Appl. 2011 Sep;4(5):660-71. doi: 10.1111/j.1752-4571.2011.00189.x. Epub 2011 May 24.
Aquaculture is a major source of invasive aquatic species, despite the fact that cultured organisms often have low genetic diversity and tend to be maladapted to survive in the wild. Yet, to what extent aquaculture escapees become established by means of high propagule pressure and multiple origins is not clear. We analysed the genetic diversity of 15 established populations and four farmed stocks of non-native rainbow trout in Chile, a species first introduced for recreational fishing around 1900, but which has in recent decades escaped in large numbers from fish farms and become widespread. Aquaculture propagule pressure was a good predictor of the incidence of farm escapees, which represented 16% of all free-ranging rainbow trout and were present in 80% of the study rivers. Hybrids between farm escapes and established trout were present in all rivers at frequencies ranging between 7 and 69%, and population admixture was positively correlated with genetic diversity. We suggest that non-native salmonids introduced into the Southern Hemisphere could benefit from admixture because local adaptations may not have yet developed, and there may be initially little fitness loss resulting from outbreeding depression.
水产养殖是入侵性水生物种的主要来源，尽管养殖生物通常遗传多样性较低，且往往不适应在野外生存。然而，水产养殖逃逸物种通过高繁殖压力和多个来源得以定殖的程度尚不清楚。我们分析了智利15个已定殖种群和4个非本地虹鳟养殖群体的遗传多样性。虹鳟于1900年左右首次引入智利用于休闲垂钓，但近几十年来，大量虹鳟从养鱼场逃逸并广泛分布。水产养殖繁殖压力是养殖逃逸物种发生率的良好预测指标，养殖逃逸物种占所有自由放养虹鳟的16%，且在80%的研究河流中都有出现。养殖逃逸个体与已定殖鳟鱼之间的杂交种在所有河流中都有出现，频率在7%至69%之间，种群混合与遗传多样性呈正相关。我们认为，引入南半球的非本地鲑科鱼类可能会从杂交中受益，因为当地适应性可能尚未形成，而且杂交衰退最初可能导致的适应性损失很小。
