Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Managing black crappie

Are the LMB keeping down the crappie population by eating the large ones, or are the tiny BG keeping down the crappie population by eating thousands of fry?

Even if only a few crappie reach the correct size to spawn, a female BCP can still produce 40,000 eggs.

If Pat has a relatively small number of trophy size bass, what is eating the 2-3" BG in the pond?

Pat, have you checked for stunting of your BG? I agree with jpsdad above where he suggests adding a few smaller bass each year. I believe that would extend the balance of your awesome pond a little while longer.

I have caught some BG this spring over a pound, the others don’t seem stunted that I can tell just a lot of them. Walking the dam I can see bunches of BG surrounding the LMB trying to spawn. This year the crappie haven’t been seen close to the bank- only LMB and BG. Last spring I caught 25 crappie 12-14” from my neighbors pond and released them in my pond. The few that I catch here are 8-10” and few and far between. I catch more bass on crappie jigs than anything. They range from 10-14” some 1-1/2# mixed in . I haven’t kept any BCP at all . We eat the LMB if under a pound plus or minus. Haven’t kept any BG to eat(don’t care for them).
Wonder if I should try to add a few breeding size WCP?

These are really good questions FishingRod

Pat, in your best judgment, what percentage of the LMB population is 8-12", 12"-15", 15"-20", and >20"?

Pat, I was just asking lots of questions about your pond as a learning exercise.

I think I remember some excellent LMB reports from your pond. I know that a managed fish population is always a moving target, but "If it ain't broke, don't fix it." is frequently wise advice.

Were the large crappie you caught at the neighbors' pond WCP or BCP? I would be reluctant to add WCP when apparently BCP have worked out very well for you in the past.

I would say that the ones I catch are mostly are 12-20

jpsdad,

Yes I understand that large LMB target the optimal size of BG forage for them.

However, I think I am missing some step in the progression.

If the LMB are predominantly eating the 3-6" BG, then I would expect a very heavy population of 2-3" BG. You frequently provide excellent data on the feed consumption required to increase the size of LMB. Apply those principles you vividly describe to the BG.

What I don't understand is how the 2-3" BG increase in size? If there are thousands of them in the pond, I would expect that they quickly consume all of the forage that is "right sized" for them. How do the small BG find enough calories to increase their size to become large BG? Is the productivity of a fertile pond sufficient to create a large enough natural food chain to amply supply calories for each size cohort of forage fish?

I do not remember if Pat runs a fish feeder to supplement the growth rate of the BG. Is that the key step? If the small BG get commercial food supplementation, then they can readily turn into large BG?

Sure. The first thing I would point you to is Anderson on Population Structure (PSD). He more or less wrote the book on this and others have expanded. They separate fish classes based on length ranges (Stock, Quality, Preferred, Memorable, and Trophy). For BG the stock designation begins with 3" and ends with 6". BG that are below 3" in length are not counted. You may ask why?. Well for one thing they comprise a very minor portion of the biomass even when they greatly outnumber all the rest of the population combined. Second, they fluctuate due to predation. At swim up there may be millions. But when a single 4" BG can eat 2200 of them an hour, they get whittled down fast. Only a minor fraction of them survive to grow beyond 1". If there is a sufficient biomass of BG in the 3-6" range, it is possible that none of the millions grow beyond 1" until the 3-6" fish are thinned down by predators. Generally speaking the biomass of 1-3" BG is always small when there is a sizable population of BG in the pond. Take a look at the image below where I depict different balance strategies as proposed by Anderson in a graph.



What I would like for you to notice is how populated the 3" to 6" are in the BIG BASS scenario. They are 25 times more populous in the Big Bass scenario than in the Big BG. Why? Because there are not enough small LMB to prevent their recruitment into the 3-6" stock class. Why does the stock class of BIG BG scenario have so few? Because there are enough LMB to prevent most all that grow larger than 1" from growing to 3". I did try to explain this before, so this is very important. The juvenile class of BG plays the pivotal role for recruitment of BG > 30mm (1.2"). When they are numerous much fewer are recruited to the 1-3" sizes. So the BIG BASS scenario both doesn't need to nor does it actually recruit as many 1" BG as the BIG BG scenario. This seems counterintuitive but it is natures balance. When LMB are less numerous, few numbers reach 1" but greater numbers reach 3". The opposite is true when LMB are more numerous. Much larger numbers of BG reach 1" but far fewer numbers reach 3". This is essential for balance under various predator densities and Nature has this baked in. Isn't this just beautiful how Nature works?

Now you asked:


As I said before, they have minor biomass and so can easily grow on things we call first consumers. They get more out these small creatures than larger BG can. There is almost always plenty of food available to BG of small sizes. That is why they grow at such remarkable rates of growth.

