Every fall adult salmon and steelhead trout return to the river. Salmon and steelhead are anadromous meaning they are born in the river, migrate to the ocean and then return back to their home stream as adults. In the Rogue River Watershed we have Chinook salmon, coho salmon and steelhead trout.
Chinook salmon are usually the first species to return as adults in the early fall. Juvenile Chinook hatch from their eggs in the winter and swim to the ocean that same spring.
Coho salmon have a different lifestyle. Juvenile coho stay in the river for an entire year before migrating to the ocean. This means coho are especially sensitive to changes in the river such as loss of habitat and high summer temperatures.
Steelhead trout are the most flexible of our Rogue River salmonid species. They can outmigrate their first spring, or the next, and return to the river at various ages. Unlike Chinook and coho that die after they spawn, steelhead can sometimes migrate back to the ocean and live to spawn again. Steelhead trout are genetically identical to rainbow trout, except that rainbow trout are not anadromous and spend their entire lives in the river.
While it might seem a little sad that salmon die after laying their eggs, their death is extremely important to the health of the river ecosystem. When the salmon die many other organisms use their carcasses. Aquatic macroinvertebrates (the larval stages of many of our common insects like dragonflies and mayflies) eat the carcasses in the water, while bears, birds and other scavengers deliver carcasses to the land. (Still not quite sure what a macroinvertebrate is? Click here to read about macroinvertebrates.)
Did you know that salmon can even help trees grow? Scientists have found marine nitrogen, nitrogen from the ocean, in trees which was brought back in the form of protein in salmon flesh. As the salmon carcasses are eaten and decompose they release important ocean nutrients back into the ecosystem making the nutrients available for the trees and other organisms. The salmon carcasses even act to feed their babies. Macroinvertebrates eat the carcasses and then juvenile salmon eat the macroinvertebrates, in a way eating their parents!
To learn more about salmon in our watershed please join the City of Ashland in celebrating Bear Creek Watershed Exploration Month. Events include salmon viewing, watershed restoration and the Bear Creek Salmon Festival. Please see their website http://www.bearcreeksalmonfestival.net/watershedMonth.html for more details and be on the lookout for salmon and steelhead in your home stream!