Well I finally returned to offer my opinion of the Carrying Capacity for Brad Biller’s 0.5 ac clear water pond managed for no pellet feeding of the fish and growing larger sizes bluegill. This will be a management challenge for sure for Brad Biller. I also included estimates going forward for the fish to be removed. Brad says the water clarity still has usually been 5ft-8ft for Secchi disk.
I have spent some time gathering various informational items; some from AI, my literature library, plus I added my opinions when appropriate.
As a review, for an unusual first fish pond stocking of just mature bluegills, the current results from a 10 month later sampling of the initial stocking of larger BG using angling, a couple types of fish traps and a 50 ft long brief seine survey all methods revealed the stocked BG are growing to sizes of 4”-8” and reproducing. The new hatchling 2025 crop of BG now range in sizes of 1.3” to 2.0”. Largemouth of at least 4 sizes up to 12” have been added.
Note the pond now has at least 4 to maybe 5 year classes of LMB.
Bass Added were as of 5/19/26 – 125 3”-4”; 12-6-8 “; 10 8”-10”; 10 -10”-12”; and 13 of 12”+ inch bass.
Mr. Biller prefers no pellet feeding to help maintain the clear water conditions. However with the clear water, he is dealing with green string algae. IMO the string algae is absorbing nutrients from the pond, competing with phytoplankton and helping to maintain clear water conditions.
Going forward, always keep in mind that my suggested weights of the fishery (carrying capacity) are for a good balanced community where fish are not overcrowded and where prey and predators are growing good or for hopefuly the best growth they can achieve in clear water of 5ft to 8ft.
Overcrowding always reduces the ability of the fishes to grow optimally. This is where good management of the populations of your herd of fish becomes important when GOALS of keeping good growth rates are important. Methods for managing a fishery are very similar to managing a herd of land animals. Basically control their numbers and keep them well fed.
Ewest’s above quote “”As to Bill's points on carrying capacity in this pond as described, my guess is no more than 200 lbs of total fish.”
Thanks ewest. I contend that carrying capacity is strongly influenced by water clarity and IF light reducing pond dye is used then it reduces the amounts of plant growth, which includes the growth of phytoplankton as the basis of the NATURAL amount of fish foods produced. Pond dye as colorant is designed and intended to reduce ‘most’ but not all forms of plant growth. Reducing phytoplankton reduces the ultimate weight of fishery production for a pond. Mr. Biller up to now is not using blue pond dye.
CLEAR WATER from AI.
• Too Clear (> 30 inches): If you can see deeper than 30 inches, the water is generally considered infertile. This limits natural food production, makes prey fish too visible and more vulnerable to predators, and leaves shallow areas open for too abundant or excessive rooted weed growth, this includes green string algae. Largemouth do not grow well when too much vegetation is present i.e. >30% coverage of the pond basin.
For non-chemically managing the overly abundant algae and weeds, I usually suggest herbivorous fish such as grass carp and or tilapia. These fish I contend the goal should be to consume around ½ if the vegetation and ¼ should be manually removed and leave ¼ of it to provide beneficial habitat and compete with nuisance algae for space and nutrients. When harvesting tilapia or ANY fish specie from the pond this removes nutrients from the pond eco-system to help minimize the total fertility that grows more plants including problematic plants and string algae (aka FA).
AI says Unfertilized Clear Ponds: Max carrying capacity is typically 50-100 pounds of sportfish such as Largemouth Bass and Bluegill PER surface acre.
AI - Carrying capacity is determined by several limiting factors. In unfertilized waters, fertility is a limiting factor as it produces living items that fish eat i.e. fish foods. If just live fish foods are the limiting factor and are the primary fish foods, then water quality will generally be good and conducive to long lived fish; also known as Bob Lusk’s “Happy Water”. For a given natural fertility, most pond water is "under-optimal" for the production of food. Then for improving fish production a good mix of structure, plants, community players, and edge habitat increases food production naturally and sometimes results with an improvement of water quality parameters i.e. more happy water.
Thus unfertilized ponds with water clearer than 30” may produce less than 100 pounds of fish per acre, thus this can result in as little as 50 TOTAL pounds of fish in 0.5 ac as roughly 40 lbs of BG and 10 LB of bass. In ponds,,,, note the proper water alkalinity has a big influenceence in the amount of total fish production starting with the amount of good types of phytoplankton at the bottom of the food chain.
In comparison, a fertilized, un-aerated pond, with good alkalinity(>40+mg/L aka ppm), the maximum carrying capacity of fish can be 300 to 400 pounds per surface acre. This is roughly three to four times the limit of an unfertilized or low fertility pond. Thus Pond Fertility makes a measurable difference in the amount of fish a pond produces.
