Cardiff School of Biosciences, Cardiff University, Biomedical Sciences Building, Museum Avenue, Cardiff, Wales CF10 3AX, UK.
J Fish Biol. 2010 Nov;77(8):1835-49. doi: 10.1111/j.1095-8649.2010.02760.x. Epub 2010 Sep 14.
This study examines seasonal (winter v. summer) differences in space-time budgets, food intake and growth of Atlantic salmon Salmo salar parr in a controlled, large-scale stream environment, to examine the direction and magnitude of shifts in behaviour patterns as influenced by the availability of overhead cover and food supply. Salmo salar parr tested in the presence of overhead cover were significantly more nocturnal and occupied more peripheral positions than those tested in the absence of overhead cover. This increase in nocturnal activity was driven primarily by increased activity at night, accompanied by a reduction in daytime activity during winter. The presence of overhead cover had no effect on rates of food intake or growth for a given food supply in a given season. Growth rates were significantly higher for fish subjected to a high food supply than those subjected to a low food supply. Food supply did not affect the extent to which S. salar parr were nocturnal. These results were consistent between winter and summer. The use of riparian shading as a management technique to mitigate the effects of warming allows the adoption of more risk-averse foraging behaviour and may be particularly beneficial in circumstances where it serves also to increase the availability of food.
本研究在受控的大规模溪流环境中考察了大西洋鲑（Salmo salar parr）的时空预算、食物摄入和生长的季节性（冬季与夏季）差异，以研究行为模式的变化方向和幅度，这些变化受头顶遮蔽物和食物供应的影响。在有头顶遮蔽物的情况下测试的大西洋鲑 parr 比在没有头顶遮蔽物的情况下测试的大西洋鲑 parr 更具夜间活动特性，并且占据更外围的位置。这种夜间活动的增加主要是由于夜间活动增加，同时冬季白天活动减少。在给定季节的给定食物供应条件下，头顶遮蔽物的存在对食物摄入或生长速度没有影响。在高食物供应下生长速度显著高于低食物供应下的生长速度。食物供应并不影响鲑鱼 parr 夜间活动的程度。这些结果在冬季和夏季都一致。利用河岸遮荫作为管理技术来减轻变暖的影响，可以采用更规避风险的觅食行为，在增加食物供应的情况下尤其有益。
