Effects of Environmental Factors on Natural Reproduction of the Four Major Chinese Carps in the Yangtze River, China
Effects of Environmental Factors on Natural Reproduction of the Four Major Chinese Carps in the Yangtze River, China
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DOI：
10.2108/zsj.30.296
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
Mingzheng Li;Xin Gao;Shaorong Yang;Z. Duan;W. Cao;Huan-zhang Liu
中科院分区：
文献类型：
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作者：
Mingzheng Li;Xin Gao;Shaorong Yang;Z. Duan;W. Cao;Huan-zhang Liu
四大家鱼是我国重要的经济鱼类，产量较高。然而，自世纪后期以来，他们在长江的招募急剧减少。2005 - 2010年，每年5 - 7月在长江中游宜都市采集4种白鲳的漂流卵，研究其产卵活动与环境因子的关系。采用分类回归树（CART）分析方法，对影响4种鲤鱼产卵活动的关键因子进行了分析。CART中包括12个预测变量（水文和气象变量）和1个响应变量（卵存在或卵数量）。CART分析表明，水温和水位日变化是影响产卵活动的两个最显著的因子。当水温在18°C ~ 24°C之间时，尤其是水位日增幅大于0.55m.d-1时，产卵活动总是有利的。与水文因素不同，气象因素似乎对产卵活动的启动没有影响。4种浮游卵密度主要受水位日变化、流量日变化、水温、湿度和气压的影响。最后，将研究结果与长江中游三峡水库的生态调控相结合。建议5 ~ 7月水温在18-24°C之间时，为保证4种鲤鱼顺利产卵，应进行生态调控，使水位日增幅大于0.55 m·d-1。
The four major Chinese carps are commercially important fish species with high production in China. However, their recruitment decreased sharply in the Yangtze River since the late 20th century. In the present study, to reveal the relationships between spawning activities of the four species and environmental factors, drifting eggs were collected at Yidu City, in the middle reaches of the Yangtze River, from May to July each year between 2005 and 2010. Classification and regression trees (CART) analysis was applied to identify the key factors associated with spawning activities of the four carp species. Twelve predictor variables (hydrological and meteorological variables) and one response variable (egg presence or number of egg) were included in the CART. Our CART analysis showed that water temperature and the diurnal increase of water level were the two most significant factors for the spawning activities. When water temperature was between 18°C and 24°C, especially in association with the diurnal increase of water level greater than 0.55 m·d-1, spawning activities was always favored. Unlike the hydrological factors, meteorological factors seemed to have no influence on initiating the spawning activities. The density of drifting eggs of the four species was mainly influenced by the diurnal variation of water level, the diurnal variation of water discharge, water temperature, humidity, and air pressure. We then related our results to the ecological regulation of the Three Gorge Reservoir in the middle reaches of the Yangtze River. We suggested that, when water temperature was between 18–24°C from May to July, to ensure the successful spawning of the four carp species, the ecological regulation should be managed to create flood peaks and make the diurnal increase of water level greater than 0.55 m·d-1.