nutsaboutfishing

What really happens to gut hooked hooks?

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As per the title. So when a fish swallows a hook we’re advised to cut the line and leave it there rather than trying to remove it and doing more damage that makes  sense. But then what happens to the hook? I’ve heard some people say that they pass through the fish others say they rust out. I find hard to believe anything except they just sit there and don’t do a lot of good to the fish

 Thoughts?

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I obviously can't speak for EVERY circumstance but can relate one experience which I observed.

I caught a Murray Cod in the Murrumbidgee River which had the eye and part of the shank of a 3/0 red hook sticking out from the anus of the fish. Naturally I carefully removed it and released the fish unharmed. It readily swam away.

When we consider the feeding methods of fish (say Murray Cod) their natural diet consists of many creatures with skeletons and hard shells (birds, fish, shrimps, yabbies, crayfish). It is therefore a natural situation that they digest foods which we humans could not digest.

I know that Murray Cod will inhale a yabbie (hard shell) and some time later "spit out" parts of the hard shell. I have never seen them do this with the skeleton of other fish which they have consumed. It's reasonable to assume that the entire fish enters the stomach and is dissolved by stomach acids.

I have examined the stomach contents of many fish species which I've caught and seen many TOTALLY WHOLE fish and crustaceans therein. This would lead me to believe that fish are capable of swallowing hooks and having them pass through their system without too much harm to the fish. Just my observations and opinion. I shall be interested to see the opinions of others in this thread. What are your thoughts nutsaboutfishing?

Cheers, bn

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It’s just guesswork unless research is done.

Fortunately, there has been a LOT of research done on this. Eg.

https://www.researchgate.net/publication/233287967_Effect_of_Hook_Type_on_Mortality_Trauma_and_Capture_Efficiency_of_Wild_Stream-Resident_Trout_Caught_by_Active_Baitfishing

https://www.researchgate.net/publication/233012131_Hook_Shedding_and_Mortality_of_Deeply_Hooked_Brook_Trout_Caught_with_Bait_on_Barbed_and_Barbless_Hooks

if you scroll down to the bottom and click on ‘Reference’ it will lead you to many other studies.

Paraphrasing Bob Dubois research:

of deeply hooked fish

74% mortality rate if hook removed.

47% mortality rate if hook left in

of those with hook left in that survived the test period, 74% shed the hook within two months, which if I read that correctly means about 35% of the total deep hooked fish shed the hook.

Another study found 55% mortality when hook removed and 21% when hook left in, but a shorter follow up period was involved.

There is a lot of research on this topic. Some bad, some good. Dubois’ research is well done because it involves catching fish by real anglers in real fishing conditions, then keeping the fish in pens in the same environment.. A lot of the research is done in fish farms or confinement ponds where fish don’t have to pursue wild food.

A couple of other interesting claims by researchers that I noted in the reading. Hold a fish out of water vertically (eg holding up by tail) and you have effectively killed it - fish are not adapted by evolution to be held upside down. %%%%%ing the air bladder of a fish caught in deep water does not increase survival rate - barotrauma kills fish regardless. I always wondered about that one.

 

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My usual reply to this sort of thing still stands, any fish thrown back has a much better chance of surviving than one in the esky, or one cut open to remove a 5 cent hook, and one carefully  handled has got an even better chance of surviving than one hung up by some sort of pliers for a photo, it's your personal choice, and I don't claim to be some hippie greenie, but, if I want a fish to eat, I keep it, if I don't want it (or it's not legal size) I make some effort to release it as healthy as possible.

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2 hours ago, Volitan said:

It’s just guesswork unless research is done.

Fortunately, there has been a LOT of research done on this. Eg.

https://www.researchgate.net/publication/233287967_Effect_of_Hook_Type_on_Mortality_Trauma_and_Capture_Efficiency_of_Wild_Stream-Resident_Trout_Caught_by_Active_Baitfishing

https://www.researchgate.net/publication/233012131_Hook_Shedding_and_Mortality_of_Deeply_Hooked_Brook_Trout_Caught_with_Bait_on_Barbed_and_Barbless_Hooks

if you scroll down to the bottom and click on ‘Reference’ it will lead you to many other studies.

Paraphrasing Bob Dubois research:

of deeply hooked fish

74% mortality rate if hook removed.

47% mortality rate if hook left in

of those with hook left in that survived the test period, 74% shed the hook within two months, which if I read that correctly means about 35% of the total deep hooked fish shed the hook.

Another study found 55% mortality when hook removed and 21% when hook left in, but a shorter follow up period was involved.

