Seasonal and spatial variation in the diet of brown trout (Salmo trutta L.) in the subarctic River Laxá, north-east Iceland

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• 作者：G&iacute ; slason ; G&iacute ; sli M&aacute ; r ; Steingr&iacute ; msson ; Stef&aacute ; n Ó ; .
• 关键词：Benthic production ; Condition factor ; River continuum ; Stomach contents ; Stream salmonids
• 刊名：Aquatic Ecology
• 出版年：2004
• 出版时间：2004
• 年：2004
• 卷：38
• 期：2
• 页码：263-270
• 全文大小：531 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Hydrobiology
  
• 出版者：Springer Netherlands
• ISSN：1573-5125

文摘

This study examines seasonal and spatial patterns in the diet composition, stomach fullness and condition of a landlocked population of brown trout (2.5&ndash;61.3&nbsp;cm) in the lake-fed River Lax&aacute; in NE-Iceland. The stomach contents consisted predominantly of benthic invertebrates, such as blackfly larvae <it>Simulium vittatumit> (58%), chironomids (24%) and the freshwater snail <it>Radix peregrait> (7%). The seasonal and spatial patterns of <it>S. vittatumit> in the stomach contents were consistent with published studies on the life cycle and production of <it>S. vittatumit> in the River Lax&aacute;. Close to the Lake Myvatn outlet (0&ndash;16&nbsp;km), <it>S.&nbsp;vittatumit> constituted 63% of the stomach content volume, and exhibited two peaks (i.e., generations) in its seasonal contribution to the stomach contents, whereas further downstream (16&ndash;35&nbsp;km) <it>S.&nbsp;vittatumit> constituted 45% of the volume and showed only clear evidence of one generation. Seasonal fluctuations in <it>S.&nbsp;vittatumit> availability appear to affect the stomach fullness and the condition factor of the trout, especially close to the lake outlet where the fluctuations are pronounced.