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Mortality rate of caught and released fish?

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Discussion Starter #1
In waters that are "Catch and Release" or when simply ?Releasing? caught fish, what is your guess of the percentage of mortality of fish you have caught and released?  Even if you practice the highest level of release strategies (barbless hook, circle hook, etc...) there still is the potential to fatally wound a fish. If anyone has hard facts (studies etc..) please post to this thread enquiring minds want to know...
 

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Taken from Catch and Release Fishing Effectiveness and Mortality, a review paper on currently available scientific literature:


Key Mortality Factors

Two factors predominate when considering the causes of angled fish mortality: the hooking location, and the degree of physiological stress suffered by the fish.

Hooking location ? This factor demonstrates the largest source of variation in mortality observed in the studies and experiments reviewed.  It is consistently shown that deep-hooking (hooking in the gills or gullet) causes relatively high mortality, up to 35% when accompanied by bleeding, whereas normal hooking (lips or jaw area) consistently causes minimal mortality, which is consistently less than 5% and often less than 1%.  The Maryland Department of Natural Resources, in its Recreational Catch and Release Mortality research program concludes that the location of the hook wound is the single most important factor influencing catch and release mortality (4). If the hook wound affects a vital organ, mortality, is high.  The location of the wound site has been demonstrated to be a function of hook size, type, the use of natural bait versus artificial lures and additional situational factors.  Studies show that when fish are hooked in the lips or jaw area (shallow hooked), mortality is negligible, typically less than 1% (4,5).  Conversely, mortality is at its highest when fish are hooked in the esophagus or gills (deep hooked) (5,11).  Necropsies performed on gut hooked fish in a study by (5) Grover, et al, found that the majority had sustained major internal damage to the heart, stomach or liver. Grover demonstrates that hooking location effectively correlates to mortality rate.

Physiological Stress ? Exercise performed by fish during a catch event, or caused by angler handling methods and air exposure all create measurable physiological responses.   Physiological stress in fish has been measured by experimenters using cortisol, lactate and respiratory gas concentrations. 

Although the catch and release mortality studies reviewed do not show statistical results directly correlating the degree of physiological stress to mortality, an experiment by Ferguson and Tufts examined the effects of artificially induced stress on rainbow trout.  They concluded that various forms of physiological stress contribute to fish mortality (12).  It is reasonable to infer that such stress also contributes to mortality in angled fish and therefore, that minimization of stress assists in reduction of catch and release mortality. 

To read the full article go here:
http://www.acuteangling.com/Reference/C&RMortality.html
 

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My humble opinion of fish mortality. :)

I did not vote because I think it is impossible to estimate the mortality of catch land release. There are too many factors to weigh. Some folks claim to have a very low mortality rate and they may. Using barbless hooks is a definite factor in my opinion as well as quickly landing and releasing the fish. But somethings that we can't factor in are things that happen after we see the fish swim away

Has the fish been stressed to the point that it dies later even though it appears healthy upon release. Has injury occurred that makes is more susceptible to predation? Has the stress of being caught and released made it more susceptible to parasitic infection? Has dropping it on the rocks caused internal injuries? Even though a fish may appear normal and able to continue on when released, we have done things to it, things so slight that we may not realize it that will affect its overall mortality, days or maybe weeks in the future.

I don't see alot of these issues addressed in the various studies about mortality. Nor do I see what time frame they based most of these studies on. I assume most of the fish die within the first couple of days and the mortality rate decreases over time but some still do die after the study period ends as a result of being caught.

So like I said, I think its impossible to estimate what the real mortality rate is. Handle the fish carefully and quickly, return it to the water insure that its equilibrium is reestablished and hope for the best. Some live and some die.

Dan
 

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TroutHunter said:
In waters that are "Catch and Release" or when simply ?Releasing? caught fish, what is your guess of the percentage of mortality of fish you have caught and released? Even if you practice the highest level of release strategies (barbless hook, circle hook, etc...) there still is the potential to fatally wound a fish. If anyone has hard facts (studies etc..) please post to this thread enquiring minds want to know...
Whoops, I read this too quickly and picked the reverse, i.e. how many fish survive a catch & release. So you can ignore my 50% + vote ;) ;)
 

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Discussion Starter #5
Yes there are alot of factors and variables to consider that is why it is an opinion poll to give your best guess weighing all the factors you want. I guess I should have put an "obstain from voting" option or a "recuse myself from voting" option just incase you were related to the case of the dead fish I found in the south platte the other day....J/K


All  jokes aside here are some water cooler comments that I have heard recently and in the past....voice your opinion on them if you'd like:

1) Is the corolation to bigger fish in the catch and release waters due mostly to the practice of releasing all the fish or to the fact that typically less people use flies and lures only and there is less pressure and success rates?

2) Great point above and that also was one that I have heard "Has the fish been stressed to the point that it dies later even though it appears healthy upon release.  Has injury occurred that makes is more susceptible to predation?  Has the stress of being caught and released made it more susceptible to parasitic infection?" Has anyone caught a fish one week with a distinquished marking and then weeks later caught that same fish? Some of you fisherman that take home a few occaisionally to eat, like myself, have noticed hooks rusting and degrading inside fish after gutting them? They seem like they have had that hook in them for quite a while.

