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Hi & Stomach Contents?

2006/10/23 13:25
From Pittsburgh
Posts: 0
Hi, I've been coming to this site just about every day for a long time. I cant say enough about all the things I've learned from everyone. Thank You. One thing that I have never seen come up is the subject of checking the stomach of the fish. I always have my net to check the drift but I always release the fish I catch (git em again the next time ) and worry about killing them if I try to see what they have been eating. What's the best way to check a fishes belly?

Posted on: 2006/10/23 14:21

Re: Hi & Stomach Contents?
2006/9/13 12:42
From Altoona, PA
Posts: 16
I've heard of people using stomach pumps to flush out the contents of a trout's stomach. There are some real problems with that:

* To do it, you're going to have to keep the fish out of the water a bit longer than you would if you just released it.

* Everything that goes down into the trout's stomach is going to get ground up, so identifying the items it eats could be pretty challenging.

* By flushing out the stomach, you are 'undoing" the trout's feeding. So you are releasing a tired trout with an empty belly. I have to think that would impact it's likelyhood of survival.

* The stomache pump could perforate or otherwise damage the trout's mouth, throat etc.

I'm sure someone out there must use one, and maybe they'll weigh in. Maybe I am overly worried about minor issues, but releasing trout unharmed is important to me. It sounds like it's important to you too.

I have seen the stomache contents of trout that have been caught for dinner. And I wouldn't be able to identify much. The only thing I can say for sure is, the nymph fishermen have it right. Trout feed on the bottom! The trout I have seen were full of nymphs, despite the fact that they were taken during a hatch with dry flies. (But who cares, I'm fishin' on top anyway )

Posted on: 2006/10/23 15:53
Never challenge a cat to a staring contest

Re: Hi & Stomach Contents?

2006/9/9 21:13
From Apollo
Posts: 2
Never used one myself. But I have heard the same thing that Padraic said, stomach pumps cause damage to the fish. Also like Padraic said there is not going to be alot of stuff you can identify. Minnows, crayfish and nymphs are about the only thing your recognize. The nymphs will be mostly digested. Just about everything else will be a mix of body parts. But to be able to identify anything in the fishes stomach depends on how long it has been in there.

Posted on: 2006/10/23 19:39

Re: Hi & Stomach Contents?
2006/9/9 19:16
From Dallastown, PA
Posts: 1255

Turn over a few rocks, look in the film as it goes by, look in the air but stay out of their bellies...As Pad said, it can't be good.

It is bad enough that we tease the fish with what isn't even food only to impale them with steel and then drag them around for a while, hold them out of the water. Do we really have to then take away the food they ate successfully?

Imagine being in a hospital and having your stomach pumped...I've never had it done to me but I can imagine your not in the mood to eat vary much for a while afterward.

Bad news IMHO.


Posted on: 2006/10/23 20:49
Don't hit me with them negative waves so early in the morning. Think the bridge will be there and it will be there. It's a mother, beautiful bridge, and it's gonna be there. Ok?

Re: Hi & Stomach Contents?

2006/10/24 0:04
Posts: 7

- With respect to "stomach pumps" for trout. You are only obtaining the contents of the esophagus and not the actual stomach contents.

- The apparatus used is quite similar to the aspirator used to expell mucus from a new born baby's mouth just after birth.

- To use, squeeze the bulb end and let it fill with water from the stream. Then insert the tube end into the mouth and gently squeeze water into the trout's mouth. This will cause the epiglottis (the throat part of the trout) to open up.

- Next, you insert the tube another 1/2 to 1 inch and let go of the bulb. This will cause a suction force and will cause the material in the "throat" to be suctioned up into the bulb.

- Next, remove the apparatus from the trout and release said trout. Squeeze contents of bulb into hand.


- Some notes:

- First, stomach pumps do not work well on trout under 10 or so inches as the tube is too big, and often you do not get any contents in return.

- Second, the whole operation should take under 15 seconds. If the back of the throat does not open up after the initial squeeze of water from the bulb, then just let the fish go. It's doubtful that the back of the throat is going to open up.


- Where this has helped:

- The Bighorn and Green Rivers...proof that midges rule. A size #14 pheasant tail that slams fish on Spring Creek in Centre County is fairly worthless on the above Western rivers (my opinion). Instead, what I learned was to go with size 20 and smaller midges for the above mentioned tailwaters.

- One reason these fish grow so big out west is that they are literally gorged with midge pupae. One trout will typically "give up" about 200 midge pupae in a sampling. Unreal!!!!

- One other thing learned. The trout on Spring Creek are jammed with those big black carpenter ants on those hot muggy June and July mornings. An average 12 to 14" brown on Spring Creek will turn up 25 to 50 carpenter ants in a typical sampling.


- Ethical dilemna:

- I'll leave it to you guys to debate whether the abobe mentioned stomach sampling harms the fishery.

- Personally, you only need one squeeze of the bulb to get a good sampling. Also, you only need to sample 1 or 2 trout (again, over 12 inches) to get an idea of what is going on. Also, don't stand their and keep trying to get a sample. If you don't get one on the first squeeze of the bulb, then forget it and go with another fish.

- Hope this helps.

John Coxey
(Syracuse, NY, USA)

Posted on: 2006/10/24 0:22

Re: Hi & Stomach Contents?

2006/10/24 0:04
Posts: 7

- Here is a picture of a stomach pump for trout.

John Coxey
(Syracuse, NY, USA)

Attach file:

jpg  71936g-t.jpg (0.00 KB)

Posted on: 2006/10/24 0:27

Re: Hi & Stomach Contents?

2006/9/13 10:18
From LV
Posts: 631
I've been lurking here since the board's inception pretty much and the subject does come up from time to time. My Credo is if I'm catching fish why do I need to check the stomach contents. Biologists don't use them, and I've got friends who harvest rubber trout that open up stomachs to see what the trout are eating, but the best you can do is size and color, but usually the color is black or brown.
Now I do talk from time to time with the biologists and the question of what trout eat in certain streams does come up. They take some trout and check there stomack contents by cutting them open. These fish are processed for other information and so would be taken anyway. They found everthing from large catepillars to aphids. That's a broad range of stomach contents. I doubt anyone would recognize an aphid from a trout's stomach, but there are a couple of streams in SE PA where that's what they eat because there is nothing else.

Posted on: 2006/10/24 18:09

Re: Hi & Stomach Contents?

2006/9/14 10:34
From Southeast PA
Posts: 3
I just squeeze em til the bugs come out. (KIDDING! )

There have been times when the latest meal has spilled out into my net or is visible in their mouth, and this can be pretty interesting but usually doesn't help much. I do remember a time that a bunch of bright green small caddis larva came out, and this helped me catch a few trouts. But I wouldn't want to do any damage to the fish or deprive them of their hard-earned dinner. If you do it, carry some fish food with you and give them a nice reward before you let them go.

Posted on: 2006/10/25 8:38

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