食蚊鱼摄食特性及其与浮游动物和环境因子的关系

Feeding traits of Gambusia affinis and their relations with zooplankton and environmental factors

2008年11月—2009年4月,利用分时段采样法对广州暨南大学明湖内食蚊鱼在秋季(11月)、冬季(12—2月)、春季(3—4月)3个季节的摄食特性进行了研究,探讨其与湖内浮游动物群体数量动态、光照和水温的关系。结果表明:食蚊鱼主要以浮游动物为食,对枝角类和桡足类有较强的选择性;明湖日平均水温与浮游动物日平均丰度在3个季节间有显著差异,而食蚊鱼消化道饱满指数的差异不显著;食蚊鱼消化道饱满指数在这3个季节的变化与浮游动物丰度、水温、光照在这3个季节的变化无明显的相关;无论哪个季节,食蚊鱼在白天时段(10:00—18:00)的消化道饱满指数均高于夜间(22:00—6:00),表现出白天高峰型的摄食节律;光照是影响食蚊鱼昼夜摄食节律的主要因素,而水温、浮游动物丰度的昼夜变化与食蚊鱼的昼夜摄食节律没有显著相关。

From November 2008 to April 2009, an investigation was conducted to understand the feeding traits of Gambusia affinis and their relations with the dynamics of zooplankton population, water temperature, and light intensity in the Minghu pond in Jinan University campus in autumn （November）, winter （December-February）, and spring （March-April）. In the pond, G. affinis mainly fed zooplankton, especially cladocera and copepod. The daily mean temperature and daily mean abundance of the zooplankton changed significantly with the three seasons, but the repletion index of the alimentary canal of G. affinis had little change. The repletion index had no significant relationships with the zooplankton abundance, water temperature, and light intensities in the three seasons. No matter what season, the G. affinis had a day-night feeding rhythm, and its repletion index in the daytime （10：00-18：00） was higher than that in the nighttime （22：00-6：00）. The diurnal feeding rhythm of G. affinis was significantly affected by light intensity, but not by the diurnal changes of zooplankton abundance and water temperature.