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Throat Sampling


duanec

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hey...lots of noise gets made re: correct handling of fish, types of nets, types of hooks, how to take photos, rod size, eye positioning [wtf] etc etc and i was reading rowley's article "bug sleuthing" in the new fusion mag and re: sampling it states throat pumps 'used incorrectly, can injure fish', and 'use comes with a level of caution'. also mentions to only use on 'fish 14 inches or longer'.

 

i have been considering finally buying the tools and taking up the pratice however as i've witnessed others doing it what i believe to be 'correctly' and others maybe not so much got me wondering if throat sampling has an effect on fish safety and/or fish mortality, and where that 14" number number comes from, and if study had been done similar to barb vs. barbless or bait vs. no bait mortality rates...

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The "throat sampling" size comes from biologists knowledge of the development and size of a fish's esophagus. The predominant issues are:

Inserting the tube past the entrance to the esophagas

Inserting the tube dry

Squeezing a bulb of water into the fish

 

If one is particular of the basic steps and uses common sense, sampling is almost 100% safe. I've watched Chan and several other biologists perform and the fish never leaves the water, and it's over in under 20 seconds. But, I think that's where "practice" comes in.

j

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I normally keep away from it as my own judgment call. Quite evasive and puts the trout through more stress than I personally like to do. It also puts them down for a while without feeding. I worked in a hatchery in my younger days and we pumped to check digestion. Through my own observations all the trout we handled like this stopped feeding for at least 24 hours. If done improperly it could induce shock an death. I know it's touted by some as a good way to check on feeding patterns. I depend on observation of insect life and trout to judge feeding patterns which I find for valuable. You should make your own judgments on this.

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Dune, there have been lots of studies on mortality rates of fish and the chief causes. While bait/baitless, barbed/barbless do play a factor, there are other factors that are much more significant, including "play time" or the amount of time it takes one to land a fish. Essentially the longer it takes you to play a fish, the higher the mortality rate. Also, the more time spent out of water also increases chances of mortality. Surprisingly, there is little to no difference from an Idaho State Gov. study on barbed vs. barbless, which is why I believe they brought back the allowance of barbed. The issue of "play time" is why I often am disappointed in the anglers on the Bow who think it is cool and fun to play a 22" rainbow on a 2-3wt rod for long periods of time. I say, use the proper equipment to get the job done...a 5-6wt is perfect, will let you "feel" the fish quite nicely and allow you to get the fish to shore quickly. In my opinion, the more skilled angler is the one who can catch the big one and bring it to shore/release the fastest....not the longest!

 

Here is the link to one study that illustrates the issue of "play time": http://www.acuteangling.com/Reference/C&RMortality.html (note the range of species in the study)

 

Here is a summary of the study from Idaho:

Barbed Hook Restrictions in Catch-and-Release Trout Fisheries: A Social Issue

 

D. J. SCHILL and R. L. SCARPELLA

 

Idaho Department of Fish and Game, 1414 East Locust Lane, Nampa, Idaho 83686, USA

 

Abstract.—We summarized results of past studies that directly compared hooking mortality of resident (nonanadromous) salmonids caught and released with barbed or barbless hooks. Barbed hooks produced lower hooking mortality in two of four comparisons with flies and in three of five comparisons with lures. Only 1 of 11 comparisons resulted in statistically significant differences in hooking mortality. In that instance, barbless baited hooks caused significantly less mortality than barbed hooks, but experimented design concerns limited the utility of this finding. Mean hooking mortality rates from past lure studies were slightly higher for barbed hooks than barbless ones, but the opposite was true for flies. For flies and lures combined, mean hooking mortality was 4.5% for barbed hooks and 4.2% for barbless hooks. Combination of test statistics from individual studies by gear type via meta-analysis yielded nonsignificant results for barbed versus barbless flies, lures, or flies and lures combined. We conclude that the use of barbed or barbless flies or lures plays no role in subsequent mortality of trout caught and released by anglers. Because natural mortality rates for wild trout in streams commonly range from 30% to 65% annually, a 0.3% mean difference in hooking mortality for the two hook types is irrelevant at the population level, even when fish are subjected to repeated capture. Based on existing mortality studies, there is no biological basis for barbed hook restrictions in artificial fly and lure fisheries for resident trout. Restricting barbed hooks appears to be a social issue. Managers proposing new special regulations to the angling public should consider the social costs of implementing barbed hook restrictions that produce no demonstrable biological gain.

