For LMB overpopulated waters, which is most, harvest is a key management tool. Take out the underperformers, throw back the healthiest. General rule of thumb in the South is below 14 inches, harvest, unless it is fat & aggressive. Above 14 inches, don't harvest, unless it is underweight.

But there seem to be two schools of thought about really small LMB, say, below 8 inches. On the one hand, they make good forage for the big LMB, so should not be harvested. On the other, they eat small forage fish themselves, like BG, that could have fed larger LMB. That being so, the little guys should be harvested.

I tend to throw back LMB under 8 inches, but maybe I shouldn't. What say you?

I got interested in the subject upon reading the March/April PB magazine. On page 36 there was a picture of a little LMB along with the caption, "Consider harvesting Largemouth bass when they are small...No sense letting them eat a bunch of forage fish prior to harvesting them." Article by fisheries biologist David Beasley of SOLitude.

I agree with David.

Thanks. That makes two experts on the harvest little bass side. Maybe I'll need to change my harvest policy, there is certainly no shortage of really small ones hanging around shallow cover at my place.

The way I look at it is weight is weight. If the pond is bass heavy, removing smaller fish will allow the fish that they would have eaten to grow and feed the larger bass. Of course by all means remove any underweight bass of all sizes that is caught. That means that there isn't forage of the size that they need to eat in the pond. Since they are underweight they have lost growth days. Removing them means that there should be larger forage for when the next class size LMB gets to be that length, and the theory is that once that happens they will have sufficient forage to continue to grow instead of stunt.

I take the under 14" to be just what it says ... everything under 14". When one starts to make exceptions then the condition is set to develop a population of small LMB ... a condition that is harmful to large bass. Small LMB cannot provide forage as efficiently as BG can. Now if you want to take a less than 8" LMB and cripple it, by all means, make it an ineffective predator and easy prey but if you allow them to grow they are going to intercept much more prey than they ultimately provide.

I think the thing to remember is that an 8 lb LMB doesn't eat a greater number of BG than an 8" LMB. Because they prey on BG that have a proportional relative size it takes the same number to sustain both. But the 8" LMB gets fed first because BG must outgrow the 8" LMB predation before they can be prey for the 8 pounders.

LMB recruitment is overrated if someone is trying to grow trophies. It just isn't required. If one has no recruitment (except that controlled by the stocking of select young adults) then it is much easier to grow trophies because the production of BG YOY feeds only those fish that are trophy path. If it seems expensive to be in the position of having to stock LMB recruits ... consider the alternative costs of time and money to feed and manage excessive recruitment. It's a fine line to carry a balance that only recruits the goldilocks number of LMB. Once it goes one way or the other momentum takes it further. Too many LMB recruits is self sustaining ad infinitum but lack of LMB recruitment is not self-sustaining. So stocking LMB adults to obtain trophy path recruits is important when this condition exists... but if too many are added ... one will swing the other way and over recruitment defines the battle from that point forward.

Managing LMB/BG ponds for balance has been described as attempting to balance on the edge of a knife blade.

Which is why it's so important to decide what fish make the cut.

Sorry, couldn't resist! But on a serious note, is it really true that "weight is weight?" Bob Lusk reports success in overstocking LMB, at least in the sense that large numbers give better chances of turning up exceptional females. Only harvesting LMB larger than 8 inches has the twin advantages of giving you a better sense of their growth potential (hard to judge for a 4 incher!) and numbers (four or five chances lost for a superior fish per 1 lb harvested, rather than just one chance).

Not trying to start an argument here, just trying to stimulate discussion. Perhaps the answer will vary with the pond, the goals, the BG population, the LMB population, how much it is fished, and how fertile the water happens to be. Heck, even the cormorants get a say, as they tend to target smaller LMB.

I never put much thought into this before. Gotta say I do like the idea of crippling the smaller ones. How would you go about this? My guess would be to clip a fin. Is there a good way to do this so they don't just die? Always feel bad throwing them on the bank to die. Just think in my head another fish could have had a good dinner from it.

Rusto, some folks like Bruce Condello feed train their bass with bluegill they've fin clipped & stunned, so something similar could certainly be done with small LMB. It does seem to work, though you might end up feeding a heron or cormorant. I used this strategy once on a 11 inch LMB to entice a large tiger musky.

Clipping the tail fin as close to the body as possible works well for me. Doing that means the fish can't easily swim away, and the flailing of the fish entices predators. If you do this at the same time of day, LMB may show up to wait on a low exertion meal. If you want to "stun" the BG, just put them in a bucket with a small amount of clove oil added to the water, and they'll be lethargic when thrown back into the pond.

Our cull cut line is a nonnegotiable 15". Overton's came and electroshocked our pond last week, and they pulled 150# out. I don't let relative weights change my decision because the amount of small forage they eat is the issue, not the under performance of some LMB.

