Effects of season and diel cycle on hydroacoustic estimates of density, Target Strength, and vertical distribution of fish in Yudong Reservoir, a plateau deep water reservoir in southwest China in a plateau deep

Hydroacoustics is a non-invasive fish stock assessment sampling technique that plays an important role in fishery science and management. However, non-standard hydroacoustic surveys could lead to biased results, and the factor of the sampling period (e.g., season and diel cycle) is extremely critical as it can greatly affect hydroacoustic results. Efforts to improve the accuracy and credibility of the hydroacoustic survey results are getting more and more attention. Thus, we conducted two diel hydroacoustic surveys in situ in summer and winter to detect whether there were diel and seasonal differences in density, Target Strength (TS) and vertical distribution of fish. The results indicated that nighttime had significantly higher fish mean density than daytime in summer and winter. No significant difference between summer and winter daytime, however, significant difference between summer and winter nighttime, but this bias could be accepted from the fisheries management perspective; The mean TS of the summer daytime was significantly higher than that of summer nighttime, winter daytime and winter nighttime, but there were no significant differences among summer nighttime, winter daytime, and winter nighttime, mainly due to mean TS may be overestimated from fish schooling behavior during summer daytime; The fish vertical distribution had significant seasonal correlations and was more dispersed in different water layers during the nighttime, proving that the assessment was better at nighttime than during the daytime. Consequently, the hydroacoustic surveys in Yudong Reservoir and other similar plateau deep water reservoirs should be performed at nighttime, which will yield relatively accurate density and TS, and dispersed vertical distribution of fish

国际鱼道适应性管理体系综述及对中国的启示

为便于目标鱼类能够在河流系统中顺利通过大坝等障碍物,已有大量的人力、物力投入到鱼道等过鱼设施的开发、建设以及修复中。如今,鱼道科学已逐步发展成为以工程学为中心,涵盖鱼类行为学、社会经济学和复杂建模(河流网络通道优先选择)等多学科交叉的一门学科。建设高效的鱼道等过鱼设施(延迟洄游时间短,洄游后负面影响小),需要适应性的管理和连续的创新。中国过鱼设施建设如火如荼,但是完善的过鱼设施全过程管理体系亟待建立。文章对1991年至2017年国外鱼道适应性管理体系相关文献(包括开发、建设和管理等方面)进行了综述。其中检索词为“鱼道(Fishway)”、“鱼类通道(Fish passage)”、“鱼(Fish)”和“大坝(Dam)”。研究表明,国外的过鱼设施逐步由经济种群保护向生物多样性保护发展、上行通道向下行通道发展、单一工程建设向流域整体发展、单一过鱼功能向生境补充发展、单纯工程建设向适应性管理发展。最后,文章讨论并展望了中国鱼道等过鱼设施的全过程适应性管理体系的发展前景

国际鱼道适应性管理体系综述及对中国的启示

为便于目标鱼类能够在河流系统中顺利通过大坝等障碍物,已有大量的人力、物力投入到鱼道等过鱼设施的开发、建设以及修复中。如今,鱼道科学已逐步发展成为以工程学为中心,涵盖鱼类行为学、社会经济学和复杂建模(河流网络通道优先选择)等多学科交叉的一门学科。建设高效的鱼道等过鱼设施(延迟洄游时间短,洄游后负面影响小),需要适应性的管理和连续的创新。中国过鱼设施建设如火如荼,但是完善的过鱼设施全过程管理体系亟待建立。文章对1991年至2017年国外鱼道适应性管理体系相关文献(包括开发、建设和管理等方面)进行了综述。其中检索词为“鱼道(Fishway)”、“鱼类通道(Fish passage)”、“鱼(Fish)”和“大坝(Dam)”。研究表明,国外的过鱼设施逐步由经济种群保护向生物多样性保护发展、上行通道向下行通道发展、单一工程建设向流域整体发展、单一过鱼功能向生境补充发展、单纯工程建设向适应性管理发展。最后,文章讨论并展望了中国鱼道等过鱼设施的全过程适应性管理体系的发展前景

国际鱼道适应性管理体系综述及对中国的启示

为便于目标鱼类能够在河流系统中顺利通过大坝等障碍物,已有大量的人力、物力投入到鱼道等过鱼设施的开发、建设以及修复中。如今,鱼道科学已逐步发展成为以工程学为中心,涵盖鱼类行为学、社会经济学和复杂建模(河流网络通道优先选择)等多学科交叉的一门学科。建设高效的鱼道等过鱼设施(延迟洄游时间短,洄游后负面影响小),需要适应性的管理和连续的创新。中国过鱼设施建设如火如荼,但是完善的过鱼设施全过程管理体系亟待建立。文章对1991年至2017年国外鱼道适应性管理体系相关文献(包括开发、建设和管理等方面)进行了综述。其中检索词为“鱼道(Fishway)”、“鱼类通道(Fish passage)”、“鱼(Fish)”和“大坝(Dam)”。研究表明,国外的过鱼设施逐步由经济种群保护向生物多样性保护发展、上行通道向下行通道发展、单一工程建设向流域整体发展、单一过鱼功能向生境补充发展、单纯工程建设向适应性管理发展。最后,文章讨论并展望了中国鱼道等过鱼设施的全过程适应性管理体系的发展前景

