The Truth About Leaving A Fishing Lure In A Fish’s Mouth [New Study]

By: Joseph Simonds on September 2, 2015
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fishing lure in fish's mouth

Before we get into the somewhat shocking (and certainly controversial) results from a recent fishing study that purposely left fishing lures/hooks in a fish’s mouth to see how they really react, let’s get one thing straight first…

By NO means are we (or the research team that did the study) trying to encourage anglers to casually leave fishing hooks or lures inside of a fish’s mouth (unless you are certain it can help save their life as you will see in the study below).

This is purely informative to those of you always wondering what happens when a lure or fishing lure/hook is left in a fish’s mouth. And let’s face it, there are some pretty unavoidable instances where a hook accidentally gets left in a fish’s mouth…

Not to mention, sometimes it can actually save the fish’s life!

So PETA, don’t get your waders in a wad just yet…

(If you never read the Salt Strong Open Letter To PETA regarding their pursuit to stop ALL Catch & Release Fishing, click here to read that next. It is a must read for all anglers).

Reasons Why Hooks Get Left In A Fish’s Mouth

hook left in fish's mouth

If you have spent any amount of time saltwater or freshwater fishing, then you know that eventually one of your hooks or lures will end up in a fish’s mouth well after the fight.

For those of you non-anglers, here are just a few reasons that hooks and lures get left or caught in a fish’s mouth:

  • While fighting a fish, the line breaks, leaving the fish swimming off with the hook/bait/lure
    • This could occur from fish going into structure and breaking you off
    • This could occur from a bad knot
    • This could occur from just a normal break-off with a big fish at any point during the fight
    • This could occur with fish like sharks, barracuda, or pike that have sharp teeth, etc
  • The fish swallows the hook to the point you can’t safely get it out without seriously injuring or potentially killing the fish
  • Many fish with nasty teeth (like large sharks and freshwater pike) are released by purposely cutting the line at the hook instead of keeping the fish out of the water for an extended period of time (and to avoid getting your hand bitten)

Fishing Lures Left In A Fish’s Mouth [New Study]

fish hooks left in mouth

A study from Carelton University’s Cooke Lab shows pike can shake a hooked lure within a matter of days. (Photo credit: Chris Pullen )

Wait until you see the results from this latest study on fishing lures left in a fish’s mouth!

Here are the details of the study:

  • Canadian Grad student Chris Pullen did his thesis project on how long do fishing lures/hooks stay in a fish’s mouth if left to fend for themselves.
  • The entire study was done with Northern Pike.
  • Chris had “control” fish (also Northern Pike around the same size/age) as well that had no hooks in them to see if they would act differently than the pikes with hooks in their mouth
  • In the study, Chris hooked pike in four different parts of the mouth with color-coded crankbait lures fitted with radio transmitters.
  • He used these floating crankbaits in a controlled lake (so they could see the crank baits float to the top once the fish shed them, and also so they could monitor and follow up on all of the fish)
  • They used both barbed hooks and barbless hooks
  • They hooked the fish in multiple places in their mouth:
    • Lower jaw
    • Through BOTH the upper and lower jaw together (with the treble hooks)
    • Back near the top of the fish’s tongue (deep in the Pike’s mouth)
  • Once hooked, Chris released the hooked fish back into the small lake so they could start tracking how the fish reacted with the lures in their mouths.
  • The study was supervised by Dr. Steven Cooke and the Fish Ecology and Conservation Physiology Lab at Carleton University. The field work was done at the Queens University Biological Research Station (QUBS).

Here are the actual crankbaits he used in conjunction with the Carleton University’s Cooke Lab:

leaving a hook in a fish's mouth

The Results:

The results of this “crankbait left hooked in fish’s mouth” came back pretty shocking!

These fish were all somehow finding ways to self-release (or most likely shake out) well set crankbait treble hooks in a matter of days. In fact, the barbless hooks usually came out of the fish’s mouth and hit the surface in 24 hours or less!

And even the deeply hooked crankbaits with barbs were usually fully free from the fish’s mouth in just a couple of days!

Pullen said the pike hooked in the lower jaw actually took longer to shed the lure than those hooked deeply near the back of the tongue.

