Population density, growth and diet of eels, Anguilla anguilla L., in two rivers in eastern England.
Population density, growth and diet of eels, Anguilla anguilla L., in two rivers in eastern England.
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DOI：
10.1111/j.1365-2109.1992.tb00596.x
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发表时间：
1992-01-01
期刊：
影响因子：
--
通讯作者：
Mason, C.F.
中科院分区：
文献类型：
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作者：
Barak, N.A.-E.;Mason, C.F.
研究了欧洲鳗鲡（Anguilla anguilla L.）来自英格兰东部两条河流的四个地点的研究超过2年。鳗鱼种群密度在不同地点和季节之间变化很大，冬季捕获的鳗鱼很少。平均种群密度为50至518条鳗鱼/公顷，平均生物量为35至210公斤/公顷。在上游，年龄较大的鳗鱼数量更多。在两条河流的增长率大致相似，但鳗鱼9-13岁的上游网站显着较大的长度和重量比下游同行。在检查的868条鳗鱼中，只有425个胃里有食物，空胃百分比与温度呈负相关。在所有的网站，在所有的季节，并在三个大小类的鳗鱼研究的主要食品项目。广翅目和毛翅目也很重要。鱼类，主要是底栖物种，主要是在最大的规模级鳗鱼和冬季，当很少有大鳗鱼喂养。生态位宽度随个体大小的增加而扩大。
The population density, growth and diets of eels, Anguilla anguilla L., from four sites on two rivers in eastern England [UK] were studied over 2 years. Eel population density varied greatly between sites and seasons, few eels being caught during the winter. Mean population densities ranged from 50 to 518 eels/ha and mean biomass from 35 to 210 kg/ha. Older eels were more numerous at upstream sites. Growth rates in the two rivers were generally similar, but eels 9-13 years old at upstream sites were significantly larger in terms of length and weight than their downstream counterparts. Of 868 eels examined, only 425 stomachs contained food, the percentage of empty stomachs being negatively correlated with temperature. Asellus aquaticus was the predominant food item at all sites in all seasons and in the three size classes of eels studied. Megaloptera and Trichoptera were also important. Fish, largely bottom-dwelling species, were found mainly in the largest size-class of eels and in the winter, when few large eels were feeding. Niche breadth expands with increasing size of eel.