What is the mortality rate for catch and release?

Matt Burke

Active Member
This question is not meant to spur on a heated debate. Wbugger has gotten me to re-think this for myself because I had always hoped that my survival rate was 100%.

What is the mortality rate for flies vs. spin fishing with all the hardware?

Do mortalty rates change for certain species?

I know how much better quality lakes are for fly fishing, but if every waterway was C & R, would it really benifit the fisheries or would we still have to deal with all the other environmental impacts?

Where is the research for this?


Matt, not being a fisheries biologist who has conducted these surveys, i can give you my blabbering. :pROFESSOR

Well, I would first of all gues that spin fishing would have a larger mortality rate overall, primarily because most lures have 3 trebs. But most of the time, i think it really is how you play the fish. If you catch a 30 inch steelie on a 2 weight that fish is definatly more prone to die than a 30 incher caught on a 8 weight. Most of the time it really depends on the circumstance.
I have found that bull trout tire more that any other trout that i have caught but thats just me.
I think that catch and release can help the fishing, while promoting bigger and fatter fish, it can also make the fishing a lot more techincal, it just depends, easier fishing for smaller fish or techical fishing for large fish.


Rob Blomquist

Formerly Tight Loops
I can't tell you what the mortality rate is, but yesterday on the NF Stilly, I saw 2 fish that were each 14" or so dead in the river. I can only assume that they died from mishandling during C&R.

Genetic pollution damages wild
stocks, bonk those Hatchery Zombies!
Follow the rules (play fish quickly, keep fish in the water, don't touch fish with dry hands, allow fish to recover in slow water) and trout survival rates are somewhere around 90% WHEN the water is cold and oxygenated.

I've heard that trout survival rates are not good (50% or less) when the water temperatures are higher. I don't remember the exact temp, but I think the cut-off was around 65F. It's a good reason not to put added pressure on fish in warm and low summer conditions.
Not real sure what the death rate is for catch and release but it's surely is lower than the death rate for catch and keep!!!


"In our family, there is no clear
line between religion and fly
fishing" Norman Maclean
I agree the fight, handling and hook depth, water temp all contribute a part in the death.
Hook depth has to be treated with care as you could severely damage the Gill area and throat of the fish.
If the fish is brought in quickly and not played to a point where it is totally exhausted that is good.
Water temperature is also a factor for an exhausted fish.
At 55f the gill absorption of Oxygen is about 40%and at 63f it is about 90%.
So it needs more loving care at the lower temps to get back its strength.
The fight,hook depth, handling and water temp all contribute to the death of a fish.
Hook depth is harmful where the hook is torn out of the throat or gill areas.
The fight to complete exhaution of the fish is not good.
Handling direstly or roughly can harm it as well.
Water temp has a lot to do with death as after the fight the fish is tired. The gill oxgen stauration of a fish in water temps of 55F is about 40% at 63F it is about 90% so it fairs beter at higher temps when being released. Therefore sometimes it is better at lower water temps to head the fish into the current for it to gain strngth, before releasing.
There are many variables some of which have been mentioned (water temp/oxygen saturation) but the biggest factor has to be artificial flies and lures versus bait. Actually along these lines, treble hooks probably do not significantly increase kill rates because they rarely get deeper than the mouth although they probably scar up the inside of the mouth more. My guess is that most C&R flyfishers or spin fishers experience a kill rate under 5% and some far less. All one has to do is go to Rocky Ford or some well know desert lakes and look for dead fish versus the numbers caught and released. Sure you will see an occasional dead fish or two but not near the numbers you would find if the rates were as high as some think. I have fished alpine lakes with others where over 100 fish are C&R daily sometimes and rarely see a dead fish. Playing big fish on 6 or 7x tippets until near exhaustion with a 2wt has a greater risk than playing the same fish with 2 or 3x on a 6wt but in both cases, a caring fisher can see the fish is sufficiently revived before release. Accidently hooking a fish in the eye, gill or tongue can increase the chance of death through shock from blood loss but that doesn't happen that often and smaller barbless flies can significantly reduce the damage.



AKA: Gregory Mine
No idea on what the percentage would be. But what I do know is they have a 100% greater chance of living if you let them go versus putting them in the bag.. You can only catch a fish you intentionally kill once.
The studies which I have seen estimate deaths at 3-6% for flies, 5-10% for lures and 30% for bait. Catch and release works if you keep the fish in the water during the release. I once got into a conversation with a fish biologist along the banks of Castle Rock Creek in Wisconsin. It is a fertile spring creek but small and very heavily fished due to great access and the fact it is a little more than an hours drive from Madison. The fish biologist said they estimated that the average 12 inch fish in the creek was caught 5 times a year.


