Autumn On The EB

Autumn On The EB

Thursday, December 1, 2016

More Conventional Wisdom Questioned - Trout Pumping

"There are some other ways to avoid catching fish. Looking good out there can definitely be a handicap. White hats and shirts, flashy rod finishes, gleaming rod jewelry, and bright metal fly reels are all big sellers among fashionable fly fishers, but they are reliable trout spookers. Combine such high visibility with any sudden movement, such as false casting and it's "Hasta la vista, Mister Trout." Bob Wyatt - What Trout Want -The Educated Trout And Other Myths

The practice of using a stomach pump seemed to rear it's head about 30 to 40 years ago, stuck around for a while, then sank without a trace. Now it seems to be re-emerging, a pseudo scientific exercise used to reinforce debunked theories and impress others. It's also harmful to trout.

We know the drill: "If done properly stomach pumping is safe and not harmful to the trout" the saying goes. The words If done properly are key here. Just because the trout is caught, admired, photographed, then pumped and released and swims away does not mean that harm has not been done. A safe release may be the case for trained fisheries personnel but not for your average untrained, ham handed Joe. (years ago, while working at a private trout hatchery, I assisted with egg stripping under the watchful eye of the hatchery manager. We were very careful and egg stripping is a lot less invasive than stomach pumping!!)

Injury to trout - Abrade the esophageal membrane of a trout and that trout isn't going to have a sore throat for a day. It's going to die and you will not even know it because it will swim away but will not be able to feed. "That doesn't happen to MY fish" the story goes but HOW DO YOU KNOW THAT? The answer is you don't! The answer may have been found on the bottom of the Tree Pool last Sunday (2 dead trout) and down through the top of Cady Lane (over a dozen since August). These fish were played out, photographed while lying on wet rocks and then lovingly released and then never recovered. Chances are they were not pumped but it is reasonable to assume that pumping may have happened and that would add to the mortality rate. Gastric Lavage (pumping) has been used by trained fisheries people and in one study done in British Columbia all fish were anaesthetized before getting pumped. Hmm....Why is that??

How Much Food - According to the late Robert Behnke, considered by most to be the world's best authority concerning trout and salmon, a one ounce trout (approximately 30 grams) would need 1 gram of food daily to not only maintain size but to also promote growth (approximately 3.3% of body weight consumed daily). A one pound trout (453 grams) would need to consume approximately 15 grams of food daily to survive. Now, this doesn't sound like a lot but when the available prey (aquatic insects) are weighted in milligrams (1000 milligrams in a gram) it comprises a vast number of insects especially in rivers like the Swift. What is pumped out could of taken hours to consume. We make the trout start all over again!!!

"I get to know what the trout are feeding on and can use the right fly" is the stale truism that props up this quackery. "Match the Hatch" followers and those who actually believe that trout are selective can be pom-pom wavers for stomach pumping. (Please read Wyatt's book quoted at the top before you contact me concerning selective trout).

Last June I did a video on the Swift. I caught a LOT of trout in that hour and almost all of them were packed to the gills with sulphur nymphs. All I had to do was look inside their mouths and see many nymphs that had not even been swallowed. Was I using a sulphur nymph as the hatch match folks preach? No. I used a size 14 partridge and olive which imitates the prey form seen in many aquatic insects. No need to take out the turkey baster!! You'll find plenty of size 28 stuff if you bother to look inside a trout's mouth too!

In short, if you care about releasing trout with the least amount of harm done then dump the plunger and become an observer. Look at what's in the air, on the water and on the shore.  Know your seasons and what each brings to us in the way of insects.  You will probably be able to predict what the trout has been eating without pumping. Start with the fly on your line if you want a clue!!



Anonymous said...


Glad to hear you're against stomach pumping. I've bumped into a few people this year that have been doing it. Definitely something I'm against.


Anonymous said...

I could not agree more. If I catch a trout I always presume it wanted to eat the fly I was using! There are some really strong opinions on this, same as barbless hooks. Take two hooks, one barbed and one barb less and stick them in your finger. You will survive both, but one causes much less damage.

Hibernation said...

Interesting to see your comments here Ken. As a teen, I remember getting a pump and I must have used it a handful of times. It always felt weird. I mean, I'm going through all this trouble to release this fish healthy, and then I'm going to empty it's stomach? Just felt weird and I have been going on solidly over 20years without a pump, and non the worse for wear.