 

You will see from the chart within the study that barbed/baited is highest mortality. I tried to cut/paste, but file is to large....

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It also puts them down for a while without feeding. I worked in a hatchery in my younger days and we pumped to check digestion. Through my own observations all the trout we handled like this stopped feeding for at least 24 hours. If done improperly it could induce shock an death.

cool, good to know. did you ever witness mortality that could be attributed to improper pumping?

i'm thinking if i had spent a day expending significant energy to fill my belly and someone sucked my guts clean it would put me off for a while too [esp. if it's full of beer...but then again sometimes that would be a good thing ha ha].

but doesn't a simple hook/fight/release also have a tendency to put a fish down for a while, perhaps just as much?

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In the hands of someone experienced who knows what they're doing and exercises extreme care I am sure the practice is fine. However, I would hate to see this becoming common use for obvious reasons. At the very least the fish will have lost all the energy necessary to collect whatever food was pumped. Personally, I'll stick to eyeing the water and flipping over the odd rock or two.

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Tightline,

 

Interesting study, I didn't really see it clearly clarified whether the time from hook-up to landing was consistant for both barbed and non-barbed hooks - From a behavioural point of view I have often sat at the Back of Emerald Lake (eating lunch or taking a break) watching anglers with both Barbed and Non-barbed flies. Without any shadow of a doubt it is very typical for those with barbed hooks to play their fish longer, further to that, I often see barbed hook anglers slack their lines, so their buddy can wander over at their leisure to take a picture or look at a fish - I've also noticed that fish on non-barbed hooks quite often escape the hook-up whereas fish caught on a barbed hook are far less likely to escape without actually making it to the landing stage of the process - I think, given both of those human factors, It is somewhat easy to conclude that, on average. fish hooked-up on a barbed hook get handled, on average, for a longer period, than those on Barbless hooks - I have to wonder if that factor was considered and accounted for in the study as it leads to a conclusion that the factor of barbed vs barbless has a direct impact on handling time thus indicating that barbed or barbless does have a measurable effect of fish mortality

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Tightline,

I have to wonder if that factor was considered and accounted for in the study as it leads to a conclusion that the factor of barbed vs barbless has a direct impact on handling time thus indicating that barbed or barbless does have a measurable effect of fish mortality

Rob,

You are basically comparing angling experience, not barb vs non-barb. The only way to do it is have the same angler(s) use barb and non-barb for the duration of the study and look at mortality. Handling time would certainly be included since they have to take the hooks out regardless of type.

 

I've seen multiple studies in fresh and salt, all saying essentially the same thing. Barbless does next to nothing for decreased mortality. Though the requirements were put in for the best of reasons, it appears they are in the end purely and aesthetic and social in nature. That said, I have no problem sticking (no pun intended) with barbless. I fish on a lot of streams where fish are caught multiple times. I imagine (not backed up with anything) that less visible damage occurs with barbless.

 

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hey...lots of noise gets made re: correct handling of fish, types of nets, types of hooks, how to take photos, rod size, eye positioning [wtf] etc etc and i was reading rowley's article "bug sleuthing" in the new fusion mag and re: sampling it states throat pumps 'used incorrectly, can injure fish', and 'use comes with a level of caution'. also mentions to only use on 'fish 14 inches or longer'.

 

i have been considering finally buying the tools and taking up the pratice however as i've witnessed others doing it what i believe to be 'correctly' and others maybe not so much got me wondering if throat sampling has an effect on fish safety and/or fish mortality, and where that 14" number number comes from, and if study had been done similar to barb vs. barbless or bait vs. no bait mortality rates...

