Managing Wisconsin Fish Ponds

G3693 Managing Wisconsin Fish Ponds

William Swenson Stanley Nichols Scott Craven Jeff Malison Thomas Thrall Susan Marcquenski Jim O. Peterson About this publication Acknowledgments his publication was written in Much of the information in this publica- response to the growing interest in tion is based on Managing Michigan managing ponds for both recre- Ponds for Sport Fishing, Third Edition, Tational and commercial fishing. Its 1994, (Michigan State University Bulletin purpose is to provide a source of reli- E-1554) written by J.D. Schrouder, C.M. able, up-to-date information for those Smith, P.J. Rusz, R.J. White, D.L. interested in building new ponds or man- Garling and G.R. Dudderar. All graphics aging existing ones. The reference and material that originally appeared in section is designed to serve as a guide the Michigan bulletin are used with per- to the vast body of information that mission. We gratefully acknowledge the deals with fish pond management. This contribution of our Michigan colleagues. publication replaces Wisconsin Farm Fish Ponds published by the University of WisconsinÐExtension in the late 1960s. Throughout this manual we explain processes and principles for you to choose from, rather than specific management practices that you must follow. Adapt the information here to your own specific interests and needs, and use it as a guide for planning pond construction and management for either sport or commercial aquaculture. Most of the general information here focuses on sport fishing ponds, but the sections on ponds and fish management apply to both sport and commercial pond aquaculture (Chapter 9 deals specifically with commercial pond aquaculture). Whether your pond is a commercial enterprise or is used for recreation, our hope is that this manual will help you achieve better results. The authors Wildlife pond/fishing contentscontents chapter 1 pond system ...... 7 chapter 6 Overview ...... 1 Surface area ...... 7 Implementing pond management . 26 The resource ...... 1 Landscaping and erosion control Keeping records ...... 26 When is a pond a “success”or in the pond’s surroundings . . . 7 Selecting the best fish for “failure”?...... 1 Construction of excavated or the pond ...... 27 Caution! Are you sure you want dug ponds ...... 8 Where to get fish for stocking 28 a pond? ...... 2 Construction of impoundments . . 8 Anticipating fish management Natural and artificial ponds ....2 Construction of levee ponds . . . 9 activities and costs ...... 28 chapter 2 chapter 4 chapter 7 General considerations ...... 3 Ponds as places for fish to live . . 11 Managing coldwater ponds for sport fishing ...... 29 Goals ...... 3 Basic pond characteristics for Investigate and plan ...... 3 fish production ...... 11 Stocking ...... 29 Management overview ...... 4 The pond ecosystem ...... 11 When to start fishing and how much to harvest...... 31 Commercial aquaculture .....4 Consequences of Supplemental feeding ...... 31 Meeting state environmental overenrichment ...... 15 regulations ...... 4 Facts about water and the Special aquatic plant control in chemicals dissolved in it . . . 15 trout ponds ...... 32 chapter 3 Pond breathing, circulation and Designing and building ponds . . . 5 stratification ...... 16 chapter 8 Managing warmwater ponds Types of ponds ...... 5 Investigating a pond’s suitability for fish...... 17 for sport fishing ...... 33 Water depth ...... 6 Selecting the right fish Water supply ...... 6 species ...... 33 Designing for control of chapter 5 Types of fish to raise in Wisconsin Stocking ...... 33 aquatic plants ...... 7 sport fishing ponds ...... 19 Angling harvest ...... 35 Safety ...... 7 Coldwater fish ...... 20 Not recommended: higher stocking Warmwater fish ...... 21 levels and fish feeding ....36 Forage fish...... 24 Pond fertilization and liming . . . 36 Fish not recommended for Emergency aeration of the pond 36 Wisconsin ponds ...... 24 Exotic species ...... 25 chapter 9 chapter 11 chapter 12 chapter 15 Managing ponds for commercial Aquatic plants and their control . . 49 Wildlife around the pond...... 63 Regulations ...... 74 fish production ...... 37 Kinds of plants ...... 49 Controlling wildlife problems. . . 63 Pond construction regulations . . 74 General considerations .....37 Algae ...... 50 Wildlife control considerations . . 63 Registration as a tool to Planning ...... 37 Submergent plants ...... 50 Problem species ...... 64 regulate pond management . 75 Water temperature and species Floating plants ...... 51 Muskrats and woodchucks . . 64 Permits as a way to regulate selection ...... 40 pond management ...... 75 Emergent plants ...... 52 Beavers ...... 65 Site selection ...... 41 Liability...... 75 Pond plant biology ...... 53 Otters ...... 65 Pond design and construction . . 42 Managing the growth of Managing for different types nuisance plants ...... 54 (continued) chapter 16 of fish ...... 42 chapter 12 References ...... 76 Physically disrupting and Moles ...... 66 Water quality and harvest ....43 removing plants ...... 54 Major sources of information . . 76 Birds ...... 66 Deepening the pond to General ...... 76 Turtles and snakes ...... 67 control vegetation .....56 Commercial aquaculture . . . 77 chapter 10 For more information or on-site Fish population control ...... 45 Water level drawdown ....56 assistance ...... 68 Videos ...... 77 Angling intensively...... 45 Discharging selectively ....57 Other problems ...... 68 Further reading ...... 78 Stocking predators...... 45 Flushing and diluting the pond 57 Swimmer’s itch ...... 68 Pond planning and Destroying spawning beds . . . 45 Inactivating phosphorus . . . 57 construction ...... 78 Mosquitos ...... 68 Seining...... 45 Aerating the pond...... 57 Pond fishery management . . 78 Leeches...... 68 Live-trapping ...... 47 Sealing and blanketing the Prospects for commercial Electrofishing ...... 47 pond bed ...... 57 aquaculture ...... 78 Shading or coloring the water 57 chapter 13 Life in ponds (General— Drawing down the water level . . 47 Fish health management .....69 identification of organisms, Fish toxicants ...... 48 Herbicides and algicides . . . 58 Factors influencing fish health. . 69 biology, ecology) ...... 78 Biological control...... 59 Managing fish health ...... 69 Identification of fishes.....78 Introduction to common fish Identification of aquatic parasites and diseases ....70 invertebrates ...... 78 Parasites ...... 70 Identification of aquatic plants 79 Nutrient over-enrichment chapter 14 and aquatic plant Pond safety and liability ...... 72 problems/control ...... 79 Installing a rescue station ....73 Wildlife damage control....79 Fish health ...... 79 Pond management ...... 79 chapter I The resource chapter I Overview Approximately 15,000 inland lakes his publication provides an overview provide Wisconsin with roughly 1.27 of ponds as aquatic systems and million acres of surface area. Portions of tells how to manage ponds to Lakes Michigan and Superior lie within Tachieve different goals. It is Wisconsin’s boundaries as well, adding designed primarily for current or nearly 8.5 million acres of water to the prospective pond owners with an inter- state. est in sport fishing, but it is also valuable In spite of the many lakes and easy to those interested in commercial pond access to fishing in public waters, many aquaculture. Chapter 9 provides an private landowners want their own introduction to this topic and much of the ponds. Having your very own fishing material from other sections also applies spot, close at hand on the farm or vaca- to commercial enterprises. Those inter- tion property, or even in a suburban ested in managing ponds for waterfowl, setting, offers convenience and swimming or irrigation, where fish pro- control—though not without cost and duction may be a side benefit, will also added responsibilities. find this publication useful. Interest in commercial fish production is Another of the publication’s main goals increasing in Wisconsin due in part to is to help pond owners achieve better the growing demand for fish, a decline in results from their ponds, and to aid production from wild stocks and aspiring owners in understanding a improved opportunities for diversified pond’s potential and problems before aquaculture brought about through they commit to building or buying one. research. The management and educa- Though the emphasis here is on pond tional challenges involved in owning a management under typical Wisconsin pond also attract many people. conditions, much of the information also Many ponds are constructed primarily for carries over to other areas of the north sport fishing. Other reasons to build a central United States. pond include commercial aquaculture, swimming, wildlife habitat, water for livestock, irrigation, hunting dog trials, fire protection, water quality improvement and scenic enhancement. If a pond is designed and managed for another purpose, do not expect it to provide the same fishing quality as one designed specifically for fishing. For example, a pond that provides good duck habitat 2

MANAGING WISCONSIN FISH PONDS may be too shallow and choked with Because satisfaction is a matter of per- This publication can help you increase plants to provide enough oxygen for fish sonal preference, we try not to tell Natural and artificial ponds fish production from a natural pond during hard winters. owners and users what kind of pond or The landscape contains many ponds whether it has high or low potential. How does a pond differ from a lake? management is the “right” kind. Instead, that have formed naturally. Most often, However, we caution owners that radical The fact is that there are no sharp differ- we explain principles and describe alter- these ponds have marshy, gradually management, especially in the form of ences between the two. Most people natives from which you can choose. sloping edges, and are only a few feet reshaping the basin or altering plant life think of a pond as being smaller than a deep at their deepest points—not to benefit fish, may destroy some wildlife lake, but opinions vary on what size Caution! Are you sure you enough to maintain good fishing, but fine habitat or damage other valuable fea- constitutes a pond. This publication for wildlife. Marshy or swampy ponds tures. Natural ponds are often protected deals primarily with ponds that range in can be extremely enjoyable just for their by state laws to preserve the wildlife want a pond? sights and sounds, and sometimes for values of wetlands. size from a quarter acre to 10 acres (0.2 Creating and managing a pond requires to 4 hectares). the hunting they offer. If they provide The artificial pond, designed for maximal substantial time, effort and money. In some fishing, it’s a bonus. If a natural Regardless of their size, sport fishing addition, there are some risks involved sport fish abundance and minimum pond is deep enough (15 feet or more) maintenance, is quite different from most ponds often provide a few years of good such as potential legal liability from to furnish proper habitat for a flourishing fishing when new or renovated; fishing injuries or drowning. Another problem natural ponds. It has steeply sloped fishery, the owner is fortunate indeed. banks, an average depth of more than often deteriorates as fish populations can be an overabundance of aquatic Many shallow ponds are suited for pro- change. Occasionally, ponds may be weeds. Trying to prevent or control 8 feet, and a maximum depth greater duction of fish bait or fingerling game than 15 feet, no matter what the surface dismal failures right from the start, weeds can be frustrating, but we offer fish. usually because of faulty design, information here to make the job easier. area. improper location or poor water quality. Maintaining a prime fishing pond is like striving to keep a racing car in good When is a pond a “success” condition. Performance depends on attention to details. You need to ask or “failure”? yourself: Do I really have time for this? In commercial pond culture, profit is typically identified with success. However, the level of profit and other rewards considered “successful” varies with each owner. An owner’s or user’s level of satisfaction is the ultimate measure of a pond’s success. Much of this publication is geared to the many pond owners and users who aren’t satisfied with their fishing success. But if the fishing in your own pond does satisfy you, enjoy it, and don’t pay much attention to someone else’s idea of what makes a successful pond. Am I willing and able to spend the songbirds and visited occasionally by chapterchapter 22 time, money and effort needed to migrating ducks. General achieve the results I want? A reasonable goal for a sport fishing pond in Wisconsin would be to obtain a considerations Goals moderate amount of angling for medium-sized fish. Angling fun and a ood fish pond management involves Lack of a clear goal is often at the root meal of fish now and then are reason- more than just putting in some fish. of unsatisfactory pond construction and able expectations. Whether you are Ponds, like gardens, need proper management. Changing goals frequently interested in sport or commercial fish design and management. Just as in can also be a problem. Select and work G toward a single primary goal based on pond management, you should under- gardening, many questions must be stand that northern ponds cannot answered before management can be careful assessment of a pond’s poten- produce as many large, fast-growing fish effective. Some of the important ones are: tial. Write down your goal and keep sight of it. Stick to it long enough to see as warmer ponds in southern states. What is my goal in having the pond? whether it works. Fishing? Profit? Swimming? Wildlife? Irrigation? Water for livestock? Satisfactory fishing is undoubtedly a Investigate and plan Nature study? Scenery? primary goal, or at least a secondary Undertake pond construction and man- one, for many pond owners. Write this agement only after carefully studying the If there are several goals, which is goal down in terms of the kinds of fish situation. After reading about ponds, the main one, and how do the others you want. Also create a list of your other examine your pond (or potential pond rank in priority? goals. Record your goals on the first site) in as much detail as possible. What, roughly, is the pond’s potential page of your pond management log Several sections of this publication for producing fish in terms of space, book (see page 26). Once you decide to suggest characteristics of ponds and water fertility and other aspects of build or manage a pond, a log book is their fish populations that can be meas- pond quality? an invaluable tool for keeping track of ured and analyzed. Consider hiring a How deep should I build (or rebuild) your management efforts. professional to analyze the pond and the pond? Trying to accomplish too many things assist you with a management plan. What kind(s) of fish should I stock? with your pond might mean that none Pond design and construction are highly What sizes? How many? When? works well. For example, maintaining important to a successful fishery. If you schools of large fish along with flocks of intend to build a pond, see Chapter 3 When can I start fishing (or harvest- ducks and geese in a clearwater envi- and contact the U.S. Natural Resource ing) the pond? ronment and also using the pond as a Conservation Service (NRCS) office in How many fish should I expect to be livestock watering area are not compati- your county about engineering design able to harvest each year and at ble goals. Concentrate on one major services. Your county Land what sizes? benefit and a few pleasant side effects. Conservation Department may also be How can I prevent or remedy fish For example, a soundly managed bass able to provide technical advice. The overpopulation and stunted growth? or trout pond might also offer a little county Extension office can help you swimming and skating, as well as an identify design services or develop a How can I prevent or control aquatic weeds and algae? emergency water supply. It can also business plan if your interests lie in serve as a scenic asset frequented by commercial aquaculture. 4

MANAGING WISCONSIN FISH PONDS

Water fertility ranges from too little to For the best bass fishing, it may be investing in commercial aquaculture Management overview just right to too much. With too little fer- best to exclude panfish. This contrasts (see Chapter 9). Knowing when to leave things alone is tility, not enough plant and animal life with management in southern states important. Overmanaging and applying grows to feed resident fish. With exces- where, due to warmer water and longer management techniques simply sive fertility (often the case), plants clog growing seasons, bass prey heavily on Meeting state because you’ve heard of them are the pond, organic matter accumulates panfish, control their populations and common management mistakes. on the bottom and the pond becomes maintain a productive predator-prey environmental regulations The construction and management of unsuitable for most desirable fish. balance. Bass in northern ponds usually The usual steps in managing a pond for ponds can cause safety and environ- don’t eat enough panfish to maintain sport fishing are: Fish grow well and produce good yields mental problems. State laws regulate such a balance, and bass are often l. Building or rebuilding for the best as long as there is enough breeding the following activities (see Chapter 15): overfished. The result of having panfish depth and slopes (Chapter 3) stock and food. Too many fish ruin the Damming and diking food supply, resulting in undernourish- in a northern pond, with or without bass, 2. Assessing and modifying fish popula- ment and poor growth. For example, if is often panfish overpopulation and Excavating and dredging within 500 tions (Chapter 10) you stock two small, identical ponds with stunted growth. Adequate numbers of feet of any surface water 3. Stocking suitable fish (Chapters 5, 6 large bass are needed to exert effective unequal numbers of fish—1,000 in one Filling wetlands and any land within panfish control. and 7) and 10,000 in the other—each pond will 500 feet of surface water If you manage a trout pond, you gener- have about the same total weight of fish Managing panfish in our climate is diffi- Discharging fish food and wastes a year later. But the fish in the pond cult but various options exist. You can ally need to restock it each year. If you into streams or lakes manage a warmwater pond, natural stocked with 1,000 will be larger. Don’t treat the pond to eradicate or reduce reproduction usually maintains the overstock, and don’t let the fish become fish populations, use sterile hybrid Stocking fish fishery. too numerous! panfish or simply accept and enjoy Federal regulations administered by the fishing for smaller panfish. Such fishing The interrelated ideas of balance In ponds managed as trout or bass fish- state Department of Agriculture, Trade is ideal for children who like to catch lots between predators and food organisms eries, angling harvest must be limited if and Consumer Protection (DATCP) and of fish. and of a happy medium, or consistently fish are to live long enough to reach a the Wisconsin Department of Natural maintaining the right amounts of certain good size. On the other hand, where Resources (DNR) also regulate the use elements in the pond, are important for panfish are present, severe cropping of of chemicals to control plants and fish. Commercial aquaculture Before undertaking any of these activi- sustained quality fishing. To maintain the small fish may be needed to avoid over- Some pond owners envision financial ties, consult the nearest DNR office on pond as a good place for fish to live, population. Keeping panfish populations profit, either by raising fish to sell or by how to proceed within the law. water fertility, chemical characteristics in check by fishing alone is difficult in charging anglers a fee to fish. Ponds for and temperature need to stay within northern ponds. commercial purposes should be Various permits may be needed. Proper certain limits. designed specifically for that purpose application for a permit may not only (see Chapters 3 and 9). Both “fish spare you future grief but might result in farming” and “fee fishing” are risky ven- tips from state officials on the best ways tures that require managerial skills and to accomplish your objectives. considerable investments in facilities. To be competitive, producers have to market their product at a profit. We strongly suggest “entering the business” via effective in-depth planning before or seepage because they can introduce A levee pond is usually built on level chapterchapter 33 unwanted species and chemical ground by removing 1Ð4 feet of material Designing contaminants. Diversion can also from what becomes the pond bottom. change the temperature and flow in The excavated material is used to build these systems, adversely impacting levees, or embankments, around the and building native fisheries. pond’s perimeter. The end result is that Because excavated ponds cannot be most of the water stays above the fish ponds drained, they can be difficult to manage groundwater level. and are most suited to sport fish produc- Clay soils are best for levee ponds tion. However, they can be designed because they hold water and the above- Types of ponds and are often used for commercial pro- groundwater construction reduces con- There are three main types of fish ponds duction of bait or fingerling game fish. struction costs. Suitable 3- to 5-acre (figure 1): Impoundments or watershed ponds levee ponds can be built for approxi- 1) Excavated ponds are appropriate for rolling or hilly areas. mately $3,000 per acre. 2) Impoundments They are formed by constructing earthen Levee ponds are appropriate for com- 3) Levee ponds dams. Impoundments are most appropri- mercial aquaculture because construc- ate in areas with steeper land slopes tion costs are low. The ponds are Each has different land requirements and low-permeability soils. Where possi- shallow, drainable and responsive to and applications. Excavated ponds and ble, material is excavated from the intensive management because of their impoundments are used primarily for future pond bottom to form the dam and regular shape. Levee ponds are not sport fishing, while levee ponds are deepen the pond. If the dam is properly good candidates for sport fishing more appropriate for commercial aqua- constructed, a watershed pond can be because they require pumping and filling culture. drained. This enhances fish manage- from wells or surface water and mainte- Excavated ponds are often built in fairly ment options. nance costs are high. level terrain where the groundwater Pond water quality is generally better if Selecting the right site and planning table is close to the surface. An exca- the water is impounded from springs construction carefully plays a large part vated pond is made by digging a pit rather than from runoff or streams. in a pond’s overall success. Contact deeper than the groundwater level. The Impoundments are not recommended if your county office of the U.S. Natural pit fills when groundwater seeps in, or their construction calls for damming a Resources Conservation Service when water flows in from nearby stream. Impoundments on streams can (NRCS) for information about soils and springs. Because the excavated pond is become settling basins for silt, sediment additional advice on site selection. Also dug below the water table (usually with and debris, causing the streams to fill in contact the nearest Wisconsin a dragline), it is typically one acre or and become less suitable for fish. In addi- Department of Natural Resources (DNR) less in size. tion, it may be difficult to stop undesirable office early in the planning stage. Find Less commonly, pits are dug that catch fish from entering the pond, making fish out what restrictions may apply to your runoff water from surrounding land or management extremely difficult. situation and what permits you need. receive water diverted from a stream. Damming streams of any size is strictly Fish managers often possess valuable These sources of water are generally regulated in Wisconsin and is generally expertise with pond management and less desirable than groundwater springs not permitted. can help assess your plans. 6

MANAGING WISCONSIN FISH PONDS

Stocking fish may require that you These design considerations are interre- Shallow water will do where a sufficient Before you begin construction, NRCS obtain a fish stocking permit (see lated, and changes to one can influence flow of well-oxygenated spring water staff or other knowledgeable individuals Chapter 15). This process involves a one or more of the others. Landscaping moderates temperatures and prevents should investigate the potential pond’s visit to the site by the DNR fish details are somewhat less important. depletion of dissolved oxygen. This is soil structure and profile. In some situa- manager. You should also try to identify the case in trout ponds with large inflow. tions, excavation to the desired depth contractors with previous experience and Aeration is used to prevent winterkills and may perforate the clayey soil layer that good reputations by talking with some of Water depth seals the bottom, allowing the pond Water depth is one of the most impor- summer oxygen depletion in shallow their customers. Experienced contractors water to drain away. If the natural clay tant elements in achieving satisfactory ponds. You need power at the pond site and pond owners serve as good sources seal is broken, the pond bed can be fish habitat in ponds. No matter how but periodically operating a good aeration of information. resealed with clay or commercial plastic large the pond’s surface area and how it system need not be cost prohibitive. In liners, which can be expensive. It is Key considerations in designing a suc- was formed, a better fish population general, greater depth is better for sport- better to avoid breaking the seal. The cessful fish pond are: usually results when most of the pond is fish ponds, providing more room and a soils may also be unstable and the side Water depth at least 15 feet deep. This depth helps greater range of living conditions for the fish and their food organisms. slopes will not hold up. Water supply avoid winterkill and summer oxygen depletion that stresses fish and can Two main problems can prevent estab- A properly formed basin and sur- cause die-off or poor growth. lishment of a 15-foot water depth: 1) roundings that will help avoid an Water supply excavation costs (which become dispro- Groundwater, either from wells, springs overabundance of nutrients and Shallow ponds are more subject to win- portionately higher as depth increases); or seepage, provides a better water aquatic plants terkill, especially in cold winters. They usually have fewer, smaller and less and 2) soil conditions. supply than runoff or stream water. desirable kinds of fish because of near Groundwater tends to be well-filtered, winterkill conditions. while runoff and stream water temperatures vary and bring excessive amounts Figure 1. Three types of pond construction. of nutrients, sediment and other materi- Excavated or dug pond als into the pond. Even stream water berm to prevent runoff into pond that appears clear and “pure” often carries nutrients into a pond. water depth at least 15 feet 3:1 slope Excessive nutrients create the overabundance of plants and other organic matter that deplete oxygen for fish. Impounded pond Avoid runoff from barnyards, pastures 3:1 slope and fertilized or eroding cropland. 2:1 slope Fertilized lawns and gardens are other earth fill dam sources of unwanted nutrients. Even with seepage and spring water, water depth at least 15 feet you should take precautions. As it emerges from the ground, such water Levee pond might be very high in iron or too low in dissolved oxygen for fish. Aeration alle- levee levee viates the problem but adds to the oper- 7

DESIGNING AND BUILDING FISH PONDS ational cost. Test the water before you Excessive runoff can also be diverted by invest in a pond fed by wells, springs or means of earthen berms or water diver- Wildlife pond/ Surface area seepage. sion ditches. A filter strip of unmowed As a rule, the larger the pond, the more grass and other low plants along the fishing pond system stable its fish population. While trout pond banks is another way to reduce Some sites may be better suited for ponds of only a quarter acre may Designing for control of nutrient inflow. Other aspects of erosion wildlife ponds. A pond built in an area of support adequate fishing if they have control are discussed in the section on heavy erosion or nutrient runoff will have strong spring flow, most ponds don’t aquatic plants landscaping. a short life as a fishing pond. Erosion will provide satisfactory fishing unless they While a moderate amount of rooted If the pond is formed by a dam, an outlet fill in areas of the pond and, combined are a half acre or more—and preferably aquatic plants benefit fish, too many can with the extra nutrients, bring increased much more. produce an overabundance of small fish structure that allows discharge from the bottom enables draw-off of nutrient-rich aquatic plant growth. Under these condi- Small ponds usually need much more and impede fishing and management. tions, it may be better to first provide You can significantly reduce this water that accumulates there in summer intensive care than large ones. Their and winter. Rapid water exchange from erosion control and then build a wildlife disadvantages may be somewhat allevi- problem with good pond design and pond or a wildlife pond/fishing pond construction. groundwater also reduces these problems. ated by making them very deep. Also, if system. something goes wrong it is easier and Rooted aquatic plants need light and Wildlife ponds or marsh ponds typically quicker to fix the problem in a small nutrients, and grow best on level pond Safety have a maximum depth of about 6 feet pond. Make your decisions based on beds. Minimize aquatic plant nuisances Side slopes that extend 3 feet into the with the average depth being about 1 to your goals. by: pond per foot of drop (a 3:1 slope) are 2 feet. The pond bank should slope 1. Minimizing inflow of nutrients sufficiently steep to reduce plant growth gradually (8:1 or flatter). These condi- while not being so abrupt as to cause 2. Keeping the bottom too deep and tions encourage aquatic plant growth Landscaping unreasonable danger to wading children. dark for plants to survive (15 feet) that will be consumed or used for cover However, a slippery clay incline of 3:1 or by various types of wildlife. Marsh plants and erosion control in the 3. Constructing steep side slopes greater can be a great hazard to people remove the nutrient input from runoff. In commercial aquaculture ponds, fertil- or animals that might wade or stumble pond’s surroundings A wildlife pond can serve as a settling ity is sometimes increased to promote into the pond. With a little planning, a fish pond and pond to cleanse water of excess nutri- adequate phytoplankton levels to restrict the area around it can be made very It is recommended that escape ramps of ents and sediments when built in con- light penetration and the growth of attractive. Decide whether you want a 5 feet horizontal distance per foot of drop junction with a fish pond. Use berms to rooted aquatic plants. However, this is natural setting or the look of a mani- (a 5:1 slope) be installed periodically divert runoff water away from the fish not recommended for sport fishing cured lawn. In a natural landscape, logs, around the pond for escape in situations pond and into the wildlife pond. ponds. where soil type and slope pose a danger stumps, rocks and uneven ground may Separate the wildlife pond from the fish be fitting. If much of the area will be One way to minimize nutrients flowing to humans or animals. If the incline is pond by a dike. The dike prevents sedi- mowed, you may need to smooth the into groundwater- or spring-fed ponds is made of fine sand, it is likely to be unsta- ments from moving into the fish pond ground and eliminate obstacles during to situate the pond where as little land ble and slump if steeper than 3:1. It is rec- and prevents fish from escaping preda- pond construction. as possible slopes toward it. This helps ommended that all other soils have slopes tion in the shallow weedy areas of the reduce the amount of surface runoff no steeper than 2 feet horizontal distance To prevent erosion, establish plant wildlife pond (see Chapter 5). Install an entering the pond. per foot of drop (a 2:1 slope) for stability. covers quickly on exposed areas. Sod or If your objectives are plant control and a overflow tube, concrete or sheet piling or a heavy stand of grasses prevent soil maximum amount of deep water, the a rock-lined channel in the dike to from washing away. Some recom- steeper the side slopes the better. prevent over-topping and dike washout mended grasses include Kentucky blue- during heavy rains. 8

