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MANAGEMENT OF

RECREATIONAL

AND

FARM PONDSIN LOUISIANA

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A farm pond or recreational pond can serve many purposes: a source of food, an aes-thetic enhancement to property, a sportfishing opportunity, a swimming area, wildlife habitat,or a reservoir for livestock, irrigation and fire fighting needs. The intended purpose or pur-poses should be well thought out before construction and stocking. This publication reviewsplanning considerations and management recommendations relating to a number of potentialuses for small ponds in Louisiana.

FARM PONDS

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TABLE OF CONTENTS

LEGAL CONSIDERATIONS ----------------------------------------------------------------------------6Permitting -----------------------------------------------------------------------------------------6Public Lands and Waters ---------------------------------------------------------------------6Other Regulations ------------------------------------------------------------------------------6Liability ---------------------------------------------------------------------------------------------6

ALTERNATE USES FOR PONDS ---------------------------------------------------------------------8Livestock Watering -----------------------------------------------------------------------------8Fire Control ---------------------------------------------------------------------------------------8Wildlife Habitat ----------------------------------------------------------------------------------8Swimming -----------------------------------------------------------------------------------------8

DESIGN AND CONSTRUCTION -------------------------------------------------------------------- 10Location------------------------------------------------------------------------------------------ 10Soil------------------------------------------------------------------------------------------------- 10Pond Size and Shape------------------------------------------------------------------------ 11Water Supplies, Water Loss and Pumping ------------------------------------------- 11Clearing the Pond Site ---------------------------------------------------------------------- 12Levees -------------------------------------------------------------------------------------------- 12Drainage ----------------------------------------------------------------------------------------- 13Sealing Ponds --------------------------------------------------------------------------------- 13Improvements to Existing Ponds ------------------------------------------------------- 14

POND HABITAT DEVELOPMENT ------------------------------------------------------------------ 15Depth Considerations ----------------------------------------------------------------------- 15Habitat Complexity --------------------------------------------------------------------------- 16Spawning Areas ------------------------------------------------------------------------------- 17

WATER QUALITY ---------------------------------------------------------------------------------------- 18Water Characteristics ----------------------------------------------------------------------- 18Surface Water ---------------------------------------------------------------------------------- 18Groundwater ----------------------------------------------------------------------------------- 19

TURBIDITY - MUDDY WATER ----------------------------------------------------------------------- 20

FERTILIZATION ------------------------------------------------------------------------------------------ 21Should You Fertilize? ------------------------------------------------------------------------ 21Types of Fertilizer ---------------------------------------------------------------------------- 21Fertilization Methods and Schedules -------------------------------------------------- 22Applying Fertilizers -------------------------------------------------------------------------- 22

LIMING PONDS ------------------------------------------------------------------------------------------ 24Liming Materials ------------------------------------------------------------------------------ 24Soil Samples ----------------------------------------------------------------------------------- 24Application Methods ------------------------------------------------------------------------ 24Frequency of Liming ------------------------------------------------------------------------ 25

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SPECIES PROFILES FOR STOCKING ----------------------------------------------------------- 26Bream --------------------------------------------------------------------------------------------- 26Bass ----------------------------------------------------------------------------------------------- 27Catfish -------------------------------------------------------------------------------------------- 27Forage Species -------------------------------------------------------------------------------- 28Fish to Avoid ----------------------------------------------------------------------------------- 28Recommended Stocking Combinations ---------------------------------------------- 29

STOCKING PROCEDURES -------------------------------------------------------------------------- 32Acclimation Procedures -------------------------------------------------------------------- 32

OXYGEN DEPLETIONS AND OTHER TYPES OF FISH KILLS ---------------------------- 33Algal Blooms and Oxygen ----------------------------------------------------------------- 33Other Algal Bloom Impacts --------------------------------------------------------------- 34Response Options - Aeration------------------------------------------------------------- 34Fish Kills from Chemical Contamination --------------------------------------------- 34

DISEASES IN POND FISHES ------------------------------------------------------------------------ 35The Role of Stress ---------------------------------------------------------------------------- 35What to Look For ----------------------------------------------------------------------------- 35What to Do -------------------------------------------------------------------------------------- 36Internal Parasites ----------------------------------------------------------------------------- 36

MANAGING BASS AND BREAM POPULATIONS --------------------------------------------- 37

RENOVATION OF PONDS ---------------------------------------------------------------------------- 40Determining Pond Volume ----------------------------------------------------------------- 40Application Rates and Procedures ----------------------------------------------------- 40Restrictions ------------------------------------------------------------------------------------- 41

AQUATIC WEED CONTROL -------------------------------------------------------------------------- 42Factors Affecting Control ------------------------------------------------------------------ 42Pond Construction --------------------------------------------------------------------------- 42Preventive Fertilization --------------------------------------------------------------------- 42Drawdown --------------------------------------------------------------------------------------- 43Mechanical Control -------------------------------------------------------------------------- 43Biological Control ---------------------------------------------------------------------------- 43Chemical Control ----------------------------------------------------------------------------- 43

NUISANCES AND PREDATORS -------------------------------------------------------------------- 45Furbearers -------------------------------------------------------------------------------------- 45Snakes-------------------------------------------------------------------------------------------- 45Turtles -------------------------------------------------------------------------------------------- 45Birds ---------------------------------------------------------------------------------------------- 45Mosquitoes ------------------------------------------------------------------------------------- 45

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LEGAL CONSIDERATIONS

PermittingPond-related permitting begins with the

site selection and construction phases.Non-wetland construction in an upland areaoutside the coastal zone, in an area higher than 5feet above sea level or in a fastland within thecoastal zone, requires no permit from the U.S.Army Corps of Engineers, Coastal ManagementDivision or the Environmental ProtectionAgency, but local ordinances should be checkedfor site selection/construction requirements. Ifthe project causes discharges into coastal watersor changes existing water flow into coastalwaters, a permit may be needed.

If water bottoms or wetlands are affectedby the construction, contact the U.S. ArmyCorps of Engineers or the Natural ResourcesConservation Service. Under state law, withinthe coastal zone - below 5 feet and not in afastland - dredging, filling or construction andoperation of water control structures, includinglevees, all require a state or local coastal usepermit.

Public Lands and WatersAnywhere in the state, any activity en-

croaching on state lands or state-owned waterbottoms must be permitted by the Division ofAdministrations’ State Lands Office. As forfederal law, any obstruction of navigable U.S.waters or discharges of dredged or fill materialsinto such waters require a permit from the ArmyCorps of Engineers.

Note that public waters may be diverted forprivate use -- unless regulated by laws related tocoastal zone management -- so long as suchwaters are returned to their natural channel afteruse. Also, federal law may require a permit forany diversion of water from a navigable river.

Any well that produces more than 50,000 gallons ofwater/day must be registered with the Department ofPublic Works. Wells drilled after July 26, 1972, thatare free-flowing and produce more than 25,000gallons/day must have control devices.

Other RegulationsThe use of chemicals is regulated by Food and

Drug Administration and the EPA. Stocking alsorequires regulatory compliance. Many exotic speciesmay not be brought into the state without permitsfrom the Louisiana Department of Wildlife andFisheries, and some – such as the piranha – areabsolutely prohibited. Many fish predators areprotected by federal and state endangered-specieslaws. Before taking action against birds or otherpredators, pond owners should consult the appropri-ate laws through the Department of Wildlife andFisheries.

LiabilityAlong with regulations, legal liability for

accidents occurring on a pond owner’s property mustbe considered. Most Louisiana legal cases involvingpond-related accidents deal with children wanderingonto property and drowning in a small water hole,such as a borrow pit. Plaintiffs in these cases usuallybase their claims on the “attractive nuisance doc-trine,” which has two requirements to make thedefendant liable. First, the nuisance must have someartificial or otherwise special feature that makes itespecially dangerous to children, or the danger mustbe a hidden one. Second, the child must be so youngas not to be responsible.

Many plaintiffs have lost cases because therewas nothing especially “attractive” about the defen-dants’ ponds or borrow pits, and/or the childreninvolved were teen-agers capable of understanding

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the danger. Defendants were also helped becausethey had fences and their ponds were in fairlyremote areas, away from areas children wouldusually be in.

Also be aware of the legal concept of“strict liability,” which means exactly what itsounds like. Some activities are judged to be sodangerous that they will result in legal liability ifanyone is harmed because of them. If a courtestablishes that the owner of a pond has someduty to keep it safe to the public, and finds thatthe plaintiff in a particular case was hurt in thatpond because it was not safe, then the owner willbe liable.

Fortunately for pond owners, such duty hasrarely been established for owners of ponds and

pits, usually because they are not in areas fre-quented by the public. Trespass laws may help,because they state that under the law the public hasno business on pond owners’ property. However, iffor some reason a court in a particular case finds aduty under strict liability analysis, the defendantwill be found liable.

Another possible source of liability for pondowners is runoff. Any obstruction of, or change of,natural drainage that affects neighboring property isa source of possible liability. If any trash or chemi-cals get into public waters because of the runoff,then the pond owner could also be subject to directfines by state agencies. For this reason, all drainageshould be planned and controlled.

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ALTERNATE USES FOR PONDS

Many small farm ponds are used forlivestock watering, rural fire control, waterfowland wildlife habitat, and improving the land-scape. Although many of these uses are gener-ally compatible, certain management practicesor modifications may be required. Theseoptions should be considered before construct-ing a pond, if possible.

Livestock WateringWhen livestock are allowed direct access to

watering ponds, they tend to stir up mud and causeexcessive turbidity, reducing pond productivity,spawning success and quality of fishing. Thisproblem can be eliminated by constructing ormodifying drainage structures to allow for water-ing troughs outside the pond and by limitingshoreline access by livestock. Ponds used forwatering livestock should be well-spaced through-out the grazing area. In smooth, level areas,livestock should not have to travel more than onemile to reach a watering pond. This distanceshould be reduced to 1/4 mile in rough, hillycountry. (see Figure 1)

Fire ControlIf ponds are to be relied on for fire control,

adequate pumping equipment and hoses will berequired. Plan to use a stream of at least 250gallons per minute at a pressure of no less than 50psi. This rate of usage will consume 1/4 acre-footin a 5-hour period. Install at least one dry hydrant,and secure a centrifugal pump and an appropriatelength of high-quality fire hose with a nozzle. (seeFigure 2)

Wildlife HabitatPonds can attract many types of wildlife if

human disturbances are minimal and sufficientcover and access are provided. Migratory water-fowl often use relatively isolated ponds as tempo-rary resting places and feeding sites. A shallowarea can be developed along one side of the pondto enhance wildlife use, but this shallow habitatmay complicate weed control if the rest of thepond does not have a steep drop-off.