 

Lots of thoughtful commentary on this thread, which is cool. For my part, I pumped once and I botched it. Likely killed the fish. I no longer pump. I see plenty of guys do it though (especially in Jack's neck of the woods and there about) and I see plenty of dudes there fumble the fish as well. Makes me a wee bit uncomfortable. I personally would not do it but that's because I do not trust myself. Also, the argument that 'biologists' do it and therefore it's safe does not wash with me. I've watched and fished with biologists and seen fish 'mishandling'. Maybe that's because they know the fish are more durable than we (without the benefit of a formal education in it) seem to think. Or maybe they get overly familiar with fish handling and get a little cavalier with it all.

 

al

 

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Sorry Dune for getting off topic,,,

 

Thanks Rick - I think I am at a point where I am finally convinced barbed hooks may not be the factor I always thought they were.

 

Re - stomach sampling,... a biologist I know showed me how to do it about 10 years ago, and I did try it quite a few times that year but I did notice that it was quite normal to find what I saw in the stomach didn't match the fly I just used to land the fish - given that, I didn't see much relevance in continuing the practice, obviously anyone who lands a fish just identified an efficetive fly so what is really gained by doing it other than satisfying a curiosity.

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Re - stomach sampling,... a biologist I know showed me how to do it about 10 years ago, and I did try it quite a few times that year but I did notice that it was quite normal to find what I saw in the stomach didn't match the fly I just used to land the fish - given that, I didn't see much relevance in continuing the practice, obviously anyone who lands a fish just identified an efficetive fly so what is really gained by doing it other than satisfying a curiosity.

Exactly my feeling on it. On rivers around here if you know the hatches and the other aquatic life (leeches, baitfish, etc) you have a place to start in your fly selection. For me, using that knowledge as a starting point and finding a fly that works is part of the satisfaction I get from catching a fish. Also, how often do you find a fly stops working after a while because the fish have stopped feeding on one thing and moved on to another? A stomach pump might tell you what they were eating half an hour ago but not necessarily right now.

 

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Dune, there have been lots of studies on mortality rates of fish and the chief causes. While bait/baitless, barbed/barbless do play a factor, there are other factors that are much more significant, including "play time" or the amount of time it takes one to land a fish. Essentially the longer it takes you to play a fish, the higher the mortality rate. Also, the more time spent out of water also increases chances of mortality. Surprisingly, there is little to no difference from an Idaho State Gov. study on barbed vs. barbless, which is why I believe they brought back the allowance of barbed. The issue of "play time" is why I often am disappointed in the anglers on the Bow who think it is cool and fun to play a 22" rainbow on a 2-3wt rod for long periods of time. I say, use the proper equipment to get the job done...a 5-6wt is perfect, will let you "feel" the fish quite nicely and allow you to get the fish to shore quickly. In my opinion, the more skilled angler is the one who can catch the big one and bring it to shore/release the fastest....not the longest!

 

Here is the link to one study that illustrates the issue of "play time": http://www.acuteangling.com/Reference/C&RMortality.html (note the range of species in the study)

 

Here is a summary of the study from Idaho:

Barbed Hook Restrictions in Catch-and-Release Trout Fisheries: A Social Issue

 

D. J. SCHILL and R. L. SCARPELLA

 

Idaho Department of Fish and Game, 1414 East Locust Lane, Nampa, Idaho 83686, USA

 

You will see from the chart within the study that barbed/baited is highest mortality. I tried to cut/paste, but file is to large....

 

finally some common sense

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granted...i can't argue there are times the value is limited, doesn't seem to stop many people from doing it [gee wonder what the steelhead are eatiin? j/k] for interest or whatever. every single time i clean a fish i go through it's digestive system for that reason.

i can see situations, like you are in new waters, or there's a feed frenzy goin on and you've got the wrong size/color [or maybe you're using barbs/bait/a 1wt]. case in point and i think where i can see it's practical application is the chirono show in a bc lake...often where chan et al have demonstrated the practice.

so...if it's done incorrectly or even correctly what's the science that says hey sucking out the daily protien intake of a 22" trout does x to it's chances of making it through till tomorrow?

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Removing protein probably not a lot, putting it in shock from handling too long or damaging delicate tissue - a death sentence. Imagine something the size of a garden hose but stiffer used on ones delicate throat. Sure would put me of my grub for a while...

 

so...if it's done incorrectly or even correctly what's the science that says hey sucking out the daily protien intake of a 22" trout does x to it's chances of making it through till tomorrow?

 

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