There is a lot of research on this topic. Some bad, some good. Dubois’ research is well done because it involves catching fish by real anglers in real fishing conditions, then keeping the fish in pens in the same environment.. A lot of the research is done in fish farms or confinement ponds where fish don’t have to pursue wild food.

A couple of other interesting claims by researchers that I noted in the reading. Hold a fish out of water vertically (eg holding up by tail) and you have effectively killed it - fish are not adapted by evolution to be held upside down. %%%%%ing the air bladder of a fish caught in deep water does not increase survival rate - barotrauma kills fish regardless. I always wondered about that one.

 

Hi Volitan. Slightly off the original topic but still worth attention is your statement in the last paragraph of your post. Barotrauma kills fish as does puncturing the air bladder of captured deep water species. It would be easy to believe these statements. Working on the assumption that these statements are correct why do Fisheries encourage release of fish which are going to die anyway? Would it not be far more suitable to allow these fish to be part of a bag limit, even if they were undersized. EXAMPLE: Say you were fishing for Gemfish. There's no benefit in releasing small ones all day long, whilst chasing a bag limit of legal sized fish, if the released fish are going to die anyway. Just a thought.

One thing that really concerns me, particularly when I watch videos of fish being caught, is how long anglers keep these fish out of the water before releasing them. There's another topic that Raiders can weigh into. How long should fish be kept out of the water before being released?

Cheers, bn

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What the hooks made out too would have to have impact as well. I was once told when i used to fish for mulloway if you want a fish to survive with a hook in it and the hook to eventually rot away don't use stainless. I used to fish for them with stainless 10 O's. 

I know virtually nothing about it personally and it's just something I was told. 

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1 hour ago, noelm said:

My usual reply to this sort of thing still stands, any fish thrown back has a much better chance of surviving than one in the esky, or one cut open to remove a 5 cent hook, and one carefully  handled has got an even better chance of surviving than one hung up by some sort of pliers for a photo, it's your personal choice, and I don't claim to be some hippie greenie, but, if I want a fish to eat, I keep it, if I don't want it (or it's not legal size) I make some effort to release it as healthy as possible.

Hi there noelm. Totally agree that we all need to treat fish as humanely as possible when we catch them. Just wondering how you remove hooks from a toothy critter without using lip grips or such like. I've seen lots of anglers lift large fish by the gills...I don't think that this is a good way to handle fish either.

Maybe some others would like to chuck their 2 bobsworth into the discussion. Cheers, bn

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Salt water would speed up dissolving of the hook & if your fishing areas of deep water& want to release fish with barotrauma then you should have a release weight on hand.

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10 minutes ago, big Neil said:

Hi Volitan. Slightly off the original topic but still worth attention is your statement in the last paragraph of your post. Barotrauma kills fish as does puncturing the air bladder of captured deep water species. It would be easy to believe these statements. Working on the assumption that these statements are correct why do Fisheries encourage release of fish which are going to die anyway? Would it not be far more suitable to allow these fish to be part of a bag limit, even if they were undersized. EXAMPLE: Say you were fishing for Gemfish. There's no benefit in releasing small ones all day long, whilst chasing a bag limit of legal sized fish, if the released fish are going to die anyway. Just a thought.

One thing that really concerns me, particularly when I watch videos of fish being caught, is how long anglers keep these fish out of the water before releasing them. There's another topic that Raiders can weigh into. How long should fish be kept out of the water before being released?

Cheers, bn

With fisheries regulations, it’s a mix of managing a wild population and managing human behaviour. The human behaviour side is the difficult one as we all know that there is a percentage of fisherman who will cheat the regs in any way they can to get a result. So you end up with regulations which are not immediately logical.

So I assume that Fisheries know

1. most people aren’t going to get a bag limit, or anywhere close to it. If the majority of people caught their bag limit the result would be catastrophic.
2. allowing people to keep undersized fish because they may die on release will lead to a certain number of people targeting undersize fish. Eventually you would have a situation where everybody catches a bag limit, mostly undersize, and all perfectly legal.

i grew up trout fishing in NZ and the regulations at the time read that it was illegal to target (catch, not just keep) undersize fish. If you found yourself catching undersize fish accidentally that was OK but you had to change location or change method to minimise the chances of it occurring. Any undersize fish you caught counted towards your bag limit even though you couldn’t keep them.

There is also the public education angle. Regulations change peoples’ behaviour, albeit very slowly. I know a lot of people scoff at this, but I know it’s true. When I was a kid we kept everything we caught. I remember hearing about catch and release and thinking it was just some crazy American thing. Things started changing when I was about 14 or so, and new attitudes started surfacing. I was pretty late joining the bandwagon, which was mostly about parental example.

