Summerfelt, R. C. , C. P. Clouse, L. M. Harding, and J. M. Luzier 1996. Walleye fingerling culture 

in drainable ponds. Pages 89-108 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC 

Culture Series 101. North Central Regional Aquaculture Center Publications Office, Iowa State 

University, Ames. 

Walleye Fingerling Culture 

in Drainable Ponds 

Robert C. Summerfelt, Christopher I? Clouse,’ Lloyd M. HardingJ2 and James M. LuzieP, Department of 

Animal Ecology, Iowa State University, Ames, IA 5001 7-3221 

Introduction 

Intensive culture of walleye from fry to fingerlings is a 

promising new technology (Summerfelt 1996), but at 

this time nearly all walleye fingerlings are raised in 

earthen ponds by state and federal agencies and by the 

private sector (Le., commercial farms). Because of the 

scope and dwersity of cultural methodologies for pond 

culture, the subject has been divided into ths chapter on 

drainable ponds and another for undrainable ponds 

(Kinnunen 1996). The objective of this chapter is to 

provide a literature review and a summary of the case 

studies on culture of walleye in drainable ponds. 

Phase I and Phase II fingerlings 

walleye harvested at a total length of 1.25 to 3.0 in 

(32-76 mm) in June to early July are called “summer 

fingerlings”, or “phase I fingerlings”; fish raised to the 

end of the growing season are called “fall fingerlings” 

or “phase I1 fingerlings”. Phase I and phase I1 fingerlings are traditional terminology in the culture of striped 

bass and its hybrids (Harrell et al. 1990). These terms 

are not common in walleye culture, but I think they are 

useful ways to designate the two size groups of fingerlings. Moreover, pond culture of phase I walleye and 

striped bass have much in common, they both use 

similar pond management strategies. The chapters by 

Geiger and Turner (1990) and Brewer and Rees (1990) 

in the culture manual for striped bass and its hybrids are 

highly recommended (Harrell et al. 1990). 

The similarity between culture of phase I1 walleye and 

striped bass fingerlings is far less, but a comparison is 

instructive, perhaps to make a case for future research. 

In striped bass culture, phase I fingerlings are fed 

formulated feed, 1-2 times daily in the pond for at least 

two weeks before harvest to convert them from live to 

formulated feed (Smith et al. 1990). After harvest, they 

may be restocked drectly into ponds, sometimes after 

grading to increase uniformity of size, or brought to the 

hatchery building for habituation to formulated feed. 

After restocking in ponds, they are raised on formulated 

feed and harvested in the fall as advanced juvenile, 

phase I1 fingerlings. Because they are raised on 

formulated feed, stoclung densities are generally higher 

and size at harvest larger (average size of 12.6 fisMb 

[27.2/kg]) than practices for raising phase I1 walleye. 

Walleye culturists also produce a phase I1 fingerling in 

ponds, typically with minnows, but sometimes on 

invertebrate prey. For example, at the North Platte State 

Fish Hatchery, North Platte, Nebraska, small-630-749/ 

lb (1 -6- to 1.7-in total length) in 1987 and 702-1,287/1b 

(1.68- to 1.37-in) in 1988-phase I walleye fingerling 

were restocked at 10,00O/ac (25,00O/ha) and raised an 

addtional79-85 days without minnows (Ellis 

1987,1988). At harvest, the phase I1 fingerlings averaged 74Ab (3.5-in ) in 1987 and 97Ab (3.2 in) in 1988. 

More typically, however, phase I1 fingerlings are raised 

by stocking minnows. Jorgensen (1996) raised a 5- to 6- 

in (13- to 15-cm) fall fingerlings in a 57-acre (23 ha) 

undrainable pond; after a partial harvest of phase I 

Current address: Milford State Fish Hatchery, Kansas Game and Parks Department, 3100 Hatchery Drive, Junction City, 

Kansas 66441. 

Current address: Coldwater Fish Farms, Inc., Box 1, Lisco, Nebraska 69148. 

Current address: University of Iowa, Hygienic Laboratory, Henry A. Wallace Building, Des Moines, Iowa 5031 9. 

NCRAC Culture Series 101 - Walleye Culture Manual 89 
fingerlings, which also reduces the population density, 

fathead minnow were stocked weekly to be used as 

prey. Raisanen (1 996) reported that it is cost prohibitive 

for the private sector to raise walleye fingerlings to 

advance size by feeding minnows, which can cost $0.5- 

3.00/lb ($1.10-6.60kg). With a 4:1 food conversion of 

minnows to walleye, a 5-in (125 mm) fingerling would 

consume $0.08-0.45 of minnows. Because minnows are 

expensive, not always available, and the fact that the 

conversion ratio is high, the preferred method by many 

state and federal hatcheries is to transfer phase I 

fingerlings to hatchery tanks or raceways for habituation to formulated feed. It is less expensive to raise 

walleye on commercial fish feed than minnows. 

Many public hatcheries raise phase II fingerling by the 

tandem pond-tank culture method (Malison and Held 

1996). In ths process, pond-raised phase I fingerlings 

that are 1.4 to 2.5 in (36-65 mm) are transferred to 

indoor culture tanks and habituated to formulated feed, 

and raised to 5 to 7 in (127-178 mm) (Bristow 1996; 

Flowers 1996; Nagel 1996). Once habituated to tank 

culture, they may be raised to food size (Flickinger 

1996). A variety of factors have been stu&ed, includmg 

stockmg density, temperature, light, &et, and feedmg 

frequency (Nickum 1986; Kuipers and Summerfelt 

1994). 

Research on training phase I walleye to feed in ponds in 

the manner that is done with striped bass or their 

hybrids, has not been reported. However, after phase I 

walleye fingerlings are habituated to feed in hatchery 

tanks, it is possible to restock them in ponds and raise 

them on pelleted feed. Nagel (1 974. 1976, 1996) has 

maintained walleye broodstock in ponds by hand 

feeding floating trout chow during at twilight or before 

sunrise. Several generations of the London (Oho) strain 

walleye have produced a walleye stock that exhbits 

behavioral characteristics of domestication: reduced 

excitability and cannibalism, and easier to train to 

formulated feed (Nagel 1995). 

Fish production in drainable ponds 

In the U.S., drainable (levee or diked) ponds are the 

major type of culture environment for raising channel 

catfish, golden shiner, goldfish, striped bass, sunfish, 

and black basses (Dupree and Huner 1984). The choice 

between drainable or undrainable ponds to raise walleye 

fingerlings by state agencies in the Midwest is usually 

influenced by the availability of natural water bodies. 

Minnesota has an abundance of prairie pothole and 

shallow lakes that do not sustain a permanent fish 

population because of winterkill; therefore, more than 

in any other state, most fingerling production in 

Minnesota is in undrainable ponds (Daily 1996; 

Lilienthal 1996). Michigan, Wisconsin, and Iowa use 

both drainable and undrainable ponds (Gustafson 1996; 

Jorgensen 1996). Ohio, Indiana, Illinois, Missouri, 

Kansas, Nebraska, South Dakota, and North Dakota 

raise most of their walleye fingerlings in drainable 

ponds. US Fish and Wildlife Service fish hatcheries in 

North Dakota (Valley City National Fish Hatchery 

[VCNFH] and Garrison Dam National Fish Hatchery 

[GDNF]) and South Dakota (Gavins Point National 

Fish Hatchery [GPNFH]), produced 73% of all fingerlings walleye raised by the federal hatchery system in 

1990 (FWS 1991). GDNF has sixty-four 1.5-acre (0.61 

ha) ponds which make it the largest pond culture 

hatchery in the Fish and Wildlife Service raising 

walleye fingerlings. It seems that the several hatcheries 

of the Ohio Department of Natural Resources have 

more total drainable ponds used for walleye fingerling 

production than any other state agency. The White Lake 

Fish Culture Station, the only government hatchery in 

Ontario that raises walleye, produces 200,000 summer 

fingerlings from 2.6 acres (1.4 ha) of drainable ponds 

(Flowers 1996). 

Comparison of drainable and undrainable 

ponds 

The characteristics of drainable and undrainable ponds 

and the cultural technology that are used in these ponds 

differ (Table 1). Apart from the unique, 100-acre (40.5- 

ha) drainable pond described in the case study by 

Wright (1 996), undrainable ponds are generally much 

larger than drainable ponds. On the other hand, the key 

to success and popularity of drainable ponds for 

production of large numbers of walleye fingerlings is 

the ability to manage water, fertilize, and harvest 

efficiently. Survival and yield to a phase I fingerling is 

greater in drainable than undrainable ponds (Table 4): 

Clearly, if the cost of fry and labor for harvest is 

important, drainable ponds are superior to undrainable 

ponds for production of phase I fingerlings. 