That said, I think some of the fish you saw, were more likely the result of people believing you have to fish 12x tippet (ok, I know, not real... My point is just SUPER light) and fight fish for 10'. Maybe you need 7x to fish a #30... But I bet with a davey knot you could do it on 6 and maybe 5x flouro. If you can land a fish in a quarter of the time, it's less exhausted and has a better shot at long term survival - I suspect at least.

I have no issues with pictures. Lord knows I'm willing to take them... But minimizing play time and getting a pic then letting it go works a lot better...


Francesco Pellizzari said...

I am just happy to catch and release. The fact that I caught the fish on a fly is adequate validation that I have found something to elicit a strike without having to pump stomach contents. They work hard to survive.....and should get to keep their last meal before being caught.

Brendan Mackinson said...

Thanks for this post and for bringing up Wyatt again. I have never stomach pumped a trout, though many angling writers I've learned from and respect have advocated the practice (the great midge fishing pioneer Ed Koch and Datus Proper, who preferred to use a marrow scoop to sample only the most recent food, among others). I have benefited from the information shared by Dan Trela after he has pumped a stomach on a couple of occasions, changing to the right fly and quickly connecting with fish, but for the most part I am content to observe the bugs on the water and in the air. The occasional pumping probably does little harm, but if everyone on the Swift pumped a fish every day they fished, the additive effect could make a real difference.

I'm more interested in Bob Wyatt and the discussion of selectivity, though. On your advice, I read What Trout Want, found it quite interesting and thought provoking, and highly recommend it to others. I found his argument against "selectivity" a bit forced and overstated (he badly caricatured the thinking of Swisher and Richards, for example, to make his case for presentation over fly selection), but I think he helped clarify what we really mean (or should mean) when we use the word selectivity. Single-mindedness is probably a better term, since the trout are not "selecting" this as food and not that, but they are instead, in certain instances, developing a very narrow profile of what counts as food. This "single-mindedness" probably occurs only in situations where lots of food of a limited type is available to fish over an extended period of time, conditions that are found on fertile tailwaters (e.g. the Swift River) and spring creeks, but not on freestones and other more variable environments, so Wyatt is correct in emphasizing presentation (and stealth). Also, for someone who at some points scoffs at those who would try to find the "right fly", he offers up some nice fly designs and thoughts on design and behavior, though Datus Proper's What the Trout Said is the best book I've read on that subject. In the end, I think I keep one foot in the "selective" or "single-minded" box... a good presentation is always crucial, but, in certain instances, having the right fly makes a big difference, provided that it is presented in the right way, with the right behavior. Just my thoughts, and thanks again for the book recommendation, Ken!

Millers River Flyfisher said...


Thank you for the insightful comment. The book by Datus Proper is a classic and he left us too soon. A major concern with the Match the Hatch and Selectivity crowd is that they never can reconcile the hook dilemma. How does the most artfully constructed artificial fly, made to imitate a specific insect, deal with a curved and pointed piece of steel protruding from it's butt end when no insect on earth has that appendage? It appears that they conveniently forget about that.

Joe, Will, Chico and Anonymous - Thank You for your comments!

Parachute Adams said...

Props, Ken, for speaking out against the stomach pumping. Trout work hard to "make a living" and along with the injury prospects, let the trout keep in their belly what helps them survive.

Regards, Sam

Falsecast said...

Hello Ken -- Great post, as usual, and another thought provoking discussion.

Personally, I am against stomach pumping and have never done it, but as Brendan points out, it has been used very effectively by people. I fished for 2 days on the Missouri in Montana with a long time, sort of legendary guide and FF author (Neale Streaks) who pumped every couple of hours. It was amazing to see what came up and it was graduate level biology lesson. He was one of the most knowledgeable trout people I've ever been around. I say this, but also point out that I'd never been to the Missouri and fished it solo wading the 2 days before and caught 20+ per day. Just pointing out that it's all about the experience you are looking for. Personally, I prefer to fish alone and love to discover what's happening and "dial in" with trial and error. It's so satisfying when it all lines up, which, occasionally it does. :)

I would add that those that are philosophically against pumping should also feel the same way about elecroshocking, a common practice by biologists. It's like getting hit with a police taser for us.

Lastly, Swift is getting too packed and still worried about the redds, just wanted to get that in. :)

Brendan Mackinson said...

