Fish Management

Proper pond construction, development, and fish stocking will not guarantee sustained good fishing. A correct start must be followed by periodic management. Some of the techniques described in this and the following section seek to affect fish populations directly, while others modify habitat within the pond, affecting fish indirectly.

Updated: 12/10/04

Improper harvest of fish ruins future fishing in more potentially good Kansas ponds than any other cause. Pond owners and other anglers are anxious to fish a newly stocked pond and they frequently overharvest the bass population in the first season of fishing. This allows bluegills to overpopulate the pond.

A pond owner can reduce the likelihood of bass overharvest from occurring by not letting anyone fish the pond. This practice is not encouraged, however, because underfishing as well can also lead to problems. Pond owners are urged to let others fish their ponds as long as the pond owner’s rules are followed.

One way to prevent bass overharvest is to release all bass less than 15 inches long for a period of 4 years from stocking, even though bass may be large enough to catch after 1 or 2 years. This means that few bass can be harvested for 4 years from the time of stocking unless adult fish were introduced. If 8-inch bass were stocked, the 15-inch minimum length limit would be needed for only 3 years (2 years if 12-inch bass were stocked).

After 4 years from stocking (2 to 3 years if adult bass were stocked) a management decision must be made. The choice made will depend upon what numbers, sizes, and kinds of fish are desired. Are good sized fish of several species preferred, or is catching large individuals of fewer species more important? Often, quantity has to be sacrificed to achieve greater size.

Five management options are presented here: (1) The “All Purpose Option”; (2) The “Panfish ption”; (3) The “Big Bass Option”; (4) The “Harvest Quota Option”; and (5) The “Catfish Only Option.” The first four options differ from one another in the ways angler harvest of bass is used to manipulate fish populations.

Bass will probably have spawned three times during the 4-year period after fingerlings were stocked or three times in 3 years if 8-inch bass were stocked. If 12-inch bass were stocked, new year classes would have been produced in both years after the original stock were introduced. Young bass produced can come to exist in surplus numbers. If unharvested, poor growth rates occur due to excessive competition. The result will be a bass population comprised primarily of individuals less than 15 inches long.

The guidelines for each of the management options include stocking recommendations for additional fish species. Expected results from a pond not managed according to one of the options are also discussed.

The “All - Purpose Option”

This option affords the opportunity to catch fish of a variety of sizes. To catch bass over 15 inches long with any consistency, numbers of 8- to 12-inch bass must be reduced. In a pond of average fertility, about 30 8- to 12-inch bass should be harvested per acre per year after the fourth year from stocking (second and third year if adult bass were stocked). For high-fertility ponds, as many as 50 small bass might be removed per acre per year. The removal of these small bass reduces competition and makes it possible for some fish to attain lengths over 15 inches.

To ensure that at least 10% of the catchable-size bass survive to lengths of 15 inches and longer, all 12 - to 15 - inch bass that are caught should be released. A good supply of 12 - to 15-inch bass will also reduce densities of intermediate-size bluegills so that some individuals grow to sizes of interest to anglers. This management option will produce bluegills of several sizes, with some reaching 8 inches.

Bluegills and catfish can be harvested as desired. Catfish that are harvested must be replaced with 8-inch or longer individuals to maintain a sizeable catfish fishery. Without periodic supplemental stocking, few catfish will be caught because few young catfish will survive bass predation.

Northern pike can be stocked in large lakes as an additional sport fish and predator as long as the pond owner realizes the fish’s limitations described previously. Rapid northern pike growth rates in Kansas present a threat to survival of original stock bass if pike are stocked too soon. Fingerling pike (6-10 inches) can be stocked at a density of 10 per acre 2 or more years after bass have been introduced. If pike are stocked sooner than this, they may prey on original stock bass or their initial reproduction, preventing a good bass population from developing. Walleye should not be stocked in an impoundment managed according to the “All- Purpose Option” because bluegills do not provide sufficient prey for walleye.

