Urbanization Effects on Overwintering Brook and Brown Trout: Fish Condition and Movement

Urbanization and wintertime are both influences on stream ecosystems and play important roles in fish condition and movement.  In the Upper Peninsula of Michigan, we examined brook trout and brown trout overwintering in two fragmented urban streams and two rural streams, including wintertime fish condition and where fish moved during unstable ice conditions.  Fishes were captured with backpack electrofishing units in October / November 2011 and marked with PIT tags.  Bi-monthly sampling via electrofishing allowed fish measurement.  Fish position was assessed monthly using either a portable PIT “wand” reader or electrofishing.  There was a significant difference in mean fish condition entering winter between urban and rural streams, in regards to brook trout (P < 0.001, F=29.9) and brown trout (P < 0.001, F=254.5).   Mean brook trout and brown trout condition was higher in the urban streams compared to the rural streams.  Mean CPUE in the urban streams was 7.44 fish/km/min while mean CPUE in the rural streams was 8.03 fish/km/min.  This data suggests that there are differences in fish condition between urban and rural streams as species enter wintertime.