Regarding the hook... some have tried to tie the dry fly in such a way that the hook rides point up. Clarke & Goddard (worse "selectivity" offenders than Swisher and Richards in my opinion) did this, but they were quite explicit that their intention was not to keep the hook point from being seen by the fish, but to avoid disturbing the footprint pattern created by the hackle and tail, which they believed triggered the trout to take. I have tried a few hook-up dries, but never found them as effective as the standard styles. Others have advocated reverse ties (with the head of fly at the bend of the hook and the tail over the eye) for a variety of reasons, including having the hook point disguised by the hackle. The hook point also exposes the lie that lighter tippets are effective because the fish can't see them as well as heavier tippets. The hook point is far more visible than any tippet, meaning any advantage of a light tippet comes from improved flexibility leading to better presentation/drift (and even then, that only seems to matter with dry flies).

There are plenty of reasons for a trout not to eat the fly, hook point not least among them. Thankfully for us, they find some reason (or reasons) to eat the fly often enough to keep us entertained. I think those who (like Proper) emphasize behavior in the fly design and/or try to incorporate certain triggers are on the right track. Even in trying to match the hatch, creating the impression of life and mimicking the behavior (like how the fly sits in the water and how it drifts) are far more important than getting the exact right shade of olive in the Blue Winged Olive pattern, for example (though having the right size fly seems to be of great importance). Impressionistic flies are actually far better match-the-hatch imitators than stiff replicas that look exact to the human eye.

Anonymous said...

I would never stomach pump a trout, and there is one big reason that I hear very few people mention... That reason is that if you have caught the trout, you have already figured out what it will eat.

There are so many clues on the water that I can't figure out why anyone would take a trout's hard fought food to figure out what is already in front of you.

Millers River Flyfisher said...


You probably recall the "Waterwisp" series of "up" hooks from the mid 1990's. They sank without a trace. I've also heard that someone wanted to apply a white coating to dry fly hooks with the reasoning that the hook would be hard to see against the light sky when viewed from below. Actually that makes sense.


Anonymous said...

I am a big fan of turning rocks over and being observant. When one spends enough time on a stream, like Ken had mentioned you can get a good idea of the hatch cycle. I've also learned that presentation is more important than fly selection nine times out of ten. When fishing new and unknown waters do a little research ahead of time either online or in some form of literature. Chances are it will be easy to figure out at least what type of fodder is on a particular stream. When all else fails swing some partridge!

Paul Fay

Mike from Andover said...

On a whim I picked up a dozen of those Waterwisp flies at the Marlboro show a few years back - can't say I ever caught a fish on them!

Yes, the Swift was packed on Thursday, but there were plenty of fish to go around (and they were spread out throughout the river). I think everyone looked at the long range forecast (as I did) and realized that it was maybe the last day to get out on the water in 2016 - the "polar vortex" is moving in, and temps look like they are plummeting from here on out. Temps in the 20s/30s with snow in the forecast should do a good job of protecting the redds from here on out I think. A pink soft hackle has been working pretty well for me lately on the Swift - just some pink floss, a muskrat thorax, and some grey hackle.

No Meio Do Atlântico said...

There is a big mistake that people do, you don't pump the stomach!
You pump the throat of the fish only!
By pumping the throat you only take what they ate 15 minutes ago.
But before attempting to do any of that have someone with experience show you how to do it!
I do throat pump trout when i'm fishing lakes, you will never figure what size and color of chironomid trout are feeding on on a certain day.
I respect everyone's opinion, so I expect the same
Rui Machado

Millers River Flyfisher said...

Mike From Andover,

I tied up some pink soft hackles and I'll try them today.


james douglas said...

I've never quite figured the need to do such a thing .. after all you have to catch a fish to use that pump in the first place. Call me crazy but if you just caught a fish maybe you are already on your way to solving the puzzle without un-necessarily handling the fish.

As an interesting side note this technique was used a number of years ago on a population of larger trout to see to what degree they were eating young of year trout relative to such notorious fish eating birds as mergansers. We of the gray hair certainly have heard the old saw about brown trout (german browns for the really gray haired fellows) cannibalizing the trout population. This very question came up at a meeting not that long ago.

The results of the study - which looked at the stomach contents of about 25 - 30 large brown trout (between 16 - 24") indicated sculpins and dace were targeted while young trout were incidental - present but not to a significant degree. At the same time mergansers showed a distinct preference for 6-9" trout.

So there is some value in stomach pumping but I would say as an angler it is really not worth the risk.