SwimmingIf ponds are to be used for swimming, they

should be free from potential pesticide or sewagecontamination and submerged obstructions such aslogs, branches, stumps or old fencing. A relativelyshallow, gently sloping area is recommended tofacilitate access.

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Figure 1. Modified drain to service a watering trough

Extend pipe abovewater level

Riser with 1 /4"holes

6" concrete base

Corrugated metal pipe with1 “ holes filled with coarsegravel

Antiseep collar

Valve

Trough

Union

Control valve

Water is piped through the dam’s drainpipe to a stock water trough

Figure 2. Fire control apparatus4 1 /2" bronze capsteamerhouse connection

24"

Cast iron elbow

Bronze nipple 4 1 /2" steamer to 4"or 6" pipe thread

Frost-free depth

Pumping lift not over 18'

4" or 6" galvanized steel orother equally durable pipe

Ground line

Suction pipe

Gravel coveringdepth of 12"

Well screen

A Typical Dry Hydrant System

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DESIGN AND CONSTRUCTION

Satisfaction and enjoyment from a pondbegin with proper design and construction. Awell-designed and constructed pond is amajor capital investment. It can enhanceproperty values or be nothing more than anattractive nuisance that may increase insur-ance costs.

LocationA desirable pond site should have three

characteristics: an adequate supply of goodquality water, topography that can be economi-cally converted into a pond and soil that willhold water. A well-constructed, properly locatedpond will provide better service and last longerwhile requiring less maintenance. Before begin-ning construction, make a master plan involvingthe pond and other property features. Plan aheadto avoid later problems. Changes are easy tomake on paper but are costly once the pond isbuilt.

A number of questions must be consideredseriously during the planning stage: Will thepond be built on owned property or leasedproperty? Will it be a business venture or just arecreational project? Will it be near a public roador the home site, or some distance off the road?What about security and safety? Will the pond beaccessible year round? Do you plan to buildother ponds later? Will agricultural demandssuch as irrigation and livestock watering requirean auxiliary pond or tank? What about powersupply for pumping? Will electricity be required?Will it be single-phase or three-phase electricity?

Before beginning construction, there areeven more considerations to address, such asservitudes, rights of way, pipelines, power lines,etc. Will friends or neighbors have fishing rights

and/or hunting privileges? Is there a possibleconflict of interest? Will the pond require fencing?

Check with the USDA Soil ConservationService (SCS) for soil type and topographic maps,as well as aerial photographs. The local office of theSCS can provide valuable assistance in determiningif soil types and proposed locations are suitable forpond construction. The Louisiana or U.S. Geologi-cal surveys may also have useful maps. Neighbors,surveyors or government planning agencies mayalso have useful maps and other information.

Although a well-sealed pond with no leakageis the number one concern, adequate drainage is aclose second. Where will surplus water go? Fishlosses caused by flooding must be avoided. Theproperty’s drainage outlet must be considered in thedrainage design.

SoilDepending on the history of the property, you

may need to check for pesticides in the soil wherethe pond will be located. Request help from yourlocal SCS representative to determine how muchsand, silt or clay it contains, to a depth of at least 2feet below the anticipated pond bottom. The soilneeds to have about 25 percent clay or silt to sealproperly. Avoid any possibility of roots and limbs inthe pond levees or bottom.

Even where clay content is high, soil compac-tion over the entire water-holding area is essential.This must be done during construction, using asheep’s-foot roller or heavy tractor. Track vehiclesdo not compact soil as effectively as these methods.

Pond Size and Shape

Recreational ponds in Louisiana mayvary in size from less than half an acre to 20acres or more. Some factors to consider when

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determining the size of a pond include pri-mary and secondary uses, watershed orgroundwater yields and cost. Ponds may beirregular in shape, especially dam pondsbetween two hillsides. On level ground,ponds are frequently rectangular or squarewith levees on all sides. These are referred to

as levee ponds. A third type of pond is theexcavated, or dug out, borrow pit pond.These may have partial levees with one sideopen to receive surface runoff from rains.(see Figures 3, 4 and 5)

Figures 3 and 4. Various illustrations of pond layouts

Figure 3

Edges shouldbe deepenedto 3 feet

pier

Spillway

Drain and stand pipe

Standing trees

Gravel beds

Brush pile

Earth pier(Shorelinedevelopment)

Dam

Excavation fordirt used in dam

Figure 4

Selective clearingand/ or plantings

Lack of transition treatmentcreates an unnatural edge

Minimumclearing limits

clearing limits

PondSelective clearing and/ or plantingcreates a natural appearance

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Figure 5. Pond Layout

Water Supplies, Water Loss andPumping

Pond water may come from rainfall, surfacerunoff or pumped-in groundwater or surfacewater. Rain falling directly into a pond will notmaintain adequate pond water levels, so water-sheds above the pond elevation are used to funnellarger areas of rainfall into many ponds. Water-sheds usually range from five to 20 times thepond surface acreage. Heavy clay soils and openpastures allow for smaller watersheds, and sandysoils and forested areas demand larger water-sheds. If large portions of a watershed are notproperly vegetated, water runoff will depositexcessive amounts of silt in the pond and greatlyshorten its productive lifetime.

Avoid excessively large watersheds,because they increase size requirements of leveesand associated construction costs. More impor-tant, oversized watersheds result in excessiveflushing. For the same reason, do not locateponds over stream beds or ditches where waterwill flow through continuously. If these situa-tions cannot be avoided, ponds may still be builtand managed successfully if a diversion channelcan be incorporated into the design at the time ofconstruction.

If groundwater is used for pond filling andevaporation replacement, the well should belocated near the edge of the pond or in a centrallocation if more than one pond will be suppliedfrom the same well. If the pond is to be used forirrigation in addition to fishing, water storageshould be approximately 1.5 acre feet for each1.0 acre to be irrigated.

Water is lost from a pond by seepage,drainage, evaporation or overflow. Seepage losscan be minimized by proper sealing and compac-

tion of the pond bottom, levee and sides. However,sand layers or isolated sand pockets and stumpholes can cause severe seepage problems and mustbe avoided. Sudden water loss can occur if a leveefails or a drain pipe cracks or is left open. Depend-ing on the time of year and the elevation of theleak, fish losses may be unavoidable in thesesituations.

Evaporation is usually negligible in thewinter, but can be as much as 1/5 inch per day ormore in Louisiana on hot windy days. Unless thiswater loss is replaced by pumping, the water levelwill continue to drop until the next rain. Theselosses can amount to as much as 1 inch per week.A loss of 1 acre-inch in one week is equal to27,154 gallons, or 3,879 gallons per day.

Pumps used for filling and maintaining pondsare of three general types: (1) centrifugal, (2) deepwell-turbine and (3) low lift. A small pump canmaintain a pond level once it is full, assumingseepage is small. A pump will require a capacity ofabout 12 to 15 GPM per pond surface acre to offseta total water loss of 0.3 inches per day, pumping 12hours per day. This will require 0.5 to 3.0 horse-power, depending on well depth and pressure.

If pumping 24 hours per day and usingautomatic float controls, the flow rate could be 6 to7.5 GPM per pond surface acre to offset a totalwater loss of 0.3 inches per day. A flow rate of 450GPM is equal to 1 acre-inch per hour and alsoequal to 1.0 cubic foot per second (CFS). Forexample: pumping 450 GPM for 12 hours will fill aone-acre pond with 12 inches of water.

Clearing the Pond SiteThe entire pond basin, plus an open strip at

least 20 feet back from the water line, should becleared of all trees, stumps, brush, dead branchesand other debris. When timber is present, irregularvariation in the width of the open strip surroundingthe pond will add to a more natural appearanceafter construction. Old stumps, trees and branchesshould especially be avoided in the area where thelevee will be constructed. These materials willgradually rot if buried in the levee, providing adirect channel for water to leave the pond. The areawhere the base of the levee will be located shouldbe scraped clean of leaves, grasses, muck andtopsoil.

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LeveesAlthough fish pond levees vary widely in

height from one site to another, they should be atleast 6 to 8 feet high. A minimum average depth of4 feet should be maintained throughout the year, anddesign specifications should make sure no part ofthe pond is less than 3 feet deep to avoid problemswith rooted aquatic vegetation. Conversely, waterdepths of more than 6 feet are generally of little usein Louisiana and do not increase overall fishproduction.

Depending on how efficiently soil is com-pacted during the construction process, levees mayrequire 15% to 20% additional height to compen-sate for settling during the first one or two years.Lighter soils may require use of a central clay coreto prevent excess seepage through the levee. Thisshould be determined with your SCS representativeduring the soil evaluation process.

Pond levees should be 10 to 16 feet wide toaccommodate bulldozer construction and vehicletraffic. Side slopes usually vary between 3:1 and5:1. If you have any doubts regarding designspecifications, consult your SCS representative or aqualified engineer.

Levee surfaces should be protected with grasssides, gravel tops and riprap along downwindinteriors. Establish a grass cover on new levees asquickly as possible. Common causes of damage tolevees after construction include intrusive tree roots,cattle damage, extreme wave action and excessivevehicular traffic.

DrainageDrain structures and pond locations should

allow for complete drainage when needed. Leveeponds need a pipe drain through the levee in thelowest part of the pond for gravity drainage. Other-wise, pump-outs will be necessary sooner or later. Alevel-control drain pipe is often recommended toregulate water depth automatically. Gate or shearvalves should be incorporated outside the levee toallow for easy depth adjustment, especially forwinter drawdowns. The inside pipe should beequipped with a screen, cage or gravel-bed filter toprevent clogging or stopping up with mud, vegeta-tion or other debris.

Ponds smaller than eight acres should have6-inch diameter drain pipes. Ponds from eight to 12acres require 8-inch pipe, and larger ponds generallyrequire 12-inch diameter drain lines for responsive

water control. Drain pipes should extend at least 2feet beyond the toe of the levee on both sides.Once drain lines are laid, concrete collars shouldalways be installed at 12-foot intervals beforecontinuing with levee construction.

Rainfall in most parts of Louisiana usuallyranges from 45 to 60 inches per year, but thisrainfall is distributed variably from day to day andweek to week. Because of this variability, aspillway should always be provided for emergencydrainage when excessive rains occur. Spillways canbe excavated channels or can be constructed withpiping equipped with trash racks. Pipe spillwaysare generally of two types: drop-inlet orhooded-inlet, both of which pass through the levee.Excavated spillways must be wide and flat to avoiderosion and fish loss during heavy water flow. (seeFigures 6 and 7)

Your SCS representative can provide guide-lines for sizing either type of spillway, but a goodrule is to make an excavated spillway width equalto at least 10% of the length of the levee. For long,narrow ponds, increase this amount. To discouragefish from leaving the pond, water flow through thespillway should not exceed 3 inches in depth.Although spillways are usually inactive exceptduring heavy rains, a good turf cover should beestablished on excavated spillways after construc-tion and maintained at all times. For ponds withlarge watersheds, levees must be constructed toallow at least 2-2 1/2 feet for temporary floodwaterstorage while excess water is drained through thespillway.

