PDF(Pubmed)
Abstract：
Despite significant population declines and targeted European Union regulations aimed at Anguilla anguilla conservation, little attention has been given to their status at their easternmost range. This study applies wide-scale integrated monitoring to uncover the present-day eel distribution in Cyprus\' inland freshwaters. These are subject to increasing pressures from water supply requirements and dam construction, as seen throughout the Mediterranean. We applied environmental DNA metabarcoding of water samples to determine A. anguilla distribution in key freshwater catchments. In addition, we present this alongside 10 years of electrofishing/netting data. Refuge traps were also deployed to establish the timing of glass eel recruitment. These outputs are used together, alongside knowledge of the overall fish community and barriers to connectivity, to provide eel conservation and policy insights. This study confirm the presence of A. anguilla in Cyprus\' inland freshwaters, with recruitment occurring in March. Eel distribution is restricted to lower elevation areas, and is negatively associated with distance from coast and barriers to connectivity. Many barriers to connectivity are identified, though eels were detected in two reservoirs upstream of dams. The overall fish community varies between freshwater habitat types. Eels are much more widespread in Cyprus than previously thought, yet mostly restricted to lowland intermittent systems. These findings make a case to reconsider the requirement for eel management plans. Environmental DNA-based data collected in 2020 indicate that \"present-day\" eel distribution is representative of 10-year survey trends. Suggesting that inland freshwaters may act as an unrealized refuge at A. anguilla\'s easternmost range. Conservation efforts in Mediterranean freshwaters should focus on improving connectivity, therefore enabling eels to access inland perennial refugia. Thus, mitigating the impact of climate change and the growing number of fragmented artificially intermittent river systems.
摘要：
尽管人口大幅下降，而且欧盟有针对性地制定了旨在保护安圭拉鳗鱼的法规，很少有人关注他们在最东端的地位。这项研究应用了大规模的综合监测来揭示塞浦路斯内陆淡水中当今鳗鱼的分布。这些都受到来自供水需求和大坝建设的不断增加的压力，在整个地中海都可以看到。我们对水样进行了环境DNA元编码，以确定A.anguilla在主要淡水流域的分布。此外,我们将其与10年的电捕/网捕数据一起呈现。还部署了避难所陷阱，以确定玻璃鳗鱼招募的时间。这些输出一起使用，除了对整个鱼类群落的了解和连接障碍，提供鳗鱼保护和政策见解。这项研究证实了A.anguilla在塞浦路斯内陆淡水中的存在，招聘发生在3月份。鳗鱼的分布限制在低海拔地区，与离海岸的距离和连接障碍呈负相关。许多连接障碍被确定，尽管在大坝上游的两个水库中发现了鳗鱼。整个鱼类群落因淡水栖息地类型而异。鳗鱼在塞浦路斯比以前想象的要广泛得多，但主要限于低地间歇性系统。这些发现为重新考虑鳗鱼管理计划的要求提供了依据。2020年收集的基于环境DNA的数据表明，“当前”鳗鱼分布代表了10年的调查趋势。这表明内陆淡水可能在A.anguilla的最东部范围内充当未实现的避难所。地中海淡水的保护工作应侧重于改善连通性，因此使鳗鱼能够进入内陆常年避难所。因此，减轻气候变化和越来越多的支离破碎的人为间歇性河流系统的影响。
