Longer days, warming water and soon you’ll be throwing Senkos in the brush. Dead fish at the weigh-in? Ain’t gonna happen.

And yet, in the deepwater lakes, when we have to go after them deep, and haul them up for the weigh-in, some of them die. And they do so whether they are vented or as we like to say, “fizzed.” There are studies on the matter in freshwater–though nothing like they have in saltwater–but if we’re really worried about mortality, then we better consider the data.

Out of a much larger report (see Feathers and Kanable), there were decompression studies I recall at Cal Poly in the 1980’s on largemouth bass and the Arizona Department of Wildlife  (click here)  has done plenty on bass tournament release. The fact that bass anglers tend to pick and choose what part of science they want to “believe,” however usually leads to maintaining the status quo.

From the California data, count on 40 percent mortality from fish brought up from 58 feet–regardless of what gallant steps you might take. And if you factor in the use of needles, according to the fisheries people in Arizona, expect “20% mortality associated with puncturing the swimbladder.”

What we need to understand is that “floaters” are a symptom of what happens to those fish. And here’s an ugly little list of some of the maladies, which are possible, from the decompression process, all under the heading of barotrauma: hemorrhaging in the pericardium, in the liver, in the kidney, ruptured swim bladders, exothalmia (eye-pop), blood or bile secretions from the vent, emboli (possibly gas, liquid or solid) in the gills or the pelvic fins.

In one freshwater species (not black bass) the existance of any above was fatal, according to a Corps of Engineers-sponsored study. Not a perfect comparison–but a fish none-the-less.

The Arizona work is telling, but possibly impractical for one-day contests. There they kept fish in pens for up to a week and used a depth-staging release of fish in crates so the fish could gather their equilibrium.

I’m not suggesting we take the route that PETA or those crazy vegetarian groups demand, but it’s apparent from me that the DFG would prefer not to interfere with organized bass fishing–unless they get enough pressure from others influencing the state laws. You know, environmental lobbyists and the like.

And who would have thought they could have put a depth limit in saltwater angling? But they did. But in those cases, there was no live release. What if we could guarantee lower mortality by limiting the depth we fish in tournaments?

But, of course, that’s not what we do. I can hear the wailing if we were to go to a 30-foot depth limit for winter tournaments. But that’s what the data says we should do.


14 Responses to “Bass release mortality: Not so good, really”

Bass release mortality: what's the scoop? « Kramer Gone Fishing…

Here at World Spinner we are debating the same thing……

Fortunately here in Minnesota the bass don’t generally live deeper than 25 feet. I have wondered about the ethics of fishing bass out of water deeper than 30 feet. Honestly I don’t know if I would do it, given the opportunity.

Bass Pundit, in the West, as you can imagine, there is a different orientation. Everyone seems to have a “caught ’em in 80 feet” story (I do). But just like there was a time when it was thought you couldn’t “catch out a lake” with conventional angling methods, as accurate information was disseminated we saw the thinking change. This is only a tournament issue, though. The daily bag limit is generally five and your neighbor can take his home. But tournament rules pit live release against the proven barotrauma of deep caught fish. Something may have to give, but I also don’t want winter (or summer) tournament black-outs.

I think a 30′ max makes sense. The fishery is VERY important. The counts would be down, but it would be an equal playing field, so what the heck?

by Bass Pro Shopper

I like the idea in principal, but it’s not practical. it would be too difficult to enforce. How is an angler going to prove his lures were no deeper than 30′ throughout the tournament, or that all his fish were caught within that limit? Is someone going to call the TD to say he spotted someone fishing in a spot that has got to be 31+’? It would just have to be up to the individual anglers to decide whether or not to purposely pull fish out of very deep water, or let them stay so they’ll be there another day.

Shopper: When you say “too difficult to enforce,” is that code for “You can’t trust tournament bass fishermen?” 🙁

You buy a license that says you can eat 5 a day as long as they meet each lakes rules. Last DVL event Kyle and I watched the bank fishermen sticken them and not letting them go. They were all over 3lbs. Lets not get to weird here folks and police the tournament guys to death when the regular public keeps what is legal. Deep fish dieoff in winter events? Give us fish taco’s at the next event. Healthier than pizza and burgers anyday.

I understand the frustration, Rick. The public does not have to abide by tournament constraints. But, remember, the tournaments are permitted (issued permits) because there is a presumption that tournaments use a public resource for commercial profit. It’s just curious to me that those on the extreme side of catch and release would rather release an injured fish (taken from extreme depth) rather than just avoiding the problem by fishing shallower. I may not have the most sophisticated electronics available, but I’m pretty sure I know when the fish I am catching or my bait is deeper than 30 feet.

by Marc Marcantonio

George, your comment that follows is interesting, and makes me feel old: “But just like there was a time when it was thought you couldn’t “catch out a lake” with conventional angling methods, as accurate information was disseminated we saw the thinking change.”