If water will be required frequently forwatering livestock or other purposes, a line can betied in to the main drain pipe outside the levee andfitted with a gate or float valve to fill a tank, troughor smaller pond. Fencing may be required todiscourage livestock from using the main pond.Uncontrolled livestock watering will damagelevees and will eventually ruin the fishing in smallor moderately sized ponds.

Sealing PondsThe entire pond bottom must be sealed to a

point well above the anticipated waterline toprevent water seepage. This is normally done byusing soil with at least 25% clay, which swellswhen wet to fill in spaces between soil particles.This layer is disked or mixed uniformly and thenpacked tight with a sheep’s-foot roller.

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Small amounts of seepage throughlevees are common in new ponds. Thiscondition usually corrects itself as leveessettle and clay particles become saturated andswell. If seepage continues or leaks develop,it may be necessary to drain the pond par-tially or completely and apply bentonite, avolcanic clay compound, to the inside sur-face of the levee. SCS representatives canprovide advice if this is necessary. Leakslarger than 1/2 to 1 inch in size often requiremore extensive repairs with heavy equipmentafter partially or completely draining thepond. Again, contact SCS if leaks persist.

Improvements to Existing Ponds

Most construction-related managementproblems in existing ponds are the result ofinsufficient water control or excessivelyshallow pond edges. Water control can oftenbe improved by installing proper drain struc-tures. In some instances, diversion channelsare required to eliminate constant flushing andallow for fertilizer to be retained in the pond.If spillways are not present, they should beinstalled to minimize levee damage. Shallowpond edges can be corrected by cutting belowthe water line and using the spoil to build uplevees or make points extending out into thepond.

Figures 6 and 7. Drainage structure options

Screen (1½-inchmesh)

Air vents

Antiseep collar

2' below permanentwater level

PVC pipe

Pipe Added to Existing Pond

Water

Screen (1½-inch mesh)Antiseep collar

Swivel joint

Splash apron

Support post

Drain Pipe with Stand Pipe Below Levee

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POND HABITAT DEVELOPMENT

To develop a successful fishery, farmponds must provide habitat that will promoteadequate reproduction and good growth of fishpopulations. From this standpoint, severalfactors could be included under the termhabitat.

Depth ConsiderationsIn general, a deeper pond provides more

habitat for fish production. However, as ponds getdeeper, there is a greater likelihood of stratifica-tion. Deeper ponds can become stratified, with awarm upper level, a transition zone where thetemperature drops quickly, called the thermocline,

and a cooler, deeper zone. Problems in deeper pondsdevelop because oxygen levels in the isolatedbottom zone drop throughout the summer and mayreach 0. If this happens, available habitat is reducedbecause fish will avoid this part of the pond. (seeFigure 8)

If the pond turns over quickly from a severewindstorm or a heavy, cold rainfall during latesummer or fall, a fish kill can occur. The bestsolution in deeper ponds (large areas over 10 feet indepth) is to install a floating windmill aerator orsimilar device to keep the water column well mixed.This will ensure adequate dissolved oxygen levelsin the hypolimnion and will increase the potentialfor fish production. (see Figure 9)

Figure 8. Stratification

Surface waters High illumination, acceptable oxygen levels from photosynthesis and wind mixing

Moderate illumination, marginal oxygen levels

Bottom waters Little illumination, no oxygen production. Heavy oxygenconsumption and production of toxic substances fromdecomposition at the pond bottom

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Figure 9. Windmill Mixer

Habitat ComplexityApart from water quality and overall pond

depth, two other aspects of pond habitat arecrucial for developing productive fishing: habitatcomplexity and spawning areas. One aspect ofhabitat complexity is variability in depth andshape of a pond. A useful concept that has beendeveloped to describe pond shape is the shorelinedevelopment index. This index compares thelength of the shoreline of a pond to the circum-ference of a circle with the same surface area. Ahigher shoreline development index providesmuch better habitat for fishes that are suited forfarm ponds in Louisiana such as largemouthbass, bluegill sunfish, redear sunfish and channelcatfish. (see Figure 10)

A second aspect of habitat complexity isdepth variability. A well-constructed pond shouldhave near-vertical sides to a depth of 3 feet todiscourage growth of rooted plants. Movingaway from the vertical walls at the edge of thepond, deeper holes, underwater mounds andsubmerged points all provide habitat variabilityand cover for sportfishes, particularly largemouthbass. In this regard, ponds formed from damsconstructed at the mouth of small hollows oftenprovide better habitat diversity than excavatedround or rectangular ponds. A third aspect ofhabitat complexity is submerged structure.Structure can be formed by anything in the water.It provides hiding places for fish, as well as aplace to concentrate fish and increase fishingsuccess. However, the type of structure presentcan have a tremendous effect on fish productionand angling success. In general, the least benefi-

cial structure in a pond is rooted vegetation. Theproblem with beds of vegetation is that they canbecome so dense that predatory fishes like largemouthbass are unable to forage effectively; this results inhigh densities of small sunfishes, which becomestunted, attaining maximum sizes of 3-5 inches, andreduces bass reproduction. By maintaining a 3-footdepth at the margin of the pond and following a goodfertilization schedule, you can usually eliminaterooted vegetation.

However, if rooted vegetation is not present,what types of cover are available, and what types arebest? One of the best types of cover is a submergedtree. Consider a 40-foot tree that has been cut down,trimmed of all branches under 1 inch in diameter andplaced in a pond perpendicular to the shoreline withthe trunk at the pond’s edge. It provides physicalstructure in the pond, but not dense structure. Smalland large fishes can easily swim among the branches,thus allowing predatory bass to crop the youngsunfishes.

The tree covers the entire range of depths fromthe surface at the edge to the bottom toward themiddle, increasing habitat complexity. It providesgood surface area for development of attached algaecommunities and the insects that serve as forage foryoung fishes. It provides protected areas wherenestbuilding fishes like bass and sunfish can spawn.Finally, it concentrates larger sunfish and bass toincrease the catch rate of pond anglers. In general, themore cover/depth combinations that can be devel-oped, the better the habitat.

Other types of submerged structures provideexcellent cover for pond fishes, and they all share atleast some of the above characteristics. Brush pilesthat are lashed together and weighted provide excel-lent cover. Several brush piles can be placed atdifferent depths and locations in a pond to increasehabitat complexity. Tire reefs can be made inexpen-sively. Tire reefs provide low-density cover for a longperiod of time and are fairly easy to build and anchor.Construction and placement are easiest before thepond is filled or if the pond can be drawn down andthen refilled after the reefs have been constructed.Piles of concrete blocks or other materials can alsoprovide cover. In fact, the only real limitations toproviding submerged structures are finding heavymaterials and getting them into the water. (see Figures11, 12 and 13)

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Spawning AreasThe other important aspect of pond habitat is

spawning substrate (what the bottom is made upof). Largemouth bass and bluegill are nestbuilders,and they prefer a substrate that is fairly firm andcoarse. Fairly new ponds with clay bottoms willusually provide adequate spawning substrate forpond fishes. Older ponds, however, tend to becomesilty, and in time the buildup of this fine mud canreduce nesting success. Check to see that there issome firm substrate in 3-6 feet of water along the

windward shoreline (so that the most of waveaction will be at the other end of the pond). Ifthese conditions are not present, the substrate canbe improved by spreading pea gravel (1/8 inch to1/4 inch in diameter) along 50-100 feet of shore-line (5- to 10-foot band, 1/4-1/2 inch deep) oralong patches of shoreline around the pond.

Figure 10. Shoreline Development

Main excavationFinal edge

Figures 11, 12 and 13.

Figure 11. Stake reefs

Figure 12. Brush piles

Figure 13. Tire reefs

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WATER QUALITY

Good water quality plays a major role inthe success of recreational and farm ponds.Water quality is one of the most importantlimiting factors in the ability of ponds toproduce quality fishing. The behavior, feeding,growth and survival of fish in ponds are allaffected by water quality. Poor water qualitymay trigger a disease outbreak and will reducefish growth and yields. Fishing success may belimited as well. In extreme cases, bad watercan cause catastrophic fish kills where most orall fish in a pond die suddenly. Most problemsassociated with poor water quality can beavoided by understanding the factors whichaffect water quality and taking proper man-agement measures.

Water CharacteristicsWater used to fill ponds must be of high

quality and free of pollutants such as sewage andtoxic chemicals. Water that is suitable for live-stock and home use or that supports wild fishpopulations is generally safe and suitable for usein farm ponds.

Fish grow best in water with certain chemi-cal characteristics. Ideally, water should have apH of 6.5 - 9.0, total hardness of 50 - 300 mg/land total alkalinity of 50 - 300 mg/l. Total hard-ness and alkalinity should not be less than 20 mg/l. Most freshwater sources across Louisiana willmeet these criteria and be suitable for fish. Simplewater tests can determine whether or not yourwater meets these basic guidelines. Other impor-tant factors include maintaining suitable oxygenlevels and controlling turbidity (muddy water orphytoplankton).

Surface WaterMost ponds in the state are watershed ponds

which depend totally on rainfall runoff acrosspastures or woodlands to fill and maintain waterlevels. Water quality is affected by the type and soilcomposition of the watershed. Waters of low alkalin-ity usually originate from acid soils. Waters withhigher alkalinities drain across soils with sufficientquantities of limestone.

Watersheds must be well vegetated to keeppond water from becoming turbid with mud. Runofffrom cropland is not suitable source water for pondsbecause of potentially harmful pesticide contamina-tion, fertilizer runoff and excessive turbidity. Pas-tures make good watersheds if not overcrowded withlivestock. Too many animals on a pasture will resultin excess nutrients entering the pond, causing seriousproblems with water quality. Ponds receiving waterrunoff from feedlots or crowded pastures oftenresemble sewage lagoons and make poor fish ponds.

Well-vegetated woodland watersheds areusually excellent sources of water. Runoff is typi-cally clear and free of contaminants, but temporaryproblems with runoff (muddy water) may occur afterheavy logging activity. Water from pine forestwatersheds is usually a bit acidic (low pH), and theaddition of limestone may be required in some pondsreceiving this water.