 

on the subject of keeping fish out of water, I did come across some research that showed keeping fish out for more then 1 minute dropped survival rates to 28%. I’d have to read more closely before accepting this, seems pretty low, and I think it would depend upon handling and fish species. 

i know that in some US fisheries fishing is not allowed in weather over (I think) 74 degrees f., as the survival rate of fish boated is too low.

All this stuff is on the net. There is an amazing amount of research done on fish survival because both recreation and commercial fishing are important industries worldwide. You need to do a bit of study on how to access scientific papers, but they are mostly out there and free.

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4 hours ago, big Neil said:

I obviously can't speak for EVERY circumstance but can relate one experience which I observed.

I caught a Murray Cod in the Murrumbidgee River which had the eye and part of the shank of a 3/0 red hook sticking out from the anus of the fish. Naturally I carefully removed it and released the fish unharmed. It readily swam away.

When we consider the feeding methods of fish (say Murray Cod) their natural diet consists of many creatures with skeletons and hard shells (birds, fish, shrimps, yabbies, crayfish). It is therefore a natural situation that they digest foods which we humans could not digest.

I know that Murray Cod will inhale a yabbie (hard shell) and some time later "spit out" parts of the hard shell. I have never seen them do this with the skeleton of other fish which they have consumed. It's reasonable to assume that the entire fish enters the stomach and is dissolved by stomach acids.

I have examined the stomach contents of many fish species which I've caught and seen many TOTALLY WHOLE fish and crustaceans therein. This would lead me to believe that fish are capable of swallowing hooks and having them pass through their system without too much harm to the fish. Just my observations and opinion. I shall be interested to see the opinions of others in this thread. What are your thoughts nutsaboutfishing?

Cheers, bn

Thanks for that BN. The reason I imagined hooks would be hard to pass is because of the barb. It's probably safe to assume the act of reeling in a gut hooked fish is going to set the barb into the stomach of the fish. Now I've never actually set a barb into my own flesh but have caught clothes, tackle bags and car seats, and once that barb's in it can be pretty hard to dislodge. I find it had to imagine that a fish stomach could dislodge itself, but your Murray cod with the butt hook would suggest otherwise.

cheers

Richard

3 hours ago, Volitan said:

It’s just guesswork unless research is done.

Fortunately, there has been a LOT of research done on this. Eg.

https://www.researchgate.net/publication/233287967_Effect_of_Hook_Type_on_Mortality_Trauma_and_Capture_Efficiency_of_Wild_Stream-Resident_Trout_Caught_by_Active_Baitfishing

https://www.researchgate.net/publication/233012131_Hook_Shedding_and_Mortality_of_Deeply_Hooked_Brook_Trout_Caught_with_Bait_on_Barbed_and_Barbless_Hooks

if you scroll down to the bottom and click on ‘Reference’ it will lead you to many other studies.

Paraphrasing Bob Dubois research:

of deeply hooked fish

74% mortality rate if hook removed.

47% mortality rate if hook left in

of those with hook left in that survived the test period, 74% shed the hook within two months, which if I read that correctly means about 35% of the total deep hooked fish shed the hook.

Another study found 55% mortality when hook removed and 21% when hook left in, but a shorter follow up period was involved.

There is a lot of research on this topic. Some bad, some good. Dubois’ research is well done because it involves catching fish by real anglers in real fishing conditions, then keeping the fish in pens in the same environment.. A lot of the research is done in fish farms or confinement ponds where fish don’t have to pursue wild food.

A couple of other interesting claims by researchers that I noted in the reading. Hold a fish out of water vertically (eg holding up by tail) and you have effectively killed it - fish are not adapted by evolution to be held upside down. %%%%%ing the air bladder of a fish caught in deep water does not increase survival rate - barotrauma kills fish regardless. I always wondered about that one.

 

They way i read it is 14 out of the 200 fish caught shed the hooks and since about 70 fish survived, this equates to 20% of surviving fish shedding their hooks. This is 20% more than I would have expected.  Incredible how a fish can get a barb out of it's stomach.

 

40 minutes ago, big Neil said:

Hi Volitan. Slightly off the original topic but still worth attention is your statement in the last paragraph of your post. Barotrauma kills fish as does puncturing the air bladder of captured deep water species. It would be easy to believe these statements. Working on the assumption that these statements are correct why do Fisheries encourage release of fish which are going to die anyway? Would it not be far more suitable to allow these fish to be part of a bag limit, even if they were undersized. EXAMPLE: Say you were fishing for Gemfish. There's no benefit in releasing small ones all day long, whilst chasing a bag limit of legal sized fish, if the released fish are going to die anyway. Just a thought.

