Spawning Rainbow Trout: A Sacred Event’s Controversy

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Sign warns 'Salmon at Work' at Piercy Creek. Salmon & trout grow here.

“Spawn.” It’s a word that will perk the ears of any fisherman and begin a debate for many. For some, the rainbow trout spawn is an anticipated event for easy harvest. For others, it’s a sacred time to avoid the water. 

A rainbow trout’s spawning season is the time of year they run upriver to lay and fertilize eggs. But why the controversy?

Traditionally, this is an optimal time to harvest big, hungry, aggressive fish. After years of studies and conservation efforts, modern fishermen want to advocate for bypassing the sacred spawn. 

Knowing the specifics of a rainbow trout’s spawn allows for ethical fishing during a controversial time. 

When Do Rainbow Trout Spawn? 

Specific spawn dates vary by region, but rainbow trout spawn in the spring. February to May are typical, but some factors will affect spawning activity. Keep an eye out for the following conditions to pinpoint peak spawning times. 

Water Temperature

Water temperatures need to pass 41 degrees Fahrenheit to activate the spawn. Temperatures near 41 degrees provide enough warmth to activate the fish, tut the water is still cold enough to keep the stream and eggs healthy.

The perfect range for spawning rainbow trout is between 41 and 51 degrees. The northern hemisphere’s slow warming of spring provides months of spawning conditions.

Water Flow

Streamflow fluctuates from weather conditions, so only some springs provide optimal fishing opportunities. Spawning rainbow trout need a constant flow that is clean and pure. More sterile water will carry more oxygen, which helps fertilize the eggs.

So, if there is high run-off from a spring melt or a river resembles chocolate milk from torrential rain, finding spawning grounds will be almost impossible. More so, it may be irresponsible even to try (more on this later). 

Where Do Rainbow Trout Spawn?

You can find spawning rainbows in riffles, runs, and pools, as long as there is enough flow and oxygen. Look for a river bottom filled with gravel and pea-sized rocks. These areas are famous for spawning rainbows since they are oxygen-rich. 

Man fishes in clear Rockies stream by Telluride.

How Do You Know Rainbows Are Spawning?

So, you know the best time of year, the optimal conditions, and all the seasonal symptoms that say, “The spawn has arrived!” But, you’re still not confident you know that rainbows are spawning. After all, it’s not easy to understand what’s happening beneath the surface. 

The quickest way to know rainbows are spawning is to look for redds. Redds are round gravel spots on the river bottom, usually lighter in color. Female rainbows, or hens, make their redd by clearing debris with their caudal fin. 

Think of these as beds for trout to lay their eggs. If trout are on a redd, they’re spawning. 

Spotting Redds

If you see a redd, avoid it and keep your distance. Their appearance should stand out, but it is easy to walk onto a redd if you’re not paying attention. 

In my home waters, trout season closes to protect these redds and their eggs. In my experience, spotting redds can be difficult where it’s legal to fish. So if you can, walk the bank as much as possible to avoid destroying any eggs.

Ethical Fishing During The Spawn

Higher aggression, increased feeding, and trout running upriver into confined quarters? What is not to like about the spawn!? But balancing sportsmanship with nature’s cycle is vital for generational trout populations. Ethical fishing requires giving fish a fair chance of survival and reproduction.

The spawning season is already taxing for these fish as they deplete precious resources and energy. Reproduction numbers diminish if you add inappropriate fishing pressure to the recipe. 

I don’t mean to be the hall monitor of fishing during the spawn. Believe me, I lick my chops if I see fish on a bed. It’s very tempting to cast a fly! But ethical fishing requires giving fish a fair chance of survival and reproduction. 

A simple rule of thumb for trout fishing is to move on if you see rainbows sitting on a redd. If you continue walking and see trout free of redds, consider them fair game

Related Questions 

Can Rainbow Trout Spawn In Lakes? 

Rainbow trout prefer coldwater streams and rivers, but they will attempt spawning in lakes if necessary. Lake-spawning has challenges since water is stagnant, murkier, and less oxygenated.

Despite trout’s fragility, they can show resilience in non-ideal habitats. In lakes, rainbow trout will spawn near inlet or outlet streams where some oxygen carries into the lake.

If there is no incoming or outgoing creek, trout will search the bottom for natural springs. These springs provide cold, clean water necessary for eggs.

Overall, the success rate of stillwater spawning is low. Wildlife management will stock “ready-to-keep” trout in lakes where reproduction is unlikely. If spawning was successful, game services may stock fingerlings intended for long-term reproduction. This is common in high-altitude lakes that are clean and cold. 

Fishing by mountains in Norway near Hemsedal.

What Color Are Spawning Rainbow Trout? 

A rainbow trout will change to a bright red color when they have reached their peak spawning period. This color change could be due to factors such as attracting a mate or a change in stream habitat.

But this isn’t the only change. Males will develop a “kype,” which looks like a hooked bottom jaw as they approach the spawn. 

Final Thoughts 

The rainbow trout spawn is a tempting event for every fisherman. Aggressive attitudes, increasing diet, and risk-taking behavior make the spawn your best chances of catching a lifetime fish. However, responsible fishing and ethical decisions during this time will sustain healthy populations for future seasons.

So, remember not to tread on redd and work around any suspected spawning activity. If you’re still uncertain about the spawning status of a stream, call a local shop or guide for answers.

David Linsmeyer Avatar


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