Pond Boss Forums INTRO Questions & Observations Fish population balance

Any thoughts or conventional wisdom on how long it takes for a ponds fish population to acheive a balance among species? Most of us stocked fathead minnows and CNBG and then later put in LMB or CC. How long does it take to determine if the food chain is in place and healthy...not favoring one or the other?
This is the 4th spring with our new pond. The pond has changed considerably. First year no plants other than grass at the shoreline - turbid water, lots of bluegill fry visible in the shallows and surface of the water. Year two - clear water (after lime addition) muskgrass in areas. Some FA. Year 3 - clear water and significantly more muskgrass. Year 4 (this year) water is higher, tea colored, no muskgrass and more variety of water plants around perimeter - a bit more FA.

I have noticed that this spring the fishing seems to be better - more bluegill and fat bass. Biggest so far has been about 3.5 pounds. I have put in Tillapia the past 2 years but did not this year. I have more FA - but somehow I think the fish are doing better. Maybe the FA is feeding the bluegill and giving them more hiding places??

Interesting question. I'm guessing the answer is "it depends." There are probably way too many variables to have a pat answer.

I have kept this quote from Bill Cody that I read over and over.....

From the thread: Stocking my pond - NE Indiana
February 22, 2009

By Bill Cody


Numerous VERY important variables occur in ponds that will affect how well any fishery, including the one proposed above, succeeds. Some of the important variables besides the numbers of fish stocked are:

1. The amount and quality of underwater habitat including submerged weed growth. A clean pond versus a congested pond. The “weed” species growing (those introduced and occurring naturally) will also be very important for how well the predators can deal with the weeds and or structure to find or locate prey.

2. Spawning AND survival success of all sport fish, includes supplemental stockings. Recruitment can be beneficial or undesirable based on the fishery balance within the pond.

3. Spawning and survival success of forage fish species; includes supplemental stockings and proper habitat for spawning of forage speices. Small sport and forage fish typically feed the predators. Ideally, the goal of a well balanced fishery is one where enough adults (25%-50%) of the main forage species survive to the next breeding season. If that does not occur, then usually there is some sort of problem and one should be finding out why and making adjustments in the management methods.

4. Water quality. Water quality throughout the year affects growth rates of all fish present. Lower quality water stresses fish. When fish are stressed feeding dramatically decreases and growth decreases or ceases. Complete pond aeration is almost necessary to contribute to the long term success of stocking densities suggested below.

5. Harvest rate and size of those harvested. This includes manual thinning. The best and highest quality fisheries occur where regular harvest is used to keep the fishery at a high quality to meet the pond owner’s goals. All forms of harvest contribute to total mortality and the balance within the fish community.

6. Mortality of all fish present - hatchlings to old fish. Mortality and harvest determine balance.

7. Predatory pressure. This is very important to overall fish density and is closely tied to mortality rate. Proper predatory pressure prevents species from becoming overabundant. One or two overabundant species are a detriment to the quality of the whole community.

8. Percentage of sport fish that are eating pellets. The pond owner has a fair amount of control in adjusting the balance of this feature. New pellet eating fish can be introduced and non-pellet eaters can be removed. A pellet eating fish tends to be less predatory on their preferred natural foods. A pond with a large percentage of pellet eating fish results in more forage fish being available and the optimal foraging theory working well for these fish to optimize growth rate and quickly make them trophy sized. Learn about Optimal Foraging Theory.


So I'm guessing that there will not be an answer as to when a fishery becomes balanced, I think there are too many variables.




Do BG eat FA?

Experts any feedback?

I would say most definitely. If the size is right they will. I had bluegills nailing my Gulp Alive minnows all afternoon yesterday.

To clarify my question on FA feeding the bluegill population - I may have stated that in a way that reads to literal. What I am asking is a question on the health of my food chain...is the FA in my pond a better base for my food chain? Past years the Tilapia have cleansed the pond of it. Is it possible that for a younger body of water that the FA is playing a more valuable role and giving the fry more places to hide and therefore survive, ultimately establishing a better natural forage base for the fishery, versus a Tilapia based forage?

I guess this begs the question... on a newer pond is is possible that Tilapia interupt the balance of a developing pond and that perhaps we should tolerate the FA as other plants get established? We all know the benefits of Tilapia - but are we converting a self sustaining ecosystem into something less sustainable by annually investing in Tilapia as forage and pond cleaners? Is it possible that if I had not stocked Tilapia the past 2 years that the FA would have sucked enough nutrients out of the water to keep the muskgrass from flourishing? It is still early in the year - but I can't find any muskgrass in the pond - last year by this year it was growing around the perimeter in the shallows.

BG do eat/ingest FA. It should not be viewed as a BG food source however. BG will not eat enough FA to be considered a control option like tilapia.

