Diel variations in the assemblage structure and foraging ecology of larval and 0+ year juvenile fishes in a man-made floodplain waterbody.
Diel variations in the assemblage structure and foraging ecology of larval and 0+ year juvenile fishes in a man-made floodplain waterbody.
复制标题
人造洪泛区水体中幼鱼和0岁幼鱼的组合结构和觅食生态的昼夜变化。
作者：
L. H. Tewson;I. Cowx;A. D. Nunn
本文研究了人工河漫滩水体中浮游动物组成和丰度的昼夜变化，以及幼鱼和0+龄幼鱼的种类组成、密度、大小结构、摄食活动、食物组成和猎物选择。有一个显着的差异，在白天和夜间渔获量的物种组成，大多数物种在白天或夜间，反映了他们的主要活动期间一直在丰富的峰值。有没有一致的昼夜模式组合结构或丰富的一些物种，但是，最有可能的是，分别由于鱼类孵化和个体发育的昼夜行为或栖息地利用的物候。有几个明确的昼夜模式，在幼虫和0+年的青少年蟑螂Rutilus rutilus和鲈鱼河鲈的饮食组成或猎物的选择，与大多数类群一致选择或避免无论白天或晚上的时间，并没有明显的转变之间的反硝化和底栖食物来源，但饮食重叠表明，种间相互作用可能是最强的在晚上。取样方案必须考虑到目标物种的昼夜生态，因为仅进行昼夜调查就可能对资源使用情况作出不准确的评估。在这项研究中，相对缺乏一致的昼夜模式表明，多个24小时的调查，需要在春末夏初提供准确的评估0+年鱼类组合结构和觅食生态。
This study investigated diel variations in zooplankton composition and abundance, and the species composition, density, size structure, feeding activity, diet composition and prey selection of larval and 0+ year juvenile fishes in the littoral of a man-made floodplain waterbody over five 24 h periods within a 57 day period. There was a significant difference in the species composition of diurnal and nocturnal catches, with most species consistently peaking in abundance either during daylight or at night, reflecting their main activity period. There were no consistent diel patterns in assemblage structure or the abundance of some species, however, most likely, respectively, due to the phenology of fish hatching and ontogenetic shifts in diel behaviour or habitat use. There were few clear diel patterns in the diet composition or prey selection of larval and 0+ year juvenile roach Rutilus rutilus and perch Perca fluviatilis, with most taxa consistently selected or avoided irrespective of the time of day or night, and no obvious shift between planktonic and benthic food sources, but dietary overlap suggested that interspecific interactions were probably strongest at night. It is essential that sampling programmes account for the diel ecology of the target species, as diurnal surveys alone could produce inaccurate assessments of resource use. The relative lack of consistent diel patterns in this study suggests that multiple 24 h surveys are required in late spring and early summer to provide accurate assessments of 0+ year fish assemblage structure and foraging ecology.