trout is native to Europe, from the Mediterranean
to the Black Sea, including Scandinavia and Siberia.
It was introduced into North America in 1883 with
eggs from Germany, and later by strains imported
from Loch Leven in Scotland. Since then, the brown
has become firmly established in many North American
waters. In Canada, brown trout are abundant in
southern Ontario and Quebec, as well as in southern
Alberta. Extensive stocking has produced a spectacular
lake-run fishery in the Great Lakes.
brown trout has a much wider range than the brook
trout, and it's been suggested they can survive
in streams that will no longer support brook trout.
However, brown trout don't survive well in warm,
polluted water either. They can survive for a
short period in 81 degree Fahrenheit water, but
usually the upper lethal limit for brown trout
is about 77 degrees. Brown trout prefer water
ranging from 54 to 67 degrees.
main reason for the success of brown trout in
streams depleted of brook trout is probably because
brown trout are harder to catch. Brown trout are
competitive with brook trout in the same stream
to the extent that the dominant brown trout were
excluding brook trout from favorable resting (not
feeding) positions in the stream, thereby making
the brook trout more vulnerable to predators.