The “Panfish Option”

If catching big panfish is more important than harvesting bass and catching big bass, the pond owner and anglers should continue to release all bass less than 15 inches long past the initial 2-, 3-, or 4-year period after stocking. Bass over 15 inches long can be harvested, but few fish will grow to such a size if the 15- inch length limit is maintained. High densities of 8- to 15- inch bass are more effective in controlling bluegills and other panfish than moderate numbers of bass of several sizes. By purposefully overpopulating bass, the “Panfish Option” will produce more 8- inch and longer bluegills. It is important to note that the “Panfish Option” should be followed only if the pond’s water has an underwater visibility greater than 18 inches. Bluegill and other panfish will overpopulate if bass cannot see well enough to feed on them.

A variation of this management option might include crappie and/or bullheads in the stocking combination along with largemouth bass, bluegills, channel catfish, and fathead minnows.

Crappie and bullheads are not usually recommended for ponds because both fish have a tendency to overpopulate if bass numbers are low or if the pond is muddy and bass cannot see to feed. Problems with crappie and bullheads as well as green sunfish and carp can usually be avoided if a good bass population has developed prior to their gaining access to the pond and if the pond’s water remains clear (an underwater visibility of at least 18 inches).

Twenty adult crappie and/or 20 adult bullheads can be stocked per acre after it is apparent that the pond has sufficient numbers of bass to prey on young crappies and/or bullheads. This situation is demonstrated by the ability of the pond to consistently produce bluegills 8 inches and longer.

Black crappie should be stocked instead of white crappie because black crappie do better than whites in clear water and this option is recommended only when underwater visibility exceeds 18 inches. After adult crappie and ullheads spawn, it will take about 3 years for their offspring to attain lengths of 10 inches and longer.

With crappie and bullheads present, it will be necessary to release nearly all bass that are caught so that crappie and bullhead numbers can be kept under control through bass predation. The quality of bass fishing will be sacrificed to produce good crappie, bullhead, and bluegill fishing because bass must be allowed to overpopulate. Few, if any, bass over 15 inches long would exist in a pond managed in this fashion. If however, fewer than 10% of the bass caught are 12 inches or longer, bass may be too dense, prey too heavily on panfish, and compete with them for food. Approximately 30 bass 8-12 inches long should be removed per acre per year until 10-30% of all bass caught are 12 inches or longer. No harvest restrictions are needed on any species but bass. Northern pike stocked as described in the “All - Purpose Option” might be used to provide additional predation on panfish.

The “Big Bass Option”

To consistently produce bass longer than 18 inches without regard for the size of bluegills, anglers should again release all bass under 15 inches for 4 ears after stocking (2 to 3 years if adult bass were stocked) just as described for the “All- Purpose Option” and the “Panfish Option.” In addition, no bass over 15 inches should be harvested during this period. After that time, densities of 8- to 15- inch bass should be reduced even more than described for the “All- Purpose Option” to allow for rapid growth by survivors. In a pond of average fertility, anglers should harvest 30-50 8-to 12-inch bass per acre per year as well as about 5 12-to 15-inch bass per acre per year. Bass over 15 inches should continue to be released unless a trophy is caught. The odds of a 9-pound bass living another year may not be good, but fish that beat the odds are those that set records.

Twenty adult gizzard shad might be stocked per acre 2 years after bass have been introduced. With adult gizzard shad stocked into the pond, the likelihood of producing a trophy bass is greatly enhanced. Bluegills will serve as the primary prey for small bass, and shad will be eaten by large bass. It is important to realize that stocking gizzard shad involves a certain amount of risk. Without sufficient numbers of bass present, gizzard shad can overpopulate a pond!

This alternative to the basic bass-bluegill-catfish combination is relatively unevaluated, but gizzard shad along with bluegills should produce bigger bass than bluegills alone. With bass eating both kinds of prey, it should be remembered that few bluegills over 6 inches will be present because survival of small bluegills will be higher than would occur without shad. The practicability of this management option may be limited to larger ponds because no more than about 10 bass 3 pounds and larger can be maintained per acre of water.

