Sokta Ly, Jiang Tao, Liu Hongbo, Xuan Zhongya, Qiu Chen, Chen Xiubao, Yang Jian
Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China.
Key Laboratory of Fishery Ecological Environment Assessment and Resource Conservation in Middle and Lower Reaches of the Yangtze River, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China.
Heliyon. 2020 Aug 1;6(8):e04571. doi: 10.1016/j.heliyon.2020.e04571. eCollection 2020 Aug.
Loss of valued diadromous fishes and their habitats is one of the most critical problems in aquatic habitat connection and resource management worldwide. In China, the Poyang, Dongting, Gaobao, Gucheng, Dongping, and Taihu lakes were known to be historical migratory spawning sites of the anadromous estuarine tapertail anchovy . However, except for Poyang Lake, it is believed that these lakes are no longer used by anadromous fish owing to overfishing, water pollution, and loss of connectivity. To confirm this assumption, we used an electron probe microanalyzer to analyze elemental strontium (Sr) and calcium (Ca) microchemical patterns in the otoliths of individuals sampled from these lakes, in accordance with our previous analysis of the otolithic patterns of the same species sampled from habitat areas characterized by different salinity gradients. The results of line transect analysis of Sr/Ca ratios and Sr X-ray intensity maps of the otoliths indicated that all individuals from Dongting, Gaobao, Gucheng, Taihu, and Dongping lakes were characterized by a freshwater-resident life history. In contrast, individuals from Poyang Lake exhibited both freshwater-resident and anadromous life histories. The findings of this pilot study suggest that anadromous can be found in Poyang Lake but are unlikely to be found in Dongting, Gaobao, Gucheng, Dongping, or Taihu lakes, despite these lakes being historical distribution areas or even spawning sites. This anchovy can possibly be used as a good model species for understanding the aforementioned global problem. Given that is a commercially important species, restoration of its natural habitats and maintenance of their connections are recommended for its management and conservation.
珍贵的洄游鱼类及其栖息地的丧失是全球水生栖息地连通性和资源管理中最关键的问题之一。在中国，鄱阳湖、洞庭湖、高宝湖、固城湖、东平湖和太湖曾是河口凤鲚溯河洄游产卵的历史场所。然而，除鄱阳湖外，由于过度捕捞、水污染和连通性丧失，人们认为这些湖泊已不再有溯河鱼类栖息。为证实这一假设，我们使用电子探针微分析仪，根据之前对从具有不同盐度梯度的栖息地采集的同物种耳石模式的分析，来分析从这些湖泊采集的个体耳石中的元素锶（Sr）和钙（Ca）的微化学模式。耳石Sr/Ca比值的线断面分析结果和Sr X射线强度图表明，来自洞庭湖、高宝湖、固城湖、太湖和东平湖的所有个体都具有淡水定居的生活史。相比之下，来自鄱阳湖的个体则同时具有淡水定居和溯河洄游的生活史。这项初步研究的结果表明，尽管洞庭湖、高宝湖、固城湖、东平湖和太湖是历史分布区甚至是产卵场，但在这些湖中不太可能发现溯河洄游鱼类，而在鄱阳湖仍能发现。这种凤鲚可能是理解上述全球问题的良好模式物种。鉴于凤鲚是具有商业重要性的物种，建议恢复其天然栖息地并维持其连通性，以进行管理和保护。
