14 Ways To Prevent Fish Mortality

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I'll Be Back to Catch You Again Photo by Louis Cahill

I’ll Be Back to Catch You Again Photo by Louis Cahill

The years we spend learning to cast and drift a fly or the thousands of dollars we spend on gear and travel are all wasted if we don’t have fish.

With more anglers entering the sport every day, sport fish are heavily pressured and in grave danger. There are a lot of common mistakes that anglers make which contribute to fish mortality. Most are innocent and many don’t show an immediate risk. With that in mind here are fourteen tips to help keep our little friends happy and healthy.

The 10 second rule

A fish’s gills are remarkably efficient at collecting oxygen but the delicate membranes that extract the oxygen molecules rely on their buoyancy to keep the collecting surfaces exposed. Out of the water they collapse and are useless. This is to say the obvious, fish can’t breathe out of water. It’s easy to over estimate how long a fish can hold its breath. The fact is, a fish can’t hold its breath at all because it doesn’t have lungs. He is out of air as soon as you lift him from the water. Add to this that his metabolism is raging because he’s been fighting for his life and you have a pretty desperate situation. While you are trying to get that hero shot, he’s dying. Use the 10 second rule and never keep his head out of the water for more than 10 seconds and give him a good 30 seconds before you lift him again.

Hold on loosely

I can’t tell you how many times I’ve seen guys squeeze a fish until its eyes pop out. Some guys just get so rattled holding a fish you’d think they never saw one. This death grip can cause serious internal injury especially to the heart. The trick is a nice loose grip. The tighter you hold a fish the more he will struggle. To control one, properly grip him just in front of his tail where there’s nothing but muscle and let him just rest on a loose hand under the boney part of his pec fins and gill plates. He will relax and the whole vibe will be nicer.

Barbless hooks

Once in a while a fish will unbutton due to a barbless hook. That’s just a fact of life but most anglers understand that they will hold hundreds, if not thousands, of fish in their life. Decreasing that number by a few is not a crisis. The fact is that barbless hooks go a long way to reducing fish mortality from hook injuries. If you are fighting fish properly you will not lose many and if you aren’t, fishing barbless hooks will teach you to fight fish smarter and you’ll be a better angler for it.

Fight with authority

The biggest mistake I see anglers make is not fighting fish with authority. Most of us are taught to play fish too long, exhausting them before they are landed. A fish that is fought with authority is landed fresher and released fresher. Keep a good angle on the fish and use good side pressure and you can put a lot more pressure on that fish than you think and you will reduce the chances of an LDR.

Use a net

I should say that the most fish friendly landing method is to not touch the fish at all. When possible instead of landing the fish I will bring him in and grab the fly rather than the fish, easing it out of his mouth and sending him on his way immediately. That’s a great method but it doesn’t always work. Sometimes the fly isn’t where you can get at it, or the fish is too green, or too big, or you just want a photo. The next best thing is a net. A good quality catch and release net, (I like the rubber ones) is very friendly to the fish and a good long handle lets you seal the deal quicker. A healthy basket is nice too. No need to fold him double.

Protect their heads

Believe it or not, head injuries are the leading cause of fish mortality, even if you don’t count the ones that bet bonked. Fish’s heads are not designed for hard surfaces. A seemingly benign blow to the head can end in a fish going belly up after 20 minutes or so. There is hard data on this. That’s why it’s a bad idea to beach a fish when landing it. If the bank is rocky a flopping fish is in mortal danger.

Never beach fish

Dry land is no place for a fish and they face several dangers. It is impossible to beach a fish without disturbing his protective slime. That slime keeps out a host of dangerous bacteria and parasites. The slime will regenerate but in the meantime the fish is vulnerable. Being on the bank also dramatically increases the risk of head injury, eye injury and oxygen deprivation. If you are by yourself and want to get a photo, find a sandy spot in the margin of the water where to fish can lie with one side submerged. Cover his face with a wet hand to settle him down. Lift your hand and shoot quick.

Wet your hands

Dry hands remove slime too. Many times I’ve caught fish with fungus in the shape of a careless anglers hand. It’s a simple thing to do. I dip my hands as a reflex action, almost as soon as I hook up.

Don’t dig around in there

Once in a while a fish takes a fly deep. The best way to avoid this is not to dally on your hook-set. Still, it’s unavoidable and when it happens don’t try to be Dr. McCoy. Start digging around in there and you’ll end up saying, “he’s dead Jim.” cut the line and turn him loose, he’ll spit it out. Flies are cheap.

Have a Coke on hand

There’s nothing like it! If a fish is bleeding pour a Coke down his throat and the bleeding stops instantly. If you missed my post on this you can read it (here).

Revive before release

You should always revive a fish before releasing it, especially after a long fight. Hold him in medium fast current where there is plenty of oxygen. Most fish are able to pump water across their gills without the aid of current but slack water has less oxygen than current. Just hold him gently under the pec fins and he’ll go when he’s ready. If he swims a few yards rolls on his side, go get him. He needs more time.

Look for predators

An exhausted fish is easy prey. Before you turn the little guy loose have a quick look around. No need in feeding the otters, herons or sharks, they do fine on their own. Chase those munchers off. That’s a little tougher with the sharks but you can tow a fish to safer water, just watch your hands.

Don’t freeze ’em

I love winter fishing and in general it’s better on the fish since the water holds more oxygen when it’s cold but there is an added danger. Fish have no body heat and when it’s below freezing the delicate membranes in their gills can freeze surprisingly quick. The colder it is the shorter the time you can safely keep them out of the water. Once it’s below zero don’t lift them at all and never, ever, put them on the snow.