MANAGING WISCONSIN FISH PONDS grass, smooth bromegrass, creeping red Fence livestock away from the pond. The water level may fluctuate signifi- improve overall appearance. Using fescue and timothy. Animals destroy vegetation in the pond- cantly in seepage ponds as the ground- some of the spoil to build a gentle berm Don’t plant deep-rooted plants such as bank buffer strip, and their droppings water table rises and falls—higher in wet around the pond can help divert alfalfa, sweet clover, shrubs and trees add nutrients to the water. Grazing and years and lower during drought. Plan to unwanted overland runoff. on earthen dams or embankments. trampling also weaken dams, embank- excavate more than 15 feet below the Deep roots weaken these structures and ments and spillways. If livestock water- lowest level that the groundwater table Construction cause leaks. Some ponds may need ing is one of the pond’s functions, pipe reaches in a very dry year. Consult reinforcement, called “rip-rap,” with the water to an area where the animals NRCS or other experienced people of impoundments 1 won’t harm the pond. about how to make test borings to find stone of 8Ð10 inches diameter piled 1 ⁄2 In impoundments or “fill-type” ponds, the water table in late summer of a dry to 2 feet thick along the shoreline. Rip- water is impounded by an earthen dam year. Depending on soil conditions, rap protects against wave erosion, espe- containing a core of watertight material Construction of groundwater can be pumped into ponds cially in the case of dam and fill such as clay. It is best to build on a site from nearby wells. Sometimes windmills embankments. where a great volume of water can be excavated or dug ponds are used for this. Mixed clumps of evergreens and decidu- Many parts of Wisconsin provide favor- stored by constructing an embankment ous trees, bordered by shrubs, provide able terrain for dug ponds because they Catchment pits for overland runoff can with a small amount of fill. be dug if soils are clay or other fine food and cover for wildlife and give pond are fairly flat, with soft, porous soils and The most desirable location is in a valley material that will hold water, or if clay or surroundings a pleasing appearance. groundwater that lies close beneath the that is narrow at the dam site. The pond other sealants can be obtained to line Don’t plant trees on embankments. soil surface. These are usually areas area should be wide and flat with steep the pond bed. Because there is usually Roots cause structural problems, and where sand and gravel are at or near sides. Excavation is usually required to less water exchange and more potential dense shade suppresses cover and the surface. Groundwater percolates deepen the site and also provides the to pick up sediments and other pollu- encourages soil erosion. easily through sand and gravel. earth for the dam. Wave erosion on the tants, using runoff water to fill ponds is Shrubs shouldn’t be planted so near the However, many areas which seem suit- dam embankment can be a problem in generally less desirable for ponds built pond that leaves or twigs fall or blow able may be designated wetlands or large ponds. If possible, try to choose a to support sport fishing. into the water. Leaves use up oxygen may adjoin designated wetlands. Under site where the prevailing wind doesn’t when they rot and create layers of litter these conditions strict restrictions apply. The type of equipment that is best for blow along the length of the pond on the pond bed. They also furnish nutri- DNR water quality specialists and NRCS digging ponds depends largely upon the toward the dam. pond’s size, site characteristics and ents for excess water plants. Keep staff can help you understand the regu- A properly designed impoundment will desired depth. Draglines or bulldozers shrubs at least as far back from the lations and evaluate the site to deter- have two water outlets; a trickle tube or are generally used. Bulldozers are more water’s edge as the greatest height the mine if it is designated as a wetland. mechanical spillway and a vegetated adapted to the drier pond beds. Ponds tree or shrub will reach—and preferably Peaty, acidic soils characteristic of many earthen emergency spillway (figure 2). dug by draglines are seldom wider than much farther. It isn’t necessary to set wetland areas are not suitable for pond The emergency spillway is for flood about 90 feet but may be much longer. evergreens back quite as far. Trees and construction. The decaying organic flows. To manage fish and control weeds Excavation width is governed by the dis- shrubs on the shore area may also inter- material in these soils depletes dis- it is very desirable for the pond to have tance a dragline can move back before fere with fishing. solved oxygen levels in pond water. The an outlet designed with a draw down it is blocked by its spoil piles—unless characteristically low pH of waters drain- capability for drainage. Contact a profes- the spoil can be moved. ing from many wetlands can retard sional engineer to design the proper size growth or even kill fish. The material dug out of the pond, called and type of spillway. the “spoil,” should be graded back away from the pond edge and landscaped to 9

DESIGNING AND BUILDING FISH PONDS

It is best for fish if the water supply Soils for earthen dams should be at To ensure proper compaction, you must comes from groundwater rather than least 20% clay by weight and contain a control soil moisture during construction. Construction of levee ponds from runoff. If the impoundment must be wide range of particle sizes up to coarse Soils that are too wet or too dry will not Levee ponds are best suited for com- designed to catch runoff water, situate it sand or gravel. Fine-grained silts and compact adequately. Carefully compact mercial aquaculture. Prior to starting so that the drainage basin is large clays are best to limit seepage. Place the soils by hand around any pipes in construction make sure the site is suit- enough to provide sufficient runoff to fill the most impervious material in the the dam. For the dam’s vegetated spill- able for the facilities being planned. An and to maintain water levels even in upstream two-thirds of the embankment. way, clay, sandy-clay and silty-clay are adequate water supply must be avail- drought conditions. The earth must be compacted to mini- suitable. Avoid loose sand and other able in terms of volume, water quality You can calculate surface runoff accord- mize seepage through the dam. easily erodible soils. Dam cross-sec- and pumping ability. The soils should be ing to the area of land draining into the Sheepfoot compactors or loaded rubber- tions, side slopes and wave protection tight enough to prevent water loss pond, the amount of precipitation, and tired scrapers are used to compact each are part of site-specific design. through the pond bed or levees and they runoff characteristics involving land layer. Typically, fill is placed in 9-inch should not have high levels of chemical slope, soil porosity, vegetation and layers and compacted. contaminants. The site should not be human disturbances of the land. subject to flooding and should be easy Generally, for a Wisconsin pond that Figure 2. Two common types of outlet structures for dams that form fish ponds. depends entirely on runoff water, five acres of runoff basin land is needed per Bottom draw-off dam acre/foot of pond water. An acre/foot is corrugated metal riser defined as the volume in 1 acre of water, (diameter at least 4 feet) level of paved emergency spillway Riser-and-stoplog 1 foot deep. 2:1 slope construction is the Clay and silty-clay are good soils for water depth 3:1 slope removable at least 15 feet stoplogs simplest design impoundment basins. Sandy-clay is suit- that allows con- able only if the cost of extra materials for trolled bottom collar to block seepage sealing the pond is acceptable. Be spillway pipes draw-off. A drop- careful not to excavate through the soils (diameter at least 18 inches) inlet spillway can core trench that best hold water. Sites in some accommodate areas of limestone or dolomite are espe- greater variation of flow. It is needed cially unsuitable—even hazardous—for where runoff from a impoundments. There may be crevices Surface overflow dam large land area allowing water to drain very quickly from concrete riser (diameter at least 4 feet) supplies the pond the pond. To get a good bond between covered by trash rack and where sudden the earth and fill material, you must and baffle plate level of paved emergency spillway high water is remove all vegetation (including stumps 2:1 slope expected. and roots) and topsoil from the dam site bottom draw-off tube with valve 3:1 slope prior to construction. water depth at least 15 feet

seepage plate bottom drain tube with valves core trench 10

MANAGING WISCONSIN FISH PONDS to drain. Generally less earth will have As with impoundments, all vegetation of appropriate diameter as soon as the The ponds should be built with a 0.1Ð0.2 to be moved and the cost will be lower and topsoil must be removed from the pond bottom is graded. Dig a small foot drop per 100 lineal feet from the in level areas than on hilly or rolling site prior to starting levee construction to sloped ditch, approximately one third the shallow to the drain end. The level of the areas. allow a good bond between the founda- diameter of the pipe, to give uniform pond bottom at the drain must be high Decisions on the number and size of tion soil and fill material. support for the pipe (figure 3). enough to drain to a ditch which carries ponds will depend on what fish you want Self-loading earth movers are the most Place moist fill materials along the sides water away from the site by gravity. to raise, the land available and other efficient equipment to use in building and over the top and compact it by hand To prevent unwanted fish from entering variables. You should look at the cost of levee ponds. They give the best com- to a distance of at least two feet above the pond through the pipe during drain- building ponds of different sizes and paction of fill material when complete the pipe. The hand-compacted fill pro- ing, elevate the drain pipe 2 feet above configurations. Typically commercial wheel track coverage is made over each vides protection from heavy equipment the ditch. Several types of draw-down levee ponds are built in sets of four. layer of fill placed in the levee. Vibrating while the levee is being completed. In structures can be used; simple turndown Square or rectangular ponds reduce or sheepsfoot compacters are also fre- some situations the pond drainpipe pipes are recommended for large fish construction cost and increase accessi- quently used. For proper compaction the should be installed first, so that storm production. More elaborate structures bility and ease of management. The soil must have at least a 15% moisture water can drain through the pipe during with harvest kettles can be used for fin- levees should be at least 8 feet wide at content. construction. In either situation, install at gerlings or small fish, but these are quite 1 the top and extend at least 1 ⁄2 feet Leave open the area of the levee where least 2 anti-seep collars around the expensive. above the intended water level. If possi- the drain is to be placed to serve as a drain pipe to avoid seepage along the Don’t forget Wisconsin’s winter ice con- ble they should be constructed with a drain for storm water until construction outside of the pipe. Such seepage can ditions. If you are using a simple turn- 3:1 or greater slope. However, the actual nears completion. Install the drain pipe cause erosion and even failure of the down pipe and keeping the pond full slope will depend on the soil type. levee. during winter, aeration or continuous water input should be installed next to the drainpipe to keep water from freez- Figure 3. Layout of typical levee type ponds. ing around the pipe and heaving or drain pipes drainage ditch breaking it. The drain system must be levee secure enough to prevent unintentional draining and large enough to allow the pond to be drained completely in 5Ð7 660' days, preferably less. Typically a 6" pipe is used for a 1-acre pond and an 8" pipe inflow pipe for a 3-acre pond. well 16'

660'

1320' 1320' Concentrations of dissolved oxygen chapterchapter 44 not much below 5 parts per million The pond ecosystem Ponds as places during the growing season, even in A pond is an organized system of water, the deepest water soils, dissolved substances, solar energy and living organisms. These ele- A balance between the amount of for fish to live ments comprise the pond ecosystem. fish and the amount of natural food so that fish grow rapidly The parts of the ecosystem continually Basic pond characteristics Few ponds are ideal in every respect change and interact. Material and and different characteristics in any of the energy enter and leave the pond contin- for fish production categories can still produce worthwhile uously (figure 4). Most minerals and The ideal Wisconsin sport fishing pond fishing. In many locations, some of the organic materials that enter the pond are possesses the following attributes: ideals cannot possibly be met, even with trapped and stored there. In contrast, A surface area of at least one acre considerable management. For most water and gases that flow in soon flow out again. The pond captures solar Steep side slopes (about 1 foot verti- example, regulating the hardness of energy to produce food and warm the cal per 3 feet horizontal) groundwater is usually not feasible, and you should not hesitate to own a pond water. At least one quarter of the pond just because hardness is not optimum. The pond is part of a larger land-and- more than 15 feet deep Throughout the state, ponds with a water ecosystem called the watershed. Water comes exclusively from maximum depth of 7Ð10 feet produce The watershed includes all the land area groundwater seepage rather than good fishing for many years. that drains into the pond either through streams or runoff from land An ideal coldwater pond for trout differs surface or groundwater. What goes on Dissolved carbonate mineral concen- from a warmwater pond primarily by within the watershed greatly affects what tration (hardness) of 150Ð250 parts having a good seepage of groundwater happens in the pond. For example, dis- per million (conductivity of 200Ð500 (springs), which keeps water tempera- turbance of vegetation in the drainage µmhos/cm) ture lower in summer. basin may increase rainwater runoff and soil and nutrients that wash into the pH between 7Ð8 This chapter explains why the pond pond. Inflow with only moderate amounts characteristics listed above are impor- Some mineral and organic material of nutrient chemicals—amounts that tant to the well-being of fish. The func- enters the pond in solid form (dirt) that would naturally enter the pond from tioning of ponds is complex—but under- settles to the bottom. This material accu- an undisturbed landscape standable and predictable enough to mulates in the pond. Other minerals and 1 help you manage for quality fishing. Less than ⁄4 of the pond bed organic matter enter the pond already covered by dense plant growth dissolved. Plants can readily use dissolved nutrients to grow. 12

MANAGING WISCONSIN FISH PONDS

Some plants are eaten by animals; The dead plants and animals, wastes others die and settle to the pond bottom. and solid materials washed into the pond Figure 4. Flow of energy and matter into and out of the pond The plant-eating animals die and drift to partially decompose and redissolve due and its drainage basin. the bottom or are eaten by other to scavenger animals, microorganisms animals—which in turn may be eaten by and chemicals (figure 5). The redissolved still others. The plant and animal mate- material serves as nutrients for further rial that animals consume is either plant growth. Materials not completely stored in their bodies or passes into the decomposed accumulate on the pond water as solid or dissolved wastes. bottom and so the cycle continues (figure 6).

Figure 5. The food pyramid of a pond. outflow of water and energy

anglers other primary producers w as te consumers p ro d large fishes u decomposers c t outward radiation of heat s small fishes and rain large invertebrates

small invertebrates that eat dead organic matter water, soil and organic matter run-off washed in by overland runoff filtered small invertebrates that by marsh eat green plants matter washed in by stream inflow

stream outflow algae, higher plants bacteria and fungi

outward seepage dissolved minerals dissolved gases water groundwater seepage filtered by soil 13

PONDS AS PLACES FOR FISH TO LIVE

Figure 6. Inner working of a pond in rough outline.

This sketch of the movement of energy and matter looks complicated, but the real situation is far more complex. Most mineral and organic matter entering the pond becomes trapped in it and is, to some extent, recycled. Most energy that enters from the sun leaves again rather soon. Water also flows through.

heat from activity heat from pond of organisms bed and decay

heat and heat and water vapor water vapor given off given off by plants by pond important gases: nitrogen, carbon dioxide, water leaves and fragments oxygen, dissolve outflow of land plants through surface groundwater table eroded soil and some leaves organic matter decay, dissolve algae and bacteria some dissolves zooplankton eat algae and bacteria large groundwater seeps rooted aquatic plants into pond some sink to bed small fishes fishes some seepage from pond sink into groundwater to bed dead organisms some decaying somematter decaying dissolves plant organic mud layer some organisms sink dissolve

scavengers and microorganisms mineral subsoil more material deposits at pond bed than redissolves back into water

R.J and S.A. White 14

MANAGING WISCONSIN FISH PONDS

Figure 7. Food web and Much of the mineral and organic matter Such artificially simplified and shortened food chain contrasted. that enters a pond stays there, even if food webs boost production of the The arrows point in the direc- water flows out. Some nutrients are desired fish. This is usually what the tion of predatory or “grazing” carried away by emerging insects or in pond owner wants, rather than an “inter- pressure. A chainlike system fish taken by natural predators or esting” and diversified natural commu- may produce more of certain anglers. nity of fish that doesn’t provide as much fish that we want, but a break angling. Phyto- The food relationships that link organ- in one link may severely plankton isms form a “food web” (figure 7). The However, keep in mind that this simpli- disrupt production. The web- like system has many more web-like structure provides a stable food fied community is less stable and may parts and is therefore more supply to fish and other pond creatures. not be able to bounce back from occa- stable and more productive When a part of the web changes, for sional catastrophes such as disease, overall. example, when disease reduces the cold snaps and drought. Substantial and numbers of one animal, other creatures repeated management is often needed still remain to serve as food for fish. to keep a pond community the way you When we manage a pond to produce want it. There is a saying in pond man- one or several kinds of fish, we often agement: “Once you start managing, reduce the kinds of habitats and organ- you have to keep managing like mad.” isms in the pond. This removes many Another problem occurs when there are links from the food web and may make insufficient predator fish (bass). Small the pond ecosystem less stable. fish (bluegills, other sunfishes, minnows) We purposely build ponds with little may become so abundant that they sig- habitat diversity so that only a few kinds nificantly reduce the “water flea” popula- of organisms can thrive—the fish we tion, which consumes algae. This leads want and a few food organisms for to an overabundance of algae, which is them. We build uniformly steep pond not only unsightly and foul smelling but side slopes to discourage plants that also harms the pond’s oxygen levels. interfere with fishing and provide habitat for too many young fish. We dredge smooth, deep pond bottoms suited for maximum fish growth and for seining to remove fish. We try to ensure a short, efficient food chain by stocking only one or two kinds of fish. 15

PONDS AS PLACES FOR FISH TO LIVE

Depending upon their amounts, the key In water with low alkalinity, a small Consequences Facts about water and the nutrients nitrogen and phosphorus can amount of phosphorus yields the kinds determine growth levels in many ponds. of algae that water fleas and other fish of overenrichment chemicals dissolved in it Algae form the base of the food web and food organisms eat. At higher phospho- A pond’s suitability for fish deteriorates Water travels, carrying along substances increasing the amount of nutrients rus levels, the added production may be severely if the pond contains too many that dissolve in it. Algae, dissolved mate- increases total production of algae. This “bluegreen” algae—a type that algae- nutrients. This happens when topsoil, rial and other substances in the water can become a nuisance. More algae eating animals don’t like. Thus, rather leaves, fertilizers, or human and live- affect the amount of light entering the does not always result in more fish since than supporting the food web that pro- stock wastes flow in—or if too much fish pond, which in turn affects the amount not all of the algae is useful to fish or fish motes fish production, bluegreen algae food is added. Algae and other plants and depth of rooted plant growth. food organisms. proliferate without being eaten. As nui- then become overabundant. Stagnant, Pond water can be rich or poor in plant Alkalinity is a measure of the acid-neu- sance algae develop, die and decay, deep areas may lose dissolved oxygen nutrients (calcium, potassium, phospho- tralizing capacity of water. The main they draw excessively on the pond’s and develop such a buildup of toxic rus and others) depending on their abun- constituents of alkalinity are carbonate supply of dissolved oxygen. The result is gases in summer and winter that fish = - oxygen stress that may harm fish. dance and solubility in the surrounding (CO3 ) and bicarbonate (HCO3 ) dis- become sick or die. This problem is land. Many ponds grow only small or solved from limestone (CaCO3) and Ponds with more alkalinity have greater especially acute in winter under ice moderate amounts of aquatic vegetation dolomite in Wisconsin’s soils and potential for producing fish. But the ful- cover. Mass die-offs of fish, termed “win- because few nutrients enter from the bedrock (figure 9). fillment of that potential will be seen only terkills,” are common in shallow ponds watershed. A well-vegetated landscape if there is just the right balance of nutri- with much organic matter. “Summerkills” reduces nutrient inputs to the pond. ents and if other conditions, such as may occur with prolonged periods of hot, temperature, are right. still weather (figure 8).

Figure 8. Hazards of Figure 9. Alkalinity of Wisconsin lakes. pond with moderate fertility overenriched pond pond overenrichment. summer summer deep light penetration shallow light penetration dense algae growth sparse algae growth warm water dead algae sink sparse thermocline rooted dense plant sparse algae growth cold water rooted growth too dark for algae growth plant growth plants replenish dissolve O2 throughout much decay of organic matter depletion of dissolved O2 in lower zone

winter winter no light penetration no light penetration snow ice overabundant depletion of enough dissolved O2 remains for fish throughout pond because rooted plants dissolved O2 little is consumed by too much algae throughout plants and dead matter decay of organic matter > 30 mg/l < 30 mg/l < 15 mg/l winterkill of fish 16

MANAGING WISCONSIN FISH PONDS

Another benefit of moderate to high Water changes in density as it changes perature, hence different density. The water alkalinity is the action of a variety in temperature and chemical content. Pond breathing, circulation heaviest water lies on the bottom and of chemical conditions unfavorable to Water is nearly unique among sub- the lightest at the top. fish and other aquatic life. The dissolved stances in being lighter as a solid than and stratification During summer stratification,or layering, minerals provide a buffer against as a liquid. The fact that ice floats atop A pond exchanges gases with the air wind circulates only the upper part of a extreme changes in pH. In addition, fish ponds in winter rather than growing above it. This is a form of “breathing.” deep pond. In shallow ponds that are need the nutrients associated with alka- upward from the bottom (or falling there Gases and other dissolved and drifting exposed to the wind, summer stratifica- linity to grow. after forming at the surface) is pro- materials are moved about the pond by tion may occur for only a few days under Ponds range in alkalinity from less than foundly important to pond life. water circulations caused by wind and extremely still conditions. In deeper pro- 10 parts per million (ppm or mg/L) to gravity. In winter, ice greatly reduces cir- tected ponds, stratification may last all over 300 ppm. Most are between 50 and culation and almost completely blocks summer. Generally, ponds less than 240 ppm. An alkalinity of 40 ppm seems pond breathing. In both summer and 8 feet deep will not stratify for long to be a pivotal value below which fish winter, the pond water may stratify into periods in the summer unless they are production declines and above which it layers representing a gradation of tem- well-protected from the wind. is moderate to high. There is no steady trend of increased production with increased alkalinity because of variability wind autumn overturn in other key conditions (table 1).

about 39ûF throughout

water all of same density fulll circulation—dissolved oygen replenished Table 1. Pond carrying capacity related to alkalinity of the water. wind summer layering wind winter layering These are very rough indications of how much fish can be supported by naturally occurring food in a pond. Particularly for trout, much greater amounts can be sus- 65-75˚F —well lighted 32ûF tained in the pond by artificial feeding, which has certain drawbacks. dark throughout

cooler Approximate carrying capacity (lbs/acre) 39ûF or a bit cooler Coldwater dissolved oxygen diminishes ———— Warmwater ponds ———— ponds due to organic decay in layers cut off from circulation Alkalinity Bass or Bluegills or of water catfish other panfish Total** Trout** wind spring overturn

More than 100 ppm* 50Ð100 200Ð400 250Ð500 150 or more whole pond same 40 to 100 ppm 25Ð50 75Ð200 100Ð250 25Ð150 temperature in range of about 40-60ûF Less than 40 ppm under 25 under 75 under 100 under 25 *parts per million water all of same density full circulation—dissolved oygen replenished **In warmwater ponds, much of the total poundage will be in the form of young fish that are too small for angling. In coldwater ponds, all or most of the trout will usually be large Figure 10. Circulation and thermal layering of water in ponds. enough for angling—and the poundage shown may provide about as much fishing as that shown for warmwater fishes on the same line. Not only temperature but the amount of oxygen available to fish is strongly influenced by the seasonal cycles of circulation and layering. Very shallow ponds (not shown) may have complete circulation for much of the summer, but are much more likely to be oxygen-depleted in winter. 17

PONDS AS PLACES FOR FISH TO LIVE

In fall and spring when cooling or As previously described, ponds are may consult a professional biologist for Working with a professional is especially warming change all the water to an complex, and their conditions change advice. valuable in designing the investigation equal temperature and equal density, continually. The foremost need is to be Judging a pond’s productive capacity or and interpretation of results. Design the water mixes easily and stratification alert for land disturbances, water runoff diagnosing its problems is best done by involves planning the right sampling at does not occur. These events are coming into the pond and the entry of a professional. Properly trained aquatic the right times, while interpretation described in figure 10. human or livestock waste that could biologists can evaluate conditions of the involves judging what the data mean in cause overenrichment. Such observa- pond site and surroundings and can terms of pond biology and what the tion of the pond’s surroundings, com- interpret temperature and oxygen data. implications are for management. Investigating a pond’s bined with a program of water tempera- You may be able to participate with a Knowing maximum water depth and cal- ture, water clarity and dissolved oxygen professional in pond investigation—or, culating mean depth are important, as is suitability for fish measurement in the pond, provides Pond owners often ask whether water after doing some research, undertake observing the abundance of aquatic enough information for basic pond man- can be simply tested for fertility and measurements on your own. Much plants and keeping records of the fish agement. other chemical characteristics to evalu- depends on your knowledge of science, caught (species, length and weight). It is ate its fish-producing capacity or to find Alkalinity, pH, inorganic nitrogen and the amount of time you can spend and essential to identify possible sources of out why fish haven’t thrived. These phosphorus are additional tests that can the equipment available. Various handy nutrient overenrichment, such as septic determinations are far more involved help you manage your pond. Some analysis kits for dissolved oxygen and systems, livestock wastes, soil and fertil- than just sending water samples to a pond testing equipment is relatively other determinations are commercially izer erosion and roadway runoff. laboratory. inexpensive to purchase or make, or you available. Dissolved oxygen and temperature are crucial to fish and should be systemati- Table 2. Water temperature at various depths1 over time. cally monitored. Electronic or chemical 1 This is an example of a pond measured on the 15th of each month at the deepest point⁄2 ft deep). (18 kits for dissolved oxygen measurement Water and sampling devices (dissolved oxygen depth temperature (ûF) at mid-month samplers) should be used. Contact the DNR or your county Extension office for (feet) Jan2 Feb2 Mar3 Apr May June July Aug Sept Oct Nov Dec2 possible sources of these items. surface 32 32 44 50 60 67 71 75 62 51 46 32 Important times to analyze water tem- 2 363344506067717562514639 perature and dissolved oxygen (DO) 4 383644506067717562514639 are: 1) in mid-or late summer after a 6 393844506067717562514639 week or more of very hot weather; and 8 393944506067717562514639 2) in winter after ice and snow have covered the pond for a month or more. 9 6067717562 For a more detailed picture, monitor the 10 39 39 44 50 58 62 65 70 60 51 46 39 complete annual cycle of pond tempera- 11 52 55 58 61 57 ture and DO by sampling every week or 12 39 39 44 50 50 52 53 54 54 51 46 39 two (table 2). A specialist can assist you 14 39 39 44 50 50 52 53 54 54 51 46 39 in developing a schedule for tests at a variety of depths. 16 39 39 44 50 50 52 53 54 54 51 46 39 18 39 39 44 50 50 52 53 54 54 51 46 39 1Measurements made at regular 2-ft intervals, except at 1-ft intervals in areas of rapid temperature change. 2Pond covered by ice. 3About 1 week after ice has melted. 18

MANAGING WISCONSIN FISH PONDS

Figure 11. Pond temperature profiles enough to destroy layering. Very cool dissolved oxygen as could the cooler Water temperature early spring groundwater seeping into the pond may water in springtime. Cool water of the change during the winter overturn & late summer make layering more distinct and stable. deep layer could hold more dissolved layering warming spring layering Autumn overturn—Surface water oxygen, but decay of organic matter year in a small, ice fairly deep surface 0 0 cools, becomes denser and sinks, consumes oxygen and the lower water warmwater pond. mixing with warmer water just beneath. cannot obtain more because density lay- 1 Thus, the upper layer is cooled to a ering prevents it from being circulated 5 density near that of the lower layer and into contact with the atmosphere. Therefore, dissolved oxygen decreases 2 wind can remix the whole pond. Complete fall mixing can occur only in the lower layer and it may become when the upper water sinks as the unfit for fish. 10 3 meters weather gets colder; wind is not needed. During winter layering—Ice and early fall Fall overturn halts when ice blocks wind snow block light and oxygen from enter- water depth in feet water 4 action and the upper water becomes ing. Plants have too little light to produce 15 late fall overturn colder, hence less dense, than water oxygen and oxygen from the atmos- and cooling 5 beneath it, which is nearer 39ûF. phere cannot dissolve in the pond. pond bed Figure 12. Dissolved oxygen at Respiration and decay consume dis- 30û 32û 40û 50û 60û 70û 80ûF water temperature different depths in the same pond, solved oxygen. Concentrations decrease the most near the pond bottom where 0û 10û 20ûC as affected by the wind mixing and there is more organic matter. Fish are Great temperature variations exist from Spring overturn and even warming thermal/density layering. forced upward into layers with enough pond to pond and even within the same —After ice melts in March or April, wind During spring and fall overturn— dissolved oxygen. pond depending on the water depth, mixes water evenly throughout as the Large amounts of wind strength, air temperature and other pond warms. Temperature stays equal oxygen can dissolve Dissolved oxygen profiles in this range during factors. Temperature affects water from top to bottom as warming occurs. into the pond from the spring and fall overturns ice density. Water is heaviest at 39ûF (4ûC). Late spring and summer layering— air because water that surface 0 Thus, water nearest 39ûF tends to be at Does not often occur in many ponds, is cooler can hold the bottom with warmer—or in winter, especially not in ones shallower than greater concentration of cooler—water floating on top of it. This shown here. Layering takes place if upper dissolved gases. 5 during vertical layering, when it occurs, causes water becomes, by intense warming, so Amounts of dissolved during summer late winter a gradation of temperature from top to much lighter than lower water that wind oxygen are the same at layering layering bottom. Fish can choose the depth with cannot overcome the density difference all depths because 10 their preferred temperature—as long as and can no longer mix all the way to the water is well circulated there is enough oxygen for them. bottom. Then mixing occurs only in upper throughout. Winter layering—Ice covers the water. The well-mixed upper layer has a Concentrations of 9Ð12 depth in feet water surface. Water is 32û just under the ice thinner layer of water with rapidly ppm commonly occur. 15 and progressively warmer at greater decreasing temperature between it and During summer lay- depths. Deepest water is near 39û. the cooler water below. ering—Warmer water pond bed 02 4 6 81012 Warming by groundwater seepage may The upper layer usually extends deeper in the upper layer alter the curve. than shown. Wind may become strong cannot hold as much Milligrams of oxygen per liter of water (parts per million) There are two basic categories of pond chapterchapter 55 fish—warmwater and coldwater. Types of fish to Warmwater fish such as bass, bluegills, other panfish or catfish, do best in ponds where summer water tempera- raise in Wisconsin tures are more than 70oF. A pond may be suited for coldwater fish (various kinds of trout) if summer water tempera- sport fishing ponds o tures remain below 70 F. t’s important to know something about Temperature should be measured a foot the lives of the fish you choose to below the surface near the center of the raise in your pond. Species differ in pond. Most species do best when dis- their requirements for feeding, I solved oxygen concentration remains growing, reproducing and surviving. If above 5 ppm, but warmwater fish can the pond is unsuitable for the kind of fish survive lower levels of dissolved oxygen stocked, be prepared for reduced growth and all fish can survive lower levels and poor reproduction or survival rates. during the winter. The so-called “coolwater” fish such as northern pike, muskellunge, walleye and perch, generally don’t thrive in small bodies of water without intensive management (see Chapter 9).