Thanks, Al. I wonder if any vegetable oil would work, helping to block respiration in the gills. Of course, my focus is on feeding small LMB to large LMB, but the same tactic should serve.

Do you then put some clove oil on your crankbait when trying to catch your big bass?

Might work better on a slow moving plastic lure. Garlic may work, too.

My pond fluctuates from a puddle to a swamp, and I've got dozens of plano boxes loaded with crankbaits. I rarely get to use them, and I sure miss fishing with them. 10" ringed curly tailed worms with a tiny 3/16oz tungsten bullet weights are my go to bait for larger LMB. Watermelon is their color of choice.

Overtons came out to a neighbors 25 acre lake last fall and shocked up a mess of fish.... they used clove oil to stun/ calm the fish . The culls were cleaned and eaten.... won’t be doing that again.... the clove oil migrated to the fish flesh giving it a not pleasant taste...

anthropic, I don't how the vegetable oil would work. We used to use shears to sever the gills.

Sounds interesting, Al. Will try it!

I think Bob wouldn't give that advice to everyone. I think he'd need to have confidence that his culling advice was practiced also. It would be nice if he would chime in, but I think he intended for that condition of too many LMB to be a very temporary one that allowed a selection of an appropriate number of exceptional females through the culling of the inferior stocked individuals. I feel pretty confident that he wouldn't recommend an ongoing condition of too many LMB.

I am reminded of Ketona Lake near Montgomery AL. This lake grew two world BG and numerous fish > 2lbs. A mecca of naturally grown trophy BG for those who could access the privately held lake. State fisheries biologists were keen to understand if they were genetically superior to other Northern BG of in the state. After their tests they concluded that there was nothing special about the BG but that there was something special about the environment of Ketona Lake. They concluded that abundant small bass, very limited BG reproduction, lower fishing pressure, and difficult fishing conditions (very clear water) made the perfect storm allowing "nothing special" BG to grow to insane World Record sizes.

I am not discounting genetics but population structure is much more important. Ask Eric, even slower growing LMB tend to live longer and attain the sizes of the faster growing LMB. We can't assume that a monster LMB was of the faster growing or slower growing clans. It is possible for slower growing females to attain very large weights.

Population mgt with LMB and BG can be a huge issue and very frustrating especially in larger ponds with limited fishing. Taking out 20-30 lbs of LMB a year in the 8-12 inch size every year can be a task for one or two fishermen. If those same fish could be fed to the bigger LMB it would help a lot. Keep in mind that the 20-30 lbs (southern ponds) is only what the human cull is suggested and does not include natural mortalities. If you have a lot of big LMB then your cull #s could go down substantially. Neither the task nor the science behind proper cull amounts is easy . It truly does "all depend" on the factors present and goals as noted in posts above.

The best easy rule I have seen is provided by Professor Richard Anderson who literally wrote the book on population analysis.

From an archived thread :

For LMB

This is what is suggested by Dick Anderson - the Prof who wrote the book on PSD.

Keep taking <12 in bass until the number 8-12 equals number 12-15. Ideal pond structure is 40% 8-12, 40% 12-15 and 20% 15+

This assumes good fish condition.

Another suggestion is take out all the fish in poor condition in all size groups. Note the size group that is stunted will have a much higher % of fish in poor condition.

These are all correlated to the concept of RW mgt.

Here are 3 archive links with a ton of info on the subject.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=255372#Post255372

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=255359

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92492#Post92492

If the only method of removal is hook and line then you need to consider the catchibility issue which underlies your question about genetics.

If one takes the mean weight of > than 15" fish to be equivalent to a 20" standard weight LMB, then this allows for 56% of the biomass of LMB to be in fish larger than 15". That's pretty darn good. For 80 lbs of LMB Standing Weight, this allows 9 > 15", 18 12-15", and 18 8-12" (46 Fish total).

Does anyone have any thoughts on how to cull to try to retain this population structure over time? For example, assuming growth, what is the best culling method to ensure that the population doesn't get over-numbered in any one of these size classes?

I HATE cormorants with a passion, but if they tend to select the smaller, more abundant bass, maybe they can be helpful in some situations. I recall Bob Lusk wrote about a neglected pond that was full of big LMB, much to his surprise. Later he figured out that while fishermen didn't cull the little guys, cormorants did. And they don't select the most aggressive fish to eat.

That said, I still hate cormorants.

That's a tough call, jpsdad, I know what your question is but the management input to control various sizes would have to be structured around a specific time frame or the results will be biased in the direction of taking smaller fish as they continue to grow. Just thinking out loud..