Most undrainable ponds lack water level control. They 

may have an excessive outflow of water, which could 

cause a loss of walleye; conversely, they may have no 

90 NCRAC Culture Series 101- Walleye Culture Manual 
Table 1. Comparative characteristics and management strategies for drainable and 

undrainable ponds (space contraints did not allow both English and metric units). Detailed information for some items is found in Table 4. 

Manage men t opt ions Drainable ponds Undrainable ponds 

Size (acres) 

Stocking density 

(No ./ac re) 

Survival (%) 

Yield (Ibs/acre) 

Harvest methods 

Trapping (fyke nets) 

Seining 

Drain fish to catch basin 

Harvest 

Options for sequential 

fish crops 

Fertilized 

Water management options 

Drain, dry, and disk pond bottom 

Seeding of pond bottom 

with rye grass 

Vegetation control 

Presence of unwanted fish 

(predators or competitors) 

0.5 to 2.0 

25,000 to 240,000 (Table 4) 

100,000 to 1 52,0005 

100,000 to 1 58,0006 

46 to 76% (Table 4); 61 .3-68.45 

19-year mean, 6O.9Yo6; 

3-year mean, 76yo7 

61 to 11 9 (Table 4) 

Yes 

Yes 

Yes 

Harvest all fingerlings that 

are alive at time of harvest 

Dou bl e-cropp i ng common: 

trout-walleye 

northern pike-walleye 

walleye-catfish 

Standard procedure (Table 3) 

Maintaining level and water 

quality control 

Common 

Possible option 

Pre-emergent treatment of pond 

bottom before flooding 

Rare (source: inflowing water) 

1 to loo1, mean 582, 

0.5 to 4031 5 to 1 504 

2,500-30,000 (Table 4) 

3.2 to 30% (Table 4) 

10-1 5%', 5-7.5Y02, 3Oyo3, 

3.5Y04 

4.6 to 33 (Table 4) 

Yes8 

Uncommon 

No 

Impossible to harvest all fish 

Double-cropping not possible 

Uncommon to fertilize 

Usually not able to add water to 

rep1 ace evapo rat ion 

Not possible 

Not possible 

Must be applied to entire water 

volume 

Common, may require fall 

poisoning 

'Commercial ponds (Gunderson 1996); 2Minnesota DNR (Lilienthall 1996); 3Michigan DNR (Gustafson 1996); 4Raisanen (1 996); 

5Harding and Summerfelt (1993); %Summerfelt et al. (1993); 7Call (1996); aHarvest with traps or fyke nets typically requires several 

applications of copper sulfate to stimulate movement of fingerlings. 

NCRAC Culture Series 101 - Walleye Culture Manual 91 
water inputs when it is most needed. Control of water 

level in drainable ponds can prevent fish loss. Ponds are 

not filled to the top- a 3- to 6- in (75-150 mm) 

freeboard is maintained to prevent overflow and fish 

loss after heavy rain. 

Many public hatcheries double-crop their drainable 

ponds; trout-walleye (Flowers 1996), northern pikewalleye (Call 1996); or walleye-channel catfish 

(personal observation). At White Lake Fish Culture 

Station in Ontario, ponds may be used to raise salmonids over winter, then drained and dried for at least 10 

days before refilling for the walleye culture season. At 

GDNFH, incubation temperature for walleye is deliberately lowered to delay walleye hatch of until a crop of 

northern pike can be harvested (Call 1996). 

Harvest from undrainable ponds requires the use of 

seines, traps, or fyke nets. The cost of seines, traps, and 

nets, annual maintenance, and substantial personnel 

time needed to harvest undrainable ponds should be 

considered when comparing costs for raising of 

fingerlings in drainable vs undrainable ponds. The large 

drainable pond described in the case study by 

Wawronowicz and Allen (1996) was also harvested by 

seining and use of fyke nets, but complete harvest of 

drainable ponds is generally accomplished by draining. 

Draining ponds eliminates unwanted fish, tadpoles, and 

crayfish. Unless a complete winterlull is obtained, a 

piscicide must be applied to undrainable ponds (usually 

in the fall), to eliminate the carryover of walleye and 

other fish which will prey on or compete with walleye 

for food. Although the unharvested portion of walleye 

stocked in the pond may die from winterkill, bullheads, 

fathead minnow and other fish that are more tolerant to 

winter conditions may survive. After harvest, drainable 

ponds can be planted with a cover crop, or the pond soil 

can be dried and disked. Drying before refilling reduces 

aquatic vegetation and oxidizes accumulated organic 

matter (Flowers 1996). 

Watershed ponds 

The visual image of a pond by many people would be a 

watershed (hill) pond; they are abundant and more 

likely to have been observed than drainable fish 

hatchery ponds. The US Soil Conservation Service 

(SCS) provided technical assistance for the construction 

of more than 2.5 million farm watershed ponds between 

the mid-1930s and 1980; since 1980, an additional 

50,000 ponds have been installed without SCS assistance (Henry and Gabell 1981). Watershed ponds may 

be equipped with drains, but these ponds were not 

designed for culture fish, and once drained, they may 

require one or more years to refill from runoff. Thus, 

when watershed ponds are used for fish culture, they are 

seldom drained and they best fit the category of 

undrainable rather than drainable ponds. Also, unless 

fish culture was intended when they were first constructed, seining may be ineffective because the pond 

may have snags or be too deep. 

Watershed ponds represent a sizable water resource: 

they are valuable for watering livestock and for sport 

fishing. For the most part, the use of watershed ponds 

for commercial fish culture is limited. Even so, watershed ponds are used for walleye fingerling production 

by a few commercial producers. 

Other types of undrainable ponds 

There are other types of undrainable ponds, including 

shallow lakes, marshes, borrow pit ponds, and dug 

ponds that are filled to the level of the water table 

(Kinnunen 1996). Commercial producers of walleye in 

Minnesota mainly operate in the west-central part of the 

state where there are numerous natural winterlull 

ponds; they are used for production of walleye, baitfish, 

and leeches by the private sector (Raisanen 1996). 

Design criteria for drainable ponds 

Typical drainable ponds are small artificial bodes of 

water with levees on four sides that are designed to 

grow fish. Harvest is done by draining the pond through 

an upright structure called a “monk.” Details on design 

features of drainable ponds can be found in most 

general aquaculture texts (e.g., Piper et al. 1982; Huner 

and Dupree 1984; Huet 1986; Stickney 1994). A 

summary of the major criteria for drainable ponds are 

listed in Table 2. 

Water supply 

Water supply issues will not be discussed, but water 

requirements for filling ponds are substantial: a 1-acre 

(0.4 ha) production pond with an average depth of 4 

feet (1.2 m), requires 4 acre-feet (4,934 m3) or 1.3 

million gallons for filling without accounting for 

seepage or water absorption in the levees. A flow of 300 

gpm (1,135 Lpm) is needed to fill this a pond in 3 days. 

Over the culture season, addtional water is needed to 

92 NCRAC Culture Series 101- Walleye Culture Manual 
Table 2. Design characteristics for drainable earthen ponds. 

Item Characteristics 

Water supply 

Size 

Shape 

Depth’ 

Basin slope 

Freeboard 

Levee slope 

Fish collection basin 

for harvest 

Sufficient to fill individual ponds in 2 to 3 days, and all ponds 

to be used in the culture season must be fillable in 20 days. 

1 to 2 acres (0.4 to 0.8 ha) 

Rectangular, length (L):width (W) ratio = 2:l 

Deep end, 4-6 ft (1 -2-1.8 m), shallow end 3-4 ft (0.9-1.2 m) 

0.2 to 1 ft per 100 ft pond length 

1.5 to 2 ft (0.5-0.6 m) between water level and crown. 

Inside levee = 3:l; range from 2.5 to 4:l. 

Outside levee, 2:l 

Location outside of the pond is superior to inside location. 

’Depth is for a production pond, not one used to overwinter fish. 

replace losses from seepage and evaporation. The 

volume needed for a fish hatchery can be substantial. 

For example, at North Platte State Fish Hatchery 

(NPSFH), North Platte, Nebraska sixteen 1-acre (0.4- 

ha) ponds (Figure 11) are filled in one week (Harding 

and Summerfelt 1993). Most state and federal hatcheries are located below large dams where they can gravity 

flow of large volumes of water. However, nearly all 

catfish farms in Mississippi, which held 65% of the 

inventory of the number of food-size (small, medmm 

and large) catfish in the US (ERS 1996) pump ground 

water to fill ponds. 

Site selection 

Site selection is critical. Ponds must be located close to 

their water supply and where the subsoil has enough 

clay to retain water. As a rule to prevent excessive 

leakage, the soil profile to a depth 5 ft (1.5 m) below the 

projected pond surface should have at least 20% clay. 

Sandy soils, gravely areas, and fissured rock substrates 

are unsuitable because they will not hold water. Plasticlined ponds, which are very expensive, are required 

when ponds are constructed on highly permeable soils. 