Table 3. Summer length ranges at various ages for fish in Wisconsin ponds. Growth may be somewhat greater where fish are uncrowded and temperature and food supply are ideal. Growth can be much slower, especially where ponds are overpopulated.

———————————————————length in inches——————————————————— first second third fourth fifth sixth Kind summer summer summer summer summer summer of fish (age 0)* (yearling) (2-yr-old) (3-yr-old) (4-yr-old) (5-yr-old) Rainbow trout** 4Ð69Ð14 14Ð17 15Ð19 *** *** Brook trout 2Ð46Ð88Ð12 9Ð14 11Ð16 *** Largemouth bass 1Ð46Ð88Ð10 10Ð12 12Ð14 13Ð17 Smallmouth bass 1Ð44Ð77Ð10 10Ð12 12Ð14 13Ð17 Channel catfish 1Ð45Ð78Ð10 11Ð13 13Ð15 15Ð17 1 1 1 Bluegill ⁄2Ð23Ð44Ð5 5-6 6Ð76⁄2Ð7 ⁄2

*Fingerling **From fall-spawning stock in hatcheries ***Very few survive to this age, and growth is extremely variable. 20

MANAGING WISCONSIN FISH PONDS

Brook trout (Salvelinus fontinalis). Coldwater fish Brook trout do best in spring-fed coldwa- The coldwater fish include trout and their ter ponds with water temperatures of relatives (salmon, whitefish). Trout are 48ûÐ60ûF. Brook trout are also easy to most suited for coldwater sport fishing catch and can provide especially tasty ponds or small lakes (figure 13). Trout table fare. They may grow as well as eat a wide variety of organisms. They rainbow trout up to a size of 10 inches, prefer zooplankton, insect larvae and after which their growth slows. A 15-inch crayfish. Supplementary feeding is not brook trout is an exceptionally large one. recommended unless the fish are For fishing variety, stock rainbow trout stocked in large numbers. together with brook trout. Trout spawn on gravel beds in streams. Brown trout (Salmo trutta). Brown Typically, they do not spawn success- trout tolerate slightly higher tempera- fully in ponds. Therefore, populations tures than other species. However, they are maintained by periodic stocking. are relatively hard to catch and therefore Brook trout can sometimes reproduce in may be less desirable. Brown trout gravel or coarse sand where springs usually produce a far lower total harvest well up in the pond bottom. As with other over the years than rainbow or brook fish, trout growth varies greatly between trout. Brown trout can live 5Ð7 years, ponds, depending on oxygen levels, despite heavy fishing even by skilled food supplies, crowding and fish size. anglers. Figure 13. Three kinds of trout that can be used in coldwater ponds. The Rainbow trout (Oncorhynchus The wary 18Ð20 inch browns are canni- brown trout is usually not advisable, however. mykiss). Rainbow trout are the most balistic which may make further stocking adaptable of the species and are readily with fingerling or yearling trout unrealis- available from dealers. They also grow tic unless the large brown trout are fast and are easy to catch. Generally removed. This may require use of fish they can withstand warmer water than toxicants. other kinds of trout, and do well in all Hybrid trout. Hybrids between various parts of the state. Rainbow trout grow kinds of trout are sometimes available best when the water is between and can be interesting to raise. They are 54ûÐ66ûF. They commonly reach a size unusual and often grow faster than pure- of 15 inches in about three years. Few bred trout, but may be hard to catch. live long enough in a pond to reach 20 They usually aren’t practical for the pond inches. owner who is simply interested in recreation and a few fish on the table. 21

TYPES OF FISH TO RAISE IN WISCONSIN SPORT FISHING PONDS

To form a nest, the male either sweeps Survival of largemouth bass embryos Smallmouth bass (Micropterus Warmwater fish a shallow circular depression in the and fry in the nests may be reduced by dolomieui). Smallmouth bass are best- The primary warmwater fish raised in bottom or cleans off a clump of grass- sudden drops in water temperature suited for ponds that have clean gravel Wisconsin ponds are members of the like aquatic plants by fanning with his during the spawning period. Smaller beds for spawning and somewhat cooler sunfish or bass family. They include the tail. Males select nest sites at depths adult males are also less successful in water than is best for largemouth bass. predatory largemouth and smallmouth between 2Ð6 feet. The nests usually are defending their nests against predation. For these reasons, old gravel pit ponds bass (figure 14) and smaller sunfish, developed near overhanging logs or They can be overwhelmed by large often furnish excellent smallmouth bass such as bluegills, pumpkinseeds and other cover. numbers of bluegills or other species. fishing. Smallmouths are sometimes green sunfish (figure 15). Black crappie The male fertilizes the eggs as the Competition for food, predation, reduced classified as a “coolwater,” rather than have also been managed successfully in female scatters them on the nest. He winter pH and starvation during winter warmwater, fish. Many anglers like small- some instances. Another commonly guards the embryos and newly hatched all influence first year survival. mouth bass better than largemouth raised warmwater fish is the channel fry, which school near the nest until they Food competition with other fishes such because they fight harder. Their feeding, catfish. Various minnows are also classi- are well developed (about one week). as young bluegills can cause mortality growth, reproductive habits and manage- fied as warmwater fish. Some species ment are roughly similar to those of Numbers of fry hatched per nest vary by reducing the growth of first year make excellent forage fish. largemouth bass. Their young are proba- considerably. An average of 4,375 was largemouth bass. Those that do not get bly more susceptible to mortality by pre- Largemouth bass (Micropterus found in one study. Young bass eat big enough starve or are killed by preda- dation in systems overpopulated with salmoides). Largemouth bass are the water fleas, insects and very small fish tors during the winter. Young bass are bluegills. The fry are black and conspicu- most commonly stocked species in and crayfish. An adult will prey on extremely inactive during the winter and ous. Smallmouth young are also subject warmwater ponds. They adapt to a wide almost any available animal that fits in do not feed even if food is plentiful. to winter pH stress and starvation. range of pond conditions, can grow quite its mouth, such as fish, crayfish, tad- large and are a very popular game fish. poles, frogs, worms and insects. Young Their growth rates are influenced by bass make an excellent forage for food supply, competition with other fish adults. By preying on their own young, and water temperature. They grow largemouth bass can live successfully in fastest when the water is above 75ûF. a pond or small lake without other Bass prefer minnows as forage over species. They also hold their numbers in bluegills and other panfish. They tend to check reducing the risk of overpopula- grow and reproduce better where they tion, stunting and poor fishing. are stocked with minnows. Largemouth bass may live for 10Ð13 years, though the average pond has very few older than 5 years. Most female largemouth bass first spawn when they are 2Ð4 years old, or about 10 inches long. Spawning occurs in May or June when the water is between Figure 14. Largemouth and smallmouth 60ûÐ70ûF. bass. The latter is especially suited to water where the temperature is a bit too cool for largemouth bass but too warm for trout. 22

MANAGING WISCONSIN FISH PONDS

Bluegill (Lepomis macrochirus). The Spawning occurs at slightly higher tem- bluegill is probably the fish stocked most peratures than in largemouth or small- frequently in warmwater ponds. Bluegills mouth bass and continues into early are caught easily, are good scrappers summer. As with bass, the male bluegill on light tackle and are very tasty. They builds and guards the nest. Nests are also provide fast action for kids. usually shallow depressions in the However, pond owners who wish to bottom, 6Ð12 inches in diameter and stock bluegills should be cautioned that, close together. The average nest con- although several years of good fishing tains about 18,000 fry which may come will probably follow the initial stocking, from more than one female. intensive management is required to Females mature at different times, and maintain desirable body growth. the eggs from a single fish ripen gradu- Bluegills breed prolifically, overpopulate ally. A female may deposit eggs in the pond and severely overgraze the batches over a period of several weeks. food supply, decreasing growth. Even The long spawning season assures that when stunted, they remain prolific. there will be offspring even if adverse Bluegills feed on a wide variety of conditions occur during parts of it. organisms, including insects, water Black crappie (Promoxis nigromacula- fleas, fish eggs and small fish. Rooted tus) and white crappie(P. annularis). aquatic plants and algae have also been Black and white crappie possess many found in their stomachs. However, plant of the characteristics of other members material provides little if any of their of the sunfish family (figure 15). Crappies nutritional needs. Bluegills, like all other have been managed successfully in northern game fish, must meet their some ponds and small Wisconsin nutritional needs by feeding on other private lakes. animals. Growth varies, depending Under the appropriate conditions, largely on how crowded they are. Under crappie grow faster and larger than favorable conditions, they reach 6 bluegills. They spawn earlier than inches in 2Ð3 years but in many ponds, bluegills and their spawning period is they reach this size only after 4Ð6 years. more restricted, reducing the probability Female bluegills reach sexual maturity of overpopulation. They eat water fleas, by the second to fourth summer of life insects and minnows and feed in more and produce 6,000Ð27,000 eggs per open water. Therefore, they do better in year, depending on their size. Bluegills waters with fewer rooted aquatic plants. spawn over almost any type of bottom in They are not generally suitable for water 1Ð3 feet deep, starting in May or smaller ponds (less than 6 acres). June.

Figure 15. Panfishes. 23

TYPES OF FISH TO RAISE IN WISCONSIN SPORT FISHING PONDS

Hybrid sunfish. Hybrid sunfish are arti- Channel catfish (Ictalurus punctatus) ficial crosses, usually between green (figure 16). Interest in stocking catfish in sunfish females and males of other Wisconsin ponds has increased. This is species like bluegills or redear sunfish. If due largely to extensive catfish farming the fish farmer producing the hybrids is that developed in southern states in the very careful in selecting the parents so 1960s. that only female green sunfish and only Catfish have certain drawbacks in north- males of other species are present in ern ponds. They do not generally spawn the breeding pond, the resulting off- successfully in these ponds unless spring should range from 65% to nearly special spawning structures are 100% males. installed. They also grow slowly com- Since most hybrid sunfish are male, pared to their counterparts in the South. reproduction is reduced in ponds that The catfish is a truly warmwater fish that contain only hybrids. Under these condi- grows fastest in water over 80ûF. But tions the hybrid sunfish may grow faster catfish will still grow large enough to than normal bluegill sunfish. provide recreational fishing in many Do not stock hybrid sunfish under the southern Wisconsin ponds because they following conditions: normally reach 12 inches after 3Ð4 If normal bluegill or green sunfish years. Females usually mature at 13Ð16 are already in the pond. The hybrids inches in length. can back-cross with their parent When the water temperature reaches types since the hybrids are fertile. 75ûF, catfish spawn in cavities such as If the ponds already have a stunted those found beneath undercut banks or sunfish population. They will in hollow logs. The male guards the compete for the same food and will embryos and fry until they school and not grow very fast. They will also leave the cavity. breed with the stunted fish. Catfish eat many types of food, both If the pond is shallow and weedy. living and dead: insect larvae, crayfish, The weeds will provide places for the snails, worms, clams, fish and various young of the hybrids to avoid preda- items that fall into the pond. tion. Overpopulation will be fore- stalled by only a few years. Figure 16. Channel catfish and bullheads. 24

MANAGING WISCONSIN FISH PONDS

All three species spawn when they are Some species present special problems. Forage fish 2Ð3 inches long. Normally, they spawn Fish not recommended The spines of bullheads (Ictalurus Small fish, such as minnows and several times throughout spring and melas, I. natalis and I. nebulosus) shiners, may be stocked as forage for summer. Spawning starts when the for Wisconsin ponds protect them from predation, allowing bass and catfish, though this won’t water warms to 65ûF in areas 1Ð2 feet The most common problems for them to take over a pond within a few always be necessary. Trout don’t need deep. Golden shiners deposit their eggs Wisconsin pond and small lake manage- years. Young bullheads are often mixed the forage and the small fish usually on aquatic plants and sometimes in ment are the presence of too many fish in with forage fish or fingerling game fish compete for food with the trout. bass nests. Fathead and bluntnose and undesirable species (figure 17). If being stocked. Inspect these carefully to Therefore, planting forage fish in cold- minnows lay eggs on the undersides of you are managing a pond for sport weed out bullheads. water ponds is not recommended. rocks, tiles, boards or logs. Fathead and fishing, there are two important things to Carp (Cyprinus carpio), suckers The most suitable bass forage species bluntnose minnows are repeat spawners remember: (Catostomus spp.) and various native are the fathead minnow (Pimephales and males protect the embryos during 1. The food resources of ponds are minnow species can also be mixed in promelas), the bluntnose minnow (P. development, thus increasing survival very limited. Placing too many fish in with fish destined for stocking. They notatus) and the golden shiner rates and the forage supply. a pond destroys the food supply. compete for food and prey on the eggs (Notemigonus crysoleucas). These all Although these forage species are pro- 2. Fish have the capacity to multiply of gamefish. Carp are bottom feeders feed on plankton and insects and will lific, bluntnose minnows seldom exceed 4 quickly. Introducing a small number which stir up the water, hampering sight- reproduce in ponds if there is suitable inches in length, and fatheads, 3 inches. of a new species “to see what will feeding by gamefish. spawning habitat. They are easy prey for largemouth and happen” often results in the expen- Fish such as walleye (Stizostedion smallmouth bass which can wipe them sive task of removing and disposing vitreum) and northern pike (Esox lucius) Fathead minnow out if the bass population is not held in of thousands of unwanted fish a few are often introduced to control an abun- check or there is not enough dense cover years later. In addition to the costs of dance of stunted bluegills. This approach to protect reproductive populations. removal (if removal is feasible) is seldom effective because bass are very Golden shiners attain a maximum length fishing can be harmed for many susceptible to predation by these species. of about 10 inches so their populations years. To produce a usable crop the Therefore, introducing them often results are less likely to be depleted by preda- focus should be on managing for in fewer bass but no change in bluegill olive gray color tion. But if many golden shiners in the one or a few species. population numbers or growth rates. Golden shiner pond reach 6 inches or larger, they may Unwanted species can be introduced in Yellow perch (Perca flavescens), pump- compete with young bass for food. a variety of ways. Well-meaning children kinseed sunfish (Lepomis gibbosus) and large scales silvery gold color or neighbors may transfer fish from near- green sunfish (Lepomis cyanellus), like by ditches or lakes. Fish may also enter bluegill, tend to overpopulate ponds and from nearby waters during periods of become stunted. Use these fish only in flooding. They may be introduced inad- lakes or larger ponds where largemouth vertently when stocking game or forage bass over 12Ð14 inches are present and deeply dipping lateral line Bluntnose minnow fishes. Pond owners should learn to their numbers are maintained through readily identify undesirable fish and try to catch and release fishing. Additional olive back above black spot keep them out of their ponds. Any fish controls may also be required to prevent dark stripe spot not included as part of the management overpopulation and stunting, such as plan should be viewed as undesirable. destruction of nests, trapping and removal of young (see Chapter 10). 25

TYPES OF FISH TO RAISE IN WISCONSIN SPORT FISHING PONDS

Besides fish, two exotic plants— Pond owners also have a responsibility Exotic species curlyleaf pondweed and Eurasian water- to ensure species are not released from Many species of fish exist in the world milfoil—invade Wisconsin ponds and their ponds into natural waterways. Even which are not native to Wisconsin and can cause serious nuisances. Purple the release of native species could alter most would not survive here in the wild. loosestrife, a wetland exotic plant, a natural system by increasing competi- However, certain species have the invades wetlands adjacent to ponds and tion, changing predator-prey dynamics potential not only to survive, but to destroys wildlife habitat. A number of or introducing diseases or parasites. reproduce. They become a nuisance, other exotic species like the zebra often destroying populations of native mussel, spiny water flea and rusty cray- fishes. To protect the state’s resources, fish are present in Wisconsin waters, Wisconsin has passed laws that prohibit ready to invade ponds of the unsuspect- importing and transporting species not ing. native to the state either as eggs, Introduction of unwanted species is a larvae, juveniles or adults. major problem in pond management. The common carp is the best example The pond owner should learn to recog- of an exotic fish species that produces nize “exotics” and undesirable native adverse effects. The European ruffe is species and take special care to guard also established in Wisconsin waters of against their introduction. the Great Lakes and is doing extensive damage. The grass carp (white amur), Japanese weatherfish, ide, rudd, bitter- ling and tench are other exotics that are present in U. S. waters and could reduce the abundance of native fish.

Figure 17. Some of the fish best kept out of ponds. chapterchapter 66 Implementing

pond management Dec. 15, 2001: Finished construction of pond. Keeping records Figured total costs at $3,000 on spread- A pond logbook is invaluable for record- sheet. ing and reviewing water quality condi- Dec. 17, 2001: Pond full. Water flowing over tions, the kinds of fish stocked, their source, weed treatments that worked, stop logs. Measured at 85 GPM. the costs of stocked fish or treatments, 2 Jan. 15, 2002: Pond ⁄3 frozen over. Oxygen 8 and the success of each management activity. Visits from wildlife, catches and ppm at surface pH 7.5. fish sizes should also be recorded (figure 18). April 10, 2002: Finished smoothing area In addition to a written logbook that you around pond and seeded with grass and cover. can carry with you in the field, a com- Installed fish screen at stop logs. puter spreadsheet helps maintain 3 records of water monitoring information, April 25, 2002: Stocked 125 1 ⁄4–2-inch costs, the number and size of fish rainbow trout. stocked, the numbers of fish caught, their size and the hours you and others June 20, 2002: Algae forming along edge of spent enjoying the pond. pond. Removed with rake. You are not likely to remember all of this information without good record keeping. Aug. 15, 2002: Temperature at surface 58˚F; In addition to being a key part of the bottom 52˚F; air temp 90˚F. Trout visible management process, reviewing the along shore around 6 in long. Muskrats in pond records may be one of the rewards pond. that you and other family members receive for your investment in pond Oct. 1, 2002: Stocked 100 6-in trout from management. Fairweather Hatchery. Oct. 20, 2002: A lot of muskrat activity.

Figure 18. Pond logbook. 27

IMPLEMENTING POND MANAGEMENT

Water temperature is probably the most thermometer in it, or use a sampler for Dissolved oxygen should be above 5 Selecting the best fish critical factor in determining the kind of dissolved oxygen measurements. If the parts per million (ppm) for coldwater fish fish to manage. The water source near surface temperature is more than but can be as low as about 3Ð4 ppm for for the pond should give some indication of whether 70ûF, the pond is probably best suited warmwater species during summer. Cold The best pond will not produce a good the pond is suitable for trout or warmwa- for warmwater fish. water holds more oxygen than warm crop of fish if the species is not suited to ter species. Unless you are sure, it is Similarly, you can obtain a bottom tem- water; therefore the higher levels required the pond’s conditions. Evaluate your best to measure water temperature on a perature by lowering a screw-top jar or by trout are not generally a problem if the pond conditions before you select fish to hot summer afternoon a foot below the can full of water, with a thermometer pro- water is cold enough and stock densities stock. Record your observations in a surface near the center of the pond. Try truding through the lid to near the bottom are not high. logbook so that you can make sound to read the thermometer at that depth for two to three hours (figure 19). Read Oxygen is more plentiful in deeper ponds judgements. (the reading can change rapidly if it is the bottom temperature when you bring and in those where plant nutrients are brought to the surface) or collect a the jar to the surface. If the bottom tem- low to moderate. Dissolved oxygen will larger volume of water and immerse the perature is the same as that on the probably not remain at or above 5 ppm surface, you know that the pond is mixing during winter months under the ice in Figure 19. Bottom temperatures can be obtained by lowering a screw-top jar or and there should be oxygen at all levels. Wisconsin ponds. However, the metabo- can of water to the bottom and leaving it until its temperature is the same as the If it is above 74 ûF, the pond is too warm lism of fish is lower during winter. Cold- surrounding water. Then take the temperature of the contents when it is brought for trout. water fish should survive at 2Ð3 ppm. to the surface. In the case of borderline temperatures, Warmwater species will generally survive try trout. They often do well in a border- in ponds even when dissolved oxygen line pond for several years until the dis- falls to 1Ð2 ppm during late winter. solved oxygen content of the water falls In some Wisconsin ponds, pH may be a too low (under about 5 parts per million) problem. Few fish grow well in acidic from accumulated organic matter. systems at pH 6 or below. You should Since trout are not likely to reproduce in suspect low pH if the water is bog- the pond, it will be easy to switch to a stained or if the pond was constructed in warmer water species if the trout plant- an area that was previously a bog. ing fails. This is not true of warmwater Low pH can also occur in ponds in sandy species that will live and reproduce in areas fed primarily by rain water. Liming is colder ponds but do not grow well. Try sometimes used to raise the water’s pH trout only before you stock any other and alkalinity to counteract acidity prob- kind of fish. This will avoid competition lems. Liming also allows the pond to from warmwater species. handle phosphorus fertility in ways that In borderline cases you can economize boost production of fish rather than of nui- by using only a token stocking of a sance bluegreen algae (see Chapter 4). dozen or so fish per acre; then follow High pH can also be a problem in some their progress by catch-and-release fertile ponds. On a sunny afternoon, pH fishing. If they survive and grow well the can reach 9.5 because of carbon dioxide first year, stock more. depletion. This can aggravate problems with ammonia toxicity. 28

MANAGING WISCONSIN FISH PONDS

You might also obtain fish from someone Determining whether aeration is Aeration systems should be designed to Where to get fish for stocking else’s pond or from public waters. In the needed and how much it will cost are meet the specific needs of each pond. Carefully consider and investigate the latter case, you must adhere to all state questions you should evaluate before One risk with circulating a trout pond in source of fish for your pond. Purchasing laws. You are also required to register beginning your pond management. If summer is that the entire pond may be fish from a licensed game fish breeder your pond as a fish farm to catch and dissolved oxygen levels are at or near warmed beyond trout’s tolerance limit. (licensed hatchery) is usually the transport game fish to plant in your own the minimum required for the desired There are special devices for aerating easiest, most economical and safest in warmwater pond (see Chapter 15). species, aeration can increase oxygen only the deep, cool part of the pond, the long run. You can get the fish at just concentrations. without mixing it with warm surface about any time, in the numbers you Anticipating fish manage- The most common and inexpensive water. Aeration may also keep part of need and at the appropriate sizes. You method is to circulate the water by an the pond’s surface unfrozen in winter. will also reduce the chances of introduc- air-lift system. A stream of air bubbles is This can help protect the outlet pipe ing unwanted plant and animal species. ment activities and costs from damage by freezing. However, the In addition to assessing what kind of fish injected near the pond bed in the deeper open water and thin ice increase a pond For coldwater ponds, purchasing trout to plant and the costs and benefits of part of the pond. Rising bubbles draw owner’s liability. If aeration is needed, represents the obvious choice. A list of various stocking options, you will want to bottom water toward the top, creating a part of the assessment process should licensed Wisconsin game fish breeders estimate the need for other manage- vertical circulation of water. At the include determining how you will protect is available at no cost from the ment activities and their costs. surface, the oxygen-poor water takes on people, livestock, pets or wildlife from Wisconsin Department of Agriculture, Subsequent chapters will help you oxygen from the atmosphere. Surface the open water and thin ice areas Division of Trade and Consumer determine the fish management activi- water circulates to the bottom to replace caused by winter aeration. Protection (see Chapter 16). Check with ties that will probably be required to it. The bubble stream can be produced several hatcheries. In addition to com- promote the success of your pond by a compressor powered by electricity. For occasional use, consider cascade paring prices, you may wish to visit them project. Developing an understanding of In some instances wind-powered com- aeration (pumping water over a cascade to see how the fish were raised and to the alternatives and their costs will be pressors are used. Air passes through a box), using a power take-off or engine- evaluate their quality. Some breeders facilitated by the same kind of careful hose along the pond bed to an air stone driven pump. are registered as “disease free “and this assessment required to build a good fish or other dispenser. A variety of air-lift cir- Knowing the costs of getting power to may be a factor to consider. Record pond. Keeping careful records in your culation systems are sold for lake and the pond site, aeration equipment, the prices and other relevant information in pond logbook will help you make good pond use. time the equipment will be running and your logbook. choices. related operating costs will help imple- It is possible to catch fish for planting in ment successful fish management on a warmwater pond. However, bear in ponds that need aeration. mind that you will want the fish to be free of unwanted parasites and in good condition. The stress that fish undergo when they are caught, held in a cooler or on a stringer and transported to your pond could make them unsuitable for stocking. Before stocking the pond, refer to The best times to stock are April, May chapterchapter 77 Chapter 6 to determine whether the and possibly June because water tem- Managing pond can support trout. peratures are still moderate and natural food organisms are increasingly abundant. Fish planted at this time tend to do coldwater ponds Stocking better and start growing sooner. Preparing the pond for stocking is usually not necessary for a new, prop- You can also stock trout in September for sport fishing erly built pond (Chapter 3). If you are and October when the pond is becoming cooler. However, there is less chance for The main steps in managing coldwater converting an old pond to support trout growth because the pond soon becomes fish ponds include: or readying a renovated trout pond, you may need to do certain things before too cold. Fall stocking is usually done 1. Stocking small trout you begin stocking. only in new or redredged ponds—or 2. Fishing for them when they grow to a where unwanted fish have been eradi- If other kinds of fish are in the pond, desirable size cated during the summer. remove them (Chapter 10). Screen 3. Restocking as the population inlets and outlets to prevent the smallest Fall-stocked fish that live on natural feed diminishes fishes from entering. Maintaining generally look and taste better than Restocking is usually done annually, but screens can be quite a problem, so it is newly stocked fish. Fall-stocked trout can be done less often if you don’t fish far better to build the pond without con- may die during harsh winter conditions, much and the trout survive other nections to other surface waters that but the losses may be outweighed by hazards. Annual stocking with fingerlings harbor fish. Caution children and friends the much lower cost of fall fingerlings. or yearlings is often good because it not to introduce minnows, panfish, gold- Stocking trout in summer is inadvisable creates an interesting population with fish or any other fish. due to the risk of thermal shock that can fish of different ages and sizes. Keep in You may wish to combine a re-digging kill many or all of the planted fish. mind that trout do not reproduce in most operation with a fish-removal drawdown. ponds, so replenishing the population Dragline digging with the pond bed depends on stocking. See Chapter 5 for exposed and somewhat dry may be information about the different kinds of much cheaper than suction dredging or trout. draglining when the pond is full. Trout usually grow best on a diet of Even if you don’t dig the pond deeper invertebrates such as freshwater shrimp during a drawdown, take advantage of (Gammarus), water fleas, insect larvae the situation to rake out aquatic plants and crayfish. They do not thrive when and debris. Reducing organic matter there are other kinds of fish in the pond. usually improves a pond for trout. See Bass, pike and catfish eat large Chapter 11 for plant control methods. numbers of trout. Panfish, bullheads, suckers, carp and even the smallest kinds of minnows compete with trout for food. When competitor fish are in a pond, trout growth and survival is poor. 30

MANAGING WISCONSIN FISH PONDS

Suggested numbers and sizes of The number and size of trout to stock As a rule, the larger the trout stocked, The first time you stock a new or reno- trout to stock for populations that will depend on an individual pond’s condi- the greater the percentage that survive vated trout pond, it may be most eco- grow well on natural food supplies are tion: the amount and size of trout to be caught—and, of course, the nomical to use spring fingerlings. Plan suggested in table 4. Only one of the already present, how fast they are to be sooner there will be fishing for big trout. not to fish them until the next spring types listed should be stocked in one harvested, the food supply and whether Whenever you stock, consider using the when they should be 7Ð8 inches long. year, although “adult” trout can be natural reproduction occurs. Adjust largest fish that the budget allows. Price However, you may want to do some test restocked as often as they are fished stocking from year to year according to per stocked fish rises sharply with fishing in the interim. out. past experience and current conditions. increasing size, but the number needed If you want an initial springtime stocking A common mistake is stocking too many Infertile ponds may support only about to adequately stock the pond decreases. to provide more immediate fishing, use trout, which results in poor growth. The 20Ð25 pounds of trout per acre. Very Experimenting in the pond over the 6- to 7-inch yearlings. In excellent current recommended stocking rates are fertile ponds may sustain upwards of years should reveal the best sizes and ponds, they will grow an inch a month conservative and lower than often sug- 150 pounds per acre on the natural food numbers to stock. Your logbook records during spring, summer and fall. gested in the past. We believe it is far supply. will be extremely useful in assessing For restocking in ponds with established better to risk starting with too few trout Pond capacity for trout production can which size to stock and how well fish trout populations, don’t use fish smaller than to risk ruining the food supply. If the be increased several fold by supplemen- from different sources grow. You can than fall fingerlings (5Ð6 inches ). There trout are fast-growing and stay plump all tal feeding, and then you may raise the compare growth rates with regional will be fewer losses to cannibalism by year, stocking can be done at a some- stocking rate. However, feeding can averages using figure 20 (see page 32). trout that have survived from previous what higher rate the next time. cause various problems (see page 31). Calculate the cost per-pound-caught, or stocking. Annual restocking may provide per-fish-of-desirable-size caught. You far more consistent fishing than restock- may find that these costs decrease if ing at greater intervals. you stock fish somewhat larger than the Inspect the trout before planting them smallest, cheapest ones available. to be sure that they are healthy. Don’t accept fish that are obviously diseased, that appear weak or behave abnormally. Fish stressed by improper handling and Table 4. A guide for stocking trout to achieve maximum growth without additional feeding and aeration. transport will die soon after stocking. Type of Size in Number to Time to Even under the best conditions, 10Ð20 trout inches stock per acre stock Comments percent of the stocked fish may die in Spring fingerlings 2Ð3 200Ð300 AprilÐMay Least expensive. the first 2Ð4 weeks. May be hard to get. Only for initial stocking of new pond or one which has had all fish removed. Fall fingerlings 5Ð650Ð150 SeptÐOct For initial stocking or restocking. Spring yearlings 6Ð750Ð150 AprilÐJune For initial stocking or restocking. More expensive than fingerlings. “Adults” over 7 25Ð50 spring or fall For initial stocking or restocking. Can be very expensive.

