Mueller Melanie, Sternecker Katharina, Milz Stefan, Geist Juergen
Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Freising, Bavaria, Germany.
Institute of Anatomy, Faculty of Medicine, LMU Munich, Munich, Bavaria, Germany.
PeerJ. 2020 Sep 16;8:e9977. doi: 10.7717/peerj.9977. eCollection 2020.
Knowledge on the extent and mechanisms of fish damage caused by hydropower facilities is important for the conservation of fish populations. Herein, we assessed the effects of hydropower turbine passage on internal fish injuries using X-ray technology. A total of 902 specimens from seven native European fish species were screened for 36 types of internal injuries and 86 external injuries evaluated with a previously published protocol. The applied systematic visual evaluation of X-ray images successfully detected skeletal injuries, swim bladder anomalies, emphysema, free intraperitoneal gas and hemorrhages. Injuries related to handling and to impacts of different parts of the hydropower structure could be clearly distinguished applying multivariate statistics and the data often explained delayed mortality within 96 h after turbine passage. The internal injuries could clearly be assigned to specific physical impacts resulting from turbine passage such as swim bladder rupture due to abrupt pressure change or fractures of skeletal parts due to blade-strike, fluid shear or severe turbulence. Generally, internal injuries were rarely depicted by external evaluation. For example, 29% of individuals with vertebral fractures did not present externally visible signs of severe injury. A combination of the external and internal injury evaluation allows quantifying and comparing fish injuries across sites, and can help to identify the technologies and operational procedures which minimize harm to fish in the context of assessing hydropower-related fish injuries as well as in assessing fish welfare.
了解水电设施对鱼类造成损害的程度和机制对于鱼类种群的保护至关重要。在此，我们使用X射线技术评估了水轮机通道对鱼类内部损伤的影响。我们按照先前公布的方案，对来自7种欧洲本土鱼类的902个样本进行了36种内部损伤和86种外部损伤的筛查。通过对X射线图像进行系统的视觉评估，成功检测到了骨骼损伤、鱼鳔异常、肺气肿、腹腔内游离气体和出血情况。运用多元统计方法，可以清晰区分与处理以及水电结构不同部位撞击相关的损伤，这些数据往往能解释水轮机通道通过后96小时内的延迟死亡率。内部损伤可以明确归因于水轮机通道造成的特定物理影响，例如由于压力突然变化导致的鱼鳔破裂，或由于叶片撞击、流体剪切或严重湍流导致的骨骼部分骨折。一般来说，外部评估很少能发现内部损伤。例如，29%的脊椎骨折个体没有外部可见的严重损伤迹象。结合外部和内部损伤评估，可以对不同地点的鱼类损伤进行量化和比较，并有助于在评估与水电相关的鱼类损伤以及鱼类福利时，确定将对鱼类的伤害降至最低的技术和操作程序。