Size and dimensions 

Although Wright (1996) reports the use of a 100-acre 

(40-ha) drainable pond in northern Michigan, a desirable size for levee ponds for fingerling production is 1 

to 2 acres (0.4 to 0.8 ha). 

Small ponds allow for 

complete and suficient 

draining and harvest. Large 

ponds require partial harvest 

by staged draining and seining 

or night harvest (Figure 9) 

with lift nets or seines. 

A 2: 1 (L:W) ratio of length (L) 

to width (W) for a rectangular 

pond is suitable. The &mensions for a given pond to 

achieve this ratio can be 

calculated from the pond size: 

e.g., for a 1 acre (43,560 ft’) 

(0.4 ha) pond, the W = dared2 

and L = 2W: thus, W = 

443,560 ft2/2 = 147.6 ft (45.0 

m) and L = 295.2 ft (90.0 m). 

The bottom must slope 

gradually to the outlet (drain): Huner and Dupree 

(1984) suggest 2.5 in (6.4 cm) per 100 ft (30.4 m) of 

linear &stance (probably with 10 to 20 acre ponds in 

mind); Stickney (1994) states that 1 % (1 ft drop per 100 

ft of linear distance) is an acceptable ratio for smaller 

ponds. A 1:lOO ratio would require a 3 ft (0.9 m) 

difference in depth (3 ft (0.9 m) at the shallow end and 

6 ft (1.8 m) at the deep end for a pond 300 feet long, 

which may be somewhat steep for a 1-acre (0.4 ha) 

pond. 

Monk and catch basin 

A water control structure (“monk”) and catch basin 

(“kettle”) for harvest are two essential components. The 

monk is usually an upright structure of poured concrete 

(Figures 1 and 2) that contains a drain pipe with a gate 

valve (Figure 3), a slot for a screen, and two slots for 

dam boards to regulate water depth. Plastic gate valves 

with simple push-pull design are available. A wooden 

monk also is available from a commercial source that 

can be installed for much less than the large concrete 

structures. A less elaborate, and lower cost monk and 

drain setup is illustrated in Figure 4. The most basic 

alternative is to use only a turndown standpipe (i.e., one 

that has a threaded elbow or swivel that can be turned 

down at the elbow) and a depression in the pond bottom 

to serve as the catch basin for harvest. 

NCRAC Culture Series 101 - W a l l e y e C u l t u r e Manual 93 
Gate valve 

Dam boards 4 /Screen 

Outside catch basin 

Dam boards 

I Screen 

-2. Water I eve I 

%. , 

Inside catch basin 

II 1 II I Pond 

bottom 

Kettle 

Drain line 

Figure 1. Cross section through the monk and dam of a drainable pond to illustrate the location of a catch basin 

inside (right) and outside (left) of the pond. 

The dam boards in the monk may be set to discharge 

water from the bottom of the pond (Figure 1); however, 

because fry cannot be effectively screened, there should 

be no outflow from the pond as the “fry go with the 

flow.’’ Fry losses from overflow may be considerable. 

Water should be maintained sufficiently below the level 

of overflow to receive a normal rain without an overflow. 

Whatever the type of control structure, a catch (capture) 

basin for harvesting the fish is essential. The catch 

basin increases the efficiency of harvest and reduces 

stress to the fish. The catch basin 

may be located inside or outside of 

the pond. When located inside the 

pond it is commonly an integral 

part of the monk. At some state and 

federal hatcheries, ponds with an 

inside catch basin are equipped 

with a concrete stairway between 

the catch basin and the top of the 

dike to facilitate carrying the fish 

from the catch basin to the top of 

the levee (Figure 2). Two types of 

external catch basins for fish 

harvest are illustrated in the case 

studies by Call (1996) and Wright 

(1 996). 

located outside of the pond (Figure 6), which is highly 

recommended to facilitate harvest. The external catch 

basin that is accessible by the hatchery truck for direct 

loading of the fingerlings increases the efficiency with 

which ponds can be drained and the fish shipped out. 

Although individual ponds may require 2 to 3 days to 

drain, an outside catch basin is an asset that allows a 

small staff at public hatcheries to efficiently harvest 

three to four ponds each day, each with 136,000 

fingerlingdacre (336,00O/ha). Staff at the Garrison Dam 

National Fish Hatchery harvest 10 million walleye 

The catch basin should be provided 

with a water supply to maintain 

water quality in the basin during 

harvest (Figure 5). At other 

hatcheries, the catch basin is 

Figure 2. Culture pond with concrete outlet structure, inside catch basin 

(kettle), and stairs. It is important that the pond slope to the catch basin for 

complete drainage into the kettle. 

94 NCRAC Culture Series 101- Walleye Culture Manual 
Figure 3. Gate valve located in 

monk. 

Figure 4. Pond at commercial fish farm with simple concrete monk that is 

built into the levee of culture pond. A supply of freshwater has been 

provided near the monk. Bumps in the catch basin are mostly turtles. 

fingerlings per season using this system (Call 1996). 

Although such structures may seem to be luxuries, the 

alternatives are to use a crane to lift the fish, which is 

how catfish are harvested in the south, or personnel will 

have to slog up and down wet pond banks with tubs of 

fish and water. Ponds of the Ohio Department of 

Natural Resources London Fish Hatchery have been 

constructed to drain ponds directly 

to a tank in the hatchery buildmg 

(Nagel 1996). A similar feature has 

been used at a large walleye farm 

in Minnesota, however, they have 

found that because mechanical 

damage occurs when fish are 

drained to the hatchery building, 

they remove most fish from the 

pond by seining. The inside catch 

basin is used only to capture fish 

that would otherwise escape during 

pond draining (Tom Hertz, 

Brandon Fisheries, Brandon, 

Minnesota, personal communication). 

tion, scheduling pond filling in relation to the anticipated hatch interval, fertilization (kinds, amounts, and 

application schedule), stocking density, zooplankton 

inoculation, control of problem organisms (aquatic 

insects, clam shrimp and vegetation), water quality 

management (aeration, etc.), and harvest (drain, drain 

and seine, or night harvest with lights). 

Management of drainable 

ponds 

Management of drainable ponds 

include options for pond preparaFigure 5. The catch basin in this pond has a water supply to maintain water 

qual i ty du r i ng harvest. 

NCRAC Culture Series 101 - Walleye Culture Manual 95 
Figure 6. An outside catch basin at the Garrison Dam National Fish Hatchery, 

Riverdale, North Dakota. A schematic design for this catch basin is given in 

the case study by Call (1 996). 

screens. When ponds have been 

left empty over winter, filling is 

usually timed in relationship to 

the expected date that walleye 

eggs hatch and in relationship to 

strategies for zooplankton 

development. The time between 

pond filling and fry stoclung 

varies from 1 to 28 days: “just 

before fry are ready to be 

stocked” (Culver 1996); 9 days 

after pond filling at GDNF (Call 

1996); 10 days after pond filling 

(Raisanen 1996); 2 weeks at the 

Ontario Ministry of Natural 

Resources White Lake Fish 

Culture Station, Ontario 

(Flowers 1996); and 4 weeks on 

the Lac du Flambeau Indmn 

Reservation (Wawronowicz and 

Allen 1996). Some differences 

Pond prepara tion 

At some hatcheries, pond preparation begins immediately after harvest. The wet pond bottom is seeded with 

rye grass (Call 1996; Wawronowicz and Allen 1996). In 

other hatcheries, the pond may be used again in the 

same season to culture phase I1 fingerlings or to culture 

another species. The pond can be dried and disked in 

the fall. After harvest, ponds 

on the Lac du Flambeau 

Indian Reservation are seeded 

with rye grass, but they are 

usually allowed to “seep” dry, 

which they regard as a natural 

way to trigger crustaceans to 

produce resting eggs for the 

next production season 

(Wawronowicz and Allen 

1996); their ponds remain dry 

over winter. 

are a matter of scheduling but definite differences in 

opinion on pond-filling strategy are also evident: two 

weeks for zooplankton development (Flowers 1996), to 

that of choosing to fill the ponds only a few days before 

fry are stocked, “...so that the abrupt plankton decline 

that occurs 4-5 weeks after ponds are filled will occur 

as late into the production season as possible” (Culver 

Pond filing 

In the case studies cited in 

this manual, the drainable 

ponds are filled from surface 

water sources containing fish; 

therefore, the water is filtered 

in various ways to exclude 

fish and fish eggs: metal 

microstrainer, sand filter, or 

Figure 7. Direct loading of phase I walleye fingerlings from the external catch 

basin to the hatchery truck for distribution at the Garrison Dam National Fish 

Hatch e ry. 

96 NCRAC Culture Series 101- Walleye Culture Manual 
1996). However, in using organic fertilizers, chironomid larvae and pupae, not zooplankton, are more 

important prey for walleye after 2 to 3 weeks, or when 

fingerlings reach about 1 in (22 mm) (Fox et al. 1989; 

Fox and Flowers 1990; Summerfelt et al. 1993). 

