Crossman James A, Korman Josh, McLellan Jason G, Miller Andy L, Howell Matthew D
Fish and Aquatic Sciences, BC Hydro, Castlegar, British Columbia, Canada.
Ecometric Research Inc., Vancouver, British Columbia, Canada.
Ecol Appl. 2025 Jun;35(4):e70042. doi: 10.1002/eap.70042.
Success in conserving or recovering endangered species requires a detailed understanding of vital rates that control population trends. Sturgeons (Acipenseridae) are the most imperiled taxon globally, with ongoing population declines despite significant conservation and restoration efforts in recent decades. Here, a long-term dataset is analyzed to describe growth rates of endangered white sturgeon (Acipenser transmontanus) in the transboundary section of the upper Columbia River over a 32-year period where conservation aquaculture was initiated in year 12 to prevent extirpation. The extent of spatial (Canada and United States), temporal (1990-2021), and seasonal variation (summer and winter) in growth dynamics was modeled to understand the potential impact of increased competition due to stocking on somatic growth of wild-origin fish. von Bertalanffy growth models were fit to observations of growth in length and mass from recaptures of tagged fish. Overall, growth rates of wild- and hatchery-origin white sturgeon were similar, with growth in length higher in summer than in winter, especially in the United States. Growth in mass was similar in winter and summer for wild- and hatchery-origin fish weighing less than ~30 kg, but growth was considerably higher in winter than summer for heavier fish. Examination of temporal random effects showed an abrupt decrease in growth partway through the time series. To evaluate the magnitude and uncertainty of the change, we fit a Bayesian changepoint model and found evidence for suppressed growth in length and mass of wild fish in years following the peak in densities of hatchery-origin sturgeon released from conservation aquaculture. Results provide an understanding of how an endangered species responds to a conservation action commonly applied for imperiled fish species worldwide and may provide insight into other important population dynamics (e.g., reproductive metrics) that are critical for recovery.
成功保护或恢复濒危物种需要详细了解控制种群趋势的关键比率。鲟鱼（鲟科）是全球最濒危的分类群，尽管近几十年来进行了大量的保护和恢复工作，但其种群仍在持续减少。在此，分析了一个长期数据集，以描述濒危白鲟（Acipenser transmontanus）在上哥伦比亚河跨界区域32年间的生长率，该区域在第12年启动了保护性水产养殖以防止灭绝。对生长动态的空间（加拿大和美国）、时间（1990 - 2021年）和季节变化（夏季和冬季）范围进行建模，以了解由于放流导致的竞争增加对野生来源鱼类体细胞生长的潜在影响。冯·贝塔朗菲生长模型拟合了标记鱼重新捕获时的体长和体重生长观测值。总体而言，野生和养殖来源的白鲟生长率相似，夏季体长生长高于冬季，尤其是在美国。体重小于约30千克的野生和养殖来源鱼类在冬季和夏季的体重增长相似，但体重较重的鱼类冬季生长明显高于夏季。对时间随机效应的检验表明，在时间序列中途生长出现突然下降。为了评估变化的幅度和不确定性，我们拟合了一个贝叶斯变化点模型，发现有证据表明，在保护性水产养殖放流的养殖来源鲟鱼密度达到峰值后的几年里，野生鱼类的体长和体重生长受到抑制。研究结果有助于了解濒危物种如何应对全球濒危鱼类普遍采用的保护行动，并可能为恢复至关重要的其他重要种群动态（如繁殖指标）提供见解。