One thing that really concerns me, particularly when I watch videos of fish being caught, is how long anglers keep these fish out of the water before releasing them. There's another topic that Raiders can weigh into. How long should fish be kept out of the water before being released?

Cheers, bn

I always wondered what's the mortality of fish that are send back into the deep with release weights. That would be a hard study to do

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Holding fish, big fish by the gills, lip grip or anything that places all the weight on the spinal area by down force is said to often result in permanent damage and the eventual death of the fish. Just common sense that one I think. Can't imagine too many creatures would fare that well being dangled around by their heads or jaw. Especially an aquatic one.

Edited by TAZ
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49 minutes ago, big Neil said:

EXAMPLE: Say you were fishing for Gemfish. There's no benefit in releasing small ones all day long, whilst chasing a bag limit of legal sized fish, if the released fish are going to die anyway.

DPI have not imposed a minimum size limit for deep water species just for that reason - the chance of survival is pretty close to zero. It’s a quantity limit (bag and boat and it’s also a combined limit across all species) with the caveat of only 2 gemfish per person and 10 per boat.

So most fishos bag out on deep water fish by hitting their gemmies limit first.  On my boat we then move onto trolling and other fishing endeavors- but I see some boats hanging around repeating drifts - makes me wonder if they have some special non-gemfish attracting bait ! 🧐🤨

cheers Zoran 

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I cant remembwr where i read ab article on this  but they found  common size 1/0  2/0  chemical sharpened hooks  were rusting or being eaten away by the antibodies in  the fishes body in bream  in less than a week   i personally dont use stainless steel hooks other than in latge trolling lures  as i believe fish stand at least a chance of survival if released   as said before they dont survive in an esky   i have caught an undersize red twice in an hr as i could see my line in his mouth that i cut off  so he survived an came bak for more

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9 hours ago, noelm said:

My usual reply to this sort of thing still stands, any fish thrown back has a much better chance of surviving than one in the esky, or one cut open to remove a 5 cent hook, and one carefully  handled has got an even better chance of surviving than one hung up by some sort of pliers for a photo, it's your personal choice, and I don't claim to be some hippie greenie, but, if I want a fish to eat, I keep it, if I don't want it (or it's not legal size) I make some effort to release it as healthy as possible.

pretty much sums it up-keep handling to a minimum and dont faf around too much with a fish you want to release, the one sure thing is if its in the esky its dead

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As an aside mentioned before   my pet hate is watching tv fisho presenters brag about how they are releasing their fish but hold it out of the water for ten minutes discussing how shiny its scales are or some other bullshit   peeves me to no end  get it in get a foto get it in the water  done 30 seconds max

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I have caught fish (different species) with hooks in their guts. The hooks appeared to be heading towards the arse end so as not to spike the gut and become stuck, that is, the rounded end first. Never found any stuck in the gut.

I pulled out a small reddie some years ago, the thing sticking out of the arse end was the tail of a soft plastic, so I gave it a gentle pull to find the jig head still attached. The reddie gave a big shake and sped off like a rocket towards the depths when released. Appears to have swallowed a discarded plastic and jig head.

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11 hours ago, TAZ said:

Holding fish, big fish by the gills, lip grip or anything that places all the weight on the spinal area by down force is said to often result in permanent damage and the eventual death of the fish. Just common sense that one I think. Can't imagine too many creatures would fare that well being dangled around by their heads or jaw. Especially an aquatic one.

Ok let's get some answers guys. You catch a toothy critter and want to release it unharmed. How do YOU go about it?

I have caught Barracuda and have used lip grips on the lower jaw and supported its body when releasing it. I also try to be very aware of how long the fish is out of the water, keeping it to as little time as possible. What do you do? bn

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If i can remove hooks i do so   on lures they generally arnt that hard  singles on wire  just snip wire n leave hook  

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11 hours ago, Volitan said:

With fisheries regulations, it’s a mix of managing a wild population and managing human behaviour. The human behaviour side is the difficult one as we all know that there is a percentage of fisherman who will cheat the regs in any way they can to get a result. So you end up with regulations which are not immediately logical.