Canals, streams and rivers may also be used assources for pond water if certain precautions aretaken. Water from these sources is often used whenponds are built in areas with little or no naturalwatershed, such as in a level field. Many levee farmponds are filled with water pumped from surfacewater sources. Surface water may be used if free ofcontaminants. Water must be carefully filtered with afine mesh screen to minimize the possibility ofstocking ponds with undesirable species of trash fish

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like green sunfish, carp and bullhead catfish. Makesure the screen does not clog with debris whilepumping, allowing unscreened water to enter thepond.

GroundwaterGroundwater sources such as water wells

and natural springs usually provide excellentquality water for farm ponds. Water wells must beused when surface water sources are unacceptableor not available. Wells are expensive to install andoperate and must be of sufficient size and dis-charge capacity to be useful. An undersized well

in an oversized pond may operate continuouslyand not even keep up with evaporation.

Groundwater is not pure and often containsdissolved gases like carbon and sulfur dioxideand minerals like iron and calcium. Groundwateralso contains no oxygen. Aeration of well watercan be accomplished by splashing supply waterthrough a series of screens which adds sufficientoxygen and takes care of problem gases andminerals. Well water can be pumped directlyinto most established ponds without beingaerated.

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TURBIDITY - MUDDY WATER

Ponds which remain muddy for extendedperiods do not produce quality fishing. Muddywater shades out sunlight necessary for thegrowth and survival of fish food organisms.

Muddy water is mainly caused byunvegetated watersheds; water entering the pondcarries suspended clay and silt particles. Oncevegetation problems are solved, so are most muddywater problems. If water remains muddy afterrevegetation of the watershed, it can be cleared upusing several methods:

1. Apply seven to 10 bales of hay or applybarnyard manure at a rate of 1 ton per acre at3-week intervals until problem is solved. Do notuse this treatment during the summer if fish arealready stocked because of the danger of oxygendepletion.

2. Add 5 pounds of commercial alum crystalsper acre-foot. Occasionally, much higher rates maybe required (up to 50 pounds per acre-foot), but alumis acidic, and high treatment rates in low alkalinitywaters may kill fish. Always check ponds to deter-mine if liming is required before applying alum.

3. Apply 75 to 100 pounds of cottonseed mealwith 25 pounds of normal superphosphate per acre at2- to 3- week intervals.

4. Apply gypsum (land plaster) at 300 to 500pounds per surface acre.

5. In mild cases a standard fertilization pro-gram can be effective.

All of these measures are temporary. Thesource of turbidity must be eliminated for the mosteffective and long-lasting remedy for muddy water.

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FERTILIZATION

Fertilization increases the capacity of apond to produce fish. Nutrients provided fromfertilizer increase production of microscopicplants (phytoplankton) that serve as food formicroscopic animals (zooplankton) and aquaticinsects. An abundance of these small creaturesgives ponds a green color and is called a “plank-ton bloom.” Plankton and insects serve as foodfor bream, which are eaten by bass. Fertilizationincreases the production of natural fish foodorganisms in ponds. This results in greater fishproduction and better fishing.

Proper use of fertilizer can increase fishyields two to five times. Fish are easier to catchin fertilized ponds because plankton turbiditylimits their vision, causing them to be less wary.Plankton blooms also reduce light penetration topond bottoms, preventing growth of trouble-some aquatic weeds. Most ponds will respond toa proper fertilization program. However, muddyponds and ponds with excessive amounts ofwater flushing through cannot be fertilizedeffectively. Ponds with soft, acid water may needto be limed before fertilization may be effective.

Should You Fertilize?Not all ponds need to be fertilized. Soils in

some areas of Louisiana are high in natural fertilityand support excellent fish production withoutsupplemental fertilization. Little or no fertilizermay be needed in ponds receiving runoff from well-managed pastures because of nutrients frommanure. Large unfertilized ponds fished by only afew people may produce excellent fishing. Heavilyfished ponds should be fertilized for best results.

No pond should be allowed to remain clear.Excessively clear ponds should be fertilized toproduce a bloom if only to control aquatic weeds.Fertilizers suitable for farm pond use are available

in liquid or granular form. Liquids are generallycheaper than granules and are superior in promot-ing phytoplankton growth in ponds. Granularfertilizers, however, may be more readily avail-able than liquids in some areas.

Types of FertilizerComplete fertilizers contain nitrogen (N),

phosphorus (P) and potassium (K). All fertilizercontainers will have the analysis or nutrientcontent listed. The N-P-K content will be listed inthat order. Each number indicates the percentageof weight of each nutrient. An example of acomplete fertilizer is 8-8-8, which contains byweight 8 percent N, 8 percent P and 8 percent K.In other words, a 100-pound bag of 8-8-8 contains8 pounds of each nutrient. The remaining weight(76 pounds) is crushed rock used for filler.

Incomplete fertilizers contain only one ortwo of the nutrients N, P and K. Common incom-plete fertilizer sources are normal superphosphate(0-20-0) and triple superphosphate (0-46-0).Another incomplete liquid fertilizer is ammoniumpolyphosphate (10-34-0). It contains 10 percentN, 34 percent P and no K. A 100-pound containerof this liquid fertilizer contains 10 pounds of Nand 34 pounds of P.

Phosphorus (P) is the most importantnutrient in pond fertilizers and usually gives amuch greater increase in fish production thannitrogen or potassium. An ideal farm pondfertilizer application should contain 4 to 8 poundsof phosphorus and 2 to 4 pounds of nitrogen persurface acre.

Granular and liquid fertilizers are com-monly available from agricultural supply stores.Most suppliers have access to liquid formulationsmade for pond use. Suitable liquid formulationsof ammonium polyphosphate fertilizer (10-34-0

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and 11-34-0) are also available from manyfertilizer bulk plants or agricultural co-ops. Pondowners usually provide their own containers.

Fertilization Methods andSchedules

Fertilization should begin during the firstwarm weather in February or March when watertemperatures stabilize in the 60s and continueuntil the water cools in the fall. Applicationsshould be made every two weeks until the waterbegins to turn a light shade of green with grow-ing plankton. The plankton should become denseenough so that a white disk cannot be seen at adepth of 18 inches. The bottom of a bleach bottleattached to a yardstick works well for checkingplankton density in this way. After the desiredcolor is reached, continue applications atmonthly intervals or whenever the water clearsenough that the disk becomes visible again.Additional fertilizer applications are not neces-sary unless the pond begins to clear. Disk visibil-ity limited to 6 inches or less, where no muddywater is present, may indicate a problem withoverfertilization.

Applying FertilizersConcentrated liquid fertilizer may be

sprayed over the shallow water edges of pondswith a power sprayer. A handheld garden sprayercan be used on the edge of small ponds. Liquidsmay also be applied directly to the pond bysiphoning through a small tube (1/4 to 1/2 inch)into the propeller wake of an outboard electric orgasoline motor while moving around the pond.For small ponds (1 acre and less), liquid fertilizercan be diluted by mixing with 10 parts water andsplashed over the pond surface. Do not pourliquid fertilizers directly into ponds because theyare heavier than water and will flow to thebottom and not mix well.

Granular fertilizers should be kept fromdirect contact with pond mud if possible becausethe nutrients become trapped in the mud and notare available to the plankton. A fertilizer platformpositioned just under the water surface keepsfertilizer off the bottom, allowing it to dissolveslowly into the water. A platform with a surfacearea of 45 square feet is sufficient for a 5- to10-acre pond. Granular fertilizers can be broad-cast directly into shallow water, but the platform

method is superior. Bags of fertilizer may be cutopen and placed directly in shallow water.

Never fertilize ponds with established weedproblems. The fertilizer will only cause weeds togrow faster, making the problem worse. In pondswith shallow edges or excessive water discharge,fertilization cannot be expected to control or preventestablishment of aquatic weeds. Fertilizing in earlyspring before some types of rooted weeds begin togrow can be effective. In most cases, weed problemsshould be entirely eliminated before fertilizing. If indoubt on whether or not to fertilize, get professionaladvice.

Common Fertilizers

Fertilizer

Type Grade

Liquid 9-32-0 10 to 2010-34-0 10 to 2011-37-0 10 to 2013-38-0 10 to 20

Granular 20-20-5 4018-46-0 188-8-8 10013-13-13 60

0-46-0 18plus plus34-0-0 24

Pounds offertilizer/Acre/

Application

23

Figure 14. Fertilizerplatform

8 - 8 - 8

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LIMING PONDS

Ponds with soft, acid water may notrespond to fertilizer. If the water does not turngreen after six weeks of fertilization, thenliming may be necessary. Ponds with waters ofless than 20 mg/l of total alkalinity normallyneed lime. The lower the alkalinity level, thebetter the pond will respond to liming. Apply-ing agricultural limestone will increase waterhardness and alkalinity and decrease acidity.This will make the fertilizer more effective.

Liming MaterialsAgricultural limestone (calcium carbonate or

dolomite), hydrated lime (calcium hydroxide) andquick lime (calcium hydroxide) are the mostcommon liming materials for ponds. Agriculturallimestone is not harmful to humans and will notcause high pH in water like the other forms oflime. It is the best and safest liming material touse in farm ponds.

Soil SamplesA pond soil sample is needed to determine

how much lime will be required. Collect samplesfrom several locations evenly spaced across eachpond, including both deep and shallow areas.Three to six samples per acre should be taken inponds larger than 5 acres and at least 10 samplesfrom smaller ponds. Samples can be collectedeasily in full ponds with a can attached to a pole.All individual samples should be mixed togetherand spread thin to dry. Dried soil samples shouldbe pulverized, then placed in a soil testing box to

be sent for analysis. Only about 2 cups of mixedsoil are necessary.

Chemical analysis of pond soils can beconducted at the LSU Agricultural Center SoilTesting Laboratory for a small fee. Soil samplesshould be delivered to the Louisiana CooperativeExtension Service office in your parish for pro-cessing. Be sure to indicate “Fish pond” on the soilinformation sheet. Test results and liming recom-mendations will be mailed directly to you.

Application MethodsNew ponds can be limed before they are

filled. Spread the liming material evenly over thedry pond bottom. A disk harrow can be used to mixthe lime into the soil. In ponds with water, lime-stone should be applied evenly across the watersurface. In small ponds, this may be done byspreading bagged limestone from a boat. In largerponds, where several tons may be required, aplatform can be built on the front of a large boat orbetween two boats tied together. Bulk limestonecan be loaded (do not overload!) on the platformand distributed across the pond surface with ashovel. Even distribution across the entire bottomis essential for good results.