At most hatcheries, once pond filling is started, ponds 

are filled in 1 to 3 days, basically as quickly as the 

water supply will allow. On the other hand, a staged- or 

gradual-filling process is a purposeful procedure to 

concentrate newly stocked fry and zooplankton to 

facilitate first-feedmg, and production of new hatches of 

zooplankton with each subsequent increment in pond 

filling. Bushman (Richard Bushman, Illinois Department of Conservation, personal communication) fills 

ponds slowly to continually add zooplankton from the 

water supply; the pond filling strategy is designed to 

take advantage of an abundance of zooplankton in the 

water supply. Slow pond filling has not in itself been a 

subject of research, it is often inadvertently done when 

a continuous addition of water is necessary to replace 

water loss from evaporation and/or seepage. At NPSFH, 

the addition of water may be equivalent to the total 

volume of the pond every 10 days. Inflow water at this 

hatchery contained about 500 zooplanktonL The 

inflow represented 54 zooplanktodL of pond volume, 

which was as much as 15% of the average density of 

zooplankton in the pond (Hardmg and Summerfelt 

1993). 

Monitoring growth and survival 

Walleye may be seined or trapped to monitor growth 

and abundance (i.e., survival). Walleye are strongly 

attracted to light when they are 9 to 32 mm total length, 

thereafter they change from positive to negative 

phototaxis (Bulkowsh and Meade 1983). During the 

interval when they are attracted to light, they can be 

attracted into an illuminated container, the so-called 

night-light trap (Figure 8). When the container is 

quickly removed from the pond, fish and zooplankton 

that swam into the circular openings are swept to the 

bottom of the trap, which allows water to be drained 

away but retains zooplankton and fish. This night-light 

trap was made by staff at the Southern Illinois UniverLight -, 6-V lantern battery I rap 

E 

Styrofoam 

5-gal bucket, with 4, 

2.5 in holes spaced 

evenly around the sides 

3-in PVC 

710 Nytex 

fi Internal light 

Styrofoam 

5/8 x 6 in Pyrex 9820@ test tube. 

Top of test tube sealed with silicone 

Light bulb and base 

Figure 8. Night-light trap used to sample walleye fry in ponds: Left photograph illustrates the trap in 

the dark as it might appear to walleye fry in the pond; schematic design (right) for the light trap. 

NCRAC Culture Series 101 - Walleye Culture Manual 97 
sity Fisheries Research Laboratory. It is a modification 

of one of several light traps designs described in the 

literature that are used in hatchery ponds for sampling 

fish larvae and juveniles (Floyd et al. 1984; Secor et al. 

1992). 

Catch per unit effort (CPUE) of larvae captured in the 

light trap may be used as an index of abundance. 

Annual monitoring in many ponds at the same hatchery 

can provide a data base; a regression equation developed from CPUE at specific days posthatch may be 

used to estimate mortality or survival rates from which 

the final population can be estimated. Also, fish that are 

captured in the trap may be measured to determine 

growth and the adequacy of the food supply. Microscopic examination of the fish can be done to determine 

gas bladder inflation, presence of food in the gut, and 

presence of parasites. 

Stocking densify-fertility relationship 

Fertilization strategies for ponds are the most central 

yet the most contentious of all management considerations. Fish culturists want to maximize survival and 

yield (i.e., lb/acre, kgha). It has long been known that a 

functional relationship exists between pond fertility and 

yield of walleye fingerlings (Smith and Moyle 1945; 

Dobie 1956). At the same stocking density, yield is 

linearly related to survival; i.e., the higher the survival 

the greater the yield (Summerfelt et al. 1993). Carrying 

capacity may be limited by stoclung density (density 

limited) or fertility limited, a hstinction that must be 

resolved to determine whether an increase in fertilization is justified. For example, traditionally, ponds at the 

NPSFH were not fertilized and stocking density was 

100,000 fry/acre (250,00O/ha). When stocking density 

was increased to 150,000/ac (375,000ha) without 

addition of fertilizers, yield was unaffected; it was 55.1 

lb/acre (61.8 kgha) from ponds stocked at 100,00O/acre 

and 54.7 lb/acre (61.3 kg/ha) from ponds stocked at 

150,00O/acre (Harding and Summerfelt 1993). Thus, the 

ponds were not density limited, and yield was not 

increased with additional stoclung density. When the 

ponds were stocked with 150,000/acre (375,000/ha), 

and fertilized with 756 lbs/acre (848 kgha) of alfalfa 

pellets, yield was 41 -6% greater from fertilized ponds 

(72.2 lb/acre, 81 .O kg/ha) than the yield from unfertilized ponds (51 .O lb/acre, 57.2 kg/ha). 

Walleye production can also be measured as number of 

fish harvestedacre (Noha). In that case, an increase in 

stocking density may be desired even though yield may 

not increase, but typically, mean size, and probably 

condition, will decrease. For example, at NPSFH, an 

increase in stocking density from 100,000 fish/acre 

(250,000/ha) to 150,000 fish/acre (375,00O/ha), did not 

adversely affect the survival (61.8% vs 61.3%) and 

there was only a small decrease in mean size 1.4 vs 1.3 

in (36.2 vs 33.5 mm). Fox and Flowers (1990) reported 

a substantial decrease in mean lengths and weights of 

walleye fingerlings as stocking density was increased 

from 24,670/ac-ft to 74,000/ac-ft (20 to 60 fry/m3: 

mean length declined from 48.9 to 41.3 and mean 

weight from 788 mg to 470 mg. 

Stocking density and fertilization may be progressively 

ratcheted upwards to some finite limit when water 

quality becomes the limiting factor. As a generalization, 

when carrying capacity for a given level of fertility is 

reached, ad&tional stoclung density will result in 

smaller fish and/or reduced survival. 

Food of pond cultured fingerlings 

The first food may be rotifers and copepod nauplii 

(Smith and Moyle 1945), cyclopoid copepods (Fox and 

Flowers 1990), or small soft-bodied cladocerans 

(Raisanen and Applegate 1983). As they grow, walleye 

progressively switch to larger cladocera (Raisanen and 

Applegate 1983; Fox and Flowers 1990) and to immature aquatic insects, typically chironomid larvae and 

pupae (Fox and Flowers 1990; Summerfelt et al. 1993). 

Fox et al. (1989) reported that zooplankton are less 

important after the second week of culture, and that 

chironomids become the dominant prey in walleye >0.8 

in (>22 mm). Studies on stomach contents of walleye at 

hatcheries in North Dakota and Nebraska consistently 

demonstrated a sequence from copepod nauplii, 

copepods, small cladocerans, then larger cladocerans, 

and chironomid larvae and pupae. Walleye fry did not 

eat diatoms or rotifers, even though rotifers were 

always the most abundant zooplankton (Summerfelt et 

al. 1993). The smaller copepods and cladocerans were 

preferred early in the culture season, but food preference shifted to large cladocerans (up to 2.0 mm) and 

chironomids in the latter stages of the culture period. 

On the other hand, Jahn et al. (1989) reported that 

walleye fingerlings smaller than 1 .I in (28 mm) ate 

mainly rotifers; those 21.1 in ate primarily copepods; 

and fingerlings >1.25 in (32mm) ate chironomids as 

well as copepods and cladocerans. 

98 NCRAC Culture Series 101- Walleye Culture Manual 
Table 3. Comparison of kinds and amounts of organic fertilizers used in drainable ponds for culture of walleye fingerlings. 

Type of fertilizer Initial amount Total amount 

Ibdacre (kg/ha) Ibdacre (kg/ha) Reference 

Alfalfa meal 

Alfalfa meal and 

Torula yeast 

Alfalfa meal 

Alfalfa pellets 

Alfalfa pellets 

alfalfa hay and 

alfalfa meal 

Alfalfa pellets 

alfalfa hay and 

alfalfa meal 

Alfalfa pellets and 

soybean meal 

Alfalfa meal and 

soybean meal 

Soybean meal 

Urea 

133 (1 18.6) 

587 (524) 

59 (53) 

1 00-200 (1 1 2-224) 

220 (246) 

240 (269) 

240 (269) 

240 (269) 

466 (523) 

466 (523) 

466 (523) 

180 (202) 

67 (74) 

189 (21 2) 

78 (88) 

392 (350) 

400 (357) 

1,064 (949) 

1,175 (1,048) 

118 (105) 

1,500 (1 338) 

880 (984) 

719 (806) 

719 (806) 

719 (806) 

1691 (1 896) 

1 632 (1 830) 

1 340 (1 569) 

720 (808) 

268 (300) 

950 (848) 

394 (352) 

4000 (3568) 

Call (1 996) 

Wawronowicz and Allen (1 996) 

Raisanen (1 996) 

Johnson (1 987) 

Clouse (1 991) 

Clouse (1 991) 

Clouse (1 991) 

Harding and Summetfelt (1 993) 

Flowers (1 996) 

Wright (1 996) 

Fertilization 

Whatever the lunds, amounts, or application frequency 

of fertilizer used, the goal of pond fertilization is to 

increase yield. Fertilization may be done with organic 

or inorganic fertilizers or both (Table 3). In limnological terms, fertilization by addition of organic matter is 

used to nourish a heterotrophic pathway for fish food 

production, with the basis of the food web being 

organic matter added to the pond (i.e., allochtonous 

origin). Those who advocate inorganic fertilizers are 

designing an autotrophic pathway for fish food production, in which inorganic fertilizers are used to promote 

algal growth as the starting point for the food web (i.e., 

autochothonous production of organic matter from 

within the pond). It is important to understand the 

basics of these two strategies to understand how they 

can be managed to increase production. 