Since the bluegill population in a pond managed in this fashion will comprise high numbers of small individuals, such a pond might serve to satisfy adult anglers seeking big bass and children trying to catch high numbers of fish with no concern for size. Channel catfish stocking is not required for this management option and harvest of both catfish and bluegills is unrestricted. Periodic supplemental catfish stocking will be required to maintain a population with bass present.

In large impoundment’s managed according to the “Big Bass Option,” fingerling walleye can be stocked 1 year after fingerling bass at a density of 100 per acre. If adult bass are stocked, walleye fingerlings can be stocked simultaneously with bass. Fingerling walleye should be stocked in the middle of the impoundment to avoid shoreline bass predation. It should be realized that by stocking walleye, fewer big bass are likely to be produced because gizzard shad that might have fed only bass will have to support both bass and walleye.

The “Harvest Quota Option”

In the past, ponds have frequently been managed by allowing only a given weight or number of bass to be harvested annually. After the desired bass harvest is achieved, angling must consist entirely of catch and release regardless of the sizes of bass caught. This may occur after one or two trips in small ponds. For the first 4 years after stocking (2-3 years if 8-to 12-inch bass were stocked), little or no bass harvest should occur. After that time, about 20 individuals or 20 pounds of bass can be harvested per acre annually without regard for length.

The potential for bass overharvest is present with this option if the pond owner does not have complete control of fishing access and does not maintain excellent records. Even under good management, this option may not produce bass populations as desirable as those that are managed by the “All- Purpose Option” because the potential for overharvest of large bass and underharvest of small bass exists.

Channel catfish harvest is unrestricted, but catfish removed should be replaced with 8-inch or larger individuals. There is no harvest limit for bluegills using the “Harvest Quota Option.” Historically, pond fish management booklets have suggested that a harvest of from 3 to 10 pounds of bluegills for every pound of bass taken would keep the pond’s fish community in “balance.” While anglers can afford to harvest as many bluegills as desired, such a practice without additional bass harvest restriction will not effectively keep a fish community in good condition. This option is difficult to manage successfully. It is generally best suited for fee fishing recreation areas and children’s fishing ponds.

The “Catfish - Only Option”

The channel catfish is one of the most popular fish in Kansas. In fact, many pond owners want to stock it alone. This is advisable in muddy ponds where sight feeding fish like bass and bluegills would do poorly or in ponds under one-half acre where bass overharvest would likely occur. In large, clear ponds, stocking catfish alone is a waste of space because a pond will produce about the same weight of catfish even if it contains bass and bluegills. The pond owner might just as well take advantage of the angling benefits of all three species.

For a muddy pond or a pond that is smaller than one-half acre, channel catfish-only is the recommended option. The pond should be free of any structure which would provide seclusion for spawning such as sewer tiles, stumps, large rocks, tires, or cream cans. Ponds which contain only catfish are often characterized by excessive numbers of small catfish, when suitable spawning sites exist. If reproduction can be avoided, replacement fish will have to be stocked periodically to maintain the population. Fathead minnows can also be stocked to provide additional food for catfish and a ready source of bait for the pond owner.

This option is the easiest of the five options to manage as long as natural reproduction does not occur. Harvest can begin as soon as fish reach a size considered to be harvestable and no restrictions need exist on the number harvested. As catfish numbers decrease, fishing success will decline, so supplemental stocking will be required to maintain catfish at a density of 100 fish per acre (200 or more per acre with supplemental feeding). Catfish at least 8 inches long should be stocked each fall or spring when the water is cool. The number stocked should equal the number harvested in the previous angling season along with an additional 10% to replace those fish lost to natural mortality.