Do not apply limestone while a pond is beingfertilized. Limestone settles phosphorus out of thewater, making it unavailable to phytoplankton.Apply lime during late fall and winter. This willgive it a chance to react with the acidic bottommud before the spring application of fertilizer.

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Frequency of LimingA liming treatment may last almost indefi-

nitely in ponds with no outflow. Most ponds havesome water discharge or are drained and refilledperiodically. Most ponds with acid soils andmoderate water outflow will probably need limeevery three to five years. A method frequently usedwith good results is to apply the amount of limerecommended by a soil test, then apply one-fourthof that amount each succeeding year to keep limerequirements satisfied.

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SPECIES PROFILES FOR STOCKING

When considering what fish to stock,determine your objectives in terms of foodproduction, recreation, aesthetics or trophyangling and how much time you have to devoteto pond management. Although many types offish could be stocked into recreational ponds,few have the characteristics needed to providequality fishing year after year.

BreamThe term bream refers generally to any of

the sunfishes, including bluegill, redear, greensunfish, their hybrids and other species. Althoughtheir general appearance and food habits aresimilar, they can behave very differently in farmponds, often with disappointing results. For thisreason, it is important to properly identify breambeing stocked into recreational ponds.

Bluegill: Bluegill are probably the best fishavailable to produce forage for bass, panfish forthe dinner table and good light-tackle fishing.These fish are well-adapted to pond conditionsand serve as a critical link in the food chain byconsuming insects, snails, occasional plantmaterial, small worms and microscopic animalswhile providing high-quality food for largemouthbass. They also provide most of the fishing in awell-managed pond. Bluegill normally live aboutfive years if not caught or eaten by larger fishfirst. They can spawn at about 3 inches long andat one year of age. Bluegill should be stocked intonew ponds in the fall and allowed to spawn beforestocking bass fingerlings the next spring. Thebluegill spawning season lasts fromApril-September in Louisiana, beginning whenthe water temperature reaches 70-75 degrees F. Aquarter-pound female will lay approximately12,000 eggs; very large females may lay up to as

many as 60,000. After spawning, the male bluegillguards the nest. In natural conditions, many nests areclustered together, called spawning beds. In Louisi-ana, mature bluegill can spawn as many as five timesin a season.

Although bluegill provide an abundant sourceof forage to support bass populations, they willoverpopulate and stunt if not tightly controlledthrough fishing and bass predation. An additionalproblem occurs when bluegill become so numerousthat they interfere with bass spawning and reproduc-tion. For this reason, pond owners should avoidexcessive cover in bass-bluegill ponds, especiallyrooted aquatic vegetation.

The coppernose bluegill is a subspecies nativeto the Atlantic coast region from Florida to SouthCarolina. Mature coppernose have a distinct copperor cream-colored bar across the nose, extending backto the gill cover and often have a thin yellow orwhite margin on their fins. Immature coppernosehave darker and more regular bars along their sidesthan common bluegill. Coppernose are aggressivefeeders and may grow faster or larger than commonbluegill, but they have not been conclusively demon-strated as a superior fish for stocking in Louisiana.(see Figure 15)

Redear Sunfish: This sunfish also produces agood forage base for bass production, but it producesthe best results when stocked as a supplement tobluegill. When stocking a new pond, you cansubstitute approximately 20%-30% of the recom-mended bluegill with redear. To maximize survival,redear (or any other species) under 5 inches in lengthshould not be stocked into existing bass-breamponds.

Redear should be managed in the same manneras bluegill, but they will spawn earlier in the springand normally spawn only twice in a season. Juvenileredear can usually be recognized by eight dark, often

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broken, vertical bands on their sides. Although theirfood habits are similar, the redear sunfish focusesmore attention on snails when they are available, andbluegill prefer insects. This feeding behavior hasearned the redear the nickname “shell cracker.” (seeFigure 16)

Hybrid Bream: Hybrid bream generally growfaster than pure bluegill or redear. Since they areaggressive feeders and usually accept pelleted foodreadily, hybrid bream are a good option if breamfishing is the objective, but they perform poorly as asustained forage for bass production. Two commontypes of hybrid bream are produced: redear male xgreen sunfish female and green sunfish male xbluegill female crosses. Both crosses produce about70% males, but some crosses, such as bluegill male xgreen sunfish female, produce almost 100% males.

Hybrid bream are usually fertile, although theymay not spawn reliably. When they occur, offspringof hybrids or their backcrosses to parent species aregenerally mongrels that cannot support fishing orbass predation for more than a year or two. For thisreason, draining or renovation is often required everythree to four years in ponds with hybrid bream.

Green Sunfish: This sunfish species is gener-ally regarded as a trash fish. Every effort should bemade to inspect bluegill or redear fingerlings to besure they are not contaminated with green sunfish.For the same reasons, assorted or wild bream are notrecommended for pond stocking. The dark spotnormally found at the rear of the dorsal fin in blue-gills is faint or absent in green sunfish juveniles,which tend to have a darker background color.

Green sunfish tend to overpopulate and stunt atextremely small sizes, and almost always reachdensities which completely prevent bass reproduc-tion. At this point, pond owners have few optionsother than to drain or poison the entire fish popula-tion and restock. Green sunfish are particularly hardyfish and sometimes difficult to kill. Even when pondsare drained, eggs of this species may survive inpuddles or moist soil. (see Figure 17)

BassLargemouth Bass: The largemouth bass is the

top-level predator in most recreational ponds andmany natural habitats in Louisiana. This fish iswidely sought both for sport and as food. As a result,it is often stocked in ponds too small to supportself-sustaining populations adequately. The large-mouth bass adapts well to ponds of one acre and

larger. It uses a variety of foods including fish,crawfish, insects, frogs, ducklings, rodents andother animals.

Largemouth bass can spawn successfullyin most ponds and grow rapidly if sufficientfood and space are available. In Louisiana, theycan reach sexual maturity at one year of age.Nesting on hard substrates, sand or gravelusually begins in the spring when water tem-peratures reach 60 to 65 degrees F. Maturefemales produce from 2,000 to 7,000 eggs perpound of body weight, which the male guardsduring the 2- to 4-day incubation period afterspawning.

Stocked alone without some foragespecies, largemouths usually stunt and repro-duce poorly. They require other fish, such asbluegill, as food to allow for good growth andspawning. Largemouth bass should generally bestocked in late spring, the year after bream havebeen stocked, so adequate forage will beavailable to support survival and growth. Inmost areas, largemouth bass normally live aboutsix to eight years if not caught by fishermen oreaten by larger fish.

Florida-strain largemouth bass havebecome widely sought after in recent yearsbecause of their faster growth rate and largermaximum size than native populations oflargemouth. Although they often attain trophysizes in large ponds and reservoirs, these fishmay not perform as well in ponds less than threeacres, or where fast-moving cold fronts can droptemperature suddenly. (see Figure 18)

CatfishChannel Catfish: This hardy fish grows

fast and readily takes artificial food in a pondenvironment. Channel catfish often havedifficulty reproducing if bass or bream arepresent in the same pond because of the extremevulnerability of their fry to predation. Thisspecies feeds primarily on invertebrates, such asinsects and crawfish, as well as on fish andfrogs. In recreational ponds, channel catfish willeat a wide variety of foods, including plants anddecaying organic matter. Channel catfish aregenerally stocked into ponds in fall beforestocking bass the next spring, but they can bestocked at almost any time in catfish-onlyponds.

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Channel catfish normally live six to eightyears. If suitable spawning areas are present,such as large pipes, cans or boxes, they willspawn readily in ponds. If bass and/or bream arepresent, almost all eggs and fry will be con-sumed, and catfish reproduction can be encour-aged. If stocked alone, catfish will tend tooverpopulate and stunt, so spawning should bediscouraged. When stocking channel catfish inestablished bass-bream ponds, use those morethan 10 inches long. (see Figure 19)

Blue Catfish: This species is similar to thechannel catfish, although not quite as hardy. Inponds, their diet is similar to that of channelcatfish, but they prefer to feed primarily on fish,such as bream. For this reason, they may bepreferable in some situations where bream tendto overpopulate. Blue catfish also tend to growsomewhat larger than channels after the secondyear of life. Unfortunately, it is usually muchharder to find blue catfish fingerlings. Bluecatfish fingerlings can be distinguished fromchannel catfish fingerlings by the absence ofspots. They also have smaller, lower-set eyes. Ingeneral, the same stocking and managementrecommendations apply for both species. (seeFigure 20)

Forage SpeciesGolden shiners are sometimes stocked as a

supplement to bluegills for bass forage in alkalinewaters or areas of high rainfall. Fathead minnows(1000/acre) or threadfin shad can be stocked intofarm ponds to help establish first-year basspopulations.

Fish to AvoidCrappie: (white perch, sac-a-lait, flathead

catfish (Opelousas or yellow cat), green sunfish,bullheads (mudcats), carp, buffalo or other roughfish should never be stocked into recreationalfishing ponds. All will eventually overpopulateand ruin fishing. Crappie, also known as whiteperch or sac-a-lait, should never be stocked intorecreational ponds smaller than 10 acres becausethey will overpopulate and stunt, eventuallypreventing bass reproduction. Even in largeponds of 10 acres or more, they require careful

management to prevent problems. Avoid stocking wildfish or fish caught from other waters; they can intro-duce diseases to your pond.

Recommended StockingCombinations

Bream-Bass-Catfish Combinations

(Fish per Acre):

For 1 Acre or Larger Ponds

Bream Bass Catfish

Bluegill Redear

1000 100 100 (fertilized)or 700 300 100 100 (fertilized)or 500 50 50 (unfertilized)or 350 150 50 50 (unfertilized)

Bream (1- to 3-inch) should be stocked in thefall with bass (1- to 3-inch) stocked the followingspring. If both species must be stocked in the spring,stock 20 6-inch bass and 30 3-inch or larger bream peracre. Double these rates for fertilized ponds. Catfishcan be stocked in the fall or spring in new ponds, butthey should be at least as large as any bass fingerlingspresent. Supplemental stocking of catfish into existingbass-bream ponds should use 10-inch fish (or larger)at a rate of 25 per acre in unfertilized ponds or 50 peracre in fertilized ponds. As catfish reach three years ofage and 3+ pounds, reproduction can be encouragedby providing cans, tires or other shelters for springspawning.

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Bream-Bass Combinations (Fishper Acre):For 1 Acre or Larger Ponds

Bream Bass

Bluegill Redear

1000 100 (fertilized)or 700 300 100 (fertilized)or 500 50 (unfertilized)or 350 150 50 (unfertilized)

Again, 1- to 3-inch bream are stocked in the fallwith 1- to 3-inch bass stocked the following spring.Advanced fingerlings may be stocked together in thespring as described above.