Active Member
Lots of good info on this so far. I would just like to add my two cents on the quality of the net used by people who drift.

My brother who is a guide out of W. Yellowstone was one of the first people I ever knew who had one of those nets with the rubber webbing material. People laughed at him, but now it is all the better shops handle.

Saw some beautiful nets in Red's Fly Shop last week on the Yakima. Beautiful wood handles, rubber webbing and made in Tacoma if I remember correct. Georgeous and very effective for properly releasing fish.

Angling method appears not to matter much at all! It's a han

I know this is counter-intuitive and counter to most of our experiences, but most studies conclude that flies vs. hardware vs. bait doesn't make a whole lot of difference to steelhead catch and release survival rates. (Do a search on C & R on www.google.com and you'll find a few recent articles out of BC and the Pac NW. But what's more surprising is the LACK of studies on this very topic.)

From (faulty, fuzzy) memory, steelhead C&R mortality was 3-4% on flies and hardware in one study vs. 4-5% for bait. I was astounded it was so low for bait and such a low differential with artificials. (There's a separate study that showed tidewater salmon swallow bait deeply and suffered high C&R mortality. There's another study that cited 30% C&R mortality among lower mainland BC coho that were caught 'bar fishing' or plunking with bait. Fish that deeply swallow bait are going to die more frequently than mouth-hooked fish. Many experienced steelhead roe fishermen claim to go an entire season without gut-hooking a steelhead. I don't fish bait so I don't know.)

Personally, I think that single, barbless hooks and 'no bait' has[I/] to result in lower C&R mortality. But that's just my opinion -- I haven't seen any research to support this view.

I bring all this up because quite often fly-only fishermen lobby for "fly only" water on conservation grounds, specifically lower C&R mortality. While everyone is entitled to their opinions, after having participated in two years' of (often heated) bulletin board and email debates I'm now convinced that gear and method (short of snagging!) restrictions damage sport fishing and the conservation ethos more than they help. The result of any group's lobbying for gear restrictions ("no bait" or "fly only") is to immediately pit them against everyone who would be excluded. This splitting of the already small, largely unorganized sport fishing community merely plays into the hands of our real foes: the commercial fishing interests, power companies and other habitat destroyers. If our goal is to reduce pressure on the fish by catching fewer of them, there are other ways of achieving this goal without gear restrictions. For example, you can institute "No motorized boats" or "no fishing from boats" rules on smaller watersheds. Close certain sections entirely for periods of time (e.g. spawning water).

Anyway, I'm well off topic so I'll shut up here (and wait for the fur to start to fly).

* * * * *

If you play your fish quickly, then hold the leader while the fish is in the shallows and then remove a barbless hook with hemostats or needlenosed pliers (without touching the fish), then you get a 10-out--of-10 for safe C&R practices. But some of the fish we catch are going to die anyway irrespective of how well we handle them -- that's one of the consequences of fishing with hook and line.

"Poor loops, but at least the fly is landing farther out than the main line these days"
Angling method appears not to matter much at all! It's a

I've read a bunch of the studies as well. Most of them show signficantly higher survival for properly handled fish. The bottom line is that whacking a fish over the head kills them and they can no longer be caught (or more importantly, spawn). I don't need more studies to convince me one way or the other. If you look at the fisheries within the various rivers of Yellowstone park, for example, you'll see great populations of trout. Mutliple age classes, big fish, small fish, healthy fish. Yellowstone rivers and lakes are not stocked and haven't been for a number of years--solely natural reproduction. Those populations wouldn't exist if the MASSIVE number of anglers who fish those waters were permitted to keep all their fish. I had the great pleasure of electrofishing the Gibbon River a few years ago. I saw dozens of browns over 20'' in there some of which had hook scars indicating they'd be caught before. They're still in there adding to the numbers. If the good ol' boys who'd just purchased 10.99 baitchucker's specials at WalMart were allowed to do it their way on those rivers I'm sure alot more of those fish wouldn't make make it much further than the next pool downstream.

I think a lot of people make the mistake of thinking that just because the fish swims away means it'll be fine. I've seen a few really small alpine lakes fish get pretty mangled on medium sized flies and I doubt they made it too far despite swimming away. Logic tells me that a salmon egg hook taken deep in the throat and gill rakers is going to 'mangle' the fish more and removal of a hook in a spot like this is going to be much more stressful on a fish than a barbless adams on the lip.


Jay Burman

Fly Fisher, Bon Vivant, Layabout.
I'm not sure of the exact percentage but it's much higher than "catch & kill". Always practice "catch & release" in Wasington trout waters and encourage others to do so too. You can catch & kill all the perch & walleyes you like and they're great eating. Trout are slow to reproduce so C&R helps keep their populations up.