Chris’s theory is that the hook in the jaw is less of an annoyance than one that is deeper and impacting their ability to forage, so the fish doesn’t use as much energy to try to release it from their mouth.

“We have a pretty good idea now, for pike at least, with crankbaits, what likely happens with the lure,” he said. “And that is faster than people might think, that fish is able to get that hook out.”

Pullen concluded from his study that anglers wanting to release a fish safely are likely better off cutting the line on a deep hooked pike then trying to pull out the hook itself.

It appears that fish are pretty good at finding ways to remove these hooks while under water! Pretty amazing for an animal without any hands or fingers!

Finally, in the second part of the study where Chris followed and compared the pike with hooks/lures in their mouth vs the normal pikes (he tracked their behavior in terms of how they dispersed around the lake, how they acted, and how they ate), he found very little difference in how the hooked vs unhooked pike acted.

This would explain why so many anglers have stories of catching the same fish in the same hour. Apparently, fish might feel some annoyance with the hook in their mouth (enough to find ways to shake it off), but it certainly isn’t affecting their ability to eat and to go about their daily life.


You can read a little bit more (and hear the short audio interview) about this fascinating fish study with Chris Pullen here.

How Long Does It Take For A Fish Hook To Dissolve?

leaving fish hooks in fish's mouth

Although there is much debate on this, the long and short of it is that there is a better chance of the fish losing or shaking off the hook before it dissolves (as Chris proved in his pike research above), especially the newer hooks that were not made to be “biodegradable” (there have even been reports of fish “pooping” out hooks).

The long and short of it is, most fish hooks are going to take a LONG time to completely dissolve.

Will they rust, weaken, and be more bendable?

Of course!

But to completely dissolve is another story. Try it yourself… go put a hook in a cup of saltwater and a cup of freshwater and see how long it takes to erode… you might be waiting a long time…

Below is a great answer from Yahoo Answers that explains how long it takes for a fish hook to dissolve in a fish’s stomach (in laymen’s terms).

A few of the variables to think about when it comes to a fish hook actually dissolving:

  • How new is the hook?
    • Older hooks will rust or dissolve quicker than brand new hooks.
  • What is the hook made out of?
    • Old wire hooks will dissolve quicker than a stainless steel hook.
  • How big is the hook?
    • As you can imagine, a smaller hook will dissolve and weaken quicker than a large hook
  • Is the hook in saltwater or freshwater?
    • Saltwater will dissolve a hook faster than freshwater

do fish feel pain

How Long Does A Hook Take To Dissolve In A Fish’s Stomach?

Question From Answers

Best Answer From Peter in Australia:

A hook will rust away in a fish, but it may take a while, especially if the hook is plated or made of thick metal. But fish’s stomachs are pretty tough. They can stand up to the spines on little fish like bluegill or pinfish. I’ve caught lots of fish which have hooks embedded in their jaws, and I’ve cleaned quite a few fish which have grown-over hooks in their guts. So cutting off a swallowed hook is not really a big deal. But if you worry about it, make sure you use thin wire, non-plated hooks.

And no, fish’s nervous systems are not especially similar to ours. I’ve actually seen the same fish caught twice within an hour (we were tagging small halibut, so we know they were the same fish and when they were caught), so hooking a fish doesn’t bother it much at all. You also see this in the big fish tank bass fishing exhibits you see at fishing shows. And of course, fish have lateral lines, we don’t. They are very different creatures.

Finally, I’ve caught a number of fish which were never hooked: lingcod which have grabbed a smaller hooked fish, or wahoo which are simply holding the middle of a metal jig, with the hook swinging free. These fish pulled the same as fish which were hooked, and held on until they were gaffed or netted. All this tells me is that they’re fighting the pull of the fishing line, not the “sensation” of the hook, and they were not bright enough to let go when it became obvious they were in danger.


hook left in fish's mouth

First and foremost, if you can get the hook or fishing lure out of a fish’s mouth with minimal issues or harm to the fish, then by all means, ALWAYS take it out.

But if you believe the fish that you are releasing might not make it if you keep them out of the water any longer, many times it is best to just cut the line.