*The lower number is for ponds with alkalinity less than 50 ppm or that will be lightly fished. The higher number is for ponds with alkalinity over 150 ppm and/or will be heavily fished; hence, more rapidly “thinned out.” 31

MANAGING COLDWATER PONDS FOR SPORT FISHING

You may need a special hatchery tress) until tempering has been accom- Under a “put-grow-and-catch” manage- replenishes the oxygen consumed by license to transport your own fish. If you plished and you are ready to release the ment scheme, trout grow while the decaying feed and fish wastes. decide on this approach, keep the water fish into the pond. harvest is spread out over the season However, there are disadvantages to at a rather constant low temperature Flushing the trout through a large tube each year. You should be able to harvest such intense management. Once the (50Ð60û F). Cool weather greatly from the transport truck directly into the an amount of trout about equal in weight population is built up to the level reduces handling stress. Besides being cold pond depths is another way to to the total poundage that exists in the needing feed, the trout must be fed cold, the water must be well-oxygenated reduce thermal shock, but few dealers pond at the start of summer. This is almost daily during the growing season. and unchlorinated. You may use small have such equipment. All in all, it is best because the remaining trout grow enough “Feedlot” conditions may be created, aeration devices that operate on batter- not to stock in summer. to compensate for mortality. and the pond’s appearance could ies or automobile current—or you can A put-and-take fishery may be appropri- become unpleasant. Excess feed and attach a tube with a clamp valve and air- ate for ponds where temperatures are the unavoidable large amounts of trout stone to a spare tire. Cool the container When to start fishing and suitable for trout only in spring and fall. feces raise water fertility to levels that of water (plastic trash cans work well) Under “put-and-take” management for can cause undesirable algae growth. with ice. However, never place ice made how much to harvest rapid catch-out of stockings of trout, The accumulation of unused feed, trout Do some catch-and-release fishing peri- with chlorinated tap water in with your many times more pounds of trout can be waste, living and dead plant matter and odically to see how the trout are fish. It is usually most convenient and caught than the pond can support. But decayed microorganisms in the pond growing. Recording their sizes in your reliable to let the dealer deliver the fish. you will never catch as many pounds of consume large amounts of dissolved logbook allows you to estimate their As mentioned, stocking trout in summer trout as were stocked. There isn’t time oxygen. Having too little oxygen growth rates. Start keeping fish as soon is not advisable. Since trout must be for the trout to make use of the food hampers trout growth and can kill them as you start catching some of desirable transported in water that is much colder supply and to grow enough to compen- if the problem is severe enough. In soft- size. A reasonable size at which to start than the summer surface water of most sate for post-stocking mortality. The cost water ponds especially, excess enrich- harvesting is 7Ð10 inches. If you delay ponds, they may undergo lethal temper- per pound of fish caught will be higher ment can cause fluctuations of pH which harvest until the fish are much larger, ature stress in the warm upper layers of than in a put-grow-and-catch manage- are intolerable for trout. High trout densi- your total return may be severely the pond and oxygen stress in the cool ment program. ties also attract predators, particularly reduced. This is because loss of fish by water below. Resulting deaths may not birds. non-fishing or “natural” causes usually be evident immediately, but may occur occurs rapidly, especially in the case of If you must feed supplementally, give no over several hours or days. Supplemental feeding rainbow or brook trout and few live to be Supplemental feeding shouldn’t be more feed at one time than the trout eat If more than a 6ûF difference exists over 3 years old. needed if you follow the stocking rates immediately. This minimizes the residue between transport water and the pond, of unused feed and reduces cost. The more fish that are taken by angling, in table 4. At these densities, the trout “temper” the trout to the new water grad- the fewer that can be lost to other should have enough natural food to Convenient pelletized dry feed is avail- ually. To do this, add small amounts of causes. The greatest yield of fish and sustain desirable growth. able. However, use only food especially pond water to the transport tank until its enjoyment is usually obtained by doing Higher population densities can be made for trout. Feeds for other animals water is at pond temperature. If you most of the harvesting in the season maintained if feed is added. Some (such as chickens) don’t have the ingre- transport the fish in plastic bags (oxygen when the trout reach 7Ð10 inches. people keep as much as 5,000 pounds dients in the right proportions and won’t packs), trash cans or other small con- Review your records over the years to of trout per acre in hard water ponds work. In most cases, floating pellets are tainers, set them in the pond until the see how best to spread out the harvest with artificial feeding—and harvest that best. They stay up where trout can find water inside is the same temperature as to get the desired results. amount annually. This can only be done them longer—and where you can see in the pond. If the transport bags have where a strong supply of spring water when they have had enough. been filled with oxygen and tied off, do keeps temperatures low and rapidly not open the bag (unless fish are in dis- 32

MANAGING WISCONSIN FISH PONDS Special aquatic plant control in trout ponds Keep the amount of algae and rooted Trout—inches plants in trout ponds moderately low. Figure 20. Determining While water plants produce oxygen in 0 4 8 12 16 20 2500 whether a trout is the proper daylight, they consume it at night. An weight for its length. overabundance of plants, together with decaying dead plants, may reduce dis- 5 Weigh the fish to the nearest half solved oxygen levels below the trout’s ounce or 10 grams, if less than 1 needs, especially on hot summer nights ⁄4 pound. If heavier, it may be or under winter ice cover. See Chapter 10 2000 weighed a bit less accurately. Measure length to the nearest1 for information on aquatic plant control. ⁄8 inch. Plot length on the horizon- CAUTION: Trout are generally more 4 tal scale and lightly pencil a ver- sensitive to chemicals used to kill algae tical line there. Plot weight on (algicides) or rooted plants (herbicides) the vertical scale and draw a than are warmwater fish. Some of these 1500 light horizontal line there. If the chemicals kill trout at the concentrations point where the two lines inter- needed to kill plants. Be very careful 3 sect lies on the heavy curved with the common algae control chemi- line, the fish is of standard grams cal, copper sulfate, in trout ponds. You pounds weight for its length. If the point lies above the curve, it is heavier need to know the water hardness to than average. If it lies below the determine whether copper compounds 1000 curve, the fish is underweight. can be used safely. Other copper com- 2 pounds such as Cutrine (chelated copper) also require extreme care. Before buying any chemical for killing aquatic plants in a trout pond, obtain the appropriate permits and determine the 1 500 effect on trout. It is safer to remove 3/ plants by mechanical means (see 4 Chapter 11). 1/2 1/4

0 100 200 300 400 500 600

millimeters Smallmouth bass work better than large- chapterchapter 88 Stocking mouth bass where water is on the cool Managing warm- While stocking is not the only important side. Smallmouth bass may also do aspect of management, the type of fish, better than largemouth in new or reno- the number stocked, their body size, and vated ponds that haven’t yet developed water ponds the time of stocking will do much to much forage. Smallmouths often don’t determine fishing quality, especially in spawn successfully, because they prefer for sport fishing the first 3Ð5 years. Special details on gravel and the young seem to require stocking various kinds and combinations more dissolved oxygen than largemouth of fish are given and summarized in fry. Selecting the right table 5. For more information on the Bass with forage minnows. Stocking biology of each species, see Chapter 5. fathead minnows before stocking bass is fish species Largemouth bass, bluegill and other safe if you carefully remove all Most warmwater fish do well at summer panfish usually won’t need restocking, unwanted species beforehand. Fathead dissolved oxygen concentrations of 5 since they reproduce well in most minnows are recommended, since they ppm and temperatures between ponds. Adding to established popula- don’t grow larger than 3 inches. You can 70ûÐ80ûF. Typically these warmwater tions of these fish generally results in also use bluntnose minnows. ponds have less water flow; therefore loss of the newly stocked fish due to Golden shiners also work well, but they need greater depth (15 ft) to competition and poor growth. You may sometimes grow too big for bass to eat. sustain oxygen concentrations above have to restock smallmouth bass, and If large bass are not maintained in the the level required for winter survival. will likely need to restock channel pond as recommended in this publica- Managing warmwater ponds is made catfish. tion, golden shiners may become too more difficult by many species’ high Bass (largemouth or smallmouth) abundant and compete with young bass reproduction rates. Overproduction of without other fish. In ponds lacking for food. If bass deplete the minnow small fish and stunting are major prob- other fish that compete for food, bass populations in a few years, you can lems, though less so in larger ponds or thrive on worms, insect larvae and cray- stock more and reduce the size of the small lakes (6Ð10 acres). Managing for fish. They also feed heavily on their own bass population by fishing. one or two species also greatly young which helps keep their population increases your chances of avoiding Restocking minnows should always be under control. We strongly recommend problems. done carefully so that unwanted species trying bass alone. If their growth is like bullheads are not unintentionally unsatisfactory, you can always add introduced. Scattering the minnows forage fish. when stocking serves to reduce immediate predation. A moderate amount of rooted plants in the pond gives minnows cover from bass predation and usually allows enough to survive and reproduce to maintain their populations. Installing tile pipes or raised spawning boards also aids minnow reproduction. 34

MANAGING WISCONSIN FISH PONDS

Channel catfish and minnows. for it to be fully evaluated. Some owners If large (6 inches or more) hybrids are Exotic species include fish and other Channel catfish grow slowly and seldom have had good success with crappies in stocked, they may improve fishing by organisms such as crayfish not native to reproduce in Wisconsin ponds. They larger ponds. changing the size structure of the Wisconsin that are sometimes desired must usually be restocked for continu- Bluegills or other panfish without sunfish population, particularly if you by pond owners. All of these, such as ous fishing. If shelters such as milk bass. This results in overpopulation and practice catch and release fishing. grass carp, tench and Japanese weath- cans, kegs or closed pipes are provided, stunting even sooner than the bass- You should check with your area DNR erfish, are illegal and have the potential they may occasionally breed. Use the bluegill combination. If a bluegill-only fish manager before stocking hybrid to damage your pond and adjoining same kinds of minnows recommended pond is desired, consider stocking only sunfish. Because green and redear public waters (see discussion in for bass forage. Sometimes, for variety, fingerlings. This delays the onset of sunfish are not found in some areas of Chapter 5). channel catfish are added to a pond stunting by giving the initial population Wisconsin, and the offsping of hybrids containing bass and/or panfish. If adult some time to grow before it produces grow slowly, stocking is restricted. bass are present, use catfish larger than offspring which compete with the 7 inches to minimize predation. Bass parents for food. and panfish will prey on any catfish fry Hybrid sunfish with or without bass. produced. Artificial crosses between green sunfish Table 5. Largemouth bass and bluegills or females and other species of sunfish (for Stocking guide for Wisconsin warmwater ponds crappies. Largemouth bass in combina- example, bluegill and redear) may have to achieve maximum growth without supplemental feeding and aeration. tion with bluegills is a favorite in south- the advantages of hybrid vigor and are Number to stock Length ern states, where it works in small predominately male. With reduced Kind of fish per surface acre (inches) Time of year ponds (0.5Ð3 acres), but it has been reproduction, the food supply and room Largemouth or 100 fingerlings* 2Ð4 JulyÐAugust less successful in the North. Bass are to grow are maintained. But beware— smallmouth bass alone or supposed to control bluegills by preda- purebred sunfish are usually included tion, but it doesn’t work that way in our 25Ð50 yearlings 6Ð10 AprilÐOctober among the hybrid fingerlings stocked. or climate, particularly in smaller ponds. These purebreds and the hybrids can 6Ð8 adults (both sexes) 12 October or May Bluegills overpopulate the pond, result- spawn and start the pond on its way to ing in stunted growth of both bass and overpopulation. Their offspring typically Bass with minnows 500 adult minnows, then, 2Ð3 April-May bluegills. If you want bass and bluegills, grow much slower than native sunfish. after minnows spawn, stock bass as above give the bass a 1- to 2-year headstart on Still, overcrowding can be delayed for growth. The combination works better in several years—with excellent fishing in Channel catfish 500 adult minnows 2Ð3 AprilÐMay larger ponds and small lakes if the bass the meantime. The advantages can be with minnows after minnows spawn harvest is greatly restricted. extended if the hybrid sunfish are -100 fingerling catfish 2-4 JulyÐAugust In Wisconsin, crappie may be a better stocked with largemouth bass because Largemouth Stock bass as above; 1Ð2 July-August choice than bluegill in combination with the bass prey upon the limited number bass** with after 1 or 2 years bass. Because crappies spawn earlier of sunfish offspring. Hybrids are of little bluegills or crappie 500 fingerling bluegills and their reproduction period is shorter, or no value when stocked in the pres- Bluegill or other panfish 500 fingerlings 1Ð2 JulyÐAugust there is less chance for overpopulation. ence of existing panfish populations or with NO bass THIS ALTERNATIVE IS In addition they tend to use the open in shallow weedy ponds. NOT RECOMMENDED water of a pond where they are more Hybrid sunfish 400Ð800 fingerlings 1Ð3 JulyÐOctober available to bass. However, too few * Reduce by half if water alkalinity is less than 50 ppm pond owners have tried this combination **Don’t use smallmouth bass; they eat very few bluegills. 35

MANAGING WARMWATER PONDS FOR SPORT FISHING

The easiest way to ensure that these Any time that bass of a certain size Channel catfish. If you stock channel Angling harvest panfish predators are available is to appear thin and poorly fed, harvest bass catfish as fingerlings, start harvesting Delay bass harvest until the fish have release all 12- to 16-inch bass. When of that size more heavily. If a bass them in the second or third year after spawned once. This ensures that they the pond contains a healthy population weighs less than 95% of the standard stocking, after they have reached 9Ðl0 are well established before other fish of this size bass, you can harvest a few weight for its length, it is too thin. Use inches. If the catfish population is one of (especially panfish) disrupt the food 10- to 12-inch bass (25Ð30cm) as well figure 21 to check whether your bass those rare ones in Wisconsin that sus- supply. It may mean waiting 2Ð3 years if as those over 16 inches. Harvesting are of standard weight. Here again, tains itself by natural reproduction, you stock fingerlings; 1Ð2 years if you some of the 10- to 12-inch bass will help keeping good records of the length and remove only 10Ð15 fish per acre each stock yearlings; or until mid-June of the select for the fastest growing fish. Since weight of the fish you catch is essential. year. Usually, however, replenishment is year following stocking of adults. slower growing fish will be 10Ð12 inches accomplished by annual restocking, and If you stock 100 bass fingerlings per for a longer time than the faster growing all fish caught above whatever size acre, expect around 25Ð30 adults per fish, they are more likely to be caught pleases the owner can be harvested. acre after 2 full summers in the pond. than the faster growing fish. The original bass stocked as fingerlings must support the first 5 years or more of Figure 21. Determining the pond’s bass fishing. Therefore, whether a bass or bluegill harvest them lightly! is the proper weight for its Light harvest means not removing more length. than 20Ð25 pounds of bass per acre Weigh the fish to the each year. Recording the length and nearest half ounce, if less weight of all fish taken in your pond 1 than ⁄4 pound. If heavier, it logbook is essential to determining when may be weighed a bit less this level of harvest is reached. After the precisely. Measure length to year’s quota is taken, you can still enjoy the nearest 1 ⁄8-inch or mil- the pond by changing to catch-and- limeter. Plot weight on the release fishing. Recording information vertical scale and length on about caught-and-released fish is also the horizontal scale. Draw a useful in estimating growth and changes horizontal line lightly with in growth. pencil at the fish’s weight and a vertical line at its There are many ways to manage length. If the point where harvest in an established Wisconsin the two lines intersect is on bass pond, especially if panfish have the heavy curved line, the also been stocked. Since panfish can fish is of standard (or easily overpopulate and stunt in average) weight for its Wisconsin ponds, it is important to length. If the point lies protect the bass that are panfish preda- above the curve, it is tors. Bass 12- to 16-inches prey on 3- to heavier than average. If it 5-inch panfish effectively . lies below the curve, the fish is underweight. 36

MANAGING WISCONSIN FISH PONDS

Bluegills and other panfish. Start har- No matter how intensively you manage If you wish to do some supplemental Liming is sometimes used to raise the vesting as soon as they are a size you the bass-bluegill pond, bluegills may still feeding, use demand or ring feeders to water’s alkalinity to counteract acidity like. In new ponds or those where fish simply take over. Bass spawning reduce food loss. Because you are problems or to allow the pond to handle have been eradicated, some bluegills success will decline, large bass and adding nutrients, supplemental feeding phosphorus fertility in ways that boost stocked as fingerlings should exceed 4 bluegills will disappear, and there will be should be done in moderation and in fish production rather than that of nui- inches the next summer and 6 inches hordes of small bluegills—all about the combination with other population sance bluegreen algae (Chapter 4). the summer after that. Follow two same size. When this occurs, the owner control measures. Higher stocking levels Fertilizing and liming ponds should be harvest rules: is often tempted to plant more and may lead to the fish outstripping the done only under the direction of a water l. Remove as many fish under 6 bigger fish—maybe even walleye or natural food supply. Although many fish chemistry expert who understands the inches as you can. northern pike. Resist such impulses! will eat pelleted fish feeds, it is usually proper balance between alkalinity and Walleye and northern pike are generally best for pond health, appearance and phosphorus content and who can deter- 2. Greatly restrict the harvest of fish not suited to life in small warmwater your pocketbook to manage so that the mine the right dosage of phosphorus or over 6 inches. This works against ponds (Chapter 5), and the only cure for fish are sustained by the food that lime. overcrowding and helps superior stunted panfish is a sound program of occurs naturally in the pond. brood stock survive. Just as with population control (Chapter 10). bass, the biggest, fastest growing Emergency aeration bluegills bite most readily and tend Pond fertilization and liming to be caught first. Not recommended: Fertilizing and liming are generally not of the pond Figure 21 shows how much bluegills recommended for Wisconsin sport Chapter 6 describes ways of injecting a should weigh at each length. If the higher stocking levels fishing ponds. Fertilization here usually stream of air bubbles at the deepest part bluegills are thin or growing too slowly, causes excessive weed and algae of the pond to circulate the water and suspect overcrowding. Apply increasing and fish feeding growth, resulting in plant control prob- keep sufficient dissolved oxygen in the catch rates and other population control Adding pellets, bread or other fish food lems (Chapter 11) and a lack of dis- deep zone. This procedure can be used techniques (see Chapter 10). may increase fish growth in a pond—but solved oxygen for fish. to rescue fish from a temporary oxygen it can also accelerate the growth of crisis, such as on hot summer nights or The bass-bluegill combination. Follow Never use fertilizer to create algal algae and other aquatic plants to exces- during an especially hard winter. the procedures outlined in the above growth to stifle rooted plants, as is done sive amounts. The result may be not sections on bass and bluegills. Harvest in the South and in commercial aquacul- Aerators are particularly useful in pre- only unsightly and interfere with fishing, at least 4 pounds of bluegills for each ture ponds. Such enrichment is so venting winterkill of fish. The circulation but a build-up of organic matter in the pound of bass harvested. This helps strong that it poses the grave risk of win- achieved by the bubble stream or a pond may cause oxygen depletion and bass keep the upper hand longer. It is terkill of fish. pump and cascade aerator system fish die-off. especially important to restrict harvest of maintains an open area of ice-free water bass over 16 inches. At that length, they through which the pond can take on may be nearly 2 pounds and are proba- oxygen. However, an aerator should not bly just beginning to eat enough bluegills be needed in a properly designed sport to have an effect in controlling their fishing pond. The open water resulting numbers. Have fun catching large bass from winter aeration can represent a and releasing them alive. Try to build up safety and liability problem. a substantial population of bass weigh- ing 3, 4 and 5 pounds. Regardless of the method used, com- In contrast to many other uses of ponds, chapterchapter 99 mercial aquaculture in Wisconsin is reg- such as recreational fishing, swimming Managing ponds ulated by both the Department of or scenic enhancement, the primary Agriculture, Trade and Consumer goal of commercial aquaculture is to Protection (DATCP) and the Department make a profit. The importance of careful for commercial of Natural Resources (DNR). planning cannot be overstated for a suc- DATCP is responsible for the annual cessful commercial aquaculture venture. fish production registration of fish farms, import permits The planning process includes an accu- for live fish and eggs and for all matters rate business prospectus and enterprise related to fish health and processing. budget. General considerations DNR regulates fish stocking into public The four basic methods commonly used waters, water use, water discharge and to raise fish for profit are: Planning importation of non-native fish. Both of Careful planning may take years, but it 1. Flow-through systems, which gen- these agencies should be contacted should be viewed as a mechanism by erally consist of a set of tanks, con- early in the planning stage. You should which you can develop much of the crete or earthen raceways or pools also contact the University of Wisconsin knowledge and skill essential to making with a large volume of fresh water Sea Grant Institute, which supports a your business a success. It is a way to continuously flowing through them. great deal of aquaculture research. enter the business before you actually This is how most Wisconsin trout are Of the four methods used for commer- invest in it. Planning helps you learn raised. cial aquaculture, open pond culture is about the species you plan to grow, the 2. Water reuse or recirculation usually the most economical way to market for your products, what is systems, which are normally built raise fish if you can meet a given required in terms of time and money, as indoors and rely on continuous water species’ environmental requirements. well as potential rewards and problems, pumping and filtration. (These work Primarily because of this economic both short- and long-term. in a manner similar to that of most advantage, pond culture is responsible The planning process helps you decide tropical fish aquariums.) for more than 60% of total worldwide if commercial aquaculture is the best 3. Open-pond culture, in which fish are fish production. A good example of a investment of your time and resources. raised unconfined, and in ponds that successful large-scale industry based on Entering any business without the are usually designed and built specifi- pond culture is the production of channel knowledge and skills developed through cally for commercial aquaculture. catfish in the southern U.S. careful planning usually leads to busi- 4. Net-pens, in which fish are confined In Wisconsin, commercial aquaculture ness failure and financial loss. It can in cloth or plastic mesh cages; gen- has traditionally used a combination of also result in the loss of self-confidence, erally located in large bodies of flow-through and pond culture techniques friends and even family. water or ponds. to raise coldwater trout. Most open-pond aquaculture currently involves raising coolwater and warmwater game fish fingerlings and baitfish. Production of food fish, particularly yellow perch, has also begun. Net pen culture is being explored and may have potential. 38

MANAGING WISCONSIN FISH PONDS

The planning process (figure 22) should Planning production of aquaculture We suggest starting with a broad per- You also need to develop enough expe- help you develop understanding and products. For many, an interest in spective and investigating a variety of rience to correctly interpret how the skills in: aquaculture starts with a strong desire to aquaculture alternatives. For example, information applies to your potential 1. Producing the product(s) rear a preferred species. The important starting with the idea of bait culture is business venture. Although most of the questions to ask yourself are: better than focusing on one species of chapters in this publication focus on 2. Operating a business, including mar- bait. This approach will increase your pond management for sport fishing, the keting the product Can I rear the species in commercial quantities? breadth of knowledge about aquaculture information provides a good starting 3. Developing the financial resource as a business, and thereby increase point for developing a basic understand- Can I sell the product at a price that base your chances of success. ing of pond management. will earn an acceptable profit? 4. Developing the personal support Efficient production of large quantities of After reviewing this publication you will You may find that the probability of base fish or other aquaculture species need to develop much more detailed success would be higher with other Throughout the process you should requires detailed knowledge of the information about the culture of appro- species or a combination of species, or maintain good records of the information species. Unless you have previous train- priate species at the high densities char- by combining aquaculture with market- you have reviewed. These records will ing with the species and the aquaculture acteristic of commercial aquaculture. ing the products of other producers. You serve as a guide in developing the busi- industry, you will need to start gathering You will want to study information on will then need to decide if you have the ness prospectus and for implementing reliable detailed information on the temperature-oxygen requirements and interest to go ahead with the project. your plan. group or species you may be culturing. management, growth under different feeding regimes, mating behavior, egg incubation techniques, the various Figure 22. Aquaculture planning. sources of stock, diets, feeding behavior fish culture Careful consideration to the four and techniques, potential diseases and knowledge areas identified below will help you their control. The reference section lists determine the feasibility of an aqua- sources of more detailed information. culture business and develop the knowledge required to make good In addition to reading, getting up-to-date decisions regarding commercial information on commercial aquaculture aquaculture. requires interacting with those already in the business. Contacting or joining the Wisconsin Aquaculture Association (see personal business the list of references, p. 76) is an excel- support marketing lent starting point. Members, the group’s meetings and its newsletter, the Creel, provide invaluable information on aquaculture in Wisconsin. In addition, the newsletter is an excellent way to learn about state, regional or national meetings that introduce the most recent information on aquaculture techniques and fiscal products. Having up-to-date information resources on culture techniques and products is critical to your business plan. 39