The heterotrophic strategy is a conceptual scheme based 

on decomposition of organic fertilizers by microorganisms, whch are consumed by infusoria and other 

detritus-feeding organisms (detritivores) and their 

predators. Zooplankton and aquatic insect larvae that 

are eaten by walleye are either detritivores (i.e., 

heterotrophic organisms that consume organic matter) 

or predators on detritivores. In the narrowest sense, the 

goal in promoting a heterotrophic pathway is not algae 

production. Most pond culturists would be delighted to 

produce walleye without algae. Blue-green algae are a 

nuisance at harvest and they are not preferred by 

zooplankton. A large algal biomass causes strong 

diurnal pulses in oxygen, pH, and carbon &oxide. Of 

course, bacterial decomposition of organic matter 

consumes oxygen, and organic matter functions like a 

slow release fertilizer, releasing inorganic nutrients (N 

and P) that eventually stimulates algal production. 

Organic fertilization does not require measurement of 

N:P ratios. 

NCRAC Culture Series 101 - Walleye Culture Manual 99 
The heterotrophic strategy, using organic fertilizers, has 

been the traditional practice at northern hatcheries for 

pond culture of walleye (Dobie 1956; Buttner and 

Kirby 1986; Richard and Hynes, 1986; Fox et al. 1989; 

Jahn et al. 1989; Flowers 1993; Harding and Summerfelt 1993; Summerfelt et al. 1993; Call 1996). Organic 

fertilizers are preferred because algal populations are 

too slow to develop at the low water temperatures in the 

ponds and because of the short interval between pond 

filling and stocking. Organic fertilizers stimulate 

heterotrophic food chains, and the organic materials 

generate a large decomposer community which can be 

consumed by zooplankton and yet also provide a slow 

release of inorganic nutrients to algae (Geiger 1983; 

Barkoh and Rabeni 1990). Green manure (e.g., flooded 

rye grass), animal manures, and ground hay, alfalfa 

pellets, and alfalfa meal, soybean meal, and Torula 

yeast are examples of organic fertilizers (Table 3). The 

type and particle size of organic fertilizers is important 

because they affect both the rate of decomposition and 

the ability to stimulate development of microbial 

populations (Barkoh and Rabeni 1990). Alfalfa, for 

example, is used as ground hay, pellets, or meal, which 

vary in particle size from large to small. 

At the White Lake Fish Culture Station in Ontario, the 

decomposition process is initiated in containers by 

mixing soybean meal with water for up to a week 

before it is used (Flowers 1996). Their pond fertilization is started at least two weeks before stocking with a 

large initial application (392 lbs/acre-ft; 140 g/m3), and 

weekly applications of 98 lbdacre-ft (36 g/m3) thereafter. 

A diverse complex of factors affect the abundance and 

composition of the zooplankton community in ways 

that are still unpredictable. The selection of specific 

types and particle sizes of organic fertilizers and 

application schedules to specifically regulate the 

abundance of particulate organic matter, its associated 

microbes, and zooplankton numbers and composition is 

a new drection in pond culture derived from experimental studies such as that done by Barkoh and Rabeni 

(1990). 

The inorganic or autotrophic strategy has been used by 

Culver (1996) at the Hebron, Senecaville, and St. 

Mary’s Fish Hatcheries in Ohio. They applied amounts 

and mixtures of fertilizers to achieve desired N:P ratios. 

After pond filling, the concentrations of N and P are 

raised to 600 mg N/L and 30 mg PO,-P/L, and are 

maintained at those levels by weekly applications of 

liquid inorganic fertilizers to achieve a 20:l N:P ratio. 

Inorganic fertilizers arc used to produce crops of small 

algae (diatoms, coccoid greens, flagellates) that are 

eaten by zooplankton. 

This procedure requires precise analysis of the fertilizers; accurate measurements of ammonia, nitrate, and 

phosphate in pond water; and one-person day of effort 

each week per 30 ponds to conduct the analyses. The 

appeal of the technique is the potential for improved 

management of algal abundance and Community 

structure, as well as reduced cost when compared with 

organic fertilization. Culver et al. (1 993) reduced the 

number of “bust” ponds (ponds with 40% survival) 

from 55% to 0% with this fertilization program. 

Tice et al. (1996) reports a comparison of organic and 

inorganic fertilization strategies. They compared 

survival, yield, and mean size of walleye harvested 

from ponds fertilized organically (alfalfa meal and 

yeast) with ponds fertilized with liquid inorganic 

fertilizer. They chd not find any chfference in survival, 

or final mean lengths of the fish; however, mean fish 

weight was significantly lower in the inorganically 

fertilized ponds, and yield was higher in the organically 

fertilized ponds: 52.7 Ib/acre (47 kgha) compared with 

37 kg/ha in the inorganically fertilized ponds. Filamentous algae was not reduced by use of inorganic fertilizers; in fact, the only two ponds where it was a problem 

was in a pond fertilized with inorganic fertilizers. 

Smith and Moyle (1 945) found no correlation between 

total phosphorus and total nitrogen and yield of 

fingerlings in 66 Minnesota walleye culture ponds. 

They suggested that “ ... basic fertility is not converted 

into a crustacean crop early enough in the spring to be 

available when most needed by the small yellow 

pikeperch (i.e., walleye).” Walleye culture in northern 

latitudes with slowly warming water over the culture 

season may not benefit from inorganic fertilization as it 

does in the southern portion of the north central region. 

The contrasting results of Tice et al. (1 996) and the 

studies by Culver (1991 , 1996) and Culver et al. (1993) 

indicate that differences in succcss with inorganic 

fertilizers may be as variable as that previously reported 

in ponds fertilized with organic matter. 

100 NCRAC Culture Series 101- Walleye Culture Manual 
Zooplankton inoculation 

Seeding walleye culture ponds with zooplankton 

inoculation may be an effective way to initiate a rapid 

increase in desirable zooplankton numbers. Zooplankton seeding serves a special need in walleye production 

in northern climates where the interval between pond 

filling and stocking is limited, water temperatures are 

low, and where there is little time to optimize zooplankTable 4. Stocking densities and harvest characteristics of phase I walleye fingerlings reported in the case studies on drainable and undrainable ponds. 

Pond type 

Reference 

Drainable 

Call (1 996) 

Waw ro now icz 

and Allen (1 996) 

Culver (1 996) 

Flowers (1 996)3 

Wright (1 996)4 

Raisanen (1 996) 

Undrainable 

Daily (1 996) 

Jorgensen (1 996) 

Gustafson (1 996) 

Gunderson et al. 

(1 996)9 

Stocking 

density 

(1,000’s) 

Nu m be r/ac re 

(N u m be r/h a) 

166-200 

(41 0-484) 

120 (300) 

100-240’ 

(247-596) 

120 (296) 

25 (62) 

75-1 50 

(185-371) 

3-5 (7-12) 

20 (49) 

30-75 

(74-1 85) 

2.5-30 

(6.2-74) 

Harvest characteristics 

No. fish/lb Length S u rv iva I 

(N 0. f i s h/kg ) inches (mm) (“w 

1,700 

(3,744) 

4 1 7-450 

(91 7-990) 

1,41 O2 

(3,102) 

792 (1,742) 

41 7(91 7)5 

25-30 

(55-66) 

400-2 1 0 

(881 -462 

983-2 1 2 

(2,163-466) 

1.25 (32) 76 

2.0 (51) 30-75 

1.2-1.6 64 

(30-40) 

1.8 (45) 69.2 

2.0 (51) 46 

5.1-4.8 3.2 

(1 29-1 22) 

2.0-2.5 6.87 

(5 1 -64) 

1.5-2.5 30 

(38-64) 

2.0-3 .O 

(5 1 -76) 

Yield 

Ibs/acre (kg/ha) 

80 (89.7) 

Not given 

61 (68) 

112 (126) 

119 (133)6 

Not given 

4.6 (5.2)8 

7-33 (7.8-37)6 

’Given an average survival of 64% survival and a harvest of 86,000 fingerlings, the average stocking density would be 134,375 (86,000 

fi ngerlings/acre+O.64). 

*Estimated from data provided by author (i.e., 86,000 fingerlings/acret61 Ibdacre). 

