Effect of mink mustela vison schreber predation on cohorts of juvenile atlantic salmon salmo salar l. and brown trout salmo trutta l. in three small streams
Heggenes, J.; Borgstrom, R.
Journal of Fish Biology 33(6): 885-894
Two cohorts of Atlantic salmon parr and one of brown trout were studied in periods with and without the presence of mink, Mustela vison. In all localities a marked increase in mortality rate was observed during periods when mink were present. Mink were observed catching salmon parr, and approximately 10% of the parr had bite marks, especially on the tail fins. In the smallest stream with brown trout, the mortality rate was 0.80 during a few days with mink present; remnants of trout were found along the stream. The present study suggests than mink predation may be a major cause of mortality of salmonids in small streams. The results indicate that predation efficiency may vary with characteristics of the habitat, especially stream width and discharge, and fish density.