MANAGING PONDS FOR COMMERCIAL FISH PRODUCTION

Presentations at aquaculture meetings Business planning and marketing. if you are growing yellow perch in Planning the personal support base. can provide key information essential to There is a saying: “You cannot make Wisconsin, you could expect a minimum While commercial aquaculture is pro- making your business a success. money raising fish.” Aquaculture is like of two years before you produce any moted by the Wisconsin Department of However, you must know how to interpret dairy farming—you not only need to product. Agriculture, Division of Consumer the information correctly. For example, a produce the product, you have to sell it Carefully assess accurate information on Protection (see the references listed at researcher’s success in growing a certain for more than it cost to produce. the product’s market and current market the end of this publication) it is important species under research conditions should Each individual must decide how much trends. Do not rely upon figures quoted to clearly understand the kind of govern- not be interpreted as evidence that the profit is acceptable. To determine profit, by those promoting the industry. Find out ment and private support available if you fish can be grown under less controlled you will need to evaluate production what people will pay for your product. invest in such an enterprise. Those conditions at a profit. involved in traditional agriculture know costs, the costs of marketing the product Generally speaking, one of the advan- that appropriate feeds, a neighbor’s Investors should continually remind (including getting it to market ) and its tages of aquaculture is that relatively few plow, the local vet and the county agri- themselves that the researchers devel- value in the marketplace. You need to people are involved in it. But the market cultural Extension agent are available to oping better aquaculture techniques are understand that aquaculture is a rela- in your area may be highly competitive assist them as needed. That level of often enthusiastic about their new find- tively new agricultural business in the or may need to be developed. Because infrastructure is not yet available to ings. Also, research presentations are U.S. and definitive information is not aquaculture is a small industry, many those investing in aquaculture. usually narrow in scope so one or even readily available on the production costs producers do their own marketing and a few presentations are not likely to tell (dollar investment) and/or market values transport their product to the market. You may need to contact individuals you everything you need to know to rear (dollar return) for many fish species. across the state or country to obtain the Developing a market takes some skill the species successfully. Accordingly, rough estimates of invest- same kind of help available locally to and may require considerable time. In ments and returns are often used for those in traditional agriculture. Touch base Presentations and published information fact, skill in developing the market may planning purposes. When using such with the many people with whom you will is often provided by for-profit consultants be just as critical to success as produc- estimates, a sound business plan should need to work before you invest. Getting to and persons selling equipment and sup- ing the product. Before investing you’ll be conservative; that is, the cost figures know people in the business well enough plies to the industry. Although such infor- want to know who will buy the product should range toward the high side and to work with them on marketing, buying mation may be honest and accurate, and what price they are likely to pay. the returns should range to the low side. large quantities of food at a lower price or keep in mind that the livelihood of the You will also want to learn about the sharing equipment helps reduce your source depends on your purchases. It is You will want to look at alternative pro- long-term market projections for your costs, increases production and the price essential to get the latest information duction methods not only in terms of the potential product. from several sources covering the range amount and quality of the product pro- you get for your product. In addition to Plan ways to develop the market for the of important topics. duced but in terms of production costs. Wisconsin Aquaculture Association various products you could raise. The Production costs include the expense of members, get acquainted with other pro- After you have gathered, summarized cost of transport equipment, marketing pond construction, water management ducers in your area, those who sell prod- and reviewed the information, ask materials and the time, travel and other (pumping and aeration), animals for ucts you may need, aquaculture research another key question: Is anyone else costs associated with market develop- stocking, feed, harvest equipment, scientists in the region and local operating this type of business success- ment should be included in the business chemicals or fertilizers and outside help. UWÐExtension, DATCP and DNR staff. fully? If the answer is no, you will want prospectus. You will want to develop a Do not overlook insurance, office sup- You will also find a wealth of information to find out why. If the answer is yes, it plan to expand production and the plies, technical services and equipment on the Internet (see references). suggests the species can be raised prof- product’s market over a several year maintenance. For most businesses, itably in Wisconsin. The next step is to period. Contact your county Extension there are start-up costs to cover the find out all you can about how the suc- office for help in developing a business operation’s expenses before the first cessful businesses operate. plan. crop is brought to market. For example, 40

MANAGING WISCONSIN FISH PONDS

Like traditional agriculture, the success Approaching the planning process as a Planning the financial needs. The of many aquaculture businesses in family promotes development of oppor- soundness of a business plan and Water temperature Wisconsin depends on the commitment tunities that might otherwise be over- prospectus will considerably influence of an entire family. If the kind of opera- looked. For example, one family was the financial resources available to you. and species selection tion you envision involves other family interested in buying a property equipped Contact the Wisconsin Department of The choice of fish species to raise is members, it is important to include them with a coldwater fish pond. However, the Commerce for information on low-inter- usually dictated by market; in other in the planning process, making sure pond could not make a profit if it was est loans. The amounts to be borrowed, words, select species you can sell at a they understand the business and their managed for food fish production. After the interest rates and the risk associated profit. From a biological perspective, the roles in it fully . some careful planning, the family real- with borrowing should all be assessed most important criteria for selecting ized that the property could be commer- carefully as part of the planning process. pond species is water temperature. cially profitable if fee-fishing on the pond To reduce risks and the cost of bor- Simply put, the temperature of a pond was paired with the operation of a bed rowed money, investigate a variety of dictates which species will survive and and breakfast. The family members scenarios. It is not uncommon for grow well. decided this was something they could someone new to aquaculture to start Ponds in most locations have an annual commit to together. Approaching the small by initiating a low investment pilot temperature cycle that depends on the planning process in this manner is project before making a major invest- climate. For example, the water temper- important to success. ment. This approach reduces risk and atures in most Wisconsin ponds are start-up cost while increasing the aqua- below 45ûF from December through culturist’s hands-on experience. March and range from 65ûÐ85ûF from June through September. The growth rate of fish depends largely on temperature, so it follows that the growth of fish depends on the season and does not occur uniformly throughout the year. When considering species and climate, a primary goal should be to keep water temperatures as near as optimal for the species’ growth as possible. A general rule of thumb for commercial aquaculture is that the growing season should be at least 180Ð200 days per year. However, each fish species has a maximum temperature that cannot be exceeded for even a short time without causing serious disease problems and heavy losses. Some warmwater fish also have a minimum temperature below which they cannot survive. 41

MANAGING PONDS FOR COMMERCIAL FISH PRODUCTION

In Wisconsin, only very deep ponds or Groundwater also contains relatively few lands can also be considered potential those with substantial groundwater input Site selection nutrients, pollutants or unwanted organ- water discharge sites. remain cold enough to raise coldwater The source of the water is a main con- isms. In many or most locations, Regardless of the factors above, all new species like trout and salmon throughout sideration in selecting a site for pond however, groundwater must be pumped ponds should be subject to the best rea- the year. Most other Wisconsin ponds aquaculture. into ponds, adding additional expense. sonable management practices to mini- simply get too warm in the summer to Compared to the other methods of fish Permits are needed from the DNR to mize the discharge of potential pollu- support coldwater fish. Cool water culture, ponds require a moderate operate high-capacity wells. tants. Settling ponds are very effective species, such as yellow perch, walleye, amount of water. On average, pond Surface waters such as rivers and lakes at minimizing the chemical and biologi- northern pike, muskellunge and some culture requires about 50 times more can often be used without pumping, but cal effluents discharged from ponds and types of baitfish are probably the water to rear each pound of fish than can vary greatly in temperature through- are relatively inexpensive to build. species best suited for Wisconsin pond recirculation systems. Flow-through out the season, and may contain The land itself is an important considera- culture. systems, in turn, require about 50 times unwanted chemicals and organisms. tion for selecting a site for pond aquacul- For these coolwater fish, the water tem- more water to rear each pound of fish You should also consider that diverting ture. Before discussing the relationship perature should never exceed 80ûÐ85ûF. than do ponds. To estimate the amount too much water from a stream can alter between the land and ponds, however, it Well-designed ponds should be able to of water needed for pond culture, keep its temperature and flow, thus changing should be emphasized that the cost of meet this criteria, and a growing season in mind the following calculation: At a the species that it supports. building a pond is often the largest single of 180Ð200 days is possible for coolwa- continuous flow rate of 50 gallons per A third source, which has yet to be used capital investment made in the develop- ter fish, at least in the southern part of minute it will take approximately 22.6 in Wisconsin, is the heated discharge ment of a pond-based fish farm—more the state. You can raise some warmwa- days to fill a one-acre pond to a depth of from industry, particularly facilities that expensive even than purchasing the ter fish, such as catfish and bass in five feet, assuming that no water is lost generate electric power. This source has land. Accordingly, the cost of construct- Wisconsin ponds, but the growing through seepage or evaporation and the potential to extend the growing ing the pond will have a major impact on season for warmwater fish is much none is added via rainfall or runoff. season to 365 days per year. the farm’s ultimate profitability. shorter than in southern states. The two primary sources of water for Water discharge is another major factor Pond construction costs are directly Accordingly, pond culture of warmwater ponds are groundwater and surface to consider when you select a site for a related to the amount of material that fish is more economical in the South water; either can be used. Ground- or commercial fish pond. Most commercial must be moved, as well as how often than in Wisconsin. well water has the advantage of a rela- ponds discharge water from time to and how far it is moved. The cheapest tively constant temperature (ranging time, or at a minimum must be drained way to move earth is with a bulldozer or from about 44ûF to 52ûF in Wisconsin); occasionally (such as at harvest time). a self-loading earth mover, which might therefore it can be used to cool ponds in The DNR regulates these discharges. typically cost $0.75Ð$1.50 per cubic the summer and to warm ponds and The regulations vary and depend on the yard. It is more expensive to use a back minimize ice buildup in the winter. species and quantity of fish produced, hoe, and it costs even more if the soil the amount and type of nutrients dis- has to be moved long distances with charged, and the water quality of the dump trucks. This may cost upwards of receiving waterway. For example, the $3Ð$5 per cubic yard. regulations and restrictions for discharging into trout streams with outstanding water quality are generally much more stringent than for discharging into large warmwater rivers. Wetlands and crop- 42

MANAGING WISCONSIN FISH PONDS

Land requirements vary greatly depend- Wisconsin under appropriate conditions, Ponds built for commercial aquaculture Fingerling game fish. Small fish fry and ing on the type of pond you want to a 3- to 5-acre levee pond suitable for are generally shallower than recreational fingerlings of many species depend on build. Construction of the three types of aquaculture can be built for $3,000 per ponds, primarily to reduce construction zooplankton and/or phytoplankton as ponds—excavated ponds, impound- acre or less; a 1- to 2-acre pond can be costs. If aquaculture ponds will be used their initial food source. Fingerling ponds ments or watershed ponds, and levee built for approximately $6,000 per acre. year-round, they should be a minimum are often fertilized to increase the ponds—are described in Chapter 3. of 7 feet deep. This helps prevent win- amount of plankton available and Excavated ponds are being used suc- Pond design terkill and also reduces excessive thereby the number of fish that can be cessfully for commercial aquaculture in warming during summer hot spells. raised. Wisconsin, but they may not be the best Smooth-bottomed ponds with an ade- Inorganic fertilizers including liquid or and construction quate slope from the shallow to the choice for commercial fish farming. They Ponds used for aquaculture in soluble phosphorus and nitrogen stimu- deep end allow for complete drainage are expensive to build and difficult or Wisconsin can range in size from less late phytoplankton growth. Organic fertil- and easy fish harvest. See Chapter 3 for impossible to drain, thereby impeding a than 1⁄4 acre to more than 5 acres. izers, such as alfalfa, soybean meal or more detail on levee pond construction. number of pond management strategies Larger ponds are less expensive to build manures stimulate phytoplankton growth important to commercial fish culture. per acre, but ponds larger than 5 acres to some extent, but also promote the Watershed ponds are currently used to get progressively more difficult to Managing for growth of bacteria and protozoans, raise fish in some parts of the country, manage. One problem with very small which in turn are consumed by zoo- but are not commonly found in ponds is that water quality and other different types of fish plankton. Often a combination of organic Wisconsin. They can be built only in factors change more rapidly than in Trout. Wisconsin’s aquaculture has his- and inorganic fertilizers are used. specific locations, and usually have an large ponds (see Chapter 3). On the torically revolved around trout produc- The optimum amount and frequency of irregular shape that can make them diffi- other hand, problem conditions in small tion. Most trout production takes place in fertilization varies greatly from pond to cult to manage. Construction costs, ponds can be more rapidly corrected areas with high water flow using flow- pond, depending on the pond’s natural however, can be quite low. than in large ones. Normally, smaller through raceway systems. These fertility. Ponds used by the University of Levee ponds are the most common type ponds are best suited for raising finger- systems allow high densities of trout to Wisconsin Aquaculture Program at the of pond used for commercial fish lings, small or bait fish, while large be raised using intensive artificial Lake Mills State Fish Hatchery are fertil- farming. They are well-suited for aqua- ponds are better suited for growing large feeding programs because the water ized weekly with 50Ð250 pounds of culture because of their relatively low fish. flow removes waste rapidly. Ponds are soybean meal and 5Ð10 pounds of 54% construction costs and because they The exact shape of a pond is often used for grow out, holding fish and fee inorganic phosphorus and 46% inor- can be built with regular shapes and determined by the topography and prop- fishing. Pond management for commer- ganic nitrogen per acre. Take care not to sloping bottoms to permit complete and erty boundaries of the land. Most aqua- cial fee fishing operations is somewhat over-fertilize ponds, as this will deplete rapid draining. The best location for a culture ponds are rectangular. Square similar to the techniques described in dissolved oxygen. levee pond (those where construction ponds are somewhat less expensive to Chapter 7 and will not be treated further costs are lowest) is a flat area with a build than rectangles, but rectangular here. deep layer of clay subsoil. For any type ponds, particularly if they are large, are of pond, plastic liners can be used easier to manage. instead of clay to prevent seepage, but pond liners typically cost $10,000Ð$20,000 per acre or more. In 43

MANAGING PONDS FOR COMMERCIAL FISH PRODUCTION

The number of fingerlings or small fish In several trials, University of Wisconsin In general, intensive aeration devices that can be produced depends on the researchers successfully raised 4,000 Water quality and harvest are becoming more popular in pond species as well as fish size at harvest. pounds of yellow perch per acre while Oxygen and aeration. One of the most culture because they can increase fish For yellow perch, 200,000 fingerlings limiting the amount of water added to important routine management proce- production. It is important to recognize, per acre can be produced if the fish are the pond to the minimum needed for dures of pond culture is to regularly however, that most oxygen in a pond is 3 harvested at ⁄4 inch. Many walleye temperature control. In another trial they measure dissolved oxygen concentra- not used directly by the fish but rather hatcheries average 80,000Ð120,000 fish raised 10,000 pounds per acre using tions just before sunrise, particularly by bacteria, plankton and plants. 1 per acre if the fish are harvested at 1 ⁄4 sufficient flow-through to exchange the when potential dissolved oxygen deple- Aeration and water circulation systems inch. When perch and walleye are har- entire volume of the pond every 2Ð3 tions are anticipated. Because of high provide several significant benefits to vested at 2 inches or more, the number weeks. fertility in commercial ponds, regular pond culture. First, because of the large of fish drops to 30,000Ð50,000 per acre Bait. Fish bait production represents the oxygen monitoring is much more critical quantities of nutrients added to them, or less. The fingerlings of walleye, large- largest aquaculture business in the than in recreational ponds. ponds used for intensive aquaculture mouth bass, smallmouth bass and other state. Bait producers grow approxi- Many types of mechanical aerators are occasionally suffer from dissolved species are usually marketed to organi- mately one-third of commercially sold used in pond culture. Some devices are oxygen depletion. During extreme situa- zations that plant them in public and bait fish. Two thirds is harvested from used primarily to circulate the water in a tions catastrophic fish losses result if private lakes. the wild. Baitfish that are grown may pond, others provide continuous active remedial action is not taken. Second, Grow-out. When the fish are 3⁄4 inch to have several advantages, such as aeration and others are of the stand-by without top-to-bottom water circulation, 11⁄2- inch long, some species learn to increased uniformity and better health type, used only under emergency condi- ponds frequently stratify. Although strati- accept commercially available formu- and “shelf life,” compared to those that tions when dissolved oxygen is depleted. fication can be desirable in recreational lated feeds. For larger fish, a floating are harvested from the wild. The amount ponds to increase habitat variety, in diet is a great advantage in pond culture of wild harvest versus production varies highly fertile commercial ponds the because you can readily observe the with the species. For example, suckers water at the pond bottom often loses all feeding response of the fish and avoid are hatched from eggs and the fry overfeeding. Some fish species, like planted in coolwater ponds or raceways. yellow perch, readily accept floating Fathead minnows are typically har- feeds only if they are fed when there vested from wild ponds but the ponds isn’t much daylight (near dusk and are managed somewhat similarly to dawn). those used for fingerling gamefish. The Currently there is little definitive informa- potential for using existing ponds lowers tion on how many pounds of fish can be the cost of bait production. raised per acre in Wisconsin ponds. These limits are determined by the maximum amount of food that can be put into a pond before dissolved oxygen is depleted. Catfish farmers in the South typically raise 4,000Ð5,000 pounds of catfish per acre. 44

MANAGING WISCONSIN FISH PONDS its oxygen. Under these conditions, Harvest methods. Several methods are For several reasons, commercial fish aerobic decomposition of waste prod- commonly used to harvest aquaculture ponds should be completely harvested, ucts, which is essential for maintaining ponds. For a complete harvest, conduct drained and allowed to remain dry for a the high productivity of aquaculture a drawdown along with seining or period of time at least once every ponds, does not occur. Third, in northern capture in internal or external catch several years. First, complete harvest climates aeration is used to keep ponds basins. Catch basins are used to allows for an accurate inventory of fish. partially ice-free and to prevent winterkill. harvest small fish or fingerlings. The use Second, drying eliminates many disease Adding water. At a minimum, some of internal basins is usually restricted to and other organisms such as snails, water is added to aquaculture ponds to small fish or fingerlings. Ponds that salamanders and crayfish, that spread make up for water lost through seepage remain full can be partially harvested disease or can otherwise be detrimental and evaporation. Water flow-through is using seines, trap nets or gill nets. A to fish culture. Third, the organic mate- also used to minimize ice formation and common technique to selectively harvest rial accumulated on the pond bottom thickness in the winter. In summer, it is large fish from ponds is to use a size- decomposes quickly when exposed to used to reduce pond temperatures selective seine in a partial pond draw- air. If the buildup is excessive it can be during hot spells. Depending on the down. mechanically removed. amount of water available, flow-through Regardless of the method used, it is can also be used to reduce the overall important to recognize that harvesting nutrient loads in ponds. procedures are very stressful for fish, due to physical and mechanical abra- sions as well as rapid changes in water quality. If harvested fish are to be kept alive, every effort should be made to minimize the stresses of harvest. chapter10 Stocking predators Destroying spawning beds chapter10 Fish population Some people reason that stocking north- Some people control sunfish populations ern pike, muskellunge or walleyes con- by destroying the fish embryos, either by trols stunted panfish. After numerous raking or trampling the nests. A large control attempts however, there are no well doc- percentage of the nests must be ond owners sometimes need to umented success stories with this destroyed for this technique to be effec- reduce or eliminate fish populations approach. tive. Because most sunfish species are before moving forward with manage- Bluegills and other sunfish have deep prolific and spawn over a long period, ment plans. Older ponds may P bodies with a spiny fin along their backs. this method requires considerable effort. contain undesirable fish, such as carp, Predators need large throats to swallow It is simple, however, and can be effec- suckers or bullheads. A trout pond may them. Even largemouth bass that attain tive in delaying or reducing overabun- contain unwanted warmwater fishes. A the necessary throat size at an earlier dance problems, particularly when used pond that has suffered a winterkill may age than other predatory fish usually do with other methods such as properly have a predator-prey imbalance. Or not keep bluegill populations in check in managed largemouth bass populations perhaps panfish are overabundant and Wisconsin ponds. and/or seining, trapping or electrofishing. stunted. When such situations occur, various methods exist to alter fish popu- All piscivorous (fish-eating) fishes, includ- lation structure or to remove fish popula- ing the largemouth bass, prefer to eat Seining tions completely. cigar-shaped forage fish without spiny Fish can be removed by drawing a fins. Thus, they tend not to eat many seine, or large vertical net, through the panfish until more favored prey, such as water (figure 23). Seining is usually Angling intensively minnows, or young largemouth bass done by two people, each holding an A common perception is that intensive become scarce. Having northern pike in upright that supports the ends of the net. angling brings fish populations into bass bluegill ponds often results in more Floats keep the seine top at the water balance. That idea is fine in theory, but it predation on bass than on bluegills. Even surface, and weights hold the bottom seldom works except in very small though they also have spines, bass are edge on the pond bed. The seine must ponds. The overabundant fish are easier for pike to swallow. stay tight along the pond bed, or fish will usually not large enough to catch, or Introducing large predators rarely con- escape underneath. Therefore, the seine else they are an undesirable species trols carp and suckers in ponds. By the should be deeper than those portions of that no one wants. The time required for time these fish become a problem, they the pond where it is to be used so that it intensive angling is also substantial. To are usually too large and numerous to will “belly” without being pulled away prevent overabundance or reduce the be controlled by piscivorous fish. from the pond bed as it is drawn along. chances that undesirable species will be introduced, follow the harvest sugges- tions outlined in Chapters 7 and 8. 46

MANAGING WISCONSIN FISH PONDS

For seining, the pond bed should be Use nylon netting. It is most rip-resistant To salvage bass, large panfish or selecting for fast growing fish while smooth and free of snags such as rocks, and lasts a long time with little mainte- minnows and return them to the pond making room for growth to occur. logs and brush. Dense weed beds also nance. However, sunlight rots nylon uninjured, leave a pocket in the seine in Subsequent generations of fish should impede seining. Water-level drawdown quickly so do not leave it exposed to the shallow water at the end of the haul, grow faster if you use this strategy. (described later in this chapter) can aid sun. For removing small panfish, use rather than dragging it ashore. Rolling or If possible, keep seining until about 80% 1 1 seining by drawing the water away from netting with mesh ⁄4- to ⁄2-inch long. sandwiching the net can bruise fish and of the pond’s estimated summer weed beds and other shore-zone Smaller mesh isn’t necessary; in fact, it remove their slimy covering and scales, poundage of panfish is removed. obstructions, as well as decreasing the is harder to draw through the water. thus increasing their susceptibility to Estimating the total weight of panfish in a area and depth to be seined. If the seine spans the pond’s width, two disease. Minnows are very prone to pond is difficult, and you may wish to Small seines are especially useful on people can draw it the length of the such injury—especially in hot weather. consult a professional biologist for assis- panfish during the spawning period. pond in one sweep. This is the most effi- To “thin out” populations of bluegills or tance. Minnow seines, 15Ð40 feet long and cient method. If the pond is too wide for other sunfish, seine frequently in the Seining is hard work but can be fun. It available at sporting goods shops, are that, pull the seines out from shore in an warm season but after the young bass provides useful information about the used along shorelines to remove panfish arc—using a boat if needed—and back have developed enough so that they can fish population. In your pond logbook, fry and fingerlings which concentrate to shore. Draw the arc tighter and into withstand capture without injury (when record the effort invested and the there. Longer, deeper seines allow shallow water or on to the shore. Draw they are approximately 1 inch long). numbers of fish removed. Also record greater coverage. Ready-made or the seine so that the bottom edge stays Remove panfish that are less than 6 the numbers of young and adult bass custom-built seines can be ordered from ahead of the upper edge. Many fish inches long, and return those larger than and larger panfish that were released, various suppliers. escape if a seine rolls up at the bottom 6 inches plus any bass or channel along with information on the forage as it is pulled along. catfish (not bullheads!). This amounts to base. Remember that bass and carp, Figure 23. A seine and bag seine. especially older ones, are adept at avoiding nets. When you seine up only Seine Bag seine small bass or carp, don’t conclude that top panel prevents big ones aren’t there. fish from jumping

bottom line with lead weights top line with floats

bottom line drawn ahead of top line 47

FISH POPULATION CONTROL

trapping success. This method adds Live-trapping nutrients and is often not necessary. Electrofishing Drawing down the water level Fish traps may be useful for reducing Place traps in shallow areas where Fish are sensitive to electricity and are Draining represents a good method of populations in ponds where seining is small fish gather. Set the traps at right “galvanotactic.” That is, they move in the population control in ponds that can be difficult. You can make an effective trap angles to the shore in water that is just direction of direct current (DC) electricity. drained easily. Not only are undesirable 1 using ⁄4- to 2-inch hardware cloth on deep enough to cover them. Run the Modern electrofishing equipment, operat- fish easily destroyed but desirable fish wooden framing (figure 24). lead into shore. Fish moving along shore ing on this principle, makes it possible to can be saved and restocked. If the pond Use traps with or without a “lead.” A lead will follow the lead to the opening and capture large numbers of fish with elec- is formed by a dam with a proper water is like a fence that typically extends from enter the trap. For panfish thinning, up tricity without injuring them. The fish swim control structure, draining should be the center of a trap’s mouth to the to 10 traps per acre may be needed. towards the probes of the shocker where easy. With the appropriate bottom slope operators capture them in dip nets. the fish will come to the outlet area shore. It guides fish moving along shore Remove the same amounts and sizes of into the trap. A seine or seine material Because electrofishing works in areas of where they can be seined and sorted as fish as described in the section on relatively heavy cover and is effective in the water level drops . (with floats and weights attached) can seining. Remove the fish from the traps be attached to the mouth of your collecting small or large fish, it can be Low head pumps or a siphon can be daily to avoid stress and turtle predation very useful in population control. wooden-framed traps to make a lead. on the desirable fish that you will want to used in some ponds. Even if the pond Hanging gauze bags of bait, such as return to the pond. Bear in mind, however, that the electrical cannot be completely drained, reducing bread, oatmeal, dog food, soybean cake current required for electrofishing can be the water level in late fall so the pond or cottage cheese in traps increases the lethal to humans. This technique is not freezes to the bottom serves to control catch. You can experiment with bait to effective in soft water and should not be unwanted fish populations. Seining can determine whether it improves on your attempted by the pond owner using be used to capture wanted fish. The homemade equipment. We recommend length of time needed for the pond to contacting one of the many private con- refill should be carefully considered Figure 24. Various kinds of fish traps. sulting companies to evaluate your situ- before a drawdown. ation and carry out the task. In addition, Contact the DNR district fisheries expert be sure that whomever you hire uses whenever you are considering a draw- modern, safe equipment and is covered down or other water release from your by insurance. pond. Permission from the DNR may be required to drain or refill a pond. Fish cannot be discharged with the pond water to other waters except under special permit from the DNR, as this constitutes stocking. Unauthorized intro- ductions of fish can disrupt natural fish populations to the detriment of the public interest. 48

MANAGING WISCONSIN FISH PONDS

Screening the outlet and/or the pond Partial drawdown can concentrate fish Only two chemicals, rotenone and discharge to prevent fish from escaping so that predators like bass can become Fish toxicants antimycin, are legally registered for use is often necessary. Take care to ensure more efficient. This tactic depends on Another method of reclaiming ponds as fish toxicants. The commercial brand that downstream waters or properties having enough predators to consume a from panfish overpopulation or the pres- names and best local sources can be are not damaged by flooding, erosion or large portion of the unwanted fish. With ence of undesirable fishes is to kill all obtained from your DNR district offices sedimentation. It is the owner’s respon- drawdown, seining is also more efficient. fish with a specially formulated chemi- (see references). Federal law requires sibility to release the water in a judi- Conducted properly, a partial drawdown cal—a fish toxicant* or piscicide. Then that only legally registered fish toxicants cious, reasonable and prudent manner. destroys overabundant aquatic plants. start anew by restocking after the water be used—and that they be applied in Total drawdown is used to eliminate all Predatory reduction of small fish is most has detoxified. Some fish can be sal- strict accordance with instructions on the fish from the pond. A special effort must effective if the partial drawdown is done vaged before or during treatment and product label. In Wisconsin, only a be made to find fish that may take for a month or more in July or August. kept alive in other water for restocking. licensed applicator may apply these refuge in residual puddles. Spot applica- Carefully consider whether a partial The amount of chemical used and the chemicals. A DNR fish farm environmen- tions of fish toxicant chemicals may help drawdown will increase the danger of cost can be reduced if the chemical tal permit coordinator will be able to help attain a complete kill. Desirable fish, oxygen depletion and whether a treatment is made in combination with a you identify licensed applicators. such as large bass, can usually be sal- summer drawdown will aggravate partial drawdown. Because discharge of The amount of toxicant needed for total vaged and kept alive for restocking if aquatic weed problems. fish toxicants into public waters is unlaw- removal of fish may depend on several other water for holding them is available. ful, partial drawdown may be required factors, including the kind(s) of fish to be for ponds that discharge into public killed, the pond volume, water tempera- waters. ture, water hardness, light conditions, Partial treatments to remove only certain abundance of aquatic plants and species or sizes of fish, or to merely amount of other organic matter present. reduce rather than eradicate the population, can be done by applying special dosages or by treating a portion of a large pond. However, partial treatments are usually very difficult and generally ineffective.

