Little Larry Swims: Some Like it Hot! Salmon Like it Cold.

Few people like the idea of a cold shower. Not me.  Cold water is the best!!

Why? Because I’m a coldwater fish. In the spring, I’m swimming through snowmelt, and that icy, crisp water flowing out of the mountains toward the Pacific is my idea of heaven. 

Cool water from snowmelt flows down a mountain stream.
Cool water from snowmelt flows down mountain creeks, streams, and rivers, in the spring. 
Credit: U.S. Forest Service

It’s not all smooth sailing, though! Did you know that several dams along the way turn the river into a big hot tub? They slow the flow of the river and turn cold streams into a series of hot water reservoirs. Yikes! Let’s cool it down, people! I’m a cold-water fish and I’m sweating it down here… 

The trouble with dams

Just like the air temperature rises, so does water temperature. Water stores heat, especially if it’s still or shallow. If you’ve ever been swimming in a little pond in August, you know what I’m talking about. 

And that’s what the reservoirs behind the dams are like, turning my little slice of heavenly habitat into something dangerously different. It’s not a fun swim anymore when I’m soaking in a hot tub and the temperature is going up, up, up. 

Salmon have superpowers, but they don’t do well when water gets hotter than about 68 degrees—it’s our kryptonite. Imagine running a marathon. Now imagine running that same marathon in the desert. No fun, right? Right! It’s a killer. 

The same goes for salmon on their return journey, migrating up to 900 miles back to their spawning grounds. Salmon are weaker in hot water, it takes more energy for us to swim. And heading back to our natal streams, we’re also swimming on an empty stomach. Hotter water short-wires our system in so many ways. It scrambles our ability as anadromous fish, to transition from fresh to saltwater and back. 

We need to keep it cool

The last few summers have been scorchers! In 2020, water behind three of the four lower Snake River dams got up to 71-73 degrees for at least two weeks. Then that hot water started moving through the whole river system, heating it to a temperature way too hot for salmon. We start seeking cold water so desperately, we may even swim in the wrong direction during migration time just to cool down. 

Another big problem for salmon are the diseases and parasites that thrive in hot water. That makes beating the odds to get home to Redfish Lake even harder.

Climate change is making it worse. The warming summer temperatures are getting hotter than they’ve ever been. In 2021, we had a “heat dome” which pushed the temperatures higher than ever recorded in the Northwest. 

People often say: “Fish need a river.” True that! But, we not only need a river, we need a cool, free flowing river. And so do many other wildlife and plant species. 

Scientists agree. They say that taking down the dams and restoring the lower Snake River is essential for salmon like me to survive. It’s our best chance—and it’s the best chance for people and the 130 different wildlife species  that depend on me.

Will you help restore my river, and help me make it home to Redfish Lake? Take the pledge

More about this series

Little Larry is a tiny fish on a big journey—swimming 900-miles from Idaho to the Pacific—tail first! His journey is a reminder that salmon could become extinct.

Follow his story and cheer him on as he swims to beat the odds!

Little Larry Swims: A Small Salmon on a Big Journey

Little Larry Swims: Every Salmon Has Superpowers

Little Larry Swims: High Tailin’ Salmon

Little Larry Swims: Salmon in the Trees?

Little Larry Swims: Some Like it Hot! Salmon Like it Cold.

Little Larry Swims: Whoop Whoop! Living the Anadromous Life

Who Was Lonesome Larry

Watch the video

Meet some kids who are speaking up for salmon.