With the addition of supplemental feeding and mechanical aeration, this carrying capacity can even push upward of 500 lbs to 800+ pounds per acre. Fertilized ponds contain various forms of green water and at times the types of green growths can be abundant or over abundant forms such as phytoplankton, filamentous algae, and other forms of submerged weeds. In over nutrient enriched water (hypertrophic), the green water can then be composed of mainly varying concentrations of harmful toxin producing Cyanobacteria (old name bluegreen algae) with sometimes some good green phytoplankton mixed in.
The total pounds of fish in all types of ponds will usually be distributed among all sizes of the fish species present. Those pounds will most always be divided by the numbers of prey and predators.
This is 'how in theory' it works. In natural food produced pond populations,,,, the prey to predator ratio is or should be at least 10 and often 20 prey (fish) or more to every predator. So right from the onset, the natural food pond will ideally have about 15 times more pounds of prey fish (forage) than predator fish.
Let's assume that the Biller 0.5 ac pond is "low average" fertility with 75 fish pounds (150lbs/ac). This means that the Biller pond should have around 70 pounds of prey fish and 5 pounds of predator. We will assume that there are 5, 1 lb bass in his pond. Each should or can eat 6-10 lbs of forage per year. This should ideally leave a remaining 20-30 pounds of preyfish (panfish) in Spring to reproduce and then provide the main foods for the next year.
However, often what happens is the predators reproduce each year, not enough are removed, and now more predators are too abundant and as a result they over eat the prey fish depleting their numbers and sizes (pounds). Now the pond is out of ideal balance. Predator growth suffers as their growth slows down and predators get skinny. This is where many pond owners use fish pellets as a supplemental food or add forage fish to compensate for the lack of natural prey food items to hopefully boost the number and sizes of sustainable larger sized prey fish and often too many predators. In theory an unbalanced situation.
Ponds can be managed and maintained without feeding pellets. The pellets cause more fish pounds to be raised, as hopefully more larger fish, and hopefully faster growing fish. To do it WITHOUT pellet feeding, one just has to MANAGE for a lot fewer fish so there is always adequate numbers of forage food items (small fish and invertebrates) available so the few remaining fish do eat well and grow well.
Good pond management depends on one’s goals but you can't have it both ways i.e. only natural foods and lots of big quality fish per acre. The all natural foods pond can have some or a few quality big fish but not lots of them. As the water becomes clearer fewer fish ponds will be raised. Lower fertility and less natural foods can produce a few high quality fish per acre.
Here are suggested AI examples for some average fish harvest rates PER ACRE for unfertilized bluegill / bass ponds.
Bluegill when they reach 7” remove 40lb (120 fish) per acre per year. (Biller = 20lb as 20-40 BG mainly as females)
Largemouth bass 2nd+ year remove 10 lbs (8fish) per acre per year. (Biller 2-3lbs).
Ref: Bluegill Standard Weights: 7”=4.4oz, 8”=6.7oz, 9”=9.9oz
LMB Standard Weight:
6”=1.5oz, 7”=2.4oz, 8”=3.7oz, 9”=5.5oz, 10”=7.2oz, 11”=10.6oz, 12”=14.0 oz
Thus I estimate the harvest rates per year in 0.5 ac of Brad’s CLEAR WATER ponds can be bluegill as 10-20 lb (20-40) and bass 2-4 lbs = 2-3 bass.
IMPORTANT NOTE
Since Mr.Biller only initially stocked several sizes of mature bluegill and no bass, one bluegill spawning season has passed. Advice of some experienced PB forum members suggested before the 2nd BG spawning season to stock several sizes and relatively large numbers of bass to compensate and have best control for future generations of BG. The management task now going forward is to MONITOR the initially stocked LMB to keep the BG/LMB fishery skewed toward a high predator balance for the goal of producing large BG. For growing extra large BG it is okay to have thin bodied bass who are continually hungry and always looking for small BG as dinner guests.
Several items to be aware of. 1. Too many LMB were probably stocked especially the 3”-4” size group to insure good predation of the first and newest crop of BG. 2. How many of the initially stocked bass survived and how is this determined?. 3. Did any of the initially stocked mature LMB reproduced their first Spring in the pond? 4. How many and what sizes of LMB should be removed in 2026?
Going forward if the water clarity and amount of plankton growth shifts to even more clear water and more weed and FA growth occurs in the even more clear water of 7-9ft this will change the movement of nutrients up the food chain and IMO fewer pounds of fish that can or should be harvested per acre because less actual plankton in the pond grows fewer pounds of fish. In the opposite water clarity shift however, with more cloudy greener water and water clarity decreases to 3ft then the fish harvest numbers could be a few more bluegill can be moved per year. Let the pond angler catch records guide you going forward as proactive fishery management tasks.
