Complex sentence: Pink salmon were introduced into the Great Lakes; this is the only location where the pink salmon have been successfully introduced into an entirely fresh water environment.They are most common in Lake Superior but are rare in Lake Michigan.
Split into simpler sentences: Pink salmon were introduced into the Great Lakes; this is the only location where they have been successfully introduced into an entirely fresh water environment. In the Great Lakes, they are most common in Lake Superior but are rare in Lake Michigan.