When people talk about salmon, it's usually about the dramatic runs Pacific salmon make into the rivers of the Northwest or how good fresh or smoked salmon taste. Rarely do they talk about Utah's kokanee salmon runs. In fact, many people are surprised when they find out salmon live and breed in Utah.
This is changing as one of Utah's secrets gets out. Salmon run watching has become a tourist attraction along the shores of Utah's salmon rivers including Sheep Creek, a tributary to Flaming Gorge; the Strawberry river and other tributaries to Strawberry Reservoir; and the upper Little Bear River, the tributary to Porcupine Reservoir.Utah's salmon populations are a completely freshwater species known as kokanee salmon. It is a land-locked subspecies of the sockeye salmon and follows a similar life cycle but, instead of migrating downstream to the Pacific Ocean, it migrates to a freshwater lake.
A kokanee salmon lives most of its life in a lake or reservoir; it is only found in a tributary twice in its lifetime, just after birth and just before it dies. Life starts as an egg which its parents deposited in a nest scraped out of the creek gravel in September or October.
The egg hatches in December or January and a young fish called an alevin emerges. The alevin still has part of its yolk sac attached which it slowly absorbs while it hides in the gravel for its first few months of life.
When the yolk sack is absorbed, the young fish are known as fry. At this stage they begin to emerge from the gravel to feed on microscopic plants and animals.
When danger threatens they return to the gravel and vegetation for cover. The fry gain size and weight over winter, by March and April they are about an inch to an inch-and-a-half long. Spring runoff triggers the next stage. As the creek begins to swell with melted snow, the young fish (sometimes called parr or small fingerlings) begin to migrate, or maybe more accurately, are swept downstream to the reservoir.
Once in the reservoir the parr begin a more pelagic (open water) life, forming schools and feeding on zooplankton (floating, often microscopic aquatic animals).
The schools of kokanee will follow the thermoclines of the water, clustering in the deeper 50-55 degree waters in the summer and winter months and dispersing when the surface waters are the preferred temperature in the fall and spring.
The kokanee will spend about four years as a pelagic fish, foraging on zooplankton and gaining size until their biological clock tells them it's time to spawn.
Those fish that survive the fishermen and natural hazards such as trout, osprey, grebes or sudden water quality changes will be between 12 and 22 inches and weigh 1 to 3 pounds when it's time to spawn.
Strawberry and Flaming Gorge reservoir fish are usually larger than the kokanee found in most other western state waters.
There are several spawning periods for kokanee in Utah. The best runs for viewing are the September runs in Sheep Creek, Little Bear River and the Strawberry Reservoir tributaries. These spawning runs begin in late August and reach their peaks in mid-to-late September.
In August, the spawning kokanee begin to change. The males develop a humped back and a hooked jaw and both the male and the female begin to turn red from the head down. As these changes first occur, they begin to stage in the reservoir where a stream enters. As the changes become more advanced, the fish begin their spawning runs.
As the fish change and begin their run, the kokanee usually quit eating. They utilize their fat reserves and then begin to burn up the oils in the muscle. The muscle eventually becomes mushy and develops a poor flavor.
The kokanee swim up the creek to get to the gravel bars. Some swim much farther than others in search of the right combination of water and gravel. It is believed the kokanee, like the sockeye, also return to or close to the gravel bar it hatched from.
The female picks the locations to build her nests. She will usually build several nests and lay eggs in each one until she deposits all of her eggs. Female kokanee from Flaming Gorge lay an average of 1,000 eggs. The males fight for the right to fertilize a female's eggs. A male can fertilize eggs from more than one female so the bigger, stronger males have the potential to be the more effective spawners.
Soon after spawning the adults die, completing the cycle. Their bodies decompose and fertilize the waters, increasing plankton growth for the young fry when they are ready to begin foraging for themselves. In four years, their young will return to the creek to spawn.