Catfish-only Stocking:Especially Recommended for Ponds Under 1 Acre

100-200 fish per unfertilized acre,200-400 fish per fertilized acre,300-600 fish per acre when fed daily

Catfish-Hybrid BreamCombinations (Fish per Acre):Especially Recommended for Ponds Under 1Acre

Hybrid Bream Catfish

150 50 (unfertilized)300 100 (fertilized)600 200 (fed daily)

Catfish reproduction should not be encour-aged with catfish-only or catfish-hybrid breamstocking. Do not provide cans, tires or othershelters for spawning. Restock with catfishwhen most of the original stock has beenremoved.

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Figure 15. Bluegill

Figure 16. Redear Sunfish

Figure 17. Green Sunfish

31

Figure 18. Bass

Figure 19. Channel Catfish

Figure 20. Blue Catfish

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STOCKING PROCEDURES

Once the decision has been made as towhat to stock, it is important to follow theproper procedures to maximize the healthand survival of the fingerlings purchased. Ifsurvival of one or another type of fish beingstocked is low, actual numbers will differgreatly from the recommended rates, andpond balance may be difficult to establish ormaintain. In some instances, high mortalityshortly after stocking may go unnoticed. Forthis reason, every effort must be made tominimize stress during transport and stock-ing.

Acclimation ProceduresFingerlings for stocking are generally

transported in hauling tanks with aeration or insealed bags with oxygen. Upon arrival, graduallyreplace water in hauling tanks with water fromthe pond to be stocked. This can be done with asmall pump or with buckets. Adjust temperaturegradually, with no more than a 7-8 degree Fincrease or a 5 degree F decrease per half hour.Continue aeration during this process. Whentemperatures have been adjusted, transfer fish tothe pond as gently as possible, with minimalhandling.

If fingerlings arrive in sealed plastic bags,float the bags in a shady area for 30 minutes, thenopen them and immediately release the fish.Normally, pond water should not be graduallymixed with shipping water in bags. Carbon dioxideand ammonia build up in shipping bags duringtransport. Since these compounds cannot dissipateinto the atmosphere, dissolved carbon dioxidereaches very high levels, lowering the pH of theshipping water. Opening the bags allows the carbondioxide to escape rapidly, and aerating or splashingaccelerates this process. The pH rises drastically,and any ammonia present rapidly converts to thetoxic form. This chain of events will kill fry andsmall fingerlings quickly.

This problem is less serious when transporttimes are short and when fish have not been fed forseveral days. Gradual mixing of pond water withtransport water in bags (after temperature adjust-ment) is usually desirable only when moving youngfish from hard water to moderately or very softwater. When attempting this procedure, monitor thefish closely for signs of stress, and introduce themdirectly into the pond if they begin to appear weakor disoriented.

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OXYGEN DEPLETIONS AND OTHER TYPES OF FISH KILLS

Although exposure to agricultural chemi-cals can occasionally result in direct fish mortal-ity, most fish kills in recreational and farm pondsare the result of oxygen depletions. Dissolvedoxygen levels depend on temperature, ponddepth, productivity and fertility, and watermovement. In almost any aquatic environment,fluctuations in natural nutrient cycles can createimbalances which lead to oxygen depletions andfish kills. Generally, these fluctuations aredifficult or impossible to predict, but highnutrient levels from feeding or over-fertilizingalmost always compound problems with oxygenmanagement.

As nutrients accumulate in the pondsystem, some end up directly in the bottom mudbut most go into solution in the water columnfirst, where they are used by plants and animals.The most abundant plants in a well-managedfishing pond are found in the algal bloom, whichgives the pond water a greenish tint. Suspendedin the water, these microscopic single-celledplants are sometimes referred to as phytoplank-ton. Except for situations where excessive vegeta-tion is present, most nutrients dissolved in thewater are taken up by the algal bloom.

Algal Blooms and OxygenLike all green plants, phytoplankton produce

oxygen during the daylight hours as a by-product ofphotosynthesis. This is usually a major source ofoxygen in fish ponds. In darkness, however, allplants consume oxygen, including phytoplankton.Blooms in natural water bodies or fish pondsnormally produce much more oxygen in the day-light than they consume during the night, but somesituations reduce the amount of oxygen a bloomproduces without reducing its nighttime oxygenconsumption.

Trace minerals or nutrients needed by thealgal bloom are occasionally used up. This usuallyresults in some, or occasionally all, of the phy-toplankton dying back temporarily. This is prob-ably the most common cause of phytoplanktondieoffs, especially for heavy blooms with competi-tion for light and nutrients. When a large portion ofthe bloom dies off at once, bacterial decompositionand the loss of normal oxygen production can leadto oxygen depletions and fish kills. Pond watergenerally changes from a deep green to black, gray,brown or clear after a phytoplankton dieoff.

Blooms respond to changes in the weather.Photosynthesis slows down under cloudy condi-tions, and, as a result, oxygen production de-creases. Extremely calm days may also reducephotosynthesis and oxygen production, even undersunny conditions, by preventing phytoplankton inthe middle layers of the pond from mixing near thebrighter surface. In summer, oxygen problems mayarise because of a simple physical property ofwater. The warmer the water, the less dissolvedoxygen it can hold. When a dense bloom producesa surplus of oxygen on a summer afternoon, theoxygen will not stay in solution and escapes intothe atmosphere. During the night, the bloomattempts to take more oxygen out of the water thanwhat remains from daytime photosynthesis. Whenthis occurs, dissolved oxygen levels approach zero.Fish begin to suffocate in the pond, and aerationmust be applied to meet the demand for oxygenand prevent fish losses.

Many ponds also experience oxygen prob-lems in early spring. As the water warms and theamount of sunlight increases, algal species whichpredominated in the bloom during the winter dieback, and other species more suited to summerconditions multiply and replace them. When thisprocess proceeds gradually, conditions remain

34

fairly stable. Occasionally, however, the winterbloom dies off abruptly and insufficient oxygenlevels may occur for several days.

This type of oxygen depletion may kill somefish directly or cause sufficient stress to weakentheir immune systems. Bacterial infections usuallyoccur within the next several days to two weeks.Various signs, such as color and odor changes or abuildup of foam on the downwind bank, cansometimes be useful in anticipating when a winterbloom will die back.

Other Algal Bloom ImpactsOther problems are associated with dense

algal blooms. In low-alkalinity waters, dense algalblooms create wide fluctuations in pH daily.Occasionally, heavy phytoplankton populationscause pH to reach extreme values in the afternoon.Algal die-offs can also result in high ammoniaconcentrations. Both processes affect fish health,growth and survival adversely. An additionalproblem caused by dense blooms, especially inexcessively deep ponds, is stratification. Asmentioned earlier, stratification involves layeringof the pond water into warm, oxygen-producingupper zones and cool, oxygen-consuming bottomwaters. Shading caused by dense blooms limitsphotosynthesis and dissolved oxygen levels at thepond bottom, resulting in a buildup of potentiallytoxic compounds, even in aerated ponds.

This situation can lead to physiologicalstress, reduced fish growth and even fish kills ifbottom waters are mixed too rapidly with the restof the pond. This type of mixing, referred to as aturnover, occurs when cool rain water or heavywind on the pond surface breaks down layeringpatterns. Turnovers are often observed in naturalwaters and ponds in the fall or spring after severeweather disturbances. The potential for a turnovercan be detected by an increasing temperaturedifference between a pond’s bottom layers and itssurface waters. If a turnover is likely, prepare foraeration when necessary.

Response Options - AerationOnce under way, oxygen depletions are fairly

easy to recognize. Partial depletions can berecognized by fish hanging at the water surfaceduring the early morning hours or a loss of appe-tite in ponds where fish are fed. Lethal oxygen

depletions begin with similar symptoms. Fishcongregate at the pond surface, gulping air. Duringthe early minutes of the depletion, they may divewhen disturbed and return to the surface. Asconditions worsen, they will ignore most distur-bances and continue gulping air.

Mechanical aeration is required to raiseoxygen levels once a depletion has begun. Irriga-tion or industrial pumps can be used to pull waterfrom a depth of 2 to 3 feet and spray it back intothe pond. Successful alternatives to agitate pondwater mechanically have included outboardmotors, bush hogs and other devices. A bush hogcan be backed into the pond to a point where theblades just touch the water. An outboard motoroperating in a fixed tilted position (keep boat tiedup or pointed into the shore) with the propellerwash directed out into the pond can also provideeffective aeration in emergency situations.

Flushing with clean, aerated water will helpimprove water quality, but this alternative is notavailable for ponds which depend on runoff as awater source. Emergency aeration will be mosteffective in smaller ponds, and the success of anyaeration practice will depend on the severity ofoxygen depletion.

Fish Kills from ChemicalContamination

Fish kills resulting from chemical contami-nation generally take one of two forms: directpoisoning of the fish or oxygen depletion resultingfrom poisoning of the algal bloom. Application ofagricultural chemicals to croplands which run offinto the pond must be practiced with great caution.Direct poisoning may be involved if small fish diebefore larger fish of the same species. If directpoisoning of fish or phytoplankton is suspected,contact the local Extension office and the Loui-siana Department of Agriculture and Forestryimmediately.

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DISEASES IN POND FISHES

The Role of StressFish disease organisms are constantly

present in most aquatic environments, and farmand recreational ponds are no exception. Underoptimum conditions, healthy fish are able to fightoff most forms of infectious diseases. Conversely,fish subjected to stress are often unable to main-tain their natural defenses against infectiousdiseases such as bacteria, viruses, fungi or proto-zoan parasites.

Stress may result from a variety of conditions,including overcrowding, handling stress, poor waterquality, inadequate nutrition and weather-relatedenvironmental stress. These forms of stress may killfish outright, in which case they can be considerednon-infectious diseases. More often, however, theydo not kill fish outright but lead to outbreaks ofinfectious diseases. Ironically, a common cause ofstress is chemical toxicity from disease or weedcontrol efforts. In summary, three factors are in-volved in fish disease outbreaks: infectious patho-gens (viruses, bacteria, fungi or protozoan parasites)must be present and capable of attacking the fish, thefish must already be in a susceptible state, andcertain environmental conditions, such as specifictemperatures or poor water quality, must be present.(see Figure 21)

As mentioned, many fish disease-causingorganisms are usually present in ponds, and little canbe done to eliminate them or prevent them fromrecurring. These organisms alone, however, areusually not enough to cause disease problems. Forthis reason, disease problems will usually reoccur infish ponds unless the conditions which caused theinitial fish stress can be identified and eliminated.Three main practices can minimize the possibility ofdisease outbreaks. These are maintenance of good

water quality, proper nutrition and elimination ofcontact with wild fish whenever possible. A soundfertilization program can contribute to the firsttwo objectives. The third can be achieved throughproper pond design and water management, aswell as prevention of fish introductions outside ofthe established stocking plan.

