Everything You Want to Know About Sockeye Salmon (Oncorhynchus nerka)

Known for their brilliant red spawning colors, sockeyes are also great fighters when hooked.
Photo by Pat Clayton, Fish Eye Guy Photography

Although a trophy shot of an angler holding a bright-red sockeye salmon is impressive, the species is not usually considered one of the “glamour” game fish in Alaska and western Canada—overshadowed by the much larger kings and more acrobatic cohoes. But in many ways, sockeyes are the key to the entire ecosystems where they live. By entering rivers in massive numbers, laying millions of eggs, and then dying, sockeye populations provide vital nutrients and food for everything from bears and eagles to rainbow trout and grayling. What is less well known is that silvery sockeyes, fresh from the sea, are a fine fly-rod quarry. When hooked, they take to the air often and will test a reel’s drag system with long runs.

Range and Behavior
The general native range of the sockeye salmon extends from the Klamath River of Northern California to Kuskokwim basin of western Alaska, although the species does range as far north as far north as the Bathurst Inlet in the Canadian Arctic and as far south as California’s Mendocino coast. In the western Pacific, sockeyes can be found from Hokkaidō Island in northern Japan to the Anadyr River in Siberia. The sockeye population enduring the longest migration travels up the Columbia River to Redfish Lake, Idaho, which is more than 900 miles from the ocean and 6,500 feet above sea level.

When they first enter fresh water, sockeyes are bright silver.
Photo by Jon Warrenchuk, via Wikimedia

There are also naturally occurring populations of landlocked sockeyes—called kokanees—throughout a similar range. These potadromous fish (which travel from freshwater lakes to rivers during the spawn) evolved where sockeye populations were cut off from the sea by geography, and the name comes from the Okanagan language of the indigenous people of the Columbia Basin. Since the early 20th century, kokanees—also known as “silver trout”—have been stocked in large, coldwater lakes throughout California and the mountain West and all the way east to Maine and south to North Carolina. Colorado’s South Platte River, for instance, is a popular kokanee hot spot in the fall.

Sockeyes are unique among Pacific salmon in that they spend one to three years in fresh water before migrating to the ocean, which is why the vast majority of sockeye rivers are connected to large freshwater lakes. The adults then spend two or three years in the salt before returning to their natal rivers or lakes to spawn. In the ocean, the fish travel in large schools, moving throughout the water column to follow prey. The diet of the sockeye is also different from other salmon, in that they feed extensively on zooplankton during both the fresh- and saltwater stages of their life. They also eat smaller prey items, such as shrimp, and insects are part of the diet of juvenile fish.

Bristol Bay, Alaska, is the home of the last great wild-sockeye runs, which need our protection.
Photo by Pat Clayton, Fish Eye Guy Photography

During the spawning run, sockeyes—especially males—undergo dramatic physiological changes, including an increase in body depth and the development of a pronounced kype. The body turns brilliant red, while the head turns green.

What’s in a Name?
The range of the sockeye spans many cultures and languages, which is reflected in both the common and Latin names for the species. Sockeye is derived from the Halkomelem word suk-kegh, which means “red fish.” Halkomelem is spoken by the indigenous peoples along the lower reaches of the Fraser River of British Columbia and is one of many Coast Salish languages. The Latin species name, nerka, is from the Russian word for the anadromous form of salmon. Many people think that the name red salmon refers to the colors of the spawning-phase males, but it actually describes the deep red flesh of the meat. Finally, sockeyes are known as blueback salmon because of the silvery blue coloration of oceangoing fish.

Pebble Mine
As most fly fishers are aware, the world’s largest remaining population of wild Pacific salmon is threatened by the proposed Pebble Project, a monstrous open-pit copper-gold-and-molybdenum mine, which would sit at the headwaters of Alaska’s Bristol Bay. Since the project first came to light a decade ago, the fly-fishing community—led by Trout Unlimited and industry partners such as Orvis, Patagonia, and Simms—has been vocal in its opposition.

At issue is the possibility that dangerous chemicals and heavy metals could be released into the streams and rivers that serve as the nursery for sockeye salmon. Recent developments, including a three-year assessment by the Environmental Protection Agency and possible protection for the Bristol Bay watershed under the Clean Water Act, suggest that the vocal opposition is having an effect, but the battle is not yet won. For more information, visit Save Bristol Bay and the Orvis Stop Pebble Mine page.

Flies and tactics
Sockeye salmon have a reputation for not taking flies readily, which makes sense, when you consider that, because they feed on zooplankton and small prey, they have no natural impulse to pursue baitfish. However, a well presented fly at the correct depth will often elicit a visible strike, and once the fish is on, the fight is impressive. Fish fresh from the sea will make multiple leaps and test even stout tackle. The world-record sockeye was caught from Alaska’s Kenai River in 1987 and weighed in at 15 pounds, 3 ounces.

Most sockeyes weigh 4-12 pounds, so a 7- or 8-weight rig is a good choice, but make sure you have a reel with a good drag and plenty of backing. Popular sockeye patterns range from flashy attractor streamers, such as the Karluk Flash Fly, to more imitative weighted nymphs and shrimp patterns.