Sometimes called "king" salmon, Chinook are the largest salmon species. Adults can grow to more than 4 feet in length. Their average weight ranges between 10 and 45 pounds. The Chinook has a greenish back, silver sides, and a silver belly. It is covered with black spots on its back, dorsal fin, and tail fin. The fish darken as they mature and males are almost black by the time they are ready to spawn. Chinook are known as long-distance swimmers and will travel to the farthest reaches of the Columbia to spawn.
Ocean fresh Chum salmon are metallic greenish-blue on the dorsal surface (top) with fine black speckles. They are difficult to distinguish from Sockeye and Coho salmon without examining their gills or caudal fin scale patterns. Chum have fewer but larger gill rakers than other salmon. After nearing fresh water, however, the Chum salmon changes color-particularly noticeable are vertical bars of green and purple, which give them the common name, calico salmon. The males develop the typical hooked snout of Pacific salmon and very large teeth which partially account for their other name of "dog salmon." The females have a dark horizontal band along the lateral line; their green and purple vertical bars are not so obvious.
The population of wild steelhead in the lower Columbia River has declined by 90 percent in the last 10 years. Steelhead are very similar to rainbow trout. The only difference is that rainbows spend their entire lives in freshwater, while steelhead are anadromous like salmon. Anadromous means that they are born in freshwater, migrate to the ocean, and then return to spawn in freshwater. Steelhead are solid gray until their skin darkens at spawning time. Occasionally, a reddish streak shows up on their sides. They migrate to the sea throughout the year. Most steelhead return upstream to spawn after two years at sea. The female digs a redd that may be as large as 60 square feet, and buries the eggs in up to a foot of gravel. She releases several hundred to several thousand eggs. Unlike other salmon species, steelhead don't always die after spawning. They can swim back to sea and return to spawn again-though only 10 to 15 percent survive the trip.
Bull trout are actually not trout but char, which broke away genetically from salmon during the Ice Age. They have small yellow to crimson spots on a dark background and have no upper teeth. They can attain a weight of 20 to 30 pounds in lakes, and up to 4 pounds in rivers. They don't spawn until age 4 to 7 and live up to 12 years. They spend winters in larger main stems, then migrate upriver to tributaries to spawn in fall. They need very cold, clear streams to spawn. These predatory fish eat smaller fish, including their own.