Sunday Classic / 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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8 thoughts on “Sunday Classic / 14 Ways To Prevent Fish Mortality

  1. One omitted which really goes along with hold them loosely, don’t lift up a large fish with your hand under the soft belly. A fish has pretty much zero buoyancy in the water because of his swim bladder. So there is no weight except for equal water pressure all around him. However, pick up a big fish with the hand under the belly, and all of that weight is on the internal organs, That’s like setting a man on a fence post and jiggling him up and down. ——Isn’t it amazing how many people get so bent out of shape when someone mentions that they may be doing something wrong that can injure the fish, whether it’s beaching the fish, fingers in the gills, death grip or such instead of taking some constructive criticism. I’ve worked with people like that before ! LOL!

  2. Never lift a fish – ANY fish – by the lower jaw (I wish all fish had teeth like a piranha). And keep your fingers out of the gills. People are being foolishly irrational when they say “oh, I don’t touch the gills, just the inside of the gill cover”.

  3. Where is the data on cutting the line if the hook up is deep? Do you have a reference? When I was a kid I did a science fair project on cutting the line on bluegills, i cut the line if the hook was too deep and took the hook out if it wasn’t then brought fish home to live in a tank, any bluegill I left a hook in died, it took a while but it seems like a hook in the digestive system killed them, so I always had the impression that leaving a hook in a fish would kill them, but it was a fifth grade science project so not full of scientific rigor, would be interested to see a professional study on the subject.

  4. I wish every guide and or fly shop required their new or “experienced” customers to read this before they get on a stream

  5. This is a much needed article. I am guilty of mis-handling these beautiful fish. We all need to be more conservation minded and do all we can to preserve this precious resource.

  6. Pingback: First Casts 10.26.16 - Orvis News

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