Catfish production in small or muddy ponds is usually quite low. If the yield of catfish is inadequate, the owner may want to consider a feeding program described later in the " Feeding Fish " section

Consequences of Unrestricted Harvest

Some pond owners do not care enough about fishing to regulate bass harvest. All species of fish are harvested in unrestricted numbers as soon as they are large enough to take a hook. While this may not be considered sound pond management, it is important to illustrate what kinds of fish populations might be expected to develop in a pond fished in such a fashion. The outcome of unrestricted fish harvest will depend upon the number of bass harvested annually. One angler could remove the majority of the original-stock bass from a small pond in a day’s fishing. Such a bass harvest would quickly allow bluegills to overpopulate the pond. Anglers rarely catch the last two bass in a pond, so young bass may continue to be produced. If anglers continue to harvest the majority of bass roduced, bluegills will continue to overpopulate and few large bass will be caught.

Some ponds receive little bass fishing pressure and harvest due to their remote location, because few people fish the pond, or because area anglers do not like to catch small bass. Such ponds eventually develop high numbers of small bass and large bluegills as described in the Panfish Option.” The results from low bass harvest due to low fishing pressure or angler preferences are the same as those that occur with a 15-inch minimum length limit and high fishing pressure. Ponds that normally receive minimal bass harvest can withstand the harvest of an occasional 12-inch bass and even periodic high bass harvests without change because bass reproduction soon returns the pond to crowded bass and large bluegills. Other than habitat changes, annual harvests of 30 or more 8- to 12- inch bass per acre are the only way to increase numbers of larger bass. If harvest of small bass and 12- to 15- inch bass becomes continually high each year, the fish population will eventually become dominated by small bluegills.

Updated: 12/10/04

All ponds produce some natural food for fish. The amount of food produced is a function of the pond’s productivity. Food quantity, in turn, determines what weight of fish the pond can support. The average amount of fish in a Kansas pond of average fertility is about 250 pounds per acre, of which only a portion (30-50% by weight) can be harvested per year. Fish populations in most Kansas ponds are not harvested heavily enough to overtax natural food production. Supplemental feeding is thus not usually required. In special cases where the harvest demand is high or where large fish are desired, feeding can be beneficial.

Formulated fish feeds in pellet form are available at most feed stores. The most common feed is formulated for catfish, but it is also suitable for bluegills. These feeds are available in the form of sinking pellets or floating pellets. The advantage of floating pellets is that the person feeding the fish can determine whether the fish are eating the feed.

Bluegills will eat artificial feed, but feeding alone will not usually increase the sizes of overpopulated bluegills. Adequate predation on small bluegills by bass along with the feeding can, however, result in increased bluegill growth rates and larger bluegills.

Channel catfish are practical to feed, either as the only species in a pond or together with other species. They quickly learn to eat artificial feed and their growth rate increases. Both catfish and bluegill should be fed no more than they can consume in 15 minutes, up to a maximum of 20 pounds per acre per day. If fish are overfed, decomposition of wasted feed can result in oxygen depletion, killing fish. It is a good idea to monitor water temperature and oxygen content. Feeding should occur daily or at least every other day when water temperatures are over 60°F. Once a feeding program has been started it should continue throughout the growing season unless the pond’s oxygen content falls below 5 ppm at the surface. If it is stopped, fish will lose weight.

Muddy ponds or ponds less than half an acre usually do not produce enough bass and luegills for consistently good angling. It is in such ponds that densities of 200 or more channel catfish per acre can be maintained through supplemental feeding.

Channel catfish can also be fed in cages constructed of 1/2- 3/4 inch mesh screen suspended from floats and anchored in a pond. A cage with a volume of one cubic yard can support 200-275 channel catfish 6-10 inches long. Diseases and oxygen deficiencies due to overfeeding are much more common with confined fish; no more than 1,000 fish per acre should be raised in cages. Food formulated for cage culture should be provided every day of the growing eason, but no more food should be furnished than can be consumed in 15 minutes.

Updated: 12/10/04

Fertilization of Kansas ponds is not recommended. Phosphate and nitrate fertilizers are used in some states to increase productivity in ponds. Kansas’ typically rich soils make this unnecessary. Fertilizers are also used in some states to control excessive rooted aquatic vegetation. Fertilizers will cause microscopic plants (phytoplankton) to develop, shading rooted plants. Without light, rooted plants do not grow. Oxygen depletion problems often develop when a pond is fertilized, so the risk of fish kills always exists. In addition, if fertilization is stopped, rooted plants will grow back in even greater quantities than existed before fertilization.

