Complex sentence: One of North America's largest and most intact wild salmon watersheds, the Stikine River is 400 miles/640km long from its headwaters in B.C.'s Spatsizi Plateau to its estuary near Wrangell, Alaska.
Split into simpler sentences: One of North America's largest and most intact wild salmon watersheds. The Stikine River is 400 miles/640km long from its headwaters in B.C.'s Spatsizi Plateau to its estuary near Wrangell, Alaska.