So I assume that Fisheries know

1. most people aren’t going to get a bag limit, or anywhere close to it. If the majority of people caught their bag limit the result would be catastrophic.
2. allowing people to keep undersized fish because they may die on release will lead to a certain number of people targeting undersize fish. Eventually you would have a situation where everybody catches a bag limit, mostly undersize, and all perfectly legal.

i grew up trout fishing in NZ and the regulations at the time read that it was illegal to target (catch, not just keep) undersize fish. If you found yourself catching undersize fish accidentally that was OK but you had to change location or change method to minimise the chances of it occurring. Any undersize fish you caught counted towards your bag limit even though you couldn’t keep them.

There is also the public education angle. Regulations change peoples’ behaviour, albeit very slowly. I know a lot of people scoff at this, but I know it’s true. When I was a kid we kept everything we caught. I remember hearing about catch and release and thinking it was just some crazy American thing. Things started changing when I was about 14 or so, and new attitudes started surfacing. I was pretty late joining the bandwagon, which was mostly about parental example.

 

on the subject of keeping fish out of water, I did come across some research that showed keeping fish out for more then 1 minute dropped survival rates to 28%. I’d have to read more closely before accepting this, seems pretty low, and I think it would depend upon handling and fish species. 

i know that in some US fisheries fishing is not allowed in weather over (I think) 74 degrees f., as the survival rate of fish boated is too low.

All this stuff is on the net. There is an amazing amount of research done on fish survival because both recreation and commercial fishing are important industries worldwide. You need to do a bit of study on how to access scientific papers, but they are mostly out there and free.

Hi Volitan. If I could comment on a couple of points from the above post. Point 2. I was really only commenting on the tragic waste of Gemfish (or other deep sea varieties). Seems such a waste of the fishes life, that it dies as a result of being caught, and ends up back in the ocean when it could easily provide a meal for an angler. Having it taken by an angler and counting towards a deep sea species bag limit would benefit overall. There would be no need to continue to catch more of them which are going to die anyway. I didn't contemplate such a (considered) regulation to apply to other species (Bream, Flathead, Whiting, etc). Maybe fishing for deep sea species should be banned altogether if it (often)results in fish deaths.

The NZ regulation seems like it may have some merit if it were applied here to certain species.

Thank heaven we don't have an ambient temperature rule applied here, we may never get to go fishing. (LOL)

I'm more of a practical person than one who studies scientific data about my hobbies. I try to keep abreast of rules and regulations but soon tire of reading. Having said that I do appreciate folks that have a more scientific /technical approach to life's queries. Thanks for your informed comments, much appreciated. bn

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On 12/8/2019 at 8:59 PM, big Neil said:

Ok let's get some answers guys. You catch a toothy critter and want to release it unharmed. How do YOU go about it?

I have caught Barracuda and have used lip grips on the lower jaw and supported its body when releasing it. I also try to be very aware of how long the fish is out of the water, keeping it to as little time as possible. What do you do? bn

Hi mate. Sometimes I almost forget the generation I come from and just "kapow" fire from the hip. Hey, thats us! Hope no offence by my comments.

Toothy's, mate, for me, I think of myself first,  the creature second. End of story. But I never just disregard the creature like crap and will do what I can to be sure that to me, I have done the best in the given situation to give it the best chance of survival on release. I will readily admit that it has been a learning process and in times past believe this fish I released died due to me and my ignorance, no ifs. Some may still die to this day, but hopefully less than before. Have caught numerous Sharks and yep, that think some swam off and kicked it, but hope as many survived. Same as all my freshies. I never head lift anything I dont want to eat, end of story. And, never dry handle anything I dont want to eat. Or, bother to take pictures of them either. The longer out of the water, snap snap snap away, the more likely they are to die. Some fish are so high octane they cant take more than half a minute out, like Macks, caught enough of them to see that too many went belly up in very short time. Watch some fishing shows and laugh at how quickly the camera pans away after mack releases after photos get taken. Shark food.

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Another point to consider when handling fish intended for release, especially after a long, drawn out fight, like a big flathead on light leader or a jew on bream gear is, if possible net or hold them beside the boat leaving them in the water for a few minutes before pulling them into the boat.

Lifting them straight into the boat for a few pics is like asking a marathon runner to hold his breath for five minutes as soon as he crosses the finish line. Obviously it isn't going to end good.

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On 12/10/2019 at 1:52 PM, Green Hornet said:

Another point to consider when handling fish intended for release, especially after a long, drawn out fight, like a big flathead on light leader or a jew on bream gear is, if possible net or hold them beside the boat leaving them in the water for a few minutes before pulling them into the boat.

Lifting them straight into the boat for a few pics is like asking a marathon runner to hold his breath for five minutes as soon as he crosses the finish line. Obviously it isn't going to end good.

Totally agree. Everything, creature, stretched to the limit has a limit. Well put mate.

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