Why Do Trout Die So Easily? Here’s How to Release Them Alive

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Man standing on his boat catching fish with his rod in the river.

Trout are resilient creatures, but they’re fragile. They are susceptible to improper handling, temperature fluctuations and injuries sustained when they’re caught.

Trout fishing can be a lot of fun. But if you plan to release your catch, you should follow a few simple pointers. 

It’s one of the more painful moments for dedicated catch-and-release trout anglers. When a fish we intend to return to the water shows signs of injury and potential death, we have to make a tough call. 

Often, it’s better to simply end it quickly and harvest the fish. Trout are fragile. They use lots of energy during extended fights. 

Trout are susceptible to injury suffered during fights. Harvesting injured fish is usually the best option.

Hatchery trout, in particular, don’t handle injury well — their blood doesn’t clot as well as it does in wild fish. Their internal organs can be easily damaged. Their gills are easy to damage, too, and that’s usually fatal to trout. 

Here are some methods you can use when handling trout to ensure they survive their encounter with you. 

Reduce the Fight Time

I used to really enjoy fishing for trout with light fly tackle and light tippet. I considered it a challenge to catch big trout on light tackle because it required skill to bring fish to hand. 

But I’ve come to realize that using light tippet (like 6x or 7x), or even light mono on an ultralight spinning rod, often stresses trout to the point that they’re near death. A quick fight is better for trout that you intend to release.

It’s simple. If you reduce the time it takes to land a trout, you’ll reduce the possibility of the fish injuring itself in the process. 

Handle Trout Properly

Man's hand holding a big trout above the clear water.
Keep trout in the water as much as possible.

Years ago, I went fishing with a work colleague in northern Utah, in the United States. Every fish he caught, he handled by putting his fingers in the fish’s gills. I repeatedly explained that a trout’s gills are fragile and that he could be damaging them. He ignored my warnings.

Later that day, as we walked back to the truck, we noticed several trout that were either dead or dying. We recognized one larger cutthroat trout that lay dead on the streamside gravel. At some point in its life, it endured an encounter with an osprey or an eagle. It had a healed scar below its dorsal fin. 

“You caught that fish earlier today,” I said to my friend. He looked at it, and then looked at me. 

“Do you think it’s dead because of the way I handled it?

“I do,” I said, trying not to be accusatory. “I never touch the gills. It’s a lesson I learned years ago. And it’s a tough lesson.” 

To this day, my friend never handles a trout by putting his fingers in the fish’s gills. 

Man holdign a big trout with his both hands in the river.
Cradle trout under the belly and never put your fingers in its gills. This will ensure that the trout will survive its encounter with you.

Here are some general guidelines for handling trout:

  • Never touch the gills. Ever. They’re extremely susceptible to injury.
  • Keep the fish in the water as much as possible. Only lift the fish out of the water for photos once or twice, and then only for a few seconds each time.
  • Cradle the fish below the belly. If it’s a big trout, use two hands. 
  • Avoid using nets if possible — they cause damage to the skin and the trout’s slime layer. If you must use a net, use a net with a soft, rubber mesh.
  • Use barbless hooks. It makes removing hooks easier, and reduces potential bleeding. 
  • If a fish takes a hook or a fly deep in its throat, it’s best to cut the line off as close to the hook as possible. In a constantly wet environment, the hook will rust and fall out on its own quickly.  
  • Don’t squeeze trout when you handle them. Their internal organs are susceptible to damage.
  • When releasing trout, point their noses into the current to allow water can move through their mouth and gills. 

Monitor the Water Temperature

All trout are susceptible to warmer water temperatures. While some trout can handle water that’s warmer than 21 degrees celsius (70 degrees Fahrenheit), most can’t. 

Generally speaking, trout become sluggish when water reaches about 18 or 19 degrees celsius (about 65 degrees Fahrenheit). When water gets even warmer, around 21 degrees (70 Fahrenheit), trout can begin to die. 

Knowing this, you can protect fragile trout by simply choosing not to fish when water temperatures get too warm. Yes, it can be a tough decision. 

But it’s the best decision for the fish. If you catch a fish in warmer water, its chances for survival diminish greatly.

I almost always fish with a water temperature thermometer. When the water gets too warm (about 18 degrees), I simply stop fishing and do something else,

Final Thoughts

Man facing the river catching fish with his rod.
Trout fishing is fun. Keep it fun by following some simple guidelines.

Like a lot of anglers, I love to fish for trout. I’m also primarily a catch-and-release angler. 

In order to make sure the fish I catch are released unharmed, I try to reduce the time I spend fighting the trout. I handle the fish carefully when I bring it in. I spend time with the fish when I release it to make sure it’s healthy. 

And, when water temperatures get too warm, I stop fishing. 

By following some simple guidelines, you can make sure the trout you catch and release back into the water will be there for the next angler to enjoy, too. 


Why Are Trout Susceptible to Warm Water?

Trout are part of the salmonid genus, just like salmon and char. All salmonids require cold, clean water to survive. Warmer water temperatures are fatal to all salmonids, including salmon and char, like lake trout, brook trout, Dolly Varden and Arctic char. 

Why Are Trout Fragile?

Trout are among the most fragile game fish, largely because they require very specific environmental conditions to survive. Their home waters must be cold all year long, and the water quality must be very good. Any stress put upon trout decreases their chances of survival.

Is Trout Water Getting Warmer?

Yes, a warming global climate is impacting wild trout populations. Scientists believe that we could see the loss of 50 percent of all wild trout habitat within the next half-century. 

Is It Better to Harvest Trout if They Appear Injured?

Yes. When trout are injured, they rarely recover. It’s best to harvest injured trout and enjoy them for a meal. 

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