After passing eight dams, 175 coho salmon climbed Wells Dam’s fish ladders on the Columbia River in seven October days
Salmon are magnificent creatures, built to endure their environment, but getting to their spawning grounds is rarely straightforward.
Each year, coho salmon leave the Pacific and begin their upstream migration through the Columbia River system.
By the time they reach Wells Dam, they have already travelled hundreds of miles and crossed a series of obstacles along the river.
The Douglas County Public Utility District says the fish have already travelled about 515 miles from the mouth of the Columbia River, passing eight other dams.
But they keep on climbing. So what’s special about the journey to Wells Dam?
The journey to Wells Dam is long
Wells Dam is on the Columbia River in Washington State and is one of the last major barriers salmon face as they migrate upstream to their spawning grounds.
The fish don’t come to Wells Dam straight out of the ocean.
The Douglas County Public Utility District says the fish have already travelled about 515 miles from the mouth of the Columbia River, passing eight other dams.
Wells Dam has fish ladders at either end of the project to provide a way around the structure for returning fish.
During migration season, cameras record fish as they move through the ladders. This means that, for the salmon, they have already completed a large part of their journey.
But the river has more challenges ahead.
Why the October count matters
The number of fish that reach Wells Dam shows how many salmon successfully migrate through the Columbia River system.
Cameras are placed to record fish passage, and fish counts are taken at Wells. They are then examined by the Douglas County Public Utility District to find out which species are moving upstream.
The October count is particularly interesting because these fish are returning to freshwater after spending some of their lives in the Pacific Ocean.
They’re not just going to the next stretch of river.
Some adult salmon travel 200 more miles beyond Wells Dam, on their way to the rivers where they were born.
Unlike their ocean phase, this part of their journey depends on suitable freshwater habitat. Reaching these rivers is essential for them to complete their life cycles.
It’s that extraordinary homing instinct that draws them upstream.
The hidden challenges for the salmon
This number of salmon counted over the seven days represents one part of the migration.
By the time they got to Wells Dam, each fish had already migrated a long way past eight other dams on the Columbia River.
Their journey requires them to travel between two very different environments. The Coho salmon spend time in the ocean but return to freshwater streams to spawn.
River systems are of particular importance due to their lifecycle in terms of successful passage.
Wells Dam is also significant as the furthest upstream dam on the Columbia River with fish passage.
Currently, there is no adult or juvenile fish passage at Chief Joseph Dam upstream. That’s why Wells Dam is a key stop on the way.
Those fish that go through the ladders can continue to their spawning destinations.
A journey measured one fish at a time.
175 coho salmon may seem like a simple statistic, but each fish represents a single journey through one of North America’s largest river systems.
Salmon from the Pacific Ocean to the Columbia River and beyond Wells Dam are a good example of how strongly wildlife can be connected to the places they travel through.
Their journey also reveals the complex relationship of rivers, infrastructure and wildlife. Fish ladders can provide an essential route around obstacles otherwise blocking migration.
Many stories lie beneath the Columbia River.
From migrating salmon to ecosystems that depend on its flow, the most remarkable discoveries start by just watching what is moving through the water.
