The official start of spring is just around the corner. You can already see signs of it throughout the city and along the rivers. Trees are budding and the water level in the river is high from weeks and weeks of rain. Under the water there are signs of spring that are not as easily noticed as the changes we observe above ground.

The next time you cross the St. Johns, Morrison, Ross Island, or any other bridge that spans the Willamette River, consider this: anadromous fish swim through Portland Harbor every spring as part of their far-reaching journey to and from the Pacific Ocean.

From January to April each year adult spring Chinook salmon return to the Willamette River from the Pacific Ocean. The majority of them ascend Willamette Falls (near Oregon City) between late April and early May. They spawn in the fall and their offspring begin emerging from the gravel right about now. While some juvenile salmon begin the migration out to the ocean soon after emerging, others spend up to a year in their natal streams. Either way, they pass through Portland Harbor on their way out to the ocean, where they spend 3 to 6 years before returning as adults and beginning the cycle anew.

Between February and June each year Pacific lamprey migrate back into freshwater rivers, including the Willamette, after spending 1 to 3 years in the ocean. They'll spend up to a year in rivers and streams, then spawn. Their offspring, called ammocoetes, then spend 3 to 7 years slowly migrating back downstream. Their final move towards the ocean happens between late fall and early spring as they morph into adults.

Next time you catch a whiff of the cherry blossoms blooming or notice new life sprouting from the ground, give some thought to the rites of spring occurring beneath our bridges.