* The chemical is absorbed into the fish’s gills and kills by interfering with respiration. This does not mean that the pond is made poisonous for humans, for any vertebrate animals other than fish, or for most invertebrates when used at the dosages prescribed for killing fish. occurs under natural conditions as chapterchapter1111 Kinds of plants small clumps about 6 to 8 inches tall. Aquatic plants It is important to know the kinds of Under some conditions it forms a plants in your pond so you can interpret continuous stand several feet high. changes and prescribe the appropriate Overabundant chara is a common and their control plant management measures. Pond pond problem. quatic plants play essential roles in plants are separated into two general Rooted, leafy plants occur in three a pond. They provide oxygen and groups: algae and rooted leafy plants. general forms: produce the pond’s food web. They Algae are single-celled plants or also furnish cover for fish and 1. Submergent (or submersed) plants A colonies of cells lacking true roots, grow rooted in the bottom with most support organisms that fish eat. leaves or flowers. There are three types growth beneath the water. Some A few well-spaced plant beds provide of algae: have a few leaves floating on the some prime fishing spots and certain 1. Planktonic algae drift free in the surface. Many thrust blossoms types of vegetation attract waterfowl and water, are usually microscopic and, above the water. Common submer- other enjoyable wildlife. when abundant, make the water look gents are pondweeds Plants easily become overabundant. murky. Their coloration ranges from (Potamogetons in many varieties), The disadvantages of too many pond blue-green to green, to yellow and coontail and waterweed (Elodea). plants include: brown, or even gray. 2. Floating plants are characterized by Unfavorable build-up of organic 2. Filamentous algae are threadlike or having all or most of their leaves and matter on the pond bed netlike. They may be small and free- flowers at the water’s surface with Nighttime depletion of oxygen drifting, but often occur as “mossy” free-dangling roots in the water or growths on rocks or thick mats float- attached in the pond bed. Duckweed Daily changes in pH that are unfa- ing on the pond surface. Most scums and water lily are examples. vorable to fish and other organisms and mats contain bacteria and fungi 3. Emergent plants (or emersed Too much cover for small fish to hide as well as algae. plants) such as bulrush, cattail and from predator fish, resulting in small 3. Chara algae, also called muskgrass arrowhead, have stems and leaves fish overpopulating the pond or stonewort, grow attached to the thrust above the water. These grow Interference with fishing, swimming, pond bed without true roots. They at pond margins and may extend boating and other activities—includ- have clustered needle-like projec- into the water several feet deep. ing seining to control fish populations tions and are often mistaken for leafy If less than a fourth of the pond’s plants. The two common kinds are surface is covered by plants, there is chara and nitella. When mashed likely no problem unless they interfere between the fingers, they feel gritty seriously with use of the pond. Even and give off a skunk-like odor. There more vegetation may pose no threat to is often a white or brownish crust of the welfare of the fish. lime or “scale” on the plants. Chara 50

MANAGING WISCONSIN FISH PONDS Algae Submergent plants

Bladderwort (Utricularia species)— Naiad (Najas species)—Leaves occur Waterweed or elodea (Elodea Planktonic algae (many species)— Tiny oval bladder near bases of finely as opposite pairs or whorled, very canadensis)—Flat, thin leaves grow in free-floating, usually minute, may be divided leaves. Often floats free under narrow, toothed on edges. Commonly opposite pairs or whorled. Commonly single-celled or found in colonies. When the surface without roots. Found in cold, grows in water 1Ð4 feet deep but some- used in home aquaria. abundant, may color the water murky acid water. Flowers yellow or purple. times much deeper. green to brown—or in extreme cases, pea-soup green. Filamentous algae (many species)— long strands, filaments or nets. Often form floating mats. Chara algae (muskgrass or stonewort) —Upright plants attached to the pond bed. Roughly resemble rooted, flowering plants, but are really algal colonies with Water star grass (Zosterella dubia)— stems and whorled branches. Each joint Looks like some narrow-leaved pond- of the stem consists of a single cell. Water milfoil (Myriophyllum weeds (Potomogeton), but leaves lack a Even-lengthed branches are clustered at species)—Leaves whorled on stem and mid-vein. Flower is yellow, star-like. each joint. Chara algae occur in shallow divided feather-like, not forked as in Hornwort or coontail (Ceratophyllum water having high alkalinity. They are coontail. demersum)—Whorls of leaves at joints rough to the touch. Feels gritty and of stems. Leaflets forked once or more, gives off a skunk-like odor when have toothed edges. Leaves densely crushed between the fingers. crowded near tip of stem. Grows in hard water.

Wild celery (Vallisneria americana)— Light green, ribbon-like leaves may be up to six feet long (but usually much less), with tips floating on the surface. 51

AQUATIC PLANTS AND THEIR CONTROL Floating plants

White (fragrant) waterlily Leafy pondweed (Potamogeton (Nymphaea odorata)—Round, floating Curly leaf pondweed (Potamogeton foliosus)—Leaves, ribbon-like, about leaves grow to ten inches in diameter, 1 crispus)—Leaves alternate; has finely ⁄16-inch wide. Lacks sheath at base. split to stem at center, often purple on toothed, crinkled or puckered edges. No the underside. Flowers are showy, floating leaves. Flowers and seeds in usually white but sometimes pink. spike at tip extend above water for fertil- Flowers open from morning until shortly ization. Grows in fertile hard water. after midday. Introduced from Europe.

Duckweed (Lemna species)—Tiny, free-floating bodies are flat and round or lobed, oatmeal-sized or smaller; often Floating leaf pondweed mistaken for algae. Barely visible roots (Potamogeton natans)—Two types of dangle thread-like. Sometimes several leaves. Underwater leaves are narrow, plants are attached. Masses of this grasslike and appear as stalks. Floating Sago pondweed (Potamogeton plant accumulate as a scum blanketing leaves are oval to heart-shaped, each pectinatus)—Fine, thread-like leaves quiet shallows. As scum dies, it turns with a notched base. Flowers and seed that fan out with a sheathed base. No yellowish or whitish. on a spike. floating leaves. Stems usually multi- branched. Tubers grow from horizontal roots. 52

MANAGING WISCONSIN FISH PONDS Emergent plants

Arrowhead (Sagittaria species)— Burreed (Sparganium eurycarpum)— Cattail (Typha latifolia)—Leaves reach Chairmaker’s rush (Scirpus ameri- Leaves usually arrow-shaped, but some Leaves, long, erect, ribbon-like, usually to 6 feet tall, ribbon-like, tapering to a canus)—Horizontal rootstocks give rise may be tongue-like or ribbon-like, espe- 1Ð3 feet high. Stems bear male flowers point. Flowers on stalks taller than to stems with triangular cross section cially at base of plant or underwater. at tip; female flowers below. Fruiting leaves. Male flowers at tips, female (but round in some bulrushes). Height Flowers white, petaled, whorled and heads are 1-inch round balls with many flowers below. The plants grow at the usually 2Ð3 feet. Flowers and seeds on grow near tip of a stalk. Fruits are tightly seeds. water’s edge, but commonly also to spikes along stem near tip. The plants packed balls of seeds. depths of 3Ð4 feet. may form dense stands after several years. 53

AQUATIC PLANTS AND THEIR CONTROL Pond plant biology Understanding how pond plants grow helps in managing nuisance plant problems. All plants need water, light, a place to be, nutrients (fertilizers) and the right temperature. If any of these elements are in short supply, plant growth will be reduced or eliminated. Water smartweed (Polygonum amphibium)—Leaves eliptical, up to 4 Water is usually not a limiting factor in inches long. Stems upright or sprawling ponds. Although, as discussed in other in water or on mud banks. Deep pink parts of this publication, if a pond is flowers in spike at tip of plant. designed so it can be drained, draining or dewatering it can offer a useful plant management option. Light diffuses rapidly in water, so plant growth decreases as the light gets dimmer. The water’s clarity determines how quickly light dissipates and thus affects plant growth. In clear lakes and ponds, rooted plants might grow in water up to 30 feet deep. In very turbid or muddy water, rooted plants may not grow in water deeper than 18 inches. Rooted plants rarely reach the water’s surface where they become a nuisance in water deeper than 15 feet. Pond design as it relates to depth is important to managing the area where rooted plants grow. Although some green, rooted plants can Pickerelweed Rush Spikerush (Pontederia cordata)— (Juncus effusus)—Clumps of (Eleocharis species)— be found under the ice, rapid growth Leaves heart-shaped, similar to those of stems rise from stout horizontal root- Clumps of stems rise from shallow usually doesn’t start until water tempera- arrowhead but rounded at tip and stocks, grow 3Ð4 feet tall resembling roots, remain much shorter than rushes. tures reach about 60ûÐ65ûF. Algae are corners. Curving veins follow leaf margin. grasses and sedges. Greenish-brown Oval fruiting spike at end of stem. more tolerant of broader temperature Blue flowers that grow in a spike. flowers near tip of stem. ranges. Different species of algae may dominate the pond depending on water temperature. 54

MANAGING WISCONSIN FISH PONDS

Although not much can be done to strategy may change as new problems are easily killed by trampling or cutting manage temperature in an outdoor Managing the growth occur. the new shoots in springtime. Cutting pond, temperature is important for When deciding on a plant management cattail shoots in the fall so they freeze chemical weed control. Herbicides work of nuisance plants technique, consider not only how well under the ice is another effective control best when plants are growing. Water The best way to avoid plant problems is and for how long the technique works, technique. Both techniques may work on temperatures should be 60ûÐ65ûF before to design the pond so that there is little but also the environmental impacts, the other emergent plants. you use herbicides. area suitable for plant growth. This use limitations imposed by using or not You can simply wade in and uproot There is a direct relationship between usually means making the pond deep using the technique and the costs in many plants by hand. This works for cat- nutrient levels (primarily nitrogen and enough so that rooted plants can’t grow terms of both time and money. tails, rushes and other emergents when phosphorus) in water and algae growth. and nutrients don’t get into the pond to they are growing as isolated plants, as Generally speaking, the more nitrogen stimulate algae and other plant growth. Physically disrupting well as for submergent plants that you and phosphorus in the water, the greater Assuming you already have a pond with can reach. The first “weeding” of a well- the algae growth. Any method of reduc- a problem, the next best thing is to try to and removing plants established plant bed may be hard work, ing nitrogen and phosphorus in the pond adjust one critical factor—light, nutrients This method is one of the simplest and but repeated follow-ups prevent the situ- will limit this growth. and sometimes water—to limit growth of most practical, akin to weeding a garden ation from developing again. or mowing a meadow. Most aquatic Proper pond design and land manage- the nuisance plants. These techniques A scythe or hoe is useful for cutting plants are more fragile than garden ment around the pond is essential to provide the most long-lasting control. aquatic weeds in shallow areas. weeds, so physical control may be prevent excessive nutrient input. If your options are limited, you may have Caution: Wielding a blade underwater easier for water plants than for land Chapter 3 discusses these techniques. to control plants by physically removing can be dangerous! Always wear protec- plants. The relationship between nutrient levels or chemically killing them. You will tive boots! You can keep areas free of weeds by in the water and rooted plant growth is usually need to do this on a regular causing frequent disturbances, such as not as direct. Rooted plants get the basis. Consider it part of pond mainte- raking the pond shallows, or letting majority of their nutrients from the pond nance much like mowing is a part of swimmers trample beach areas. Cattails bottom. Therefore, it is more difficult to lawn maintenance. control nutrient availability to rooted Certain control techniques are more plants. Limiting nutrients in the water effective for certain species. Some tech- may cause rooted plants to spread niques are best suited for algae control because the clearer water will allow and others for rooted plants. This re- deeper light penetration and thus emphasizes the importance of knowing provide more area for plants to grow. the species that are causing problems. The type of plants in ponds often changes Eliminating one type of vegetation may even when the plants aren’t managed. make room for some equally bother- One type of plant replaces another. By some replacement. This phenomenon this process a pond vegetation problem takes place soon in some cases. For may alleviate itself or get worse depend- example, less than a month after cutting ing on the species involved. Nuisance or poisoning rooted plants, the area may growths of chara, for example, have been be clogged with stringy algae. You replaced by other plants that are less should keep records of vegetation bothersome—with no control needed. changes because your management Pulling plants out by hand is often the simplest way to control vegetation in shallow water. 55

AQUATIC PLANTS AND THEIR CONTROL

Cut plants will float and should be Mechanized harvesters are available in It is best to remove plants during the removed from the pond as soon as pos- a range of sizes. Small models, costing spring or summer because you can sible. Deposit them where the nutrients about $1000, can be mounted on a remove the largest number of plants and will not run back into the pond as the rowboat. These have cutter bars like still allow full recreational use of the plants decay. those on hay mowers. With this type of pond. The timing depends on your knowl- A rake can be used for uprooting, boat-mounted unit, weeds can be cut to edge of the growth habits of the plants in tearing loose and dragging out plants. a depth of about 4 feet. After the weeds your pond and your plans for the pond’s The head of a garden rake, fitted with an are cut, they are raked to a removal use. Often, the best approach in a small extra-long handle and manipulated from point on shore. Other weed cutters are pond is periodic trimming as in caring for a boat or while wading is suitable for manufactured as mower bars on small a lawn or garden. In new ponds, control reaching into deep water. A floating rake paddlewheel barges. These can operate plants by frequent hand or rake removal is less tiring for work near the surface. in very shallow water, as well as to before they become abundant. depths of 5 feet or so. They range in You can construct a floating rake from Harvested plants make good garden price from $2000Ð$20,000. Large har- an 18- to 20-inch, 2x2 board by driving a mulch, soil conditioner and composting vester units which draw plants onto the row of spikes two or three inches apart, material. The thin cell walls of aquatic barge as they are cut are available for then cutting off the heads. A bamboo plants break down rapidly and the result- upwards of $50,000. pole makes a good handle. It can be ing fine-textured matter is also suitable long, yet light. Hand-operated and Some plants are difficult to control with for spreading on lawns. power-operated weedcutters designed mechanized harvesters. Chara sinks for underwater use are available from when cut and is therefore hard to pick up. commercial sources, as are floating Milfoil, coontail and elodea are also hard rakes. to collect once they are cut. These kinds of plants spread by fragmentation. Each A log and barbed wire drag for removing For weed growth too extensive to cut piece cut and not picked up may become vegetation. with a scythe or rake, a log wrapped a new plant. In small ponds, removing loosely and stapled with barbed wire can them by hand or rake is probably prefer- be dragged through the pond behind a able to mechanically harvesting them. tractor driven along the shore. A heavy chain connecting the log to the tractor helps sink the log to the pond bed. Add more weight as needed. The log can be guided with a rope manipulated by someone on the opposite shore. The barbed wire log seems to be an improvement over the often recommended method of dragging bed springs. Weeds are difficult to remove A floating rake. from bed springs. 56

MANAGING WISCONSIN FISH PONDS Table 6. Plant susceptibility to drawdawn

Summer Winter Deepening the pond to control Water level drawdown Scientific name Common name drawdown drawdown vegetation Lowering the pond’s water level and Bidens beckii water marigold - I exposing all or much of the pond bed to Brasenia schreberi water shield D D You can renovate a plant-clogged pond air can have several favorable effects by dredging out the pond bed, or if it is Carex sp. or spp. —— I- and may cost little. Table 6 lists common dammed, by raising the water level to Ceratophyllum demersum hornwort V V aquatic plants that are susceptible to deepen the pond. One effect of greater Chara sp. or spp. muskgrass V V summer and winter drawdowns. Drying pond depth on aquatic vegetation is to Eleocharis acicularis needle spike rush I D kills many kinds of aquatic plants. It is put more of the bed at a level that is too preferable to conduct the drawdown in Elodea canadensis common waterweed V V dark for rooted plant growth. It is hard to winter when the freezing of plant tissues, Lemna sp. or spp. —— VV say what water depth will be critical to including the roots, gives more extensive Myriophyllum heterophylium various leaved water milfoil V V prevent nuisance growth of rooted and lasting control. Summer drawdown Myriophyllum sibiricum spiked water milfoil V V plants. That depends on the water is particularly ineffective on plants such Myriophyllum spicatum eurasian water milfoil V V clarity, the kinds of plants present and as coontail and elodea which grow as nutrient supplies. Maintaining a depth of Najas flexilis slender naiad V I free-floating fragments. Other plants 15 feet should greatly reduce problems. Najas guadalupenis southern naiad - D increase as a result of summer draw- Nelumbo lutea american lotus V V Dredging reduces the amount of nutri- down, and cattails or other emergents Nuphar advena yellow pondlily D - ents available to plants from organic can invade exposed mud flats. deposits in shallow water, and can Nuphar variegatum bull-head pondlily V D Where sediments are composed of soft create steeper side slopes where plants Nymphaea odorata fragrant waterlily V D organic material, drying consolidates seem to grow poorly. Polygonum amphibium water knotweed I V them, and you may gain several inches Potamogeton amplifolius large leaf pondweed - V Increasing the depth and volume of the or feet of pond depth. Drawdown can pond can have other beneficial effects also facilitate dredging. See Chapter 10 Potamogeton diversifolius water thread pondweed - I on nutrient levels and suitability for fish. for a discussion of drawdown techniques. Potamogeton epihydrus ribbon leaf pondweed - V Consider these in deciding whether the Potamogeton gramineus variable leaf pondweed - V A word of caution: If shallow water expense is justified. See Chapter 3 for a remains in the pond for much of the Potamogeton natans floating leaf pondweed D I discussion of the techniques, relative growing season, the extra light may Potamogeton pectinatus sago pondweed - V cost and environmental impacts of pond permit seeds or plant fragments to Potamogeton richardsonii clasping leaf pondweed - V deepening. sprout and take root. When the pond is Potamogeton robbinsii fern pondweed - D refilled, especially if the water level is Potamogeton zosteriformis flatstem pondweed - V raised too slowly, the plants may con- Scirpus americanus chairmaker’s rush - I tinue to grow and become a nuisance. Scirpus validus softstem bulrush I I To prevent this, draw the water down as Sparganium chlorocarpum —— VV far as possible, and when the drying Spirodela polyrhiza great duckweed - D and/or freezing has had its effect, raise Typha latifolia broadleaf cattail V V the water level rapidly. If plants have begun to grow in shallow pools, it may Utricularia purpurea purple bladderwort D - be advisable to destroy them by raking Utricularia vulgaris great bladderwort - D or other means before refilling the pond. Vallisneria americana eel grass - I I = increases with drawdown D = decreases with drawdown V = variable response - = indicates information unknown or unreported 57

AQUATIC PLANTS AND THEIR CONTROL

alum, used in combination (to maintain phorus from mud to water which occurs Discharging selectively pH) may be available to the pond owner, during winter stagnation. Running aera- Shading or coloring the water In a pond formed by a dam, designing as may zeolite, fly ash, powdered tors in the winter causes safety hazards Sheets of black plastic supported by a the outlet facilities so you can vary the cement and clay. from thin ice and open water—use care. floating wooden or styrofoam framework depth from which water is released may Selective discharge, pond flushing, nutri- can be used to cover parts of the pond help control water fertility. At certain Aerating the pond ent inactivation and aeration are tech- surface. Such a covering is anchored in times of the year when dissolved nutri- one spot for the 3Ð4 weeks needed to Pumping air into the depths of a pond niques designed to reduce algae blooms ents are more concentrated, discharge shade out plants beneath it, then moved and creating a rising stream of bubbles by limiting nutrients in the water. They water can be drawn from those depths to a new place. Shading with plastic is helps aerate a pond. You can do this will probably have little impact on rooted to reduce the pond’s total nutrient apparently effective on most submergent with an on-shore compressor that plants and may aggravate the problem supply. Possible adverse effects of nutri- plants (except chara) but not on emer- passes air through a hose to the of nuisance rooted plant problems by ent-rich discharge on downstream gents, and the device may be cumber- deepest part of the pond. There a increasing water clarity. These tech- waters should be considered. some and unsightly. special dispenser, such as an air stone, niques usually require a close estimate plastic foam block or metal baffle, of the nutrient “budget” in the pond. Special dyes are available (for example, Flushing and diluting the pond breaks the air into fine bubbles. The Before spending time, effort and money “Aquashade”) that temporarily color the It is sometimes feasible to remove nutri- rising bubbles draw water upward, on these techniques, you should consult water to cut off light and control plants. ent-rich pond water and replace it with causing the pond water to circulate from a competent limnologist to decide if they For dyes to be effective, you must main- “sterile” water. If enough water is avail- bottom to top and take on oxygen from will work in your pond. tain the recommended concentration in able, continual flushing keeps planktonic the atmosphere. More oxygen is gained the water. This can be difficult in ponds algae population low. Diluting nutrient- through the pond surface than from the Sealing and blanketing with streams or a lot of groundwater rich water may also alleviate algae stream of bubbles. With the water at the entering the pond. Dyes should be blooms. To accomplish this, truly nutri- pond bottom oxygenated, the surface of the pond bed applied early in the growing season ent-poor water must be available from a the pond mud is kept oxidized, holding To control rooted plants, pond beds can before plants reach the surface. well or elsewhere. The benefits of this phosphorus in an insoluble form and be covered with black plastic sheeting Sediment in the water reduces the effec- strategy will be brief, however, if the making it less available for growing weighted with gravel or rocks. However, tiveness of some dyes. Dyes should not source of the nutrients that caused the plants. research shows that the results of this be applied to ponds where the water is technique are short-lived. As soon as used for human consumption. problem remains. In the case of deep trout ponds, special sediment accumulates on top of the equipment (the hypolimnetic aerator) is Another method of shading portions of plastic, weed growth resumes. Black Inactivating phosphorus available. This brings the cool water of the pond is by planting trees on the plastic isn’t recommended unless you Introducing certain chemicals can the deep zone to the surface and back south and east sides of the pond so that are willing to continually manage the change dissolved phosphorus to forms during summer without allowing the cool they shade the water. Conifers are pre- area. less available to plants or can trap and water to mix with the upper layers. Thus, ferred because they provide year-long carry it down to the pond bed. The effect an undesirable warming of the deep Newer products made of fiberglass shade and don’t drop leaves into the of this action may be brief. Various com- waters is avoided. screening are commercially available pond. and effective. It is recommended that pounds of aluminum, iron, calcium and It may be especially important to aerate these products be removed periodically, other elements can be used. The chemi- the pond in winter. This keeps the area usually annually, and cleaned for them cals are typically broadcast as a powder ice-free and allows oxygen to move con- to remain effective. or injected as a slurry into outboard tinually from the atmosphere to the pond motor wash. Sodium aluminate and depths. It also reduces transfer of phos- 58

MANAGING WISCONSIN FISH PONDS

Most chemical treatments require increases the risk of killing fish and it may take much more copper sulfate to Herbicides and algicides that pond use be restricted after- other organisms. Most plant poisons kill the algae, yet the danger to fish may Killing pond plants with chemicals is wards (for example, no swimming, work best when water temperature is be much less. See your nearest DNR another form of treatment. Substances irrigation or fishing). Make sure you above 65ûF. biologist for locally recommended toxic to algae are called algicides. can abide by these restrictions. Carefully follow safety precautions dosages. Those for poisoning rooted, leafy water To use chemicals effectively and present printed on the product label. Don’t let Copper sulfate is best applied by dis- plants are aquatic herbicides. You may the least hazard to other life, you must the chemical reach crops and other solving the crystals in water and spray- need a permit from the Wisconsin DNR identify the kind of plant you wish to desirable plants or trees. Choose a calm ing the pond’s surface or by placing the or be certified by DATCP to use herbi- destroy, obtain the proper chemical, cal- day to avoid wind drift. Don’t use the crystals in a burlap bag and pulling it cides and algicides in your pond (see culate the volume of the pond and apply treated water for irrigation, agricultural through the pond until the crystals dis- Chapter 15 on permits and licenses). the proper dosage. Also, for personal sprays, livestock watering or swimming solve. Simply throwing copper sulfate Chemical treatments have the advan- safety, wear proper protective clothing. until the time period advised on the label crystals into the water may result in their tage of convenience, but consider the Use safe procedures for handling pesti- has elapsed. accumulation on the bottom where they following drawbacks: cides and disposing of empty containers. Most emergent plants have a waxy outer have little effect on the algae problem. Poisoning kills plants without remov- A list of chemicals generally used for surface. For chemical treatments to If you wish to poison algae with copper, ing them from the pond. After they weed control, their trade names and use work, an adjuvant or surfactant must be you may lower the risk somewhat by die, plants sink, consuming oxygen, restrictions are provided in tables 7, 8 added to the herbicide so it “sticks” to using chelated copper. It achieves the creating odors and releasing nutri- and 9. These recommendations and the plant and penetrates the waxy same algicidal effect as copper sulfate ents for new plant growth. restrictions change rapidly so check with surface to vital parts. Check with the with a much lower concentration of Poisoned plants disappear only the DNR at least annually for current DNR’s or DATCP’s aquatic nuisance copper. This is less likely to harm fish slowly from the treated area. One to regulation. Using chemicals other than control specialists for adjuvant and sur- and other pond life and is much more several weeks may pass before the those on this list may be illegal and dan- factant recommendations and use effective in hard water ponds. masses of nuisance plants sink gerous! Use only chemicals labeled for restrictions. Chara algae can be particularly hard to away. use in lakes and ponds so you have Copper sulfate is widely used to kill control with toxic chemicals because it complete instructions on their use and Since each herbicide kills many algae and is commonly available from often has a crust of lime (calcium car- know of any special precautions. kinds of plants, beneficial species agricultural supply outlets. Extreme care bonate scale). Therefore chara should may be killed along with the nui- Dosage rates will be shown on the is needed when using copper sulfate or be chemically treated only in the spring sance plants. product label. Follow these closely. Do other copper-based chemicals in fish before a heavy crust forms. The amount not overtreat! Avoid thinking “If a tea- ponds. Even though it is frequently of copper sulfate needed to kill chara is Localized treatment is difficult. Even spoonful is called for, then a whole described as suitable for use in human more than for other algae. Additional ponds that appear placid have cur- shovelful will do the job better.” This not drinking water supplies or where fish will caution is advised because copper con- rents that can carry poison from a only wastes money, but may cause plant be consumed, a high copper content centrations could be hazardous to other problem area to one where plant decay so rapid that dissolved oxygen harms fish food organisms and kills fish. pond life. beds should be preserved. becomes depleted and fish suffocate. A Copper sulfate is difficult to use properly. There is risk of harm to other life in chemical overdose may poison fish and Its effects vary greatly depending on the pond and the surrounding area. other life. Distribute the chemical evenly water hardness and other factors. In over the area to be treated, whether extremely softwater ponds, very little using spray, powder or granular plant copper sulfate may kill the algae—but poisons. Too much applied in one place also may kill the fish. In very hard water, 59