3Flowers presented several data sets; these data are means of values from Table 3 of his report. 

4Wright’s report is for a phase II fingerling, harvested from early August to the end of October. 

5Length was used to estimated number of fish/lb Table 14 in Piper et al. (1982). 

6Calculated from number harvested/acre+number fish/lb = Ibs/acre 

7A partial harvest, an additional 9.6% of phase II fingerlings are harvested in October 

*Only phase I fingerlings; the combined yield of phase I and II fingerlings is 106 Ibs/acre (1 18 kg/ha) 

gMost harvest is of phase II finglerlings in the fall; specifics for phase I fingerlings could not be identified. 

NCRAC Culture Series 101 - Walleye Culture Manual 101 
ton populations. Geiger (1 983) recommended zooplankton inoculation for pond production of fingerling striped 

bass and Richard and Hynes (1986) suggested using the 

procedure to culture walleye fingerlings. As previously 

noted, ponds filled with filtered water from surface 

water sources often contain populations of zooplankton 

which serve as an artificial inoculum. However, the 

kmd and size of zooplankton dffer substantially, and an 

inoculum of cladoceran species too large for first 

feeding larval walleye may reduce survival (Clouse 

1991). 

Stocking density 

Fry stochng densities varying from 25,00O/acre 

(62,000ha) to 240,00O/acre (596,00O/ha) have been 

reported for drainable ponds (Table 4). In these ponds, 

harvest characteristics were not correlated with stocking 

density. Typically, at carrying capacity, fish size at 

harvest is inversely related to fish stoclung density 

(Schroeder 1978), and mean weight inversely related to 

number of fish harvested per unit area. This has been 

reported in many experiments (Harding and Summerfelt 

1993; Summerfelt et al. 1993). 

Nevertheless, whatever the tradtional stoclung density 

at a hatchery, stoclung density may be increased if a 

partial harvest of small fingerlings (1.0 in, <25 mm) can 

be made to reduce the density during production of 

phase I fingerlings. Because walleye are strongly 

attracted to light before they reach 1.25 in (32 mm) 

(Bulkowslu and Meade 1983), fingerlings can be 

attracted to a floating light, surrounded with a soft, finemesh seine, and hauled to shore where the seine is 

cribbed and the fish carefully dipped out (Figure 8). 

This strategy permits increased stocking density 

because the partial harvest of the small fingerlings 

reduces the density to the carrying capacity of the pond 

for grow-out to the standard size. 

Harvest from drainable ponds 

Undrainable ponds must be harvested with traps or 

seines, but drainable ponds can be harvested by 

draining water into a catch basin. Wawronowicz and 

Allen (1996) described the use of fyke nets and a seine 

to harvest drainable ponds that were not equipped with 

catch basins. Drainable ponds may be partially harvested with seines or fyke nets, or seined during 

draining. Most state and federal production hatcheries 

drain the ponds to a catch basin and harvest the entire 

/,’ I 

Figure 9. Technique used for partial harvest of small 

(<32 mm) walleye fingerlings that are strongly 

attracted to a night light. Submerged lights are 

attached to floats in the pond (upper). After fish are 

attracted to the light (middle), a boat is used to 

extend a seine and at the same time the lights are 

slowly pulled back to shore while the fish are 

surrounded by the seine (lower). 

pond in one day. If desired, walleye may be partially 

harvested over several days by using traps, seines, night 

harvest with lights, or a drain-and-seine procedure. 

Harder (Tom Harder, Max McGraw Wildlife Foundation, personal communication) found that a nightharvest technique using floating lights was an effective 

method for harvesting walleye fingerlings (Figure 9). 

This system was a modfication of procedures described 

by Manci et al. (1983) for harvesting yellow perch. A 

special advantage of the night harvesting technique was 

that fingerlings were captured without the usual 

abundance of tadpoles and salamander larvae, which 

were a nuisance with daylight pond seining. Bulkowslu 

et al. (1983) reported that fingerlings are photopositive 

102 NCRAC Culture Series 101- Walleye Culture Manual 
up to 1.25 in (32 mm) gradually becoming photonegative by 1.6 in (40 mm). 

Yield 

In the drainable ponds reported in the case stu&es in 

this chapter, yields range from 61 to 119 lbs/acre (68- 

133 kg/ha); the lowest yield and smallest fish size (no 

fish/lb) was from ponds fertilized with only inorganic 

fertilizers (Culver 1996). 

Because of the complexity of pond ecosystems, 

survival, production, harvest, and mean size of fingerlings is variable (Mathias and Li 1982; Richard and 

Hynes 1986; McIntyre et al. 1987). Fox et al. (1989) 

reported survival ranging from 0.7 to 73% and a yield 

ranging from 1.8 to 26.1 g/m3 in experimental ponds. 

Reducing this type of variability is dependent upon 

careful management, especially the fertility, prey 

population, and control of cannibalism (McIntyre et al. 

1987). 

Culture interval 

The length of the culture interval for production of 

phase I fingerlings reported by case study authors is 

varied: 29 (Call 1996), 40 (Wawronowicz and Allen 

1996), 42-56 (Flowers 1996). The 29 day interval 

reported by Call (1996) is exceptionally because the 

walleye are typically stocked after northern pike at the 

GDNFH, which results in a higher average temperature 

than typical of most walleye culture. There is an 

obvious inverse relationship between the length of the 

culture interval and mean water temperature: 68°F 

(20°C) water temperature for 24-29 day culture season 

at GDNFH; 626°F (17°C) water temperature and 39-52 

day culture season at VCNFH; and 59°F (15OC) water 

temperature and 40-60 day culture season at North 

Platte State Fish Hatchery, North Platte, Nebraska 

(Summerfelt et al. 1993). There is also a relationship 

between average water temperature, size at harvest and 

length of the culture interval. 

We have found a strong negative correlation between 

the length of the culture interval and survival (-0.77), 

and number of fingerlings harvested (-0.90). We have 

found equally strong positive correlations between 

length of the culture interval and yield (0.77-0.85), 

number of fingerlingdacre (0.90), and length (0.84- 

0.89), and weight (0.67-0.96) (Hardmg and Summerfelt 

1993). These findings demonstrate that larger fish can 

be obtained by lengthening the culture season, but at a 

cost, which is lower survival. In research involving 

large numbers of ponds, differences in the length of the 

culture season of individual ponds can strongly bias the 

findmgs unless harvest dates are randomized among 

treatments or appropriate statistical methods (e.g., 

analysis of covariance) used to adjust for the length of 

the culture season. 

Problem organisms 

weeds, invertebrate predators (both air-breathing and 

gill-breathing insects) and clam shrimp reduce survival 

and cause problems with harvest. It has been a common 

practice to control air breathing invertebrate insect 

predators in ponds by applying motor oil and diesel fuel 

to the water surface (Dupree and Huner 1984; see 

summary of methods used in undrainable ponds by 

Kinnunen 1996). 

Net algae (Hydrodicton) has been reported to be a 

problem in walleye ponds in Ohio (Culver 1996) and 

VCNFH (Clouse 1991). In the past, copper sulfate and 

AquazineTM have been used to control this problem at 

VCNFH. 

Clam shrimp are small crustaceans that superficially 

resemble small clams (Figure 10). When abundant, 

clam shrimp are a nuisance in ponds used for production of fingerling fish because they clog screens during 

draining, and they are reported to cause a substantial 

reduction in fish production. When abundant, clam 

Figure IO. Photo of a clam shrimp, a nuisance 

organism in culture ponds because they clog the 

screens during draining. 

NCRAC Culture Series 101 - Walleye Culture Manual 103 
shrimp have reduced the 

production of fingerling 

northern pike and goldfish 

(Dexter and McCarraher 

1967). Clam shrimp also 

consume detritus, &atoms, 

and green algae (Strenth and 

Sisson 1975), competing for 

the same food resources used 

by copepods and cladocerans. 

Because clam shrimp lack 

predators, their populations 

continue to expand during the 

culture season; they can 

become so numerous that they 

clog the outlet screens in the 

kettle which may require 

frequent cleaning. 

Research needs 

A driving force in pond 

management is the need to 

optimize capital costs for pond 

construction and to meet the 

increasing demand for 

fingerlings. Survival and 

growth of walleye at high 

densities (e.g., >100,0OO/acre, 

250,000ha) are dependent on 

pond management strategies 

that result in: (1) maintenance 

of good water quality (e.g., 

Figure 11. Aerial view of North Platte Fish Hatchery, North Platte, Nebraska, a 

facility of the Nebraska Game and Parks Commission. The 40 acres of ponds 

have been used for raising fingerlings of several species of coolwater (northern 

pike, walleye, muskie and tiger muskie, hybrid striped bass) and warmwater 

(channel catfish and grass carp fish). The block of 20, 1-acre (0.4 ha) ponds in 

the foreground are excellent for controlled experiments. Photo courtesy of 

Terrence B. Kayes. 

adequate dissolved oxygen); (2) development of large 

populations of desirable zooplankton and chironomids; 

and (3) minimization of undesirable animal and plant 

species that compete with the fish for food or which 

prey on fry. 