Background Info of Trophic Levels and Energy Structure in a Pond
Energy is transferred up in a food web or food chain from the lower plant & zooplankton levels to the animal consumers in higher trophic levels. Typically, only about 10% of the energy at one trophic food level is made available to the next level. This representation is usually shown simplified by the standard ecological pyramid.
The remaining 90% of the energy from each higher consumer level to the next higher level is used for metabolic processes for swimming and hunting or is released into the environment as heat. The energy loss simplifies why there are rarely more than four trophic levels in a food web or food chain. At times there can be a 5th trophic level, however, generally, there is not enough energy remaining to support any extra trophic levels.
Rationale and Reasoning. If we use B.Billers 4-6ft of clear water with no pellet feeding, this average water clarity equates to a low eutrophic production category. Using the standard 10% of the energy of each level is transferred to the next level, I calculate that the usual amount of phytoplankton (plant) production in this type of pond having a medium high alkalinity will amount to a total of 9,180 pounds PER ACRE as a basic production level of annual plant production hopefully consisting mainly as phytoplankton and not composed mainly of FA and rooted plants. This equates to 4500 pounds of phytoplankton in Biller’s 0.5 acre 1,000,000 gallons pond.
Moving up from 4,500 lbs of phytoplankton production to the next trophic level will be a consumers level consists as mostly all invertebrates that includes the zooplankton and all “bugs”. Then this amounts to around 450 -500 pounds of ‘bug’ life in his 0.5 acre 1,000,000 gallons pond. The third consumer level will be small fish and panfish (BG) and the carrying capacity of panfish (forages) will then be around 40-45 total panfish pounds. Predatory fish weight of largemouth bass at the very top of the pond food chain or level then results in a Biller bass poundage of around 4 - 5 lbs that are living in the 1,000,000 gallons of a 4ft to 6ft clear water ecosystem.
FROM BOB LUSK’S POND BOSS ARTICLE FOR GROWING BASS AND BLUEGILL
The article was based on discussions of four BG/LMB pond managing pros.
https://www.pondboss.com/news/free-articles/selective-harvest-or-catch-and-release---by-bob-luskMain points for growing BG-LMB were as follows.
"You need to have a goal of what you want the dominant fish species to be, and what you hope their sizes will be," Cody said. "Once you have that objective, you can manage the populations toward that goal."
For every surface acre in a CLEAR-WATER pond you might end up with only 4-to-5 pounds of predators and 40 pounds of forage," Cody said. "In fertile, naturally alkaline waters, the numbers might be 40 pounds of predators and 400 pounds of forage."
"In an all-purpose fishery, most of the harvest will be 5-to-7 inch bluegill and bass that range 8-to-12 inches," Cody said. The management goal here should be to maintain large numbers of 12-to-15 inch bass that will control bluegill numbers and provide a good run on a medium-action fishing rod. Cody's recommendation: Impose a "slot limit" that will protect bass in the 12-to-15 inch class. A plump 15” bass should weigh 1.8lbs.
As population densities go up, the likelihood for top-end trophy size goes down.
• Bass convert food at a rate of 10:1. Ten pounds of food for one pound of weight gain. To grow bigger fish, the pond owner must feed his forage base and/or reduce the competition for food or as Cody said, "thin out the brothers and sisters."
• To keep panfish numbers in check, anglers should consider keeping most bluegill they catch. But, don’t remove the largest bluegill. Keep the next smaller size.
• When bluegill are marquee species, Cody says pond owners are always tempted to lop off the population at the top. Give those mature fish a chance to do their jobs, the consultants say.
• "Be very careful not to overharvest the large bluegill," Cody said. "Harvest mostly the mid-sized fish 5-to-8 inch range, and release all the fish greater than 8 or 9 inches long." Release especially the males and you can harvest some of the large females.
"You can manage for trophy panfish by limiting harvest of your largemouth," Cody said. "Leaving a dense population of bass will directly control the abundance of bluegill. The panfish that manage to escape predation will have lots of food and space to grow quickly." When on the annual paper catch records that the largest size of BG is not getting gradually larger then there are too many of the smaller sizes of BG in the pond. More foods are needed for the group of largest BG be it natural foods and or pellets.
When big or even giant bluegill are your goal, Cody suggests not removing bass less than 15 inches long. These vigorous predators will be the most active when serving on bluegill patrol. If bass become skinny, looking as though they are all head and no body, Cody recommends removing some bass in the 8-to-12 inch class.
In trophy bluegill waters of the Midwest, where growing seasons may run from Easter to Labor Day, the harvest of large bluegill should be moderate and thoughtful as for which sizes and numbers that are removed .
"You should take no more than about 20-to-30 bluegill per surface acre per year," Cody said. "In this scenario, bluegill should weigh two or three times more than bluegill in the general all-purpose fishing ponds."
Thanks for attending and reading Pond Boss Forum.