Common water quality stressors are lowdissolved oxygen and/or a buildup of toxicnitrogenous compounds, especially ammonia andnitrite. Dissolved oxygen problems are mostcommon in the early spring and the mid-to-latesummer. Nitrogenous compounds are more of aproblem in cold water during the winter.

What to Look ForFish should be observed every day, if

possible, or as often as practical. The followingsigns should be noted immediately: reducedfeeding, scratching or rubbing against submergedobjects and/or the pond bottom, piping or gaspingat the water surface, convulsions or erraticmotion, abnormal swimming (spinning or spiral-ing), blisters or sores, swollen bellies, listlessness,bulging eyes, bloody or bruised fins, discolorationor erosion of fins and skin, excessive mucus,puffy or bleeding gills and growths or spots on thebody surface.

What to DoRates of mortality should be carefully

recorded and monitored over time to help deter-mine the cause of the problem. Your county agentcan assist in obtaining a disease diagnosis andtreatment recommendation if disease problems

36

develop. The sooner a diagnosis is obtained, thesooner corrective measures can eliminate thecause of the outbreak. Although direct treatment ofcertain diseases may be possible in recreationalponds, these options are limited to situationswhere fish such as catfish or bream can be fedmedicated pellets or where external parasites canbe treated without further stress on the fishpopulation. Do not attempt disease treatmentwithout a professional diagnosis and treatmentrecommendation. Indiscriminate use of chemicalsor medications almost always wastes money, timeand fish.

Internal ParasitesMany ponds produce fish with worms or

cysts in the flesh. Perhaps the most common ofthese organisms is the yellow grub, although thewhite, black and eye grubs are also widely foundin pond fish. All these parasites have similar life

Figure 21. Disease-Host-Environmental Stress Diagram

A

Disease occurs

cycles, based on intermediate hosts such as snailsand birds. Although these grubs are not harmful tohumans eating the fish, they are unappetizing andresult in physiologic stress to fish.

To control these parasites, their life cycle mustbe broken. Perhaps the easiest way to achieve thiswith the yellow grub is to eliminate snails, whichserve as intermediate hosts. Pond owners shouldavoid introducing snails and infected fish duringstocking. If snails become established, vegetationcontrol will limit their available food and cover.Perhaps the best approach to snail control is stock-ing of redear sunfish, which will further reduce snailpopulations. If these measures fail to control theproblem within an acceptable period, it may benecessary to drain and dry the pond to eradicatethese parasites.

Acceptable Environment

Pathogen Host

Stressful Environment

Pathogen Host

B

37

MANAGING BASS AND BREAM POPULATIONS

Management of bass and bream populationsrequires maintaining a balance in thepredator-prey relationship of these two species.Sustained fishing success will not be possiblewithout careful attention to the number, size andcondition of bass and bream being caught. Forthis reason, harvest records are essential in themanagement of ponds stocked with bass andbream.

In Louisiana, bass stocked as fingerlings shouldbe allowed to remain in the pond until the secondsummer after stocking. In most cases, no more than30 to 35 pounds of bass per acre per year can beremoved from a fertilized pond if balanced popula-tions are to be maintained. This limit is reduced to15-20 pounds in unfertilized ponds.

Whether you keep track of numbers or poundsof fish, most of the fish harvested from a bass-breampond should be bream. A general recommendation isto harvest at least 5 pounds and as much as 10 poundsof bream for every pound of bass. In many instances,any bluegill which is caught should be removed fromthe pond, whether it is large enough to eat or not.Redear sunfish are not as prolific as bluegill, and maybe thrown back except when bream populations areextremely high.

Another point to remember is that when abream is removed from the pond, another individualwill grow to take its place within several months.When a bass is caught, however, it will take roughlyone year for a younger fish to take its place. For thisreason, bass harvests must be spread out over theentire fishing season if pond balance is to be main-tained.

If both bass and bream exhibit good repro-duction, a pond can probably be considered inbalance. One way to ascertain spawning successis to sample shallow areas from mid-May to lateJune with a small-mesh minnow seine, approxi-mately 15 to 30 feet in length and 4 to 6 feet deep.Ideally, various sizes of both species will bepresent, including young-of-the-year in the 1- to2-inch size range. The late Dr. H.S. Swingle ofAuburn University developed the followingmethod of evaluating pond balance based onseining samples: (see page 38)

Another way to determine whether bass andbream populations are in balance is to evaluatethe size of fish being harvested. If most of thebream are small (less than 5 inches long) and fewsmall bass are present, the pond is probablyoverpopulated with bream. This is common. Onthe other hand, if only a few very large bream arepresent and many small bass are in the pond,additional bass harvests may be necessary.

The percentage size distribution (PSD)method of evaluating pond balance is useful ifgood records are available for the pond. Recordsshould be kept of all largemouth bass larger than8 inches caught from the pond. Of those bass, anyfish larger than 12 inches can be considered a“quality” fish. The PSD for the bass population isdetermined by the percentage of all bass over 8inches long which can be considered quality bass(over 12 inches.) If 10 fish over 8 inches in lengthare caught and six are over 12 inches, the PSD is60. Balanced bass populations generally havePSD values between 20 and 60.

38

Fish Collected by Seine

No young bass. Many recentlyhatched bream and few or no 3- to 5-inch bream.

No young bass. No recently hatchedbream but many 3- to 5- inch bream.

No young bass. No recently hatchedbream. Many 3- to 5- inch bream andmany tadpoles, minnows or crawfish.

No young bass. No recently hatchedbream and few or no 3- to 5- inchbream.

Same as above but with many 3- to 5-inch green sunfish.

Young bass present. Many recentlyhatched bream. Few 3- to 5- inchbream.

Young bass present No recentlyhatched bream No 3- to 5- inch bream.

Young bass present. No recentlyhatched bream. Few 3- to 5- inchbream.

Condition ofPopulation

Bass slightly crowded.

Bream overcrowded.

Bream overcrowded.

Other types of fish competing with bream.

Green sunfish competingwith desirable bream suchas bluegill and redear.

Balanced population.

Bass overcrowded.

Other species may becompeting with bream.

Recommendation

Harvest more bass.

Remove excess 3- to 5-inch bream. Correctproblems such as excessvegetation or turbidity.Bass stocking may bedesirable.

Same as above, but bassshould be stocked at 50per acre the next spring.

Undesirable fish must beeliminated by draining orrenovating. Restock asnew pond.

Same as above, or reducegreen sunfish by inten-sively seining accessibleareas.

No action required.

Stock bluegill and/or redear adults(4- to 6- inch fish) at up to 200 fishper acre.

Monitor situation to determine ifremoval or eradication of compet-ing species is required.

39

For bluegill, quality fish are considered to be 6inches or longer, with any fish over 3 inches included inthe PSD calculation. If 10 fish over 3 inches long arecaught and two are over 6 inches, the estimated PSD is20.

Management Recommendations forVarious PSD Values

Bass Bream RecommendationPSD PSD

More than 60 Less than 50 Increasebluegill harvest. Returnall bass.

20 to 60 Less than 50 Increase bluegillharvest. Return largebass.

Less than 20 50 to 80 Harvest more smallbass.

Less than 20 More than 80 Harvest more smallbass. Return largebluegills.

20 to 60 50 to 80 Balanced. Return largebass.

These PSD recommendations apply togeneral situations. Individual ponds vary widelyin their ability to support different ratios of bassto bream, so use PSD values as indicators ratherthan management goals. Several years ofdiligent management may be required to bringbass and bream populations back into balance.Occasionally, however, ponds may go so far outof balance that more drastic corrective measuresare needed, as described in the next section.

40

RENOVATION OF PONDS

Sooner or later, many ponds becomecontaminated with undesirable species such ascrappie or green sunfish. Alternately, pondsmay go so far out of balance that only stuntedbream populations remain. In this situationponds may have to be drained and dried and anew stocking program established. Whendraining is not possible or too costly, an accept-able alternative may be to kill all fish presentwith rotenone, a natural compound which killsfish by interfering with their respiration. Thispractice is known as renovation. When the fishpopulation and previous history of a pond areunknown, as when an old pond has recentlybeen purchased, one of the simplest and mostreliable management approaches is to renovateand restock.

Since treatment is most effective duringwarm weather and recommended schedulescall for fall stocking of bream, August or earlySeptember is the best time to renovate ponds inLouisiana. This should allow for sufficientdetoxification before restocking bream in thefall, even if repeat treatments are needed.

Determining Pond VolumeThe first step in effectively poisoning the

existing fish population is to determine the volumeof water to be treated. Rotenone and other chemi-cals are applied based on the “acre-feet” of waterpresent in a pond. To determine the acre-feet,multiply the surface area of the pond by theaverage depth.

If the average depth is not known, takereadings at 10- to 20-foot intervals across thelength and the width of the pond. The averagedepth will equal the total of all the depth readingsadded together divided by the number of readingstaken. (see Figure 22)

The surface area of a circular pond can bedetermined by multiplying the circumference (infeet) times itself and then dividing the result by547,390. For rectangular ponds, multiply the lengthtimes the width (both in feet) and divide the resultby 43,560. For triangular ponds, multiply the lengthtimes the width (both in feet) and divide the resultby 87,120. (see Figure 23)

Application Rates andProcedures

Although published recommendations mayvary, a rate of 1 gallon of liquid rotenone or 10pounds of 5% powdered rotenone per acre-foot ofwater is usually sufficient for eradication of bream.If bullheads, green sunfish, gar or bowfin(choupique or grinnel) are present, two to threetimes this amount may be required for effectivecontrol. Repeat treatments may be required forgreen sunfish problems. For good results, applyrotenone when water temperatures are higher than70 degrees F. Renovation using rotenone is usuallyunsuccessful at lower temperatures.

Liquid rotenone should be mixed with water ata 1:5 ratio; powdered rotenone should be mixed withwater to a milky consistency, then diluted at thesame 1:5 ratio. For large ponds, you can pour therotenone solution into the prop wash of a boat whileslowly crisscrossing the pond. Smaller ponds maybe treated from the shore by spraying the solutionalong the upwind bank.

It is essential to treat all areas and depths ofthe pond, especially shallow, vegetated areas. Deepareas may have to be specially treated usingweighted hoses or downspout pipes to ensurecoverage. Avoid stirring up too much mud, however,since this will reduce the effectiveness of thetreatment. When ponds can be only partiallydrained, remaining pools and puddles can be treatedwith rotenone.

