Janowitz-Koch Ilana, Rabe Craig, Kinzer Ryan, Nelson Doug, Hess Maureen A, Narum Shawn R
Columbia River Inter-Tribal Fish Commission Hagerman Idaho.
Department of Fisheries Resources Management Nez Perce Tribe McCall Field Office Idaho.
Evol Appl. 2018 Nov 15;12(3):456-469. doi: 10.1111/eva.12725. eCollection 2019 Mar.
While the goal of supplementation programs is to provide positive, population-level effects for species of conservation concern, these programs can also present an inherent fitness risk when captive-born individuals are fully integrated into the natural population. In order to evaluate the long-term effects of a supplementation program and estimate the demographic and phenotypic factors influencing the fitness of a threatened population of Chinook Salmon (), we genotyped tissue samples spanning a 19-year period (1998-2016) to generate pedigrees from adult fish returning to Johnson Creek, Idaho, USA. We expanded upon previous estimates of relative reproductive success (RRS) to include grandparentage analyses and used generalized linear models to determine whether origin (hatchery or natural) or phenotypic traits (timing of arrival to spawning grounds, body length, and age) significantly predicted reproductive success (RS) across multiple years. Our results provide evidence that this supplementation program with 100% natural-origin broodstock provided a long-term demographic boost to the population (mean of 4.56 times in the first generation and mean of 2.52 times in the second generation). Overall, when spawning in nature, hatchery-origin fish demonstrated a trend toward lower RS compared to natural-origin fish ( < 0.05). However, when hatchery-origin fish successfully spawned with natural-origin fish, they had similar RS compared to natural by natural crosses (first-generation mean hatchery by natural cross RRS = 1.11 females, 1.13 males; second-generation mean hatchery by natural cross RRS = 1.03 females, 1.08 males). While origin, return year, and body length were significant predictors of fitness for both males and females ( < 0.05), return day was significant for males but not females ( > 0.05). These results indicate that supplementation programs that reduce the potential for genetic adaptation to captivity can be effective at increasing population abundance while limiting long-term fitness effects on wild populations.
虽然补充放流计划的目标是为受保护物种带来积极的、种群层面的影响，但当圈养繁殖的个体完全融入自然种群时，这些计划也可能带来内在的适应性风险。为了评估补充放流计划的长期影响，并估计影响濒危奇努克鲑（）种群适应性的人口统计学和表型因素，我们对跨越19年（1998 - 2016年）的组织样本进行了基因分型，以生成返回美国爱达荷州约翰逊溪的成年鱼的谱系。我们在先前相对繁殖成功率（RRS）估计的基础上进行扩展，纳入了祖父母分析，并使用广义线性模型来确定来源（孵化场或自然）或表型特征（到达产卵地的时间、体长和年龄）是否能显著预测多年间的繁殖成功率（RS）。我们的结果表明，这个使用100%自然来源亲鱼的补充放流计划为该种群带来了长期的人口统计学增长（第一代平均增长4.56倍，第二代平均增长2.52倍）。总体而言，在自然产卵时，与自然来源的鱼相比，孵化场来源的鱼表现出繁殖成功率较低的趋势（<0.05）。然而，当孵化场来源的鱼与自然来源的鱼成功产卵时，它们与自然与自然杂交的繁殖成功率相似（第一代孵化场与自然杂交的平均RRS = 雌性1.11，雄性1.13；第二代孵化场与自然杂交的平均RRS = 雌性1.03，雄性1.08）。虽然来源、返回年份和体长对雄性和雌性的适应性都是显著的预测因素（<0.05），但返回日期对雄性显著，对雌性不显著（>0.05）。这些结果表明，减少对圈养遗传适应可能性的补充放流计划在增加种群数量的同时，能够有效限制对野生种群的长期适应性影响。