Updated: 12/10/04

Undesirable fish populations can develop if bass numbers are low, if bass were never stocked, or if the pond has turbidity or vegetation problems. If anglers catch mainly 3- to 6-inch bluegills and few or no bass are taken, it is likely that either (1) bass overharvest has occurred, (2) bass are not present, (3) bass cannot see to feed, or (4) excessive aquatic vegetation has made bluegill unavailable to bass. The first two problems can be rectified by stocking 50 8- to 12-inch bass per acre. If the pond has an underwater visibility of less than 12 inches or if over 50% of the surface area of the pond is covered by vegetation, these problems must be treated before bass are stocked. Procedures for dealing with “problem ponds” are discussed in the next section. If turbidity problems cannot be overcome, the pond owner might consider stocking 100 8-inch and longer channel catfish per acre and forget about trying to produce bass and bluegills. After 8-inch bass have been stocked in a clear pond, bass less than 15 inches long should not be harvested for a 3-year period (2 years if 12-inch bass were stocked). Then, one of the four management options previously described should be followed, depending upon pond owner and angler desires.

If only small bass and no bluegills are caught, 100-250 4- to 5-inch or larger bluegills should be stocked per acre. Then, appropriate bass harvest restrictions and stocking strategies should be followed as outlined in one of the four management options.

If the pond contains neither bass or bluegills and small bullheads and green sunfish are present, 50 8- to 12-inch bass should be stocked per acre. Once the bullheads or green sunfish are under control, 100-250 4- to 5-inch or larger bluegills should be stocked per acre because bullheads and green sunfish will not provide adequate prey to sustain a desirable bass population.

In the absence of bass, bullheads and carp sometimes develop such dense populations that their bottom feeding activities roil the water severely. Even if bass were stocked in such ponds, they could not see to feed, and their impact on bull heads and carp would be negligible. Draining the pond is the most economical alternative for removing unwanted fish given these circumstances. If the pond cannot be drained, the fish community can be chemically removed. Liquid rotenone (5% or 2 1/2% synergized) is the chemical most frequently used. The chemical kills only animals with gills and is not harmful to warm-blooded animals. It should be mixed at a volume of 1 gallon per acre-foot of water. The amount of rotenone required may be reduced if the pond’s water volume can be lowered through siphoning or pumping. This is desirable because the chemical is expensive. Application of rotenone must be conducted by a registered herbicide applicator and a permit is required from the Kansas Department of Health and Environment. Contact a district fisheries biologist for further information.

Treatment should occur when the water temperature is 70°F or above. In ponds smaller than about 2 acres, the chemical should be mixed into the water using the propwash of a stationary outboard motor. The front end of a small boat should be pointed into the pond’s bank and the motor should be run in forward gear while the rotenone is poured slowly into the propwash. It is best to dilute the rotenone with water before it is poured into the pond so that the treatment is done gradually. The propwash will circulate the chemical to all depths of the pond. The motor should be run as fast as safely possible to assure maximum circulation. The front and sides of the boat should be tied to stakes driven into the pond’s bottom to keep the boat from running up the bank.

It is important to change the location of the boat several times so that the mixing action reaches all areas of the pond. Shallow areas or areas not reached by the propwash should be treated with a hand sprayer or by “bucketing” in the chemical. The mixing action is ineffective when the boat is only driven around the pond. While the upper 3 feet of water may be well mixed, little chemical will reach lower depths.

Rotenone may not reach all areas of large ponds or ponds deeper than 10 feet when the chemical is mixed with an outboard motor. The chemical should be pumped into areas not reached by motor mixing and into the deepest portions of such ponds. Fish can be stocked back into a pond within 3 weeks after rotenone has been applied.