Don’t beat ‘um up in the heat

As water warms up it holds less oxygen. Trout can get highly stressed as water temperatures approach seventy degrees. The stress of a fight can raise their metabolism to the point that they just can’t get enough oxygen. The effects can be lethal. When water temps are high head for high elevation streams or tailwaters. You’ll be cooler and the fish will stay healthy.

Keep these tips in mind and your catch and release technique will be golden. Teach your friends and your kids these valuable practices and we will all reap the reward of a healthy and prolific fishery.

Come fish with us in the Bahamas!

Louis Cahill
Gink & Gasoline
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36 thoughts on “14 Ways To Prevent Fish Mortality

  1. Great advice that I wish more people paid attention to. Saw someone “fight” a 12″ trout on the Caney Fork one time for 5+ minutes. Have also seen big spawners body-slammed on the South Holston and then the fisherman wondered why the fish didn’t swim off for the next hour. Some people are clueless which is why education like this is so valuable. Keep spreading the word and thanks!

  2. This post is fantastic. In fact you should repost it every few months. We could all use these tips as reminders. Our beloved resource deserves it.

    • Thanks Brian. Kent and I believe very strongly that if we are going to teach folks to be more effective fishermen we are morally obligated to teach them to respect and preserve the resource. What god has made, let no man tear asunder.

  3. I can attest to the coke idea. We had a 20″ doe on the Monday last year who was bleeding badly. After two drinks of coke no more blood! Took about 5 more minutes until she swam away. It was awesome!

  4. One thing that I don’t get is when people take a pic with them holding a trout (of any size) while holding it up just by its lip as if it were a largemouth bass. Or worse, with their hands and fingers all in the gills. This can’t be good for a trout. It just looks horrible, and seems like a lot of stress on the head and jaw of a trout. When it all boils down to it, all lot of people need more education, like this, when it comes to handling our beloved trout species.

  5. Great article! Ive been guilty and have never heard the “Coke method” As a bass fisherman i think it needs to be said that holding a Bass horizontal with his lower jaw aka “the bass master” is a good way to put that fish on a terminal diet (off my soap box now)

    Great article.

  6. Pingback: Tippets: Worth Reading Twice, Bluefin Tuna Decline, Tips for Safe Handling | MidCurrent

  7. This was a WONDERFUL post. My husband and best friend fish, and I’ve started to follow in their footsteps. I’ve come to truly enjoy the experience and relationship you form with the fish and nature around you. I’ve always been uneasy with taking fish out of the water but keeping these things in mind will definitely help. Thank you!

  8. Great post. Our local TU chapter educates our members and also the kids and vets we teach to fish. Making sure the “teachers” know how to safely play and release fish is a priority. We will use your list to help spread the word.

  9. Some good tips. I’d add a couple things. 1-Voluntarily reduce your hook size when possible because large hooks do more damage than small hooks. 2-If you do use larger hooks, you might consider not going barbless. Large barbless hooks penetrate deeper and multiple times during the fight, which is known as the “stilletto effect”, as reported in one university study. A same sized barbed hook held the hook in place better, generally only doing superficial damage. In fact, studies show that going barbless doesn’t really help the fish except when considering the handling it takes to release the fish. Meaning: beginners can get barbless hooks out of fish (and themselves) easier, while an expert can generally release a barbed hook from a fish without touching the fish or bringing it out of the water. So my conclusion is that how one handles (or doesn’t handle) a fish is much more important than if the hook is barbless or not. The barbed vs barbless debate is more of a social distinction than one of sound biological data.

    • Thanks Larry. That’s an interesting idea. I agree that the biggest problem is over-handling. Sometimes it’s just dumb bad luck. No matter how you slice it losing the occasional fish is bound to happen. Hopefully this will put folks on the right track.

  10. Great article and great tips. I know you’re an outstanding, professional photographer and know how to handle fish properly for a picture, but I think the worst offenders are folks holding fish out of the water for those hero shots. I simply don’t get it. The worst offenders are the folks on fishing shows on TV and in videos. On the rare occasion that I snap a picture of a fish, its done in 5 seconds or less.

    • You’re dead on Steve. I wrote a post about this a while back but didn’t publish it because it was so inflammatory. There are some very unethical people in the fly fishing media and it makes me crazy. Maybe they should take away my assault riffle.

      • The shame of this is this compounds the problem as an extremely bad example for viewers and the so-called experts on fishing shows should know better. Maybe it’s time for an inflammatory piece calling them out.

          • Ah, yes, food on the table is important. We will take what we can get. As our education chair, I tell our TUers that guides are the most important educators and conservationists we have. Just keep leading by example and teaching folks the right way one at a time. No need for self-immolation by flaming your clients on the internet.

  11. Pingback: 14 Ways to Prevent Fish Mortality from Gink and Gasoline « Big Hole Lodge

  12. Pingback: 14 Ways to Prevent Fish Mortality from Gink and Gasoline « Big Hole Lodge

  13. Thanks for a great post. The warm water factor is so pertinent for our fishermen here in sunny South Africa, and I reckon coupled with playing the fish too long is our single biggest problem.

    • Water temperatures are a bigger and bigger problem everywhere I go these days. Unfortunately I think we will all see a lot of that in the future. At least we don’t have fucking baboons here! I hate those guys.

  14. Pingback: 14 Ways To Prevent Fish Mortality | Fly Fishing | Gink And Gasoline | Fly Fishing Tips, Techniques & News: What Is Fly Fishing? We Fly Fish.com

  15. This is a great timely piece!! One thing I would add, is that we land and release fish in at least a foot of water. Too often you see a fish, especially larger steelhead, released in water so shallow it doesn’t even cover their backs and they bash and crash their way back to deeper water. I think it was Lani Waller who advocated for this. I agree whole heartedly that this column should be repeated more often.

  16. Pingback: Helping your fish to survive | Canberra Anglers Blog

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