As the recent study on Northern Pike proved, not only were the hooked fish able to disengage the hooks, they also didn’t appear to be eating or acting any differently than fish that were not hooked.

Finally, does this eye-opening study showing Northern Pikes being able to somehow shake off well set treble hooks in a matter of days mean that ALL fish can just as easily shake off all hooks?

Of course not!

But it certainly is an incredibly interesting insight into how quickly these fish can recover and shake off treble hooks!

Related Post: “How To Properly Catch & Release Fish Without Killing Them” (see it here now)

P.S. – If you think your angler friends would like this post, please Tag them or Share this with them. It would mean a lot to me. You Rock! Pa-POW!


Why does PETA want to put an end to Catch & Release Fishing so bad?

CLICK HERE to find out.

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PeterAnonymousAnonymousGlenn CAlgis Kemezys Recent comment authors
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The study used crankbaits with trebles, so presumably the same results would apply if jig heads with barbed hooks were to be used? I fish for European Perch in waters that also contain pike, but I don’t like to use wire because I believe it negatively effects the action of UL lures, but as a result I do get bitten off from time to time by pike, so it would be reassuring to know that the pike can shed the hook over a shor period. In future I will flatten the barbs on my jig heads to make the job that little bit easier for the pike if I am unfortunate enough to get bitten off


your best answer to how long a hook takes to dissolve in a fish’s stomach is “a while.” what was the worst answer?

Glenn C
Glenn C

While fishing up North in Canada, I had gotten a bite from a large fish using a 1/O drop shot hook and KVD plastic, the fish eventually snapped me off as I was not expecting something so large to bite. The next day, using my heavier rod and line, I managed to land a relatively large pike, about 36 inches in length. This fish absolutely destroyed my in-line spinner. After I removed the trebles, I noticed there was still line dangling from its mouth and to my surprise, it was the hook from the previous day. This thing was lodged back along the edge of the tongue and was removed as well. Clearly the hook didn’t deter this guy from eating or being aggressive!

Algis Kemezys
Algis Kemezys

That’s great news. Congrats


Great post. Very informative


Great packing tips for your fishing equipment. More people should see this to avoid any damage.


Awesome article, so good to see these kinds of studies being done.


Other animals get caught on the barbs and tangled in the fishing line too. Swans, geese, ducks, seagulls and turtles in the lake in our park sometimes suffer immensely because of them. Some we can save, some die a long and painful death. It’s horrifying to witness.

Kent Lewandowski
Kent Lewandowski

Seems like a different study contradicts your findings :


I think a big difference is that the study you mention just placed hooks & line in the fish’s mouth, whereas this study used an entire crankbait. If you’re a pike shaking your head, the weight of the crankbait will act to help pull the barbs free. WIth just a hook, shaking your head does little.

Bottom line is that if you know pulling the hook out will kill the fish, it’s likely better to leave it in. Some chance is better than no chance. If you can get it out without much damage, we always try to get it out. I’ve been poked many times trying to get hooks out of little catfish’s mouth when it would’ve been much simpler to cut the line. But it comes with the territory.

Kent Lewandowski
Kent Lewandowski

I agree it’s best to try as much as possible to remove hooks, even if it’s tough and can result in poked fingers.
Why don’t you advocate for barbless hooks?

Roy Crader
Roy Crader

Kent , If I want to fish and actually catch the fish I will need a barb on the hook unless I am
fishing for a non-jumping fish. We ( people) were given these animals to eat , and if anyone want to use a dip net to catch them, more power to them, but the friends I have are in it mostly for the thrill of the “catch”
When it comes to these issues and PETA , you automatically know there stand. I just know they do not know where the food comes from while buying in their grocery makets !


Peta is opposed to buying any meat so they do know.

James Bergman
James Bergman

I’m really glad that the fish hook study turned out with possible results. I don’t loose hooks all that often, but I always feel bad for the fish when I do. It is good to know that the hook normally comes out within a day or two. It means I don’t have to feel as bad when I can’t get the hook out.


i found a hook inside the fish stomach. is that a common thing ?

Matt Schorner

I recently lost a snook that had a topwater plug deep in his mouth… Do you have any idea if the vmc treble hooks could have pulled out or rusted to the point that he lived? Thanks alot