Although pond production of walleye fingerlings in 

drainable ponds is commonplace by governmental 

agencies and is expanding in the private sector, site 

specific cultural procedures are used. Few experimental 

studies have been undertaken on many issues. Survival 

and yield of walleye in ponds is intimately associated 

with production of the right size and type of prey. Even 

though ponds are small, and the manager has control 

over fish stochng density and water and fertilizer 

inputs, ponds are complex ecosystems that defy precise 

control. Differences of opinion on the merits of 

inorganic and organic fertilizers means further studies 

to determine proper rates and types in relation to 

climate, water quality, and other site specific variables 

are needed. Although variation in yield among ponds is 

less than year-to-year variation, variability inherent in 

pond culture experiments requires many replicates to 

determine significant differences at conventional 

probability levels (Figure 11). Research also is needed 

to initiate feeding of phase I fingerlings on formulated 

feed before harvest, and for culture of a phase I1 

fingerling in ponds on formulated feed rather than 

minnows. 

104 NCRAC Culture Series 101- Walleye Culture Manual 
Ref ere n ces 

Barkoh, A,, and C. F. Rabeni. 1990. Biodegradability and 

nutritional value to zooplankton of selected fertilizers. 

Progressive Fish-Culturist 52:19-25. 

Beyerle, G. B. 1975. Summary of attempts to raise 

walleye fry and fingerlings on artificial diets, with 

suggestions on needed research and procedures to 

be used in future tests. Progressive Fish-Culturist 

37: 1 03-1 05. 

Brewer, D. L., and R. A. Rees. 1990. Pond culture of 

phase I striped bass fingerlings. Pages 99-120 in R. 

M. Harrell, J. H. Kerby, and R. V. Minton, editors. 

Culture and propagation of striped bass and its 

hybrids. Striped Bass Committee, Southern Division, 

American Fisheries Society, Bethesda, Maryland. 

Bristow, B. T. 1996. Extensive-intensive production of 

advance fingerling walleyes at the Spirit Lake State 

Fish Hatchery. Pages 209-212 in R. C. Summerfelt, 

editor. Walleye culture manual. NCRAC Culture 

Series 101. North Central Regional Aquaculture 

Center, Publications Office, Iowa State University, 

Ames. 

Bulkowski, L., and J. W. Meade. 1983. Changes in 

phototaxis during early development of walleye. 

Transactions of the American Fisheries Society 

1 12:445-447. 

Buttner, J. K. and J. Kirby. 1986. Response of zooplankton and walleye fry to cladoceran inoculation and 

fertilization of earthen ponds. New York Journal of 

Fish and Game 33:43-49. 

Call, J. E. 1996. Pond production of fingerling walleye at 

Garrison Dam National Fish Hatchery. Pages 109- 

110 in R. C. Summerfelt, editor. Walleye culture 

manual. NCRAC Culture Series 101. North Central 

Regional Aquaculture Center, Publications Office, 

Iowa State University, Ames. 

Cheshire, W. E, and K. L. Steele. 1972. Hatchery 

rearing of walleyes using artificial food. Progressive 

Fish-Culturist 34:96-99. 

Clouse, C. I? 1991. Evaluation of zooplankton inoculation and organic fertilization for pond-rearing walleye 

fry to fingerlings. Master of Science Thesis, Iowa 

State University, Ames. 

Colesante, R. T. 1996. Intensive culture of walleye using 

brine shrimp and formulated diets. Pages 191-1 94 in 

R. C. Summerfelt, editor. Walleye culture manual. 

NCRAC Culture Series 101. North Central Regional 

Aquaculture Center, Publications Office, Iowa State 

University, Ames. 

Colesante, R. T., N. B., Youmans, and B. Ziolkoski. 1986. 

Intensive culture of walleye fry with live food and 

formulated diets. Progressive Fish-Culturist 48:33-37. 

Culver, D. A. 1991. Effects of the N:P ratio in fertilizer for 

fish h at c h e r y p o n d s . I n t e r n at i o n a I e Ve re i n i g u n g f u r 

Theoretische und Angewandte Limnologie 

Verhandlungen 24: 1503-1 507. 

Culver, D. A. 1996. Fertilization procedures for pond 

culture of walleye and saugeye. Pages 115-122 in R. 

C. Summerfelt, editor. Walleye culture manual. 

NCRAC Culture Series 101. North Central Regional 

Aquaculture Center, Publications Office, Iowa State 

University, Ames. 

Culver, D. A., S. P. Madon, and J. Qin. 1993. Percid 

pond production techniques: timing, enrichment, and 

stocking density manipulation. Journal of Applied 

Aquaculture 2(3/4):9-31. 

Daily, J. B. 1996. Pond culture of fingerlings in undrainable ponds. Pages 147-149 in R. C. Summerfelt, 

editor. Walleye culture manual. NCRAC Culture 

Series 101. North Central Regional Aquaculture 

Center, Publications Office, Iowa State University, 

Ames. 

Dexter, R. W., and D. B. McCarraher. 1967. Clam 

shrimps as pests in fish rearing ponds. Progressive 

Fish-Culturist 29:105-107. 

Dobie, J. 1956. Walleye pond management in Minnesota. Progressive Fish-Culturist 1751 -57. 

Dupree, H. K., and J. V. Huner. 1984. Third report to the 

fish farmers: The status of warmwater fish farming 

and progress in fish farming research. U.S. Fish and 

Wildlife Service, Washington, DC. 

Ellis, T. E. 1987. North Platte Hatchery, North Platte, 

Nebraska. Pages 94-1 06 in 1987 Annual Report, 

Fisheries Division, Nebraska Game and Parks 

Commission, Lincoln. 

Ellis, T. E. 1988. North Platte Hatchery, North Platte, 

Nebraska. Pages 103-1 15 in 1988 Annual Report, 

Fisheries Division, Nebraska Game and Parks 

Commission, Lincoln. 

ERS (Economic Research Service). 1996. Aquaculture 

outlook. LDP-AQS-3 (March 7, 1996), Economic 

Research Service, U.S. Department of Agriculture, 

Washington, DC. 

NCRAC Culture Series 101 - Walleye Culture Manual 105 
Flickinger, S. A. 1996. Production of food fish. Pages 

233-235 in R. C. Summetfelt, editor. Walleye culture 

manual. NCRAC Culture Series 101. North Central 

Regional Aquaculture Center, Publications Office, 

Iowa State University, Ames. 

Floyd, K. B., W. H. Courtenay, and R. D. Hoyt. 1984. A 

new larval fish light trap: the quatrefoil trap. Progressive Fish-Culturist 46:216-219. 

Flowers, D. D. 1996. Fingerling production in drainable 

ponds at White Lake Fish Culture Station. Pages 

123-128 in R. C. Summetfelt, editor. Walleye culture 

manual. NCRAC Culture Series 101. North Central 

Regional Aquaculture Center, Publications Office, 

Iowa State University, Ames. 

Fox, M. G., and D. D. Flowers. 1990. The effect of fish 

density on growth, survival and production of juvenile 

walleye in rearing ponds. Transactions of the American Fisheries Society 1 19: 1 12-1 21. 

Fox, M. G., J. A. Keast, and R. J. Swainson. 1989. The 

effect of fertilization regime on juvenile walleye 

growth and prey utilization in rearing ponds. Environmental Biology of Fishes 26:129-142. 

FWS (Fish and Wildlife Service). 1991, Fish and fish 

egg distribution report of the national fish hatchery 

system. Fiscal Year 1990/Report No. 25. U.S. 

Department of the Interior, Fish and Wildlife Service, 

Washington, DC. 

Geiger, J. G., 1983. Zooplankton production and 

manipulation in striped bass rearing ponds. Aquaculture 35:331-351. 

Geiger, J. G., and C. J. Turner, 1990. Pond fertilization 

and zooplankton management techniques for 

production of fingerling striped bass and hybrid 

striped bass. Pages 79-98 in R. M. Harrell, J. H. 

Kerby, and R. V. Minton, editors. Culture and propagation of striped bass and its hybrids. Striped Bass 

Committee, Southern Division of the American 

Fisheries Society, Bethesda, Maryland. 

Gunderson, J., P. Goeden, and T. Hertz. 1996. Walleye 

fingerling culture in undrainable, natural ponds. 

Pages 157-1 60 in R. C. Summerfelt, editor. Walleye 

culture manual. NCRAC Culture Series 101. North 

Central Regional Aquaculture Center, Publications 

Office, Iowa State University, Ames. 

Gustafson, C. 1996. Pond culture of walleye in Michigan: 

fry to advanced fingerling. Pages 153-155 in R. C. 