My personal experience at my pond was I never had to cull the lmb. I am pretty sure the pond was culled through several different methods. The lmb did great as far as growth for the first five yrs up until the fish kill caused by excessive growth of Southern Niad. Here is a list of the things I saw that culled the lmb for me. Bald eagles, Osprey, Cormorants, Otters, HSB and larger sized lmb and the larger sized CNBG. Even now a year later, I do not see too many small lmb. And just yesterday I jumped two cormorants off the pond and watched an Osprey circle overhead looking for an easy meal while I see the larger sizes lmb swimming and looking for something to eat. Every pond is different and has its own personality. So cull from what you see and not what someone else sees at their pond.

+1

I was just thinking from the perspective of method or protocol to maintain the 40-40-20 year after year after year. So a sustainable management method that is effective at maintaining the population structure. Considering the 8" to 15" fish comprise 80 % of the population, its obvious that a minimum of 75% of them must go (assuming they are replaced by recruitment maintaining their numbers). Because the production is the mortality, only mortality allow the fish to grow. So the mortality of say a 24" fish allows all the fish >15" to grow larger and a 12" to 15" fish to grow into the >15" class ... the mortality of 12"-15" fish allows an equal number of 8'-12" fish to grow into the 12"-15" class ... so what remains sufficient mortality <12" to restrict the population in that class to 40% of the population. The challenge, Is understanding the amount of annual mortality required to restrict each class to its respective population goal. It is complicated because recruitment varies with strong year classes and because it also depends on annual growth of individual fish. I am not sure how to employ a method ... it would be helpful to have survey metrics one is confident to estimate relative abundance of each class.


BG, while they many not be very good cullers of LMB. BG are pretty good at preventing swim up fry when BG numbers are high in the intermediate sizes. They may have restricted recruitment of swim up or prevented it altogether. So if you were seeing lots of 2" LMB fry then the ospreys, cormorants, and LMB were doing a good job of limiting recruitment of LMB adults. If you didn't see lots of 2" fry, they may not have been any.

The 40-40-20 system that Dr Anderson proposes intends for annual natural recruitment and probably depends on it (or at least bi-annual success of LMB recruitment) in order work smoothly.

Wise words. And not only is every pond different, every year at the pond is different, too. The balance is always shifting, we just need to keep up.

In answer to my initial question, I guess it's best to assess relative abundance of different size classes via angling & electro-survey every year. If very abundant LMB under 8 inches, harvest them. Not so abundant, throw them back. Strategy will flex with population dynamics.

Usually I have loads of really small LMB, but used herbicide that wiped out 90% plus of my pondweeds last summer. Not much has regrown, either. Perhaps there will be fewer small LMB this year, as they had less cover. We'll see.

Quote - jpsdad Does anyone have any thoughts on how to cull to try to retain this population structure over time? For example, assuming growth, what is the best culling method to ensure that the population doesn't get over-numbered in any one of these size classes?


I should have posted the rest of the previous thread in my prior post - here it is wrt culling method.



If the only method of removal is hook and line then you need to consider the catchibility issue which underlies your question about genetics. Catachability is a genetic trait and only using angling to cull can give negative results - see below. Angling removes the most catchable fish.

Look for threads here on catchability. The info is here as is the research.



Here are a couple with links

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=274175&page=1

http://forums.pondboss.com/ubbthrea...=catchability&Search=true#Post200220

http://forums.pondboss.com/ubbthrea...=catchability&Search=true#Post260622

Electroshock is the best culling method I know to avoid the catachability problem long term.

Last night on Pond Boss Live, Bob said an 8" bass in the springtime is a year old and should be 12 to 14 inches...cull it! And worse, the 8" bass will be eating all the little 1/2 to 1 inch bluegills, robbing the future food for the larger bass.

Good post, Eric. I wonder if periodic stocking of aggressive F1 and/or N LMB might also be helpful in maintaining catchability.

Yes indeed. I need to harvest those little guys, though it goes against the grain to take out a five incher. Probably the smartest move is to cut off their tails then throw back to make an easy meal for the bigguns.

Since LMB are often over abundant this is a VERY good idea posted by 'anthropic' """the smartest move is to cut off their tails then throw(them) back to make an easy meal for the bigguns.""" Plus this method can be used for any overabundant fish in the pond and this helps somewhat to reduce the tendency for creating hook smart fish. As per ewest above - too bad small LMB do not readily enter traps which makes them mostly available via angling and electroshocking and maybe seining.

I figure that only crazy bass are in seine.

When you use a seine in the beach area one is most likely mostly catching young of year (YOY) bass and not very many larger bass in the size range of 12"-15". . That is why I used the 'maybe seining' in my post. LMB are not the easiest fish to efficiently reduce their numbers. This is probably why there is a beginning trend to use tiger Musky or northern pike and maybe chain pickerel to use predation help thin bass.

Seining can help especially depending on how and with what you seine. It is very hard to catch LMB over 8 inches in a seine.