Phenology Files: May 2022

phenology fi-ˈnä-lə-jē 1 : a branch of science dealing with the relations between climate and periodic biological phenomena (such as bird migration or plant flowering) 2: periodic biological phenomena that are correlated with climatic conditions.

Steelhead Trout jumping at Salmon Cascades along the Sol Duc River, photo by John Gussman.

These Steelhead trout are rounding out their spring migration during this time of the year. If you plan to see some fish jump – you better jump on it, as their spring migration runs from late March through May! If you miss it this month, you might look again this winter.

There are typically two Steelhead runs per year. Adult fish will run in the winter, December through March, whereas Juveniles will run in the spring, late March through May.

What are these “runs” all about?

Steelhead trout live the majority of their lives in the salty ocean, but return to fresh water rivers to spawn. Their migration home to rivers is called a run! The fish are known as anadromous, which is the amazing phenomena of being able to survive and adapt to life in both fresh water and salt water.

When making their runs, these fish return to the same river or stream that they were born in to spawn. Most species of salmon will die after spawning – they only make one run in their lifetime. However, Steelhead are unique in that they can make multiple runs in their lifetimes.

Steelhead have a lifespan of up to 11 years, traveling from rivers to the ocean and back. Though our human lifetimes are much longer than that – we can help protect fish during their lifespan by keeping our rivers, streams, and creeks clean.