By combining field research and careful laboratory analysis of samples over the course of an eight-year study, we met the challenge of assessing the life history traits and health status of eels restocked in freshwater ecosystems. We found that restocked eels exhibited good growth performance; moreover, the stocks were female-dominated, showed a good Fulton's condition factor (K) and lipid stores and had high survival probability estimated using the best model of Jolly-Seber stock assessment method for open populations. A necropsy revealed the absence of internal lesions. A swim bladder examination revealed the absence of the parasite Anguillicola crassus. Polymerase chain reaction (PCR) analyses revealed an increase of Anguillid herpesvirus-1 (AngHV-1) prevalence throughout the study. Most positive subjects expressed viral loads compatible with a latent infection and correlated positively with K. All restocked eels were contaminated by at least one of the organic pollutant congeners studied, but the pollution loads corresponded to the lowest range of pollutant concentrations reported in the available literature for European eels and did not exceed the maximum residue and contaminant limits in food and feed of several national and international regulations. Pollutant loads were negatively correlated with K, lipid content and eel density for polychlorinated biphenyls PCB 138, 153 and 180 and K for pesticides p.p’-DDE, p.p’-DDD, p.p’-DDT and PBDE47. This study highlights the potential role played by upland aquatic ecosystems in enhancing riverine silver eel production from the perspective of species conservation. To be successful, restocking must be accompanied by improved ecosystem quality and migration routes for eels in inland freshwaters. We also provide some recommendations for future research to improve the management of restocking programmes.

通过在为期八年的研究过程中结合实地研究和仔细的实验​​室分析样本，我们遇到了评估淡水生态系统中重新放养的鳗鱼的生活史特征和健康状况的挑战。我们发现重新放养的鳗鱼表现出良好的生长性能；此外，这些种群以雌性为主，显示出良好的富尔顿条件因子 (K) 和脂质储存，并且使用开放种群的 Jolly-Seber 种群评估方法的最佳模型估计具有较高的存活概率。尸检显示没有内部病变。鱼鳔检查显示没有寄生虫Anguillicola crassus。聚合酶链反应 (PCR) 分析显示Anguillid 疱疹病毒增加-1 (AngHV-1) 在整个研究中的流行。大多数阳性受试者表达的病毒载量与潜伏感染相容并与 K 呈正相关。所有重新放养的鳗鱼都被至少一种所研究的有机污染物同系物污染，但污染载量对应于现有文献中报告的最低污染物浓度范围用于欧洲鳗鱼，并且没有超过多项国家和国际法规在食品和饲料中的最大残留和污染物限制。污染物负荷与多氯联苯 PCB 138、153 和 180 的 K、脂质含量和鳗鱼密度呈负相关，而农药 p.p'-DDE、p.p'-DDD、p.p'-DDT 和 PBDE47 的 K 与 K 呈负相关。本研究从物种保护的角度强调了高地水生生态系统在提高河流银鳗产量方面的潜在作用。要想取得成功，重新放养必须伴随着改善生态系统质量和内陆淡水鳗鱼的迁徙路线。我们还为未来的研究提供了一些建议，以改进重新进货计划的管理。