The reason I say this is because I remember (before organized bass tournaments were commonplace) when the public would think their local lake was “fished out.” Then a bass tournament would be held there and lots of bass would be caught, and the public realized they had not adapted as well as the bass had.

Although I don’t have the statistical data at hand, bass populations nationwide are higher than anytime in history; despite vastly increased angling pressure, tournament pressure, and increased opportunity for delayed mortality due to all the increased angling pressure.

The “data” referenced by this news story is contradicted by other studies (especially those done in Canada) regarding the effect of barotrauma to tournament caught bass. Much of the more comprehensive study on freshwater bass barotrauma has been accomplished in the past 6 years, and the information continues to evolve.

All should recognize that bass don’t reside at a single depth in which one can predict when it will suffer barotrauma if caught. You could catch a bass in ten feet of water that suffers from barotrauma if it ascended from deeper water in order to feed. Sure, this is an exception rather than the rule, but the issue is not so simple as establishment of a maximum depth in which to hold tournaments.

I would suggest that biologists should determine the health of any fishery before imposition of regulations intended to address population health.


Marc: Unfortunately, in California, biologists don’t make fisheries policy–from crappie limits to rockfish stocks–political party appointees do most of that. FYI, the ’83 California studies put black bass in a pressure tank, and adjusted conditions to the water pressure found at a depth of 18-plus meters and 40 percent of those fish succumbed. I recall speaking with one of the researchers and he said fish taken from deeper than 25 feet (meaning exposed to those conditions) all showed some kinds of internal damage. The Arizona fisheries work–pretty much the last six years from FLW, WON BASS and local events was pretty straight forward in my view. My stance is really a question: “If these things occur as described, shouldn’t we as anglers consider measures that might help survival?”

by Marc Marcantonio

George: I have some experience in this issue as a fisheries biologist myself, and while I won’t question the data of the Delta study I will affirm there are other more recent studies with different results. There are numerous explanations in the Delta study that can be argued, from a genetic perspective to scientific study considerations.

I understand the premise of your question ultimately has no bearing on the Delta data referenced, but the discussion you hoped to achieve instead seems to morph into a denigration of sound fisheries management principles.

But to your question I would still answer, “it all depends on the health of the bass population.” If anglers choose to always take the path of optimal survival, then harvest would have no place in game management of any type.

Incidentally, just as an interesting anecdotal true story regarding this topic, on Lake Washington as documented in my log, I have caught the same 3+ pound smallmouth bass from the same spot in 38 feet of water 3 years in a row. All three times I deflated the swim bladder with a syringe through the side of the bass. How do I know it was the same bass? Simple, it had a WDFW Tag number 236 on it, each time. Of course who knows, maybe the third time caused it to perish as I didn’t succeed in catching this bass again; or maybe it finally learned its lesson!


George, Marc misread Californin ‘data’ study as California Delta study! The Delta would not have this problem of course, most is about 20′ deep on the average.

by George Kramer

Thanks, OM. No worries, we’re all looking for usable info. I will say, though, I haven’t heard from any team tournament directors here. And I think I know why. They are the ones who have been seeing these losses in their winter tournaments and they’re not sure how to handle it.

by Marc Marcantonio

I apologize for the misread, thanks for the clarification.

Regarding not hearing from team tournament directors, I am not sure they have read your blog. On Feb 18 in Washington on Lake Sammamish the Evergreen Bass Club held their annual charity tournament called “Freeze Your Bass Blast”.


This is an open team event and raises money to support the Wounded Warrior program. This year there were over 70 anglers and there were 6 dead bass after the weigh-in (these expired fish were consumed). Of course nobody knows the delayed mortality, but there is no reason with these numbers that the tournament director would have something to hide and not post here.

This club runs a great tournament, and they teach how to properly handle the bass and fizz the bass, including providing laminated directions and diagrams, and providing the proper needles. They also have boats on the water to help those teams that are new to the procedure, and will fizz their bass for them. The lake is not that large so that help is available within 5 minutes of a phone call.

This was the 5th year for this event, and while we cannot get the WDFW to conduct a population study on bass in this lake, anecdotally the bass fishing contnues to get better each year as evidenced by tournament catch reports all year long.

Fishing in the winter is tough for most anglers, and it is not unusual for many to blank in a February tournament. Most of the bass caught are between 45 feet deep and 65 feet deep. They imposed a 3 fish limit for this tournament to reduce keeping more bass than necessary in a livewell all day. My partner and I caught a limit, and had no problem with fizzing them immediately and keeping them in good condition.

This club is very mindful of the issues associated with handling deep bass, and if they had any indication it was contributing to a decline in the fishery they would be the first to police themselves.

It is too bad all clubs can’t be like this, but there are some out there that take their responsibilities seriously.