"but are we converting a self sustaining ecosystem into something less sustainable by annually investing in Tilapia as forage and pond cleaners?"


Yes and no. Not many ponds are self sustaining without intervention in a manner that meets the pond owner's goals. That is why tilapia are used. Most studies on pond balance relate that ponds in balance are temporarily poised in an unstable state between unwanted alternative stable states:

Cutting Edge article in the Nov/Dec issue of Pond Boss Vol. XVIII, No. 3 on the difficulty of achieving and maintaining a desired balanced state while teetering between two undesirable steady states, being overpopulation of predators with low predator body condition vs. overpopulation of prey with low predator recruitment.

Same for plants – achieving the right balance of amount and type without going to far in any unwanted direction.

Hmmm, that also describes several of the forum members.

Now I know why I had to diagram sentences in the 7th grade.

They still taught Proper English way back then, huh?

Hmmm, that also describes several of the forum members.
let me guess, you will PM the list

I think what Captain1 is referring to, and it's true, that FA, as all aquatic vegetation harbours all types of thingys for the small fish to forage on. I havent seen tadpoles in my pond the last 2 yrs., but with the FA this year, when I raked it out there were a good many as well as other critters including small fish.

Theo, until I heard my Grandkids speak, I thought they were still teaching English

My thought - if at year 4 you do not add tilapia or other forage to match you will be on the way to one of the two undesirable steady states, being overpopulation of predators with low predator body condition . Typically in southern ponds year 3-4 is the last year of top rated original growth. The pond has reached carrying capacity and the original stocker fish are in top condition. From that point on its about how you manage the populations.If you reduce the prey amount the predators who have been relying on that source will not get enough to eat to maintain condition.

Thanks Burgermeister and ewest - this is exactly what I am interested in knowing. So in year 3-4 my fish are in top shape. It is a certainty that I am seeing more "life" in the FA and I believe that my bluegill population is healthier as a result. I think that I am going to choose to cull bass. I have only taken 5 or 6 bass out of the pond all this time and zero bluegill. I seem to have many 10-14" bass and roughly 1 in 5 bass caught are in the 15-16 inch range. I am going to increase fishing pressure (which is low) and catch and eat bass in the 10-12" range and go this year without Tilapia. Does this make sense to the experts? Is my size range correct? Cull female bluegill also?

How many lbs of tilapia have you been adding?

Its a 2 acre pond and I have been adding 20 pounds of Tilapia.

I think your pond is way too young to start culling, or selective harvest. It is still growing, changing and finding it's place. It's sounds like you are right on track for a great balanced pond. When I start culling is when things appear to be or have got out of control. Plus you are adding tilipia on a irregular basis. My point is, I'd let it settle, and get a better snapshot of where it is heading. If if ain't broke I would not try to fix it. Give it a few years and see if things are going where you want it. Those LMB have a lot of growing and feeding left in thier lifespans. I'd leave the female bg and let the LMB eat thier young. Maybe stop the tilipia and see if you really need them. I tend to adjust my populations slowly, tweak them and wait. I have a pond that was stacked with 10-12's lmb. I just kept feeding them rather than culling. Yesterday my 8 year old and I caught 45. Only 1 fish was under 12, and they were all fat. But my intent on this pond was to create awesome lmb C and R, action, not lunkers. If you want that, nevermind.

Problem with letting it run too long in East Texas, or southeast, is it gets so dang hot and when you lose 1/2 your water, you can get in trouble quickly.

After 2 years, I already feel the need to take out a good many; and will next weekend with the grandkids helping.(too bad they're too young to wield a fillet knife.

Jeff, it is nice to know your self-realization classes are paying off, for both you AND Sock Puppet.

Criticize me all you want, but I wouldn't mess with Sock Puppet if I were you.

That goes double for TJ.

The system is less energetic when domains of opposition alternate.

Well said. If you intergrated that with the third-generational systematized logistical projection there is no way that the reciprocal synchronized time-phased policies don't fit with the futuristic, parallel policy balance of your fish.

Exactomundo.

Whew! You guys are way over my head but it certainly gives me something to think about.

I read a study from Cornell or some Ivy League school that stated a pond really never achieves balance. And then questions balance for what? Balnce for species maintaining a sustained population? That is always fluctuating. For fishing? Not going to happen if you are fishing.

Like I said. I just try to get close to some type of sustained population, control vegetation, and make fishing friendly ponds. You start worrying too much about balance you have lost the fun part of even having a pond. But Burger does bring up an issue a bit away from balance, and that is holding capacity. That is an issue. You don't want to exceed that or balance concerns will be out the window. A crash is an imbalance of floating dead fish and live fish. If you are going to harvest for that reason, do it across the board.