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RestrictionsA pesticide applicator’s card is required to

purchase and apply rotenone. Additionally, the FDAhas not approved fish killed with rotenone forconsumption by humans or animals. Althoughrotenone-treated water is safe for livestock, 10 to 14days are usually required for rotenone to breakdown or detoxify. During this period, no watershould be released into streams or other publicwaters. After 10 to 12 days, several goldfish orsmall bluegill can be placed in a minnow bucket inthe pond. If these fish survive for one or two days,it is generally safe to begin restocking the pond.

Figure 22. Determining Average Depth

Figure 23. Determining Surface Area and Acre-feet

Number of ReadingsTotal of ReadingsAverage Depth

17 4917 49

2.9 feet

13 3913 39

3 feet

16 4516 45

2.8 feet

Example 1.

shoreline shoreline average length length depth

547,390

250’ x 250’ x 2.9’

547,390

0.33 acre-feet

x x

Example 2.

averagelength length depth

43,560

200’ x 100’ x 2.8’

547,390

1.3 acre-feet

x x

Example 3.

(base x averageheight) x depth

87,120

200 x 400’ x 3’

87,120

2.8 acre-feet

42

AQUATIC WEED CONTROL

Aquatic plant life is desirable in aquatichabitats. One-celled aquatic plants (algae) arethe basis of the food chain and supply oxygento the aquatic system. Larger plants offershelter and breeding habitat for many aquaticorganisms. A balance between plants and otheraquatic life is therefore beneficial.

When aquatic plants begin to flourish andaffect human activities negatively, these plantsare referred to as “weeds.” The “weed” deter-mination may be based on the location inwhich the plants are growing such as boatinglanes or around boat docks. Problems alsoarise when the aquatic plants interfere with theintended use of the body of water such asswimming, skiing or fishing.

Most problems are caused by introducingexotic species which have no natural controls tokeep growth in check. Without these naturalcontrol mechanisms, the plants quickly replacenative vegetation. Exotic species that havebecome problems are water hyacinth,alligatorweed and hydrilla.

Factors Affecting ControlEnvironmentally sound and cost-effective

management decisions should be the basis of anyaquatic weed control program. Plant identificationis critical because control methods are usuallyspecies specific. All control measures will affectthe environment, so it is important to consider theintended use of the water body. Physical con-straints such as shallow water or obstacles canimpair herbicide applications. Water qualityvariables such as total alkalinity or the possibilityof dissolved oxygen depletions are importantconsiderations. Potential impacts on fish andwildlife populations must also be considered.

Pond ConstructionPrevention is the easiest and most economi-

cal method to control aquatic weeds. Proper siteselection is the first step in preventing aquaticweed problems. Sites should be selected thatminimize erosion, nutrient enrichment from runoffand high water flows through the pond. Avoidusing a flowing stream as a water source becausethe continuous flushing creates clear water andcauses low contact times for herbicides andfertilizers. Maintain proper watershed-to-pondratios. Limit livestock usage in the watershed tolessen erosion and levee destruction. Pond banksshould be as steep as possible without causingexcessive sloughing. Inside levee slopes shoulddrop 1 foot for every 3 feet the slope extends intothe water. Avoid areas shallower than 3 feet deepto minimize excessive weed growth. Encouragegrass species along banks such as Bermuda andrye.

Preventive FertilizationFertilization provides nutrients for algal

growth, which reduces light penetration below thelevel required for submerged plant growth. Oncefertilization has begun, you must continue theprogram to prevent adverse effects on fish popula-tions. Do not start a fertilization program until thecurrent weed infestation is controlled. The plantsyou are trying to control will use the nutrients andincrease their growth. Liquid fertilizers arepreferred because they give faster results.

DrawdownDrawdown is limited to lakes and ponds with

adequate water control structures and a reliablesource of water for refilling the pond. Drawdowns

43

are usually conducted during winter to exposeplants to drying and freezing. The advantagesinclude low cost as well as oxidation and consoli-dation of sediment. Drawdowns also increaseoptions for chemical control because somechemicals are more effective when applied to drywater bottoms. One disadvantage of drawdowns isthat they may reduce desirable species and allowtolerant species to spread further. There may alsobe some loss of recreational benefits such as duckhunting and spring fishing.

Mechanical ControlPhysical harvesting by hand or equipment

can be effective at removing small populations ofnuisance weeds such as duckweed, cattail andwater hyacinth. This can be accomplished withvarious methods such as dip nets, sickles orblades, and by placing barriers across incomingstreams to restrict floating plants. The mainadvantages to mechanical control are low cost andlow environmental impact.

Biological ControlThere have been many attempts to control

aquatic plants with biological control methods.These include pathogens, insects and herbivorousfish. For the average pond owner, the use ofherbivorous fish like triploid grass carp is the onlybiological control method available. Triploid grasscarp are functionally sterile, meaning they cannotreproduce in ponds. The Louisiana Department ofWildlife and Fisheries has developed a permit toallow farm pond owners to use these fish tocontrol vegetation.

The number of grass carp that should bestocked depends on the type of weed, condition ofthe ponds and severity of the weed problem.Triploid grass carp prefer submerged plants, butsome emergent species are also controlled. Somerecommendations for stocking rates are given inthe next column.

Recommended Stocking Rates forTriploid Grass Carp

Weed Evaluation Number ofFish to Stockper Acre

New pond or very slight weed problem 5

Moderate weed problem(10 to 20 percent coverage) 10 to 15

Severe weed problem 5 to 20 ormore

Chemical ControlAbout 200 herbicides are registered in the

United States, but only 10 are labeled for aquaticsites. These chemicals can control aquatic weedseffectively. However, correct weed identificationand matching the proper herbicide to the particularweed problem are extremely important.

Aquatic plants which are usually consideredproblems are divided into four groups: algae,floating, submergent and emergent weeds. Algaeare small, usually microscopic plants lackingleaves, roots and stems. These plants may be madeup of only one cell, an aggregate of cells called acolony or a chain of cells called a filament. Algaemay grow freely suspended in the water (plank-ton), floating at the water surface (pond scum) orattached or unattached on the bottom.Free-floating weeds such as duckweed and waterhyacinth have leaves and stems above the surfaceand roots that suspend in the water below.

Submergent weeds are usually rooted at thebottom and often extend to the water surface.Common weeds in this group are pondweed,coontail and watermilfoil. Emergent vegetation isalso a problem in ponds and lakes. Growth usuallyoccurs on or near shore and in shallow waterareas. Plants are rooted in the bottom, and theirleaves and/or stems extend above the watersurface. Common emergent weeds are smartweed,

44

alligatorweed and cattail.When considering herbicides for control of

aquatic weed problems, remember two importantpoints. First, the label on the herbicide containerprovides specific information on the proper useof the chemical. Protect yourself and others byreading and abiding by directions and warningson the product label.

A second consideration is that as deadaquatic plants decay, oxygen in the surroundingwater is used in the process. If large quantities ofplants are killed with one treatment, dissolvedoxygen in the water may be reduced to the pointthat fish and other aquatic organisms die. There-fore, it is usually desirable to treat only a portionof a weed problem at a time. This allows the bodyof water to recover lost oxygen before subsequenttreatments. The possibility of low oxygen be-comes more serious as water temperatures rise inlate summer. If possible, weed problems shouldbe dealt with when water temperatures arebetween 70 and 80 degrees F.

There are several methods for applyingherbicides. Some herbicides can be applieddirectly from the container. Handheld or back-pack sprayers are used for spraying emergentvegetation around the shoreline. Boat-mountedtank sprayers can be used for either surface sprayor subsurface injection. Hand-operated ormechanical spreaders are used for dispensinggranular material. Granular material can also bedissolved by towing it in a bag behind a boat.

When considering chemical control, checkwith the parish Cooperative Extension Serviceoffice or a fisheries biologist for plant identifica-tion and current herbicide recommendations.Additional information on aquatic weed controland related topics is available from your localExtension office. Request these publications:Handbook for Common Calculations in FinfishAquaculture, Pub. 8903; Aquatic Weed Manage-ment: Herbicides, Pub. 2398; Aquatic WeedManagement: Control Methods, Pub. 2410.

45

NUISANCES AND PREDATORS

FurbearersDamming and burrowing activities of beavers,

muskrats and nutria may cause physical damage toponds by weakening levees and interfering withcontrol structures. Local conservation agents canrecommend legal control measures and possiblyassist in trapping and relocating certain animals.

SnakesAlthough it is difficult to eliminate snakes

from most ponds, they can be encouraged to leavethe area by removing cover such as brush, rocks andhigh grass in the immediate vicinity. Snakes whichremain or appear later can be destroyed as opportu-nities permit.

TurtlesAlthough turtles rarely prey on fish directly,

they can increase to the point where they become anuisance. In this situation, they can be trapped anddestroyed. A number of trap designs have been usedsuccessfully. (see Figure 24)

BirdsA number of bird species may visit farm

ponds, but few are serious predators on game fish. Ifa particular type of bird causes unacceptable losses,frightening techniques are generally recommended.Many birds are protected under state and federallaws, which effectively rule out shooting or poison-ing.

MosquitoesExcessive mosquito reproduction can usually

be avoided by eliminating rooted vegetation fromponds. If this does not control the problem, it maybe necessary to introduce mosquitofish, alsocalled gambusia minnows, from ditches or otherestablished water bodies in the area. Be carefulnot to introduce any fingerling trash fish whencollecting and stocking mosquitofish.

Figure 24. Turtle Trap Designs

46

NOTES

47

48

C. Greg Lutz, Professor(Aquaculture)Thomas M. Hymel, Area Agent (Watershed Educator)

Louisiana Cooperative Extension ServiceLouisiana State University Agricultural Center

William E. KelsoLSU School of Renewable Natural ResourcesLouisiana State University Agricultural Center

Jeff SladeFormerly LSU Sea Grant Legal Program

Visit our Web site: www.lsuagcenter.com

Louisiana State University Agricultural CenterWilliam B. Richardson, Chancellor

Louisiana Agricultural Experiment StationWilliam H. Brown, Vice Chancellor and Director

Louisiana Cooperative Extension ServicePaul D. Coreil, Vice Chancellor and Director

Pub. 2573 (20M) 11/03 Rev

Issued in furtherance of Cooperative Extension work, Acts of Congress ofMay 8 and June 30, 1914, in cooperation with the United States Depart-

ment of Agriculture. The Louisiana Cooperative Extension Serviceprovides equal opportunities in programs and employment.