When I first started studying Anderson, one thing stood out. He stated that when a pond was balanced and running on all cylinders, the carrying capacity was about 50% full. I have since really learned to appreciate this. Consider this, at 16% of a ponds biomass, LMB must consume 80% of the biomass yearly in order to tread water and maintain their weight (at 5 lbs BG per 1 lb LMB). Now stop just for moment and contemplate the magnitude of this consumption need. If the biomass proportion of LMB is 16%, then the biomass proportion of the BG is 84%. IOWs, for maintenance the LMB need 95% of the standing weight of BG every year. Let that sink in.

Because we know that most of the BG population is to big for the LMB to eat, there is only one way this can happen. Large numbers of small BG must grow and die as LMB prey that are not part of this adult population. Now in this context what Anderson said about 50% of the carry capacity makes sense. The 50% of unused carry capacity is growing a weight of consumable BG that is very nearly equal to or possibly exceeds the standing of adult BG that are too big to eat. That's where the food comes from to grow the consumable sizes. It comes from reserved unused carrying capacity. So when we say carry capacity for BG, we really do mean the carry capacity of BG under predation. For a pond that carries 300 lbs of BG and 50 lbs of LMB, this same pond might max at 600 lbs BG with no LMB present. Its counter intuitive, and few here agree with me, but I have argued for a long time that it is important to ensure that the adult BG population does not become excessive. I will always stand by that even though I am a minority on that position.

Hey, jpsdad, how many ponds do you have with Black Crappie in them?

Theo back to being confrontational. Sorry Theo, I am not biting.

Considering the tomes of commentary put forth, Theo's question is valid, and not at all confrontational, in my opinion.

Regardless, the answer to his question is most likely "none" or "zero."

However, the original poster does indeed have a small lake at 22 acres, as opposed to a pond.

Sunil,

No, it isn't valid. Essentially he is trying to discredit commentary based on ownership of a pond with crappie.

I have a question for you.

What are your thoughts on my arguments and analysis of the OP's own population proportions?

I ask this question because I reviewed considerably before replying with my analysis. I did worry little about how much abuse from Theo and Sunil will I have to take. To be sure, I didn't recommend stocking predators after the OP responded with population proportions and I worried you would be either offended by the disagreement or just peeved. To be sure, its a much easier path to avoid any disagreement. So I was presented with a dilemma, either present the analysis of his data, in his pond, OR meek out say nothing. I wanted to help the OP, so I didn't meek out and if not me ... then who else? If his data is good, then so was my analysis of his population structure and my restraint from recommending predators at this time is warranted. The advice I gave about harvesting was proportional to the catch and so would work with any carrying capacity of crappie.

I would just say, I do not mind disagreement. When someone disagrees, I stop and listen. When I read something in the literature that doesn't jive with what I currently think, I just have to understand why the author has come to those conclusions. It's one of the biggest drivers of expanding knowledge. Hey, I want to be a part of that. So I guess what I am saying, is that if you disagree with my analysis, you are welcome to explain why and make your arguments as where my analysis of the OPs data of his unique small lake is faulty. If you do that in a logically consistent way that I cannot disagree with, I will graciously change my mind and thank you. On the other hand, if the source of disagreement is that I don't own a pond with crappie, then all I can say is "Your analysis of the OPs population proportions is "none" or "zero" while your analysis of whether I own a pond with crappie is "spot on". I will just add, that if you were to take the OPs populations and worked with it to estimate biomass proportions ... I very much doubt that you would disagree.

Anyways, judging the validity of the analysis of a unique lake's unique crappie population proportions based on whether the analysis was done by someone owning a pond with crappie just doesn't make sense. If it did, the same would apply to every other poster recommending things. For example, one could ask "How many ponds with crappie have you corrected with the OPs crappie population structure by stocking tiger muskie at your recommended rates?" If you have, by all means provide the diligent metrics that demonstrate the cause and effect.

So I totally understand that you and Theo don't like me. The tone is very clear, not just to me, but I think to most everyone. I would say, I don't feel that way. I would much prefer to be friends with both of you. But I also understand that is totally up to you. Friends just accept each other as they are with what ever faults each may have. Anyways, the invitation is always open if you are ever a mind to.

What's the source of your "expertise"? If it s experience, state it. If it's someone else's work, give credit. If it's common wisdom, add that disclaimer.

People you are giving "advice" to deserve to know.

P.S. It ain't just me and Sunil.

Sure Theo, the source of my expertise is Willis, Anderson, Swingle, among many, many others. I take their findings and apply these principles with models. In the analysis I provided the inspiration comes for Anderson and Bill Cody.

If the proportions of the different length classes are known, then it stands to reason that the biomass proportions can be determined. That is all me, as for as I know, I am just trying to apply what I have learned from them. It is intuition that owning a pond with crappie will NEVER endow a person with. All the same, its is analysis of the biomass structure of the crappie that is unique to the OPs pond according the OPs own observations. I just disagree that someone else's pond is a clear example of what should be done with his pond. It is often said here that every pond is different. I agree with that, The advice should be pertinent to his pond and his data ... applying principles that are sound.