AQUATIC PLANTS AND THEIR CONTROL

Plant-eating waterfowl have also been Biological control tried for controlling leafy aquatic plants. Controlling aquatic vegetation with plant One pair of domesticated swans and disease organisms, plant-eating fish, their one or two offspring can keep an waterfowl or other animals has been acre of pond plant-free. However, the tried in many parts of the world, but swans must be provided with some holds little promise for northern ponds. open water and shelter in winter (or kept The plant-eating Asian grass carp in a barn), and they may need supple- (Ctenopharyngodon idella), also called mental feeding which adds nutrients to the white amur has been imported into the pond. the southern U.S. to control weeds in Ducks and geese that eat plants aren’t fish ponds. In addition to eating problem suitable for pond weed control. They plants, it eats beneficial plants that are obtain much food through supplemental used as breeding habitat by some desir- feed or by foraging outside the pond, able fish, serve as cover for young bring nutrients to the pond as feces, and game fishes or that supply food for increase the plant problem. wildlife, especially waterfowl. Since grass carp do not eat all aquatic plants Algae typically replace the higher and algae, the plants they don’t eat aquatic plants consumed by animals grow in place of the plants they do. used to control pond plants. In some cases, dense blooms of planktonic algae It is illegal to bring grass carp into may be more tolerable than large Wisconsin or to possess them, including weeds. the sterile, triploid grass carp. Often in a pond, rooted plants and algae The rusty crayfish (Orconectes rusticus) compete for nutrients and light. One has invaded some Wisconsin lakes and problem acts as a biological control over eliminated aquatic plant growth. another. You may be able to choose Although this may sound appealing to your problem, but managing both at the some pond owners, the crayfish causes same time is difficult. problems because it eats fish eggs and burrows into pond banks. Furthermore, it requires some gravel substrate to reproduce and achieve abundance levels required for plant control. Planting crayfish in ponds to control plants is not recommended and it is illegal to possess or transport live crayfish in Wisconsin. 60

MANAGING WISCONSIN FISH PONDS

Table 7. Susceptibility of aquatic plants to herbicides* Scientific name Common name Endothall Diquat 2,4-D Glyphosate Fluridone Acorus calamus sweetflag N N C - - Brasenia schreberi water shield N N C - N Ceratophyllum demersum hornwort C C C - C Chara sp. or spp. (1) muskgrass ? NNNN Eleocharis acicularis needle spikerush ----? Eleocharis palustris creeping spikerush ----? Elodea canadensis common waterweed ? C N - C Juncus pelocarpus brown-fruited rush ----C Lemna sp. or spp. — NCN - C Lemna minor small duckweed N C N - C Myriophyllum sp. or spp. — ?CC- - Myriophyllum heterophyllum various leaved water milfoil ? - - - ? Myriophyllum sibiricum spiked water milfoil ? - - - C Myriophyllum spicatum eurasian water milfoil ? CCNC Najas sp. or spp. — CC - - ? Najas flexilis slender naiad ? CNNC Najas guadalupensis southern naiad C C N - C Nelumbo lutea american lotus ? ? C ? - Nitella sp. or spp (1) — ----- Nuphar sp. or spp. — NNCCC Nuphar variegatum bull-head pondlily ? - C C - Nymphaea sp. or spp. — ?NCC C Nymphaea odorata fragrant waterlily ? - C C C Phragmites australis common reed - - - C ? Polygonum sp. or spp. — ?NCC? Potamogeton sp. or spp. — ?--?- Potamogeton amplifolius large leaf pondweed C ? N - - Potamogeton crispus curly leaf pondweed C C N - C Potamogeton diversifolius water thread pondweed C ? N - C For use as a general guideline only. C = plant generally controlled. ? = questionable control; results highly dependent on chemical formulation or environmental conditions. N = plant generally not controlled. (1) = plant usually controlled with copper compounds. - = information unknown or unreported. 61

AQUATIC PLANTS AND THEIR CONTROL

Table 7. (continued) Scientific name Common name Endothall Diquat 2,4-D Glyphosate Fluridone Potamogeton filiformis thread leaf pondweed C - - - C Potamogeton foliosus leafy pondweed C C N - C Potamogeton illinoensis illinois pondweed ----? Potamogeton natans floating leaf pondweed C C ? - C Potamogeton nodosus long leaf pondweed C ? N - ? Potamogeton pectinatus sago pondweed C C N - C Potamogeton pusillus small pondweed C C N - - Potamogeton richardsonii clasping leaf pondweed C N N - C Potamogeton strictifolius stiff pondweed C C N - - Potamogeton zosteriformis flatstem pondweed C N N - - Ranunculus sp. or spp. — ?C? - - Ranunculus tricophyllus white water crowfoot ? C - - - Ruppia maritima widgeon grass N C N - - Sagittaria sp. or spp. — NNC - ? Sagittaria latifolia common arrowhead - - - - ? Scirpus sp. or spp. — N?C-C Scirpus acutus hardstem bulrush ----? Scirpus americanus chairmaker’s rush - - - - ? Scirpus validus softstem bulrush ----? Sparganium sp. or spp. — CN N- - Spirodela polyrhiza great duckweed - C ? - ? Typha sp. or spp. — NC?C? Utricularia sp. or spp — NCN - - Utricularia gibba humped bladderwort ----C Vallisneria americana eel grass ? ? - - N Wolffia sp. or spp. — NCN - Wolffia columbiana common watermeal ----? Zannichellia palustris horned pondweed C ? N - ? Zosterella dubia water star grass C C N - -

For use as a general guideline only. C = plant generally controlled. ? = questionable control; results highly dependent on chemical formulation or environmental conditions. N = plant generally not controlled. (1) = plant usually controlled with copper compounds. - = information unknown or unreported. 62

MANAGING WISCONSIN FISH PONDS

Table 8. Aquatic herbicides commonly used to control weeds in Table 9. General restrictions on use of treated water (number of days) ponds ——————Human————— ——Animal—— ——Irrigation—— Drink- Swim- Fish con- Drink- Food Common name Trade name Herbicide ing ming sumption ing Turf crop Forage Copper Sulfate Copper Sulfate Medium Crystals Copper sulfate 0000000 Triangle Brand Copper Sulfate Copper chelate 0000000 Copper Sulfate Instant Bluestone Endothall 0 0 3 7-25 7-25 7-25 7-25 Copper Sulfate Superfine Crystals Diquata 1-3114151414 Kocide Copper Sulfate Crystals 2,4-Db 14 0-2 c 14 14 14 14 Copper Chelates Algimycin Pll-C Glyphosateb 0000000 Aquatrine Algaecide Fluridoneb 00007-30 7-30 7-30 AV-70 (also AV-70 plus) Cutrine-Plus Algaecide/Herbicide a = A drinking water tolerance of 0.01 ppm has been established for Diquat. Slow Release Algimycin b = Although no waiting period is established for recreation or domestic purposes, a drinking water Stocktrine II tolerance of 0.07 ppm has been established for 2,4-D, 1 ppm for glyphosate and 0.15 ppm for fluridone. Komeen c = No established waiting period. K-Tea Algaecide Endothall Aquathol Aquathol K Hydrothol 191a Diquat Reward 2,4-D Weed R-64 Aqua-kleen Navigate Glyphosate Rodeo Fluridone Sonar A.S. Sonar S.R.P. a Fish will be killed by dosages greater than 0.3 ppm. Because this publication focuses on Also, don’t expect animal damage chapterchapter1212 ponds for fish production and fishing, control to be totally effective or perma- Wildlife around wildlife here is discussed primarily in the nent. The control techniques described context of nuisance and damage prob- here will reduce or eliminate losses, but lems. If you are interested in creating or in most cases you will need to repeat the pond managing a pond for wildlife, refer to them from time to time. onds are an excellent way to your local Wisconsin DNR office, NRCS enhance wildlife habitat on your office, Extension wildlife specialist or property. For many species, a one of the many informative print Wildlife control Psource of water provides much more materials available. than just a place to get a drink. To repro- considerations duce, most amphibians (frogs and Keep these things in mind as you toads) must make a seasonal move to Controlling wildlife problems attempt to resolve conflicts with wild water. Waterfowl (ducks and geese) The mere presence of wildlife does not animals. feed, rest and nest in, on or near water. necessarily mean you will have problems. Anticipate rather than react. Try to Turtles and aquatic mammals such as Furthermore, you and your guests will anticipate a problem and take steps muskrat and beaver all depend on water likely enjoy the opportunity to observe the to prevent it. For example, if fish- for a home. Thus, if you have a pond, wildlife around a pond. However, it is very eating birds are common, remove you can expect these animals to be important to be aware of the problems potential perches before damage present. that can occur and be prepared to take occurs. Wildlife problems are much the necessary steps to control them However, there is a difference between easier to avoid than stop after an should they arise. Many mammals and wildlife ponds and ponds constructed to animal has established a behavior birds eat fish, several mammals can do propagate and harvest fish. Any water pattern. significant structural damage to dikes, will attract some animals, but wildlife Understand wildlife laws. You must dams and shorelines, and some species ponds are generally shallower and more find out what you can and cannot do (such as Canada geese) can be a nui- vegetated with sides that slope more with regard to harassing, relocating sance on grassy shorelines. gradually than fish ponds. Resource or killing any wild animal. A few agencies may provide technical assis- Animal damage problems are usually species (rats, mice, some other tance and cost sharing for construction much more complicated than aquatic small mammals and a few birds like of wildlife ponds, but usually not for fish weed or insect control. Wild animals are pigeons and starlings) are not pro- ponds. In the case of ponds designed mobile, often wary, usually protected by tected by laws. Most, however, are for fish production, the presence of state and/or federal law—even on private protected by state and/or federal law. abundant and diverse wildlife is more land—and are often highly valued by Although there are some special pro- often a liability than an society. In addition, problems are con- visions for landowners, you will not asset. founded by differences in site, weather, be able to kill or capture certain season and other factors. Consider the species, no matter how serious the following general guidelines, techniques problem. Permits, licenses or other and sources of assistance. Advice spe- forms of permission may be cific to individual species is presented for required. Laws also vary from state the major problem species. to state and even within some 64

MANAGING WISCONSIN FISH PONDS

municipalities (use of firearms, for The following general options are used 6. Increased tolerance. Rethink the Woodchucks, also called groundhogs, example). The sections of this publi- in wildlife control: situation! Examples: The sounds or burrow into pond dams and banks well cation dealing with problems caused 1. Exclusion. Prevent the animal from sights provided by the animal in above the waterline. The burrows may by certain species contain basic getting to a site where it may cause question may be worth the hassle or penetrate 50 feet or more and rise to the legal information but check first with damage. Examples: a fence, a mesh loss, or maybe there are more fish surface creating a second burrow your local DNR office or warden. cover over a small rearing tank or than you really needed anyway. entrance on the other side of the dam, Be sensitive to values other than pond, or monofilament lines strung in or well away from the pond. The tunnels your own. A problem for you may be parallel rows over a raceway for bird Problem species lead to underground nesting chambers a delight to your neighbors or vice exclusion. and chambers for food storage, body waste and traps for water that enters the versa. Neighbors may have differing 2. Removal. Remove the animal from Muskrats and woodchucks opinions about killing or relocating burrows. the scene. Examples: remove live Muskrats and woodchucks dig burrows “pest” species or the use of pesti- Habitat management. Eliminating or animals—capture and relocate via that may cause pond bank cave-ins, cides. This is especially true in the reducing habitat reduces or eliminates wire live trap, net, hand, etc.; kill weaken dams or result in leaks. They case of fish-eating birds. the attractiveness of banks and dams to animals—shoot, use toxicants, kill- prefer to dig in steep banks. Muskrats woodchucks and muskrats. Maintain Know your adversary. Your efforts traps (like a wooden-base rat trap). tunnel from beneath the pond surface dams and banks in grasses such as to control a wildlife problem can be 3. Repellents. Prevent the animal from while woodchucks typically tunnel into fescue and brome. Eliminate all broad- greatly enhanced by an understand- doing damage or gaining entry by the high portions of the banks or dams. ing of the animal’s basic life history. leafed plants, especially legumes like using olfactory or taste-based repel- Muskrats make burrow entrances 6"Ð18" What does it eat (helps with bait clover, alfalfa and trefoil. Eliminate lents. Examples: Rejex-it¨ applica- below the water line, sometimes deeper. choice)? Where does it live (helps muskrat food, such as cattails, arrow- tions on grass to discourage Canada Burrows may penetrate banks or dams 9 with trap placement or habitat modifi- head and other emergent plants. If the geese. feet or more, but the average length is cation)? How prolific or mobile is it? pond is not properly constructed, con- 4. Scare tactics. Frighten the animal 5Ð6 feet. The tunnel leads to a dry nest Furthermore, better knowledge of the sider regrading the banks, and deepen- away. Examples: gunfire over a chamber above water level. Frequently wildlife in question may lead you to ing the pond to reduce the zone where pond, owl decoys, mylar or plastic muskrats also burrow upward from the decide your problem is really not so emergent plants grow (see Chapter 3). streamers, other noisemakers, nest chamber tunnel to the surface, thus bad given the benefits the animal “scare-eye” balloons, propane creating a second burrow entrance high may provide. cannons, radios. on the bank or dam. Understand the basic tools and 5. Habitat modification. Eliminate a techniques of wildlife damage key component of the animal’s control. Wild animals are much dif- habitat thus causing it to leave the ferent than weeds or insects. Few area. Examples: eliminate dead chemical pesticides are registered snags or posts used as perches by (available) for animal control (that’s fish-eating birds; riprap a bank used good!) and cookbook solutions by muskrats. (apply X to Y, wait 3 days, problem is gone) are rare for wildlife problems. 65

WILDLIFE AROUND THE POND

Remember, habitat modification will help Cover with vinyl-coated chicken wire Pond Leveler” if this idea sounds useful. to solve problems, but will also reduce from 3 feet below low waterline to 3 Beavers There is an excellent chapter on beaver the attractiveness of your pond to other feet above normal water level for Beavers may cause problems by felling control in the Handbook of Wildlife more desirable species. To completely muskrats and from the normal water- trees, plugging culverts and spillways Damage Control published by the eliminate the possibility of muskrat and line to the top of the dam or bank for and digging bank dens. Major revisions University of Nebraska. Most Wisconsin woodchuck damage to bank and dam, woodchucks. in Wisconsin regulations in 1990 county UW-Extension offices have a reinforce banks and dams with materials Reducing muskrat and woodchuck changed private landowners’ beaver copy, or you can request a copy of the that will prevent burrowing. Reinforcing populations. If the pond is not adjacent control options. Consult your local DNR section on beavers from your Extension these embankments is the only way to to extensive muskrat or woodchuck office and request a copy of Beaver wildlife specialist. completely prevent muskrat and wood- habitat, damage caused by muskrats Damage Control. In general, you may chuck damage when the pond is located and woodchucks can be greatly reduced shoot or trap beaver on your own prop- Otters near other waterways, wetlands or erty and remove dams without a special by eliminating as many of the animals Otters are playful creatures but fish are uplands that are in unmowed meadows, permit. In northern Wisconsin the USDA as possible. If the area surrounding the the main component of their diet. A hay fields or other agricultural uses. Wildlife Services office in Rhinelander pond has extensive wetlands or family of otters in a fish pond is a major runs an intensive beaver control Reinforcing the shore and dam. The meadows, hayfields or agricultural lands, problem. The otters should be captured program. shore and bank can be reinforced to the animals that are eliminated will be and removed as soon as possible. Mink deter muskrat or woodchuck burrowing replaced very quickly by new ones from Beaver are most likely to be attracted to may also take some fish but they earn in one of the following ways. the surrounding habitat and damage will moving water where they can engineer their keep by preying on muskrats. Cover with at least 2 layers of rocks be reduced only slightly, if at all. their own flowage. In this case, there are (called riprap) at least 6 inches in Because these regulations change occa- several devices that utilize PVC pipes diameter from 3 feet below the low sionally, check the annual hunting and installed through the dam with intakes waterline to 3 feet above the normal trapping regulations and consult your and outflows well above and below the waterline for muskrats. For wood- local conservation officer about special dam. For some reason, the animals do chucks, cover with 2 layers of riprap provisions for damage control. not seem to figure out the “leak” in their from normal waterline to the top of pond and water continues to flow. Look the dam or to the top of the bank. for information on the “Clemson Beaver Use soil cement in the top 6 inches of earth from 3 feet below low waterline to 3 feet above normal water level for muskrats and from the normal waterline to the top of the bank or dam for woodchucks. 66

MANAGING WISCONSIN FISH PONDS

Discourage herons by grading the A pair of Canada geese and their Moles Birds pond’s edges to form steep underwater goslings may be a welcome addition, but Mole burrows cause erosion by destroy- Several kinds of fish-eating birds side slopes. Three feet of horizontal dis- large flocks of local or migrating geese ing patches of sod on dams or pond consume fish from ponds, especially tance per foot of slope is the maximum can be a major nuisance if your pond is banks. Applying any mole damage kingfishers, herons, osprey, mergansers slope recommended for safety (see the surrounded by a well-maintained turf. control method to inactive mole burrow and domesticated ducks. Fish-eating information on pond construction in Geese defecate profusely which leads to systems is futile. In all cases, treat only birds may also carry parasites that infect Chapter 3). If necessary, suspend a visual and sanitation problem. active tunnels. To see if a tunnel is being fish. All of these birds can be scared chicken wire horizontally at or near the Persistent grazing by geese can actively used, gently flatten a short away by noise-making devices, such as water surface along the shallow parts of damage turf. Scare tactics such as bird section of the ridge above the tunnel. If gas-powered automatic cannons and the pond edge. Discourage kingfishers screamers, shell crackers or gunfire will the tunnel is in use, the ridge will be bird-scaring shotgun shells that fire by removing all perches, such as posts help. Hunting pressure during the appro- raised again within 24Ð48 hours. explosive charges designed to detonate and dead tree limbs, close to the pond. priate open season is very useful. A rel- A new repellent, Mole-Med¨ can be 50Ð100 yards away. Use exploders and If Muscovy ducks are kept in the pond, atively new repellent called ReJex-It¨ (a applied directly to grassy areas, for 1Ð2 scare shells in combination. You must confine them to a small part of it. formulation of methyl anthranilate) can months of relief from burrowing activity. vary the locations, firing intervals and All birds that may cause potential prob- be applied directly to the turf to discour- For further details contact your local firing times at least every third day or lems around ponds are protected by age geese. UW-Extension county office for a copy of the birds soon become accustomed to federal (and often state) law. In extreme the publication Mole Control (G3200). these techniques. Use of these devices cases, a permit may be issued to shoot Pocket gophers could be confused with requires a federal permit if endangered offending birds. But be aware of the moles but they are found only in the or threatened species are involved. public relations consequences of such west-central and southwestern parts of Noise ordinances may also be a factor if actions. For more information and Wisconsin. Gophers are rodents (moles you are near a developed area. necessary control permits, are not) and can be controlled with Scarecrows, artificial snakes, hawk or contact the nearest USDA Wildlife poison baits. owl decoys and special balloons that Services office. There is an excellent frighten birds can also be used to scare chapter on “Bird Damage at Aquaculture birds away. These devices must be posi- Facilities” in the Handbook of Wildlife tioned imaginatively and moved fre- Damage Control from the University of quently, at least every other day, or they Nebraska mentioned earlier. will soon become ineffective. They are most effective if used together with scare shells and automatic explosion cannons. 67

WILDLIFE AROUND THE POND

Indiscriminate killing of all snakes To use the trap, place it in shallow water Turtles and snakes regardless of species accomplishes little where turtles are most likely to feed. In recreational fish ponds, turtles and and may create or intensify other prob- Make sure that the snakes rarely eat enough fish to affect lems, such as rodents. In recognition of top part of the trap the fish population. Unlike mammals and the value of many reptile species, laws is above water so birds, turtles and snakes may not feed and regulations change rapidly. Be sure that entrapped turtles or other daily and they concentrate on minnows to check with your local DNR office animals accidentally trapped do and other small fish. before taking action. not drown. Nylon rope or metal Some pond owners want to remove If it becomes necessary to remove cable should be fastened turtles and snakes simply because they turtles from a pond, they are easily to the trap and tied are afraid of them or don’t like them. caught using a trap constructed of securely to a tree, rock, Snake and turtle populations can be chicken wire. Commercial turtle traps stake or other nonmov- reduced by mowing pond bank vegeta- are also available. To make a trap, roll a able object on shore so that tion and removing logs, tree roots, piece of one-inch mesh chicken wire 60 entrapped animals do not roll the trap branches and large stones from the inches wide and 60 inches long into a into deeper water and drown. Almost shoreline. Mowing this habitat reduces cylinder 60 inches long. On both ends of any meat or fish bait will work in the the opportunity for these animals to the cylinder, make four cuts, 15 inches trap, but one of the most convenient and survive, but it also reduces the effective- apart. Each cut should be 12 inches effective baits available is a partially ness of a vegetated buffer strip for nutri- deep. Next fold these ends of the cylin- opened can of sardines. Place the parent and sediment control. der inward and reattach the cut ends to tially opened can into the trap before each other to create funnels pointing putting the trap in the pond. Captured inward with a small end opening of turtles can be removed by hand or with approximately 12 inches by 6 inches. A a dip net through the door panel. trap of this size will catch all but the Check with the local DNR office for reg- largest snapping turtle. ulations on trapping turtles in your pond. To trap a very large snapping turtle that weighs more than 20 lbs., start with a piece of chicken wire that is 6 by 8 feet. Follow the previous directions, but this time make the opening of the small end of the funnel leading into the trap approximately 10 inches by 18 inches. Cut a door panel in the side of the trap and wire it tightly closed. 68

MANAGING WISCONSIN FISH PONDS

Self reliance—With some good informa- For more information or tion, a little thought and good equip- Mosquitos Leeches ment you can solve most wildlife In general, mosquitos don’t thrive in fish Most leeches feed on animals, such as on-site assistance problems yourself. ponds because fish eat mosquito larvae. turtles, or on dead matter. Only four Wisconsin Cooperative Extension — Moreover, mosquitos need calm water to species attach to humans. Therefore, County extension offices or state develop. Any spot where a breeze can the first thing to determine is whether wildlife specialists have a wealth of Other problems ripple across a pond’s surface is unsuit- leeches are attaching themselves to information available. Extension Swimmer’s itch able for mosquitos. Only very shallow, people or whether they have merely wildlife damage control publications protected pond edges support them, and been sighted in the water. No control is contain the details needed for most Swimmer’s itch is caused by a minute, small fish usually dispose of mosquito needed unless the leeches are definitely problems and most county offices free-swimming parasite that burrows into larvae in these places. causing a human problem. and irritates the skin. This parasite have a copy of the Handbook of Most mosquitos that cause problems Often, the most effective way to reduce develops only in certain kinds of snails Wildlife Damage Control (University come from temporary puddles. leech populations is to reduce the before it attacks humans. Ducks also of Nebraska, 1995). Maintaining a stable pond level prevents amount of organic debris on the pond assist in the life cycle of the parasite but State Natural Resource Management flooding of shoreland which creates iso- bed. Leeches dwell in accumulations of any attempt at duck control is likely to Agencies (DNR) —Agency staff can lated puddles for mosquito breeding. twigs and leaves at the bottom of the be undesirable and ineffective. Feeding provide information, legal advice and Don’t try to control mosquito breeding pond and they swim up or reach out to ducks at pondside will only exacerbate permits. unless you have found exactly where it attach to host animals. Some leeches potential swimmer’s itch problems and occurs. Then confine your control efforts attach to aquatic plants and stretch to U. S. Department of Agriculture- should be avoided. Animal and Plant Health to those sites. amazing lengths in search of passing Ridding a pond of swimmer’s itch means Inspection Service-Wildlife A safe, effective and pleasant mosquito food. Controlling beds of dense vegeta- controlling the snails. To control snails Services—This agency’s role varies control is to install a purple martin house tion may also help control leeches. with least harm to the pond’s fish, from state to state but Wildlife near the pond or at the area of human Another method for controlling leeches remove plants and pondbed debris, Services staff can be a great help in activity. One colony of martins will help is to have plenty of bass or trout in the which provide the snails’ habitat. Sowing agricultural and aquacultural prob- keep mosquitos at a tolerable level pond. These fish prey on most of the pea-sized copper sulfate crystals onto lems. The agency maintains district during daytime and early evening. troublesome leeches. In fact, some the pond bed (2 lb/1000 sq ft or 87 offices in Waupun (800-433-0663) Beware of using insecticides to control kinds of leeches are highly effective lb/acre) poisons snails but also kills and Rhinelander (800-228-1368) and mosquitos near ponds. These chemicals fishing baits, and they are a hot-selling many other fish food organisms, and a statewide office in Sun Prairie are very likely to kill the fish. item at bait shops. Stocking 25 to 50 possibly some fish, especially trout. To (608-837-2727). yearling (6- to 8-inch) bass per acre avoid chemical control, simply be sure should reduce leech populations so that Private contractors—There has been a all swimmers quickly and vigorously they are no longer a problem. recent proliferation of individuals who towel dry themselves immediately upon will handle wildlife damage problems leaving the water. for a fee. Check the Yellow Pages or the county Extension office for a reference. 2. Increased environmental stress chapterchapter1313 directly or indirectly causes fish Managing fish health Fish health health problems. Decreased oxygen Pond design specifications, stocking in the water, increased ammonia rates and other fish management rec- levels and low pH can directly affect ommendations in this manual were management the gill structure, leading to bacterial developed to promote healthy fish popu- or enviromental gill disease. lations. But some health problems may Factors influencing Exposure to poor water quality, pesti- occur even when these recommenda- cides or limited food supply can indi- tions are followed. Close attention to fish health rectly affect fish health by supressing pond conditions, oxygen, temperature The health of fish, whether they live in the the immune system. and the relative growth of fish, coupled wild, in a hatchery or in a pond depends 3. New fish stocked into a pond may with regular observation of fish behavior upon the interactions of the fish (the sus- carry new disease organisms that is important to assessing the health of ceptible host), the presence of disease can result in significant fish health fish. Fish that are lethargic, pip for air at organisms (bacteria, viruses, parasites or problems. Or disease organisms the surface, or “flash” against rocks or fungi) and the living environment (figure already present can mutate to more the pond bottom may have underlying 25). virulent forms and cause disease health problems. In general, make sure fish introduced into your pond are not Fish and disease organisms can co- outbreaks. stressed or carrying heavy loads of fish exist without causing significant fish parasites or disease organisms. health problems or mortality. But health problems occur when one (or some combination) of three conditions exists. 1. Something happens to affect the fish’s susceptibility to a disease or parasite. For example, when fish populations reach a high density, fish improved stressful can become stressed, and disease environment environment can occur and spread quickly. Over time, the genetic makeup of a fish population can disease change so that the occurs fish are more or less pathogen host susceptible to certain pathogen host pathogens.

