Migration delays and mortality of adult Atlantic salmon (Salmo salar) en route to spawning grounds on the River Allier, France

摘要: During summer periods when water temperatures are high, Atlantic salmon Salmo salar forced to halt their migration. This phenomenon was observed in our study the River Allier France. Between 200 and 1200 S. have come spawn every year for last 2 decades, but population has suffered a severe decline. In 2009, 30 individuals were radio tracked; of these, 11 died during period, while other 19 resumed migration fall. mortality level higher amongst that arrived towards end i.e. those tended spend lower, warmer stretch river. view continuing rise freshwater temperatures, measures are urgently needed reduce impact increased on fish Allier. This could be achieved by (1) promoting delays further upstream making it easier for fish pass through dams (2) protecting spawning adults, particularly locations of halt. is consistent with growing body literature suggests climate change devastating effects phase anadromous salmonids.