3) Law is the Law we all are Americans citizens or Legal Foriegners who live here thus agreeing to follow the laws of the land (hopefully)...What would you rather see?  A fish that you know you have mortally wounded and is bleeding releasing that fish back because it is catch and release area, full well knowing that you could have ate it and not let it go to waste???Has this thought ever crossed your mind? Remember in this hypothetical question you followed all the regulations to the "T". If you want to take it to and even greater extreme say that you used barbless / circle hooks, so in essence you tried everything you could to be able to be in the position to release the fish however the cards just did not fall that way and you have a dying bleeding fish on your hands?
 

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thats a rough one. i have in the past kept a fish (pacific barracuda) that was short because it was practicaly dead before it got to the boat. we used to get checked all the time and i expectted to be checked at the dock, but this day the warden was somewere else. i have also released trout here that were bleeding so bad from inhaleing a spinner that i was shure they were going to die it made me sick to my stomach. i cant say at this moment what i will do if this situation rises its ugly head again, one thing i always do is if i have to release a mortaly wounded fish due to being under size is that i count it in my bag limit, also if this happens on a catch and release only section i call it a day and go home
 
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#3-

I wouldn't consider the fish as "going to waste" just because I didn't eat it. The nutrients from that fish's decaying body are going to enter the stream/lake when it dies from my hook wound, just as they would have if it died from old age. The carcass will feed crawdads and other aquatic life which, may be eaten by small fish, which will be eaten by bigger fish, etc. You know, the whole "circle of life" business.

So, if I have chosen to fish a catch & release area, I prefer to see that fish returned to continue to feed the system.
 

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circle of life, good point!

although when im fishing a stream and i see the dead trout drifting by that is kinda depressing
 

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TroutHunter said:
1) Is the corolation to bigger fish in the catch and release waters due mostly to the practice of releasing all the fish or to the fact that typically less people use flies and lures only and there is less pressure and success rates?
The best two rivers in colorado allow bait in pretty much the whole thing; including the prime water. (colorado river, white river) They have more and bigger fish than the nearby roaring fork and yampa rivers, respectively. most people can't baitfish for crap in rivers anyway, and catch absolutely nothing with heavy line, a large egg sinker, and power bait. I fish bait differently though and have a mortality that couldn't be any higher than someone that uses flies or lures because I hook nearly every fish in the lip. There are more anglers like me than is believed though.

I believe however, that mortality is often higher than we as fisherman believe. Especially during the drought years. Fish then were stressed; the water was insanely low, thus warmer, more silty, and the trout habitat just wasn't as good. If you catch a fish, fight it, then release it, nomatter if they were hooked barely in the lip and handled perfectly, some of them died. Also, a lot of fish die on flyfisherman's paradise, because of ridiculously light tippet use and very long fighting of even small trout. This leads to lactic acid buildup which isn't good for a fish. It often can kill them. Big fish however, are generally more exempt from this I have heard. I think when the water temperature is warmer, that if we want most of our trout to live when released, we should just not fish.
 

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Discussion Starter #10
TroutFishingBear great post again....I will ask this question in leu on TroutFishingBear's post....Do you think Catch and Release waters are there to allow trout to be released and grow bigger or to keep all the bait fishermen away?

The thought behind TroutFishingBear's post is that there is a similar death rate of trout that are hooked and released by bait fishermen and those released by lure and fly fishermen?? Does any one second that notion?

I personally have caught several fish in the dream stream that look as if a muskie had bit there faces but really it was from being caught and released several times..Do these fish really survive? One may never know....
 

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TroutHunter said:
The thought behind TroutFishingBear's post is that there is a similar death rate of trout that are hooked and released by bait fishermen and those released by lure and fly fishermen?? Does any one second that notion?
A similar death rate by skilled baitfisherman. Skilled is the key there. A powerbait guy using 17 lb. test and a 1/2 oz weight and a treble hook isn't going to release too many fish alive tos ay the least. I'm sure there are others that second that notion; there are some " wiggly drifters" out there.
 

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One thing is for sure, if you don't release the fish, he will die. I've caught and released a lot of Atlantic sailfish. There are times, when fishing live bait in particular, that these fish come up gut hooked or in and around the gills. Unless the fish is belly-up and not revivable, I always let him go. It may be 5% or it may be 95% that survive, if you put him in the boat, he's dead.
 

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TroutFishingBear said:
A similar death rate by skilled baitfisherman. Skilled is the key there. A powerbait guy using 17 lb. test and a 1/2 oz weight and a treble hook isn't going to release too many fish alive tos ay the least. I'm sure there are others that second that notion; there are some " wiggly drifters" out there.
is this notion of yours for trout or other fish as well...?
 

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From what I learned from private biologists, in college, and from observations and studies I have done via fishing and field observation in college studies, fishing mortality via method is APPROXIMATELY AS FOLLOWS:

Properly Fished Flies (Heavy enough gear to play fish) -

4.5%

All Artificial Lures (4.5% to 6%)

Actively Fished Bait (Properly Fished Bait) - 6%

Passive Bait Fishing (still fishing, tip ups) - 20 - 30%

Improperly fished flies or lures (too light of gear) - Over 50%

Another big factor though is not handling fish right. Dropping them on sharp rocks, squeezing them, placing fingers in gills, keeping them out of water too long, Is a HUGE factor in mortality.
 
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