poor management good management

Figure 25. Relationship of management to disease problems. 70

MANAGING WISCONSIN FISH PONDS

Your understanding of fish parasites and ted) rather than fish. Fish cannot be a fish. The larvae then burrow into the disease organisms will help you evalu- “disinfected” and may carry any combi- Parasites skin or muscle of the fish and secrete a ate the status of the fish intended for nation of fish pathogens. Parasitic infections are common in protective wall around themselves. The planting and those already present in pond-reared fish and can be difficult to fish also secretes a protective layer your pond. Establishing that a group of control. Some parasites live their entire around the parasite and we see this as fish are disease free requires the skills Introduction to common fish life on the same fish, while others the black spot. When the kingfisher eats of a trained professional. require a variety of intermediate and an infected fish, the larvae mature to the parasites and diseases final hosts (figure 26). adult stage and the cycle repeats. Since If you plan to raise trout or salmon, it is Table 10 gives an overview of some of the parasite spreads via free-flying king- always a good idea to ask potential fish the more common organisms that can The life cycle of the parasite causing fishers, susceptible fish and resident suppliers for a copy of the most recent make fish sick and explains how you “black spot” is typical of most fish para- snails, it is very difficult to eradicate it fish health inspection report for their can tell if those organisms are present. sites. Adult flukes live in the intestines of from a pond. facilities. Results from an inspection Parasites and bacterial infections are kingfishers and shed eggs that are indicate the disease organisms that most common in pond fish. passed in the bird’s feces. Once in the Other birds and mammals carry similar were detected at the time of the inspec- water, the eggs hatch, releasing a larvae types of parasites that spend part of tion. To minimize the introduction of new that infects certain species of snails. their life cycle on fish. Therefore, wher- disease organisms, it is always best to Larvae develop in the snail and then ever there are abundant wildlife popula- receive eggs (that are surface disinfec- emerge and “swim” until they encounter tions, it is very likely that parasites will infect fish that are reared outdoors. In Table 10. Common fish diseases and their symptoms. general however, these types of parasites do not pose a threat to the fish or Name of disease those who eat them. By keeping the fish (and fish affected) Causative agent Symptoms population at low densities, you may be Skin fungus or Saprolegnia fungus Tufted growths of fine white or gray threads able to reduce the number of encysted 1 water mold (all fish) (often results from injury to skin) radiating ⁄3 inch or more from body. larvae per fish, but this may not be Columnaris Flavobacterium columnare Grayish-white spots surrounded by red on acceptable if low fish densities are not (all fishes) bacterium parts of head, gills, fins or body. part of your pond management plan. Red sore (northern pike) Aeromona hydrophila bacterium Open bleeding sore from which scales are lost. Columnaris is a disease caused by the Furunculosis Aeromonas salmonicida Boils or furuncles on skin, inflammation of inner bacteria Flavobacterium columnare. This (trout and salmon) bacterium body walls, many small internal hemorrhages, bacterium is very common in lakes and bright red spleen and swollen kidneys. ponds. The bacteria invade gill and skin Black spot or black grub Digenetic trematodes Small black spots just under skin and in muscle. tissue and sometimes infect the internal (mostly warmwater fish*) These are cysts containing a microscopic organs. Signs of this disease include stage of this parasite. yellow to grey mucus on the gills, erosion “Ich” or white spot Ichthyophthirius multifilis Tiny white spots on body. of the skin on the head and body and (mostly warmwater fish) protozoan erosion of gill filaments. Trout or salmon Lymphocystis (perch, a virus Raised nodular masses of light-colored tend to develop “saddle back” lesions walleye, sunfishes) tissue resembling warts on skin. that look like grey patches of skin on Fish lice (warm and Injuries, dietary problems, External and internal tumors of various sorts, either side of the dorsal fin. Under coolwater fish and brook trout) genetic causes, etc. spinal deformities, shortened or flattened heads. certain conditions the disease can cause *Also trout where the water is unfavorably warm. high levels of mortality. The bacteria 71

FISH HEALTH MANAGEMENT thrive at temperatures above 65û F. Fish There are many opportunities to learn can develop an immunity to this bac- more about fish health. The U.S. Fish Blue heron terium if they survive the initial infection. and Wildlife Service conducts a week- final host Columnaris bacteria increase on fish long course entitled “An Introduction to under stress and pose a particular Fish Health.” The course is usually held problem in commercial ponds with high in February in LaCrosse. Contact the fish densities. Stress caused by low dis- U.S. Fish and Wildlife Service LaCrosse solved oxygen, high temperatures, high Fish Health Center for more information ammonia levels, an inadequate diet or about this course. See the references on insufficient space or water flow page 77 for the address for the Parasite eggs increases the likelihood of mortality LaCrosse Fish Health Center and a list released into water when disease organisms are present. of reference materials on fish diseases. Heron eats infected fish and adult stage with bird droppings. Depending upon the situation, develops. Columnaris disease and parasitic infections are controlled by a variety of treatments. Guidance for treatments can be obtained from other fish farmers, some Second stage larvae veterinarians, the U.S. Fish and Wildlife burrow into skin of fish Service, DATCP, the DNR and fish and develop into a third health reference books. The U.S. Food stage larvae. Larvae enter snail and Drug Administration regulates fish and develop to therapeutants. Anyone who treats fish Second stage larvae second larval form must follow U.S. FDA guidelines. swim out of the snail If your pond has an outlet, you should and search for be aware that fish health problems will susceptible fish. be passed downstream to other fish. Responsible natural resource steward- ship will minimize fish health problems Figure 26. Life cycles of the yellow grub (above) and at your pond and in fish downstream. the “ich” skin parasite (below). The key to successfully raising fish in a pond is to remember that fish are living organisms. If you can provide an adequate food supply and a quality environment for your fish, the chance for disease problems to occur will be small. chapterchapter 1144 Find out about both community and Keep boats used on the pond in state liability laws regarding injury or good condition. Never overload them. Pond safety and death resulting from use of the pond. Instruct passengers never to stand Local laws may vary greatly. This is up in the boat. Provide one Coast especially important if an owner intends Guard approved life preserver or per- liability to open the pond to the public and sonal flotation device (PFD) for each fishing pond may furnish some charge user fees. person on board. Use common- swimming, boating, hunting, ice Here is a list of fairly economical safety sense safety in all other respects! skating, wading and picnicking, even measures. Beware of thin ice! Test the strength though it may be designed primarily of the ice with a spud or auger, and A Grade the pond bed to eliminate for fish. It will be a special attraction to actually measure its thickness before children. steep slopes or drop-offs. venturing over deep water. Don’t Remove broken glass and other Because ponds attract people, they walk or skate on freshly formed ice sharp objects, stumps, logs, large present an accident hazard. Drownings that is less than three inches thick. If rocks and trash that could pose a are second only to motor vehicle the ice is thawing, it may need to be hazard to waders, swimmers and mishaps as a cause of accidental death much thicker than that. Snowmobiles boats. among people in the active age groups, should not be driven onto ice less particularly children. Place warning signs near specific than five inches thick. danger areas, giving the depth of the Each pond owner has moral and legal Keep a wooden ladder at the pond’s water and the location of the nearest obligations to family, friends, neighbors edge in winter. This can be shoved telephone. and even trespassers to make the pond out to someone who has fallen as safe as possible. Providing certain If you permit swimming, mark a safe through the ice. safeguards can prevent an incident from special area for it with buoyed lines. Never let a child play at the pond becoming an accident or even a fatality. Install life-saving equipment on the alone, no matter what the season. Simply posting a notice prohibiting pond bank where it can be easily Everyone who lives, works or plays trespassing at a pond does not seen and used. near a pond should know how to relieve an owner of responsibility. Be sure that piers, rafts and landings swim and how to give cardiopul- Legal liability is often based on whether are well-constructed and braced. monary resuscitation. Find out more an owner has taken all reasonable pre- about it from your local Red Cross. cautions against mishaps. Pond Erect adequate fencing and locked owners should consult their attor- gates to prevent unauthorized neys and insurance companies about entry—especially by children. liability for serious accidents or death, as well as about the legal requirements for safety precautions at the pond. 73

POND SAFETY AND LIABILITY

4. Pole—A 10- or 12-ft bamboo pole or Installing a rescue station sapling. Since the pole will be Use the materials and process described extended to anyone struggling in the below to install a rescue station. water, its tip and butt should be 1. Post—A 6-ft two-by-four or four-by- wrapped with friction tape to reduce four, preferably painted yellow. Set slippage. Paint the pole white. Hold it the post about 2 ft into the ground, in an upright position by placing it in standing no more than 4 ft out of the two 6-ounce tin cans, nailed near the ground, near the water at any point bottom of the post about 6 inches where swimmers might get into apart. trouble. Paint “THINK, THEN ACT” 5. Tin container—A 46-ounce juice down the length of the post on all can or a 2- or 3-lb coffee can. 2. 3. sides. About 1 ft from the top, attach Remove one end, then slide the can a metal shelf bracket, wooden arm over the top of the post. Fasten it or 60-penny spike to use as a hook down with one nail through the for coiled rope and the jug float. center of the top so it is impossible 2. Jug—A gallon plastic jug with an to rotate. inch of water inside to be thrown to a 6. Poster—A sheet of safety tips, person in trouble. Paint “FOR rescue methods and emergency 4. 5. EMERGENCY USE ONLY” on the telephone numbers. After applying a side. coat of varnish to the can, attach the

3. Line—A 40-ft length of 3⁄8 inch poster to the can and mount the can polypropylene. Tie one end to the at the top of the post. Let dry thor- handle of the plastic jug. At the oughly; then varnish the poster to opposite end, fasten a 4-inch piece protect against weather. of two-by-four to prevent the line Note: Add a ladder to the rescue station from slipping completely through if the pond is likely to be used in winter. hands or from underfoot when 1. 6. thrown.

Steps in making a rescue station. chapterchapter 1155 You should contact your DNR fish expert Pond construction at the nearest local or district office (see Regulations references) to find out which permits o protect Wisconsin’s priceless regulations apply to your project. You should also natural resources for future genera- The type of pond and its placement contact your county, city and village tions, legislation has been enacted determine the regulations that concern zoning office or building inspector to find Tthat regulates pond construction and you. As suggested earlier, ponds that out whether local permits are required. management. While the permit process might affect public navigable waterways Any pond to be located within the flood- may seem cumbersome, it serves to or wetlands are of particular concern. plain of a navigable waterway may remind those interested in pond con- A navigable waterway is any body of require a permit. A permit is always struction and management of their water large enough to float a canoe at required if you are planning to build a responsibility to the state’s natural any time of the year. Generally, a stream pond within 500 ft of a navigable water- resources and the potential liability that 3 feet wide and 8 inches deep at any way. A special permit is also required if may be involved. You can start the time of the year is classified as a navi- the project involves changing the course process by requesting a fish farm infor- gable waterway. A wetland is any area of a navigable waterway or diverting mation packet from DATCP. with water at or near the surface that water from or discharging water to a In Wisconsin, all navigable waters are supports wetland plants. navigable water. public property and are protected to The DNR determines whether the water Navigation and safety are a considera- promote the public interest. In addition, is a navigable waterway or a wetland. tion for impoundments. Federal as well because over 50% of Wisconsin’s and Your county or local units of government as state regulations prohibit construction the nation’s wetlands have already been may also have designated sites as wet- of dams on navigable waterways. If your destroyed, both state and federal laws lands. The U.S. Army Corps of plans call for placing a dam on a non- protect existing wetlands. Engineers reviews permits involving navigable waterway, the law requires wetlands. that the plans be reviewed and approved by the DNR to protect public safety as well as the public’s natural resources. Some county land conservation departments have professional staff who can assist in the pond design and the permit processes. 75

REGULATIONS

DATCP has the right to inspect private Registration as a tool to fish farms and to revoke a registration if Permits as a way to regulate Liability violations are observed. The Fish Farm Certain pond management operations regulate pond management Registration Law is provided in Chapter pond management may affect other people. If this effect is The destruction caused to waterways by 95.60 of the State Statues. A permit process is used to regulate the detrimental, the parties involved may the European carp illustrates why fish Bait dealers are regulated by the DNR importation of all plant and animal bring legal action. In this respect it pond management is regulated. and are required to obtain a Class A species for the purpose of introducing or makes little difference if the pond is a Registration is used to implement many license ($49.25) if they sell more than stocking. The purpose of the regulations registered private fish hatchery. Fish regulations related to fish pond manage- $2,000 worth of bait per year, or a Class is to protect the native animal popula- poisons or plant toxicants that damage ment, and the collection of wild animals B license ($9.25) if their sales are less tions of the state from foreign species or public resources may result in legal for sale by the bait industry. than that. disease organisms that might be carried action. Damage to another’s property by species coming into the state. during construction or as a result of an The state gains a way to keep track of The license allows for the sale of any uncontrolled discharge may initiate a who is involved in fish management and Under the new statutes, if a fish farm is species of minnow (the state lists spe- lawsuit. Drowning of pets, livestock or the specific sources of fish being self-contained, it does not need an cific native species as bait) or frog used people can occur and result in legal stocked in public waters through the aquatic pesticide permit to use toxicants. as fish bait. Crayfish may only be sold action. Always manage your pond with natural waterbody permits and stocking If the fish farm discharges to surface dead in Wisconsin. The gear that can thorough consideration of its effects on permits issued by the DNR. legally be used to collect bait by the water, a permit is needed to use the chemicals unless the discharge of that the surrounding area. Fish farms are registered by DATCP. If license holder is specified by the state. chemical is allowed under a (WPDES) you choose to register your pond with For example seines to capture bait from Wisconsin Pollution Discharge DATCP, you may: public waters cannot exceed 35 ft except for smelt seines which may be Elimination System permit. 1. Fish on your pond without a state 75 ft. The law governing bait harvest is fishing license found in Chapter 29 of the Wisconsin 2. Stock fish into the pond without Statutes. obtaining a DNR stocking permit Wisconsin residents who hold a bait 3. Ignore state fishing regulations on dealer’s license can import bait into the size, bag limits or open/closed state. All fish imported into the state seasons require an importation permit from If you do not register your pond with DATCP. If the imported species are DATCP, anyone older than 16 must have exotic, DNR and DATCP will co-issue a state fishing license to fish there; they the import permit. Licensed bait dealers must abide by state fishing regulations; file annual reports and wardens may and you must obtain a stocking permit inspect their businesses at any reason- from DNR to put fish in your pond. able hour to ensure compliance with the There is no fee for the stocking permit. terms of the license. chapterchapter 1166 West-Central Region Listservers are automated e-mail listings Box 4001 and can be very useful in getting References Eau Claire, WI 54701 answers to specific questions. When 715-839-3700 subscribers to the listserver group send Major sources of information South-Central Region a message, the message is distributed 3911 Fish Hatchery Road to all subscribers. PONDS-L is an General Madison, WI 53711 example of a listserver that deals with pond aquaculture. To subscribe, send Wisconsin Department of Natural 608-275-3266 the e-mail message: “subscribe ponds-l” Resources South-East Region to [email protected]. Many list- Box 12436 Aquaculture, fish health servers offer summaries of messages Milwaukee, WI 53212 608-266-7715, 608-266-2871 for you to review before you join. Regional offices 414-263-8500 The World Wide Web offers access to a Contact the nearest Wisconsin Wisconsin Cooperative Extension whole universe of information in the form Department of Natural Resources (DNR) Your Cooperative Extension county of web sites. One web site typically links regional office or your local DNR Service office is listed in the phone book under to others with related information. You Center about permits for the following “county government.” The county agent can select the various links to find infor- pond management activities: damming; can put you in contact with state fishery, mation you want. You can get to a par- pond digging or dredging within 500 ft of wildlife or plant specialists, local people ticular web site by knowing its address, any navigable water; fish stocking; pond who can assist in planning and manag- or URL (uniform resource locator). Two draining; use of algicides or weed-killing ing your pond, or, if you are interested in examples of URLs for aquaculture sites chemicals; use of fish toxicant chemi- commercial aquaculture, with one of the are the AquaNIC homepage cals; and aquatic weed cutting or UWEX Small Business Development (http://ag.ansc.purdue.edu/aquanic/) harvest. Centers. and the The Aquaculture Health site Northern Region Aquaculture Information Center, (http://geocities.com/capecanaveral/ Box 309 National Aquaculture Library, 10301 lab/74901). Spooner, WI 54801 Baltimore Blvd, Room 111, Beltsville, You can also find information on the 715-635-2101 MD 20705, 301-344-3704 Internet by conducting a search using or The Internet key words like “aquaculture,” “recre- Northern Region Many companies that produce aquacul- ational pond,” “fisheries,” “bass,” or Box 818 ture products advertise and conduct other terms that might take a search Rhinelander, WI 54501 business on the Internet. All aspects of engine to sites of interest. When you 715-365-7616 pond aquaculture are represented by find a good web site, save it as a “book- North-Eastern Region various home pages and mail groups. mark” so you can return to it quickly. Box 10448 Listservers and web pages can provide Green Bay, WI 54307 you with much valuable information. 920-492-5800 77

MANAGING WISCONSIN FISH PONDS

North Central Regional Swenson, W. A. 1999 Commercial aquaculture Aquaculture Center Videos Fish Farming: Some Industry AquaNic homepage Office of the Associate Director, The videos listed below provide either Perspectives. http://ag.ansc.purdue.edu/aquanic/ Department of Animal Ecology general or detailed information on pond Contact: University of WisconsinÐ Provides access to information on 124 Science II, Ames, Iowa, 50011 culture. Most titles are available through Extension county Extension offices commercial aquaculture. 515-294-5280 the North Central Regional Aquaculture or Media Resources Center Aquaculture Institute More than 100 specialized publica- Center. For more titles, see the AquaNic University of WisconsinÐSuperior Great Lakes Research Facility tions and videotapes on most web site. Superior, WI 54880 600 E. Greenfield aspects of commercial aquaculture. Kulka, K. and E. Norland. 1993. Weed 715-394-8340 Milwaukee, WI 53204 University of Wisconsin Control in Ohio Ponds Contact: (General. 22 minutes). 414-382-1700 Aquaculture Program Ohio State University Extension Swenson, W. A. 1990 A research center that focuses on 123 Babcock Hall Piketon Research and Extension Managing Ponds aquaculture. 1605 Linden Drive Center, 1864 Shyville Road Contact: University of WisconsinÐ Aquaculture Magazine University of WisconsinÐMadison Piketon, Ohio 45661 Extension county Extension offices P.O. Box 2329 Madison, WI 53706 614-289-2071 or Media Resources Center Asheville, NC 28802 608-263-1242 (Detailed. 30 minutes, University of WisconsinÐSuperior 704-254-7334 A research center that can provide Note: Fifteen titles covering a range Superior, WI 54880 A trade magazine with articles on all up-to-date information on pond of topics available). 715-394-8340 subjects of aquaculture; aquaculture. Swann, L. 1993. Investing in (General. 22 minutes). issued bi-monthly; $19/year. Wisconsin Aquaculture Association Freshwater Aquaculture Aquaculture News Box 115 North Central Region Aquaculture P.O. Box 416 Lewis, WI 54851 Center Video Series 103 Jonesville, AL 71343 715-653-2271 Contact: Aquaculture Extension 318-339-4660 http://www.wisconsinaquaculture. Office. Dept. of Animal Science A monthly newspaper providing com/ Purdue University information on aquaculture, Meetings and the newsletter, West Lafayette, IN 47909 especially in the U.S. Creel, provide key information on 317-494-6264 aquaculture in Wisconsin. (Detailed. 95 minutes Fish Farming News Note: Other titles available). P.O. Box 37 Wisconsin Department of Agriculture, Stonington, ME 94681 Trade and Consumer Protection 207-367-2396 2811 Agricultural Drive A bi-monthly newspaper that Madison, WI 53704 provides information on all aspects 608-267-9644 of aquaculture; $10/year. Information on planning, grants and loans. 78

MANAGING WISCONSIN FISH PONDS

Marriage, L. D., A. E. Borell, & P.M. Further Reading Schaefer. 1971. Trout Ponds for Life in ponds Identification of fishes Recreation. Farmer’s Bulletin No. (General—identification of Becker, G.C. 1983. Wisconsin Fishes. Pond planning and construction 2249, U.S. Dept. of Agriculture Soil University of Wisconsin Press, Gibson, G. R., Jr. 1979. Conservation Service, organisms, biology, ecology) 114 North Murray Street, A riparian’s guide for self-help inland Washington, D.C., 13 pp. Amos, W. H. 1967. The Life of the Pond. Madison, WI. 53715, 1054 pp lake water quality management. Schrouder, J.D. et.al. 1994. Managing McGraw-Hill Book Co., New York, Eddy, S. and J. C. Underhill. 1974. Extension bulletin E-1117 Michigan Ponds for Sport Fishing 232 pp. Northern Fishes. University of Michigan State University (E1554). Michigan State University, Coker, R. E. 1968. Streams, Lakes, Minnesota Press, East Lansing, 67 pp. Lansing, 67 pp. Ponds. Harper & Row, New York, Minneapolis, MN, 414 pp. U.S.D.A. Soil Conservation Service 327 pp. Scott, W. B., & E. J. Crossman. 1973. (revised 1997). Prospects for commercial Klots, E. B. 1966. A New Field Book of Freshwater Fishes of Canada. Bull. Ponds—Planning, Design, aquaculture Fresh Water Life. G. P. Putnam’s 184, Fisheries Research Board of Construction. Sons, New York, 398 pp. Canada, Ottawa, 966 pp. Agriculture Handbook No. 590. Cain, K. and D. Garling. 1993. Reid, G. K. 1967. Pond Life: A Guide to U.S. Dept. of Agriculture. Trout culture in the North Central Common Plants and Animals of Identification of aquatic Washington, D.C., 85 pp. Region. North Central Regional Aquaculture Center. North American Ponds and Lakes. invertebrates Golden Press, New York, 160pp. Pond fishery management Fact Sheet Series # 108. Pennak, R. W. 1978. Freshwater Ward, H. B., & G. C. Whipple. 1959. Bennett. G.W. 1971. Chopak, C.J. 1992. Promoting fee Invertebrates of the United States. Fresh-water Biology. 2nd Edition Management of Lakes and Ponds fishing operations as tourist attrac- Wiley, New York, 803 pp. (W. T. Edmondson, ed.). Wiley Sons, Van Nostrand Reinhold tions. Michigan State University Hilsenhoff, W. L. Aquatic Insects of New York, 1248 pp. New York, 375 pp. Extension bulletin E-2409 Wisconsin (G3648). Publ. No. 2, Eipper, A. W., & H. A. Regier. 1962. Chopak, C.J. 1992. What consumers Nat. Hist. Council, Univ. of Fish Management in New York want: advice for food fish growers. WisconsinÐMadison, 60 pp. Available Farm Ponds Extension Bull. 1089. Michigan State University Extension from Cooperative Extension Cornell Univ., Ithaca. Bulletin E-2410. Publications, Rm. 170, 630 W. Mifflin St., Lopinot. A. C. 1972. Pond Fish and Chopak, C.J. 1992. What brokers, Madison, WI 53703, Fishing in Illinois. Fishery Bull. wholesalers, retailers and restau- toll free 1-877-WIS-PUBS (947-7827). No. 5, Illinois Dept. of Conservation, rants want: advice for food fish Division of Fisheries, growers. Michigan State University Springfield, IL 62706, 72 pp. Extension Bulletin E-2411. Garling, D.L. 1992. Making Plans for Commercial Aquaculture in the North Central States. North Central Region Aquaculture Center, Fact Sheet Series #101. 79

MANAGING WISCONSIN FISH PONDS

Nichols, S.A., S. Engel and T. McNabb, Further reading on fish parasites and Identification of aquatic plants Nutrient over-enrichment and 1988. Developing a plan to manage diseases. Note that there are numerous Borman, S., R. Korth and J. Temte. aquatic plant problems/control lake vegetation. Aquatics 10:(3) free pamphlets available on this topic. 1997. Through the looking glass, a 10Ð19 Applied Biochemists, Inc. 1976. How to Post, G. 1987. Textbook of fish health. field guide to aquatic plants. Pub. identify and control water weeds and Smith, S.A., D.R. Knauer and T. L. TFH Publications, Neptune City, FH-207-97, Wisconsin Department of algae. 5300 West County Line Road, Wirth. 1975. Aeration as a lake man- New Jersey Natural Resources, Madison, WI, Mequon WI, 64 pp. agement technique. Tech. Bull. 87, Hoffman, G and F. Meyer. 1974 248 pp. Wis. Dept. Natural Resources, Helsel, D. and S. Syzmanski, 1999. Parasites of freshwater fishes: A Fassett, N. C. 1957. A manual of aquatic Madison, 39 pp. Management of Aquatic Plants and review of their control and treatment. plants. University of Wisconsin Algae in Ponds: Protecting Your TFH Publications, Neptune City, New Press, 2537 Daniels St., Madison, Piece of Paradise. Department of Wildlife damage control Jersey, 224 pp. WI. 53704, 405 pp. Natural Resources (DNR) publcation University of Nebraska. 1995. Handbook Sniezko, Stanislas. 1971. Diseases of Hoyer, M.V. and D. E. Canfield, Jr., eds. #FH228. Wisconsin Lakes of wildlife damage control. Available fishes—bacteria.TFH Publications, 1997. Aquatic plant management in Partnership, Stevens Point, WI 15 pp. from most Wisconsin county Extension Neptune City, New Jersey. lakes and reservoirs. Prepared by offices, or from your Extension wildlife Lopinot, A.C. 1979. Aquatic weeds: their the North American Lake specialist. identification and control. Fishery Pond management Management Society and the Bull. No. 4. IL Dept. of Conservation, Aquatic Plant management Soceity Illinois Dept of Conservation, 1990. Springfield, 56 pp. Fish health for U.S. Environmental Protection Management of small lakes and Richard Nelson, Director Agency, Washingtn, D.C., 103 pp. McNabb, C. D., Jr. 1977. Aquatic Plant ponds in Illinois. Div. of Fisheries, Problems in recreational lakes of U.S. Fish and Wildlife Service Springfield. 72 pp. Prescott, G. W. 1964. How to know the southern Michigan. Extension Bull. LaCrosse Fish Health Center freshwater algae. Wm. C. Brown E-1 135, Michigan State Univ., East 555 Lester Ave. Co., Dubuque, Iowa, 348 pp. Lansing, 25 pp. Onalaska, WI 54650 Stodola, J. 1967. Encyclopedia of water 608-783-8444 McComas, S. 1994. Lake smarts. plants. T. F. H. Publications, Terrene Institute, 1717 K Street NW, Neptune City, N.J, 368 pp. Washington, DC 20006, Voss, E.G. 1972. Michigan flora Part I. 202-833-8317 Bull. 55. Cranbrook Inst. of Science, Nichols, S. A. 1974. Mechanical and Bloomfield Hills, MI, 488 pp. habitat manipulation for aquatic plant management. Tech. Bull. 77, Wis. Dept. Natural Resources, Madison, 34 pp. Authors: Jim O. Peterson and Stanley Nichols are professors and Extension specialists with the Environmental Resources Center at the University of WisconsinÐMadison. William Swenson is a professor and Extension fishery specialist at the University of WisconsinÐSuperior. Scott Craven is a professor of wildlife ecology with the University of WisconsinÐMadison and a wildlife specialist with the University of WisconsinÐExtension. Jeff Malison is director of the University of Wisconsin- Madison Aquaculture Program. Thomas Thrall is an aquatic biologist with the U.S. Natural Resources Conservation Service. Susan Marcquenski is a fish health specialist with the Wisconsin Department of Natural Resources. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, University of WisconsinÐExtension, Cooperative Extension. University of WisconsinÐExtension provides equal opportunities in employment and programming, including Title IX and ADA requirements. If you need this information in an alternative format, contact the Office of Equal Opportunity and Diversity Programs or call Extension Publishing at (608)262-2655. © 2000 by the Board of Regents of the University of Wisconsin System doing business as the division of Cooperative Extension of the University of WisconsinÐExtension. Send inquiries about copyright permission to: Director, Cooperative Extension Publishing, 201 Hiram Smith Hall, 1545 Observatory Dr., Madison, WI 53706. You can obtain copies of this publication from your Wisconsin county Extension office or from Cooperative Extension Publications, 45 N. Charter St., Madison, WI 53713 (608)262-3346. Outside Madison, call our toll free number: 1-877-WIS- PUBS (947-7827). Before publicizing, please check on this publication’s availability. To see more Cooperative Extension publications, visit our web site: http://www.uwex.edu/ces/pubs/ Managing Wisconsin Fish Ponds (G3693) I-6-00-3M-000