You complain about "tomes" and to be sure I really do wish I could explain things with much fewer words. But I do try to provide enough detail that anyone ... who with a mind to ... can replicate and review the analysis. For example, it is hardly any trouble to put together a spreadsheet and see for oneself. I can assure you, that if you, Sunil, and anyone were to do that they won't find fault with biomass proportions estimate. Some may even appreciate it. But as long as advice has to come from some prerequisite pond experience that isn't the same pond, I don't think the advice will ever be as good as it could be.

Rod I would say that all the large crappie were BCP that were transferred from neighbors pond and as I haven’t caught and removed any BCP since they were stocked . Still no signs of BCP recruitment or LMB. Very frustrating sometimes. Low pond level doesn’t help .

It's too long for me to read, frankly.

Of course, all we are doing is speculating on the original poster's anecdotal information. As such, it's hard to see how one can then make conclusions that seem to be presented as definitive information.

From what I can tell, the OP has strong case of overpopulation of Black Crappie, a lack of forage, and a lack of predators that can keep Black Crappie numbers down. Material changes have to be made to right the ship.

I'm going to step in this pile in regards to the missing Crappie element in Pat's pond.. At one time, I believed BG were possibly affecting BCP recruitment, but That is an assumption, not any fact. I believe there is another element missing that is needed for both species to recruit to some level.
I've seen crappie recruit in plain, cover free ponds, massive habitat ponds and everything in-between.
I'd love to spend a week down there with my compliment of nets to look at population structure as an experiment. Not sure we could come to a conclusion but there "might" be something show it's ugly face.

I'm going to add one other comment, then I've got fish to tend to... TM are NOT a good choice for crappie control.

I believe the OP said he does not really want LMB. That doesn't leave a lot of options for a predator that can do anything with Black Crappie. If you could hook him up with some Saugeye........

Thanks for dropping in to add your 2 cents.

Take good care of your fish, spring is rapidly approaching. I hope your fish find very good new "homes" this year!

OK, so at least extend me the courtesy of withholding judgment of the merits of my commentary. If you don't have a thorough understanding of the commentary then you are unqualified to judge its merits. I will encourage you to doubt it and seek to find fault with it. In so doing, you will learn what the commentary is and why I made the rec I did. What you will find, is that I will do everything I can to answer your questions and provide the basics of the analysis. If you like, we could take it offline. I am a very helpful person that you don't even know yet. Honestly, I don't think you would disagree with the commentary based on the information the OP provided if you take a deeper look under the hood. You may appreciate some things you might learn from it to apply elsewhere.

I agree that the OP data appears rather anecdotal and subject to the error of memory. I addressed this and presented the recs as "tongue in cheek" and "tentative". I warned the OP that for the analysis to be good, that his data from whence the analysis is derived must also be good. I tried not to inject my own impressions of a pond I have never seen nor fished. I trusted his observations because that is all I had to work with.

This is very interesting water that seems to have produced 4 lb LMB in 5 years in Minnesota. Reasonable growth, I think. The BG per the poster just meet minimum expectations for quality fish. The BCP have attained lengths >12" with more than 50% of the biomass of crappie concentrated in >10" BCP (per the OPs population proportions). Dang, its a dandy lake really. The crappie are thin (maybe other species are too), but this can be corrected by harvest. Having only the OPs observations to work with, the >10" population was already over represented but I just can't see thinning this size of BCP with predators. It makes a lot of sense to me to filet them. The effect of adding predators may help down the road after the existing populations >10" BCP have long since died. It will take time to influence the condition of fish in the >10" tier of BCP by using predation.

Oh, I've read many of them, so I can certainly judge any of them if I were to want to; I just don't want to.

Respectfully, Theo's question is valid especially set against the vast writings you've developed based on conversational and anecdotal information. So, from my perspective, if the foundation is weak to begin with (and that's no offense to the original poster, or you), then I don't really put any weight in any kind of scientific analysis based on stacked assumptions, let alone spend the time to read it. As such, I'm not bothered by it.

Obviously you enjoy writing.

Can the OP get Saugeye???

This would be a great study on Snipe's project if we could get it to happen.

It would, but they'd need a LOT - 20-40 per acre fro a 21-22 acre lake? Hopefully Snipe can chime in sometime. But being HighSchool Seniors, I don't know how much disposable $$ they have!

Sunil, if you had a choice, would it be beer or fish at that age? ROFL

It'd be both!!! But only bucket stocking!!

I'll chip in some funds if it's possible to get Saugeye there with no strings attached.

If Snipe is down with it, maybe there's a way to ship Saugeye frye. I thought he had the capability.