DataSheet_1_Phytoplankton control by stocking of filter-feeding fish in a subtropical plateau reservoir, southwest China.docx

Stocking of filter-feeding fish (mainly Hypophthalmichthys molitrix and Aristichthys nobilis) is a common method used in lakes and reservoirs in (sub)tropical China to control phytoplankton, but the results are ambiguous and lack long-term data to support. We analysed a decade (2010-2020) of monitoring data from a subtropical plateau reservoir, southwest China, to which filter-feeding fish were stocked annually. We found that the total phytoplankton biomass, cyanobacteria biomass and average individual mass of phytoplankton decreased significantly during the study period despite absence of nutrient concentration reduction. However, the grazing pressure of zooplankton on phytoplankton also decreased markedly as judged from changes in the ratio of zooplankton biomass to phytoplankton biomass and Daphnia proportion of total zooplankton biomass. This is likely a response to increasing predation on zooplankton by the stocked fish. Our results also indicated that water temperature, total phosphorus and water level promoted phytoplankton growth. Our results revealed that filter-feeding fish contributed to the decline in the biomass of phytoplankton but that it also had a strong negative effect on the grazing pressure of zooplankton on phytoplankton, even in this deep reservoir where zooplankton may have a better chance of survival through vertical migration. The particular strong effect on zooplankton is most likely due to imbalance of stocking and harvesting of fish. In the management of eutrophic reservoirs, the reduction of external nutrient loading should have highest priority. In highland (low temperature) deep-water eutrophic reservoirs, stocking of filter-feeding fish may help to control filamentous phytoplankton provided that the fish stocking is properly managed. The optimal stocking intensity of filter-feeding fish that can help control phytoplankton in such reservoirs without excessive impact on large-bodied zooplankton is a topic for further elucidation, however.</p

Quantitative assessment of fish passage efficiency at a vertical-slot fishway on the Daduhe River in Southwest China

Fish passage facilities are constructed to enable fish to pass anthropogenic barriers such as dams though their efficiency varies across species and location. There are a number of studies that assess the efficiency of fish passage facilities, yet rarely have such assessments been conducted in Asia. We conducted one of the first quantitative assessments of the efficiency of a vertical-slot fishway in Asia on the Daduhe River in Southwest China. Quantitative assessment of fish passage efficiency was conducted using a combination of methods, including fish sampling, video recordings and a Passive Integrated Transponder (PIT) system for tracking individually-tagged fish (N = 69 of 6 species). Fish sampling revealed 40 species assembled downstream of the dam. Fish captured closer to the fishway tended to be larger than fish caught more distant from the fishway. Half of the fish species observed downstream of the fishway were also observed at the entrance to the fishway (i.e. 153 individuals across 20 species). Video records revealed that overall passage rates were 71.2% based on the number of fish observed at the exit of the viewing chamber relative to that observed passing the entrance viewing chamber. Most fish passed the fishway at night with peak passage occurring in June. PIT technology results revealed that passage efficiency among the six tagged species ranged from 0% to 60% (four species successfully ascended the fishway). Transit time from the fishway entrance to exit was variable both among and within species that successfully ascended the fishway (i.e. 17.9–20.3 h for Schizothorax davidi, 6.4–88.8 h for Schizothorax preuanti, 46.4 h for Silurus meridionalis, 22.1–53.9 h Semilabeo prochilus). Fishway performance varied by species such that there is evidence that the fishway may be useful for maintaining river connectivity for some species. However, passage was often restricted during periods when there was sufficient flow in the fishway. Additional research is needed to put these findings in an ecological context given the overall low number of fish that passed the dam

A chromosome-scale reference genome provides insights into the genetic origin and grafting-mediated stress tolerance of Malus prunifolia

27openInternationalInternational coauthor/editoropenLi, Z.; Wang, L.; He, J.; Li, X.; Hou, N.; Guo, J.; Niu, C.; Li, C.; Liu, S.; Xu, J.; Xie, Y.; Zhang, D.; Shen, X.; Lu, L.; Gend, D.; Chen, P.; Jiang, L.; Wang, L.; Li, H.; Malnoy, M.; Deng, C.; Zou, Y.; Li, C.; Zhan, X.; Ma, F.; Zu, Q.; Guan, Q.Li, M.; Wang, L.; He, J.; Li, X.; Hou, N.; Guo, J.; Niu, C.; Li, C.; Liu, S.; Xu, J.; Xie, Y.; Zhang, D.; Shen, X.; Lu, L.; Gend, D.; Chen, P.; Jiang, L.; Wang, L.; Li, H.; Malnoy, M.; Deng, C.; Zou, Y.; Li, C.; Zhan, X.; Ma, F.; Zu, Q.; Guan, Q