Moon phase and nocturnal density of Atlantic salmon parr in the Sainte-Marguerite River, Québec

• Main Authors: I. Imre, D. Boisclair
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Canada; Marguerite; Marguerite River; Atlantic salmon; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.484.1785; http://www.bio.ulaval.ca/cirsa/Publications/Imre moon phase paper.pdf

Nocturnal underwater counts of Atlantic salmon Salmo salar parr were made on four con-secutive occasions (two lunar cycles, samplings at both the full and new moon) at four 40m long sites in the Sainte-Marguerite River, Québec, Canada, between 30 June and 14 August 2003. Atlantic salmon parr counts did not differ significantly between moon phases. Cloud cover ranged from 0 to 100 % during the study, and had no significant effect on parr counts. There were significantly more Atlantic salmon parr in the near shore than in the midstream areas. The findings of this study suggest that the sampling strategy of summer studies aimed at assessing population abundance or developing habitat quality models can be designed without taking moon phase or cloud cover into consideration, but it should account for the higher relative abundance of Atlantic salmon parr in the near shore areas as compared to areas closer to the middle of streams. # 2005 The Fisheries Society of the British Isles Key words: moon phase; nocturnal density; population assessment; Salmo salar.