Summerfelt, editor. Walleye culture manual. NCRAC 

Culture Series 101. North Central Regional Aquaculture Center, Publications Office, Iowa State University, Ames. 

Harding, L. M., and R. C. Summerfelt. 1993. Effects of 

fertilization and of fry stocking density on pond 

p rod u ct i o n of f i n g e r I i n g wa I I eye, Stizostedion vitreum. 

J ou r n al of Applied Aquaculture 2 (3/4) :59-79. 

Harrell, R. M., J. H. Kerby, and R. V. Minton. 1990. 

Culture and propagation of striped bass and its 

hybrids. Striped Bass Committee, Southern Division, 

American Fisheries Society, Bethesda, Maryland. 

Henry, J. R., and E. L. Gambell. 1981. Two and a half 

million “little waters,” our farm ponds. Pages 23-38 in 

H. G. Stefan, editor. Proceedings of the symposium 

on surface water impoundments, Vol. I, June 2-5, 

1990. American Society of Civil Engineers, New York, 

New York. 

Huet, M. 1986. Textbook of fish culture, 2nd edition. 

Fishing News Books, Ltd., Farnham, Surrey, England. 

Huner, J. V., and H. K. Dupree. 1984. Pond culture 

systems. Pages 6-16 in H. K. Dupree and J. V. Huner. 

1984. Third report to the fish farmers. US Fish and 

Wildlife Service, Washington, DC. 

Jahn, L. A., L. M. O’Flaherty, G. M. Quartucci, J. H. Kim, 

and X. Mao. 1989. Analysis of culture ponds to 

enhance fingerling production. Completion Report, 

Federal Aid Project F-50-R, Illinois Department of 

Conservation, Springfield, Illinois. 

Johnson, S. R. 1987. Effects of organic enrichment and 

artificial aeration on walleye fry, Stizostedion vitreum 

vitreum, growth and survivorship. Master of Science 

Thesis, University of North Dakota, Grand Forks. 

Jorgensen, W. D. 1996. Extensive culture of walleye 

fingerlings. Pages 151-152 in R. C. Summetfelt, 

editor. Walleye culture manual. NCRAC Culture 

Series 101. North Central Regional Aquaculture 

Center, Publications Office, Iowa State University, 

Ames. 

Kindschi, G. A., and F. T. Barrows. 1991. Optimal screen 

mesh size for restraining walleye fry. Progressive 

Fish-Culturist 53:53-55. 

Kinnunen, R. E. 1996. Walleye fingerling culture in 

undrainable ponds. Pages 135-145 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture 

Series 101 North Central Regional Aquaculture 

106 NCRAC Culture Series 101- Walleye Culture Manual 
Center, Publications Office, Iowa State University, 

Ames. 

Kuipers, K. L., and R. C. Summerfelt. 1994. Converting 

pond-reared walleye fingerlings to formulated feeds: 

Effects of diet, temperature, and stocking density. 

Journal of Applied Aquaculture 4:31-57. 

Lilienthal 1996. Distribution of walleye fry and fingerlings. Pages 85-87 in R. C. Summerfelt, editor. 

Walleye culture manual. NCRAC Culture Series 101. 

North Central Regional Aquaculture Center, Publications Office, Iowa State University, Ames. 

Malison, J. A., and J. A. Held. 1996. Habituating pondreared fingerlings to formulated feed. Pages 199-204 

in R. C. Summetfelt, editor. Walleye culture manual. 

NCRAC Culture Series 101. North Central Regional 

Aquaculture Center, Publications Office, Iowa State 

University, Ames. 

Manci, W. E., J. A. Malison, T. 6. Kayes, and T. E. 

Kuczynski. 1983. Harvesting photopositive juvenile 

fish from a pond using lift net and light. Aquaculture 

157-1 64. 

Marzolf, G. R., and J. A. Osborne. 1971. Primary 

production in a Great Plains reservoir. lnternationale 

Vereinigung fur Theoretische und Angewandte 

Limnologie Verhandlungen 18:126-133. 

Mathias, J.A., and S. Li. 1982. Feeding habits of walleye 

larvae and juveniles: comparative laboratory and field 

studies. Transaction of the American Fisheries 

Society 1 11 :722-735. 

Mclntyre, D. E., F. J. Ward, and G. M. Swanson. 1987. 

Factors affecting cannibalism by pond-reared juvenile 

walleyes. Progressive Fish-Culturist 49:264-269. 

Nagel T. 1974. Rearing of walleye fingerlings in an 

intensive culture using Oregon moist pellets as an 

art if ici al diet. Progressive Fis h-C u lturist 36:59. 

Nagel T. 1976. Intensive culture of fingerlings on 

formulated feeds. Progressive Fish-Culturist 38:90- 

91. 

Nagel T. 1985. Development of a domestic walleye 

broodstock. Progressive Fish-Culturist 47: 121 -1 22. 

Nagel, T. 1996. Intensive culture of fingerling walleye on 

formulated feeds. Pages 205-207 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture 

Series 101. North Central Regional Aquaculture 

Center, Publications Office, Iowa State University, 

Ames. 

Nickum, J. G. 1986. Walleye. Culture of nonsalmonid 

freshwater fishes. CRC Press, Inc., Boca Raton, 

Florida. 

Piper, R. G., I. 6. McElwain, L. E. Orme, J. P. McCraren, 

L. G. Fowler, and J. R. Leonard. 1982. Fish hatchery 

management. U.S. Fish and Wildlife Service, 

Washington, D.C. 

Raisanen, G. 1996. Culture of advanced fingerling 

walleye in Minnesota ponds. Pages 131-1 34 in R. C. 

Summerfelt, editor. Walleye culture manual. NCRAC 

Culture Series 101. North Central Regional Aquaculture Center, Publications Office, Iowa State University, Ames. 

Raisanen, G. A., and R. L. Applegate. 1983. Prey 

selection of walleye fry in an experimental system. 

Progressive Fish-Culturist 45209-21 4. 

Richard, P. D., and J. Hynes. 1986. Walleye culture 

manual. Ontario Ministry of Natural Resources, Fish 

Culture Section, Toronto, Ontario, Canada. 

Schroeder, G. L. 1978. Autotrophic and heterotrophic 

production of microorganisms in intensely-manured 

fish ponds, and related fish yields. Aquaculture 

14:303-325. 

Secor, D. H., J. M. Dean, and J. Hasbarger. 1992. 

Modification of the quatrefoil light trap for use in 

hatchery ponds. Progressive Fish-Culturist 54:202- 

205. 

Smith, L. L., and J. 6. Moyle. 1945. Factors influencing 

production of yellow pike-perch, Stizosfedion vitreum 

vitreum, in Minnesota rearing ponds. Transactions of 

the American Fisheries Society 73 (1 943):243-261. 

Smith, T. I. J., W. E. Jenkins, and R. V. Minton. 1990. 

Production of advanced fingerling and subadult 

striped bass and striped bass hybrids in earthen 

ponds. Pages 121-139 in R. M. Harrell, J. H. Kerby, 

and R. V. Minton, editors. Culture and propagation of 

striped bass and its hybrids. Striped Bass Committee, Southern Division, American Fisheries Society, 

Bethesda, Maryland. 

Stickney, R. R. 1994. Principles of aquaculture. John 

Wiley & Sons, Inc., NewYork, NewYork. 

Strenth, N. E., and S. L. Sissom. 1975. A morphological 

study of the post-embryonic stages of Eulimnadia 

fexana Packard (Conchost raca, Crustacea). Texas 

Journal of Science 26:137-154. 

NCRAC Culture Series 101 - Walleye Culture Manual 107 
Summerfelt, R.C. 1996. Intensive culture of walleye fry. 

Pages 161 -1 85 in R. C. Summerfelt, editor. Walleye 

culture manual. NCRAC Culture Series 101. North 

Central Regional Aquaculture Center, Publications 

Office, Iowa State University, Ames. 

Wawronowicz, L. J., and W. G. Allen. Walleye fingerling 

production techniques in drainable ponds on Lac Du 

Flambeau Indian Reservation. 1996. Pages 11 1-1 13 

in R. C. Summerfelt, editor. Walleye culture manual. 

NCRAC Culture Series 101. North Central Regional 

Aquaculture Center, Publications Office, Iowa State 

University, Ames. 

Summerfelt, R. C., C. P. Clouse, and L. M. Harding. 

1993. Pond production of fingerling walleye, 

Stizostedion vitreum, in the northern Great Plains. 

Journal of Applied Aquaculture 2(3/4):33-58. 

Wright, G. M. 1996. Walleye culture in a 100-acre 

drainable pond in northern Michigan. Pages 129-1 30 

Tice, B. J., R. W. Soderberg, and J. M. Kirby. 1996. 

Growth and survival of walleyes reared in ponds 

fertilized with organic and inorganic materials. 

Progressive Fish-Culturist 58:135-I 39. 

in R. C. Summerfelt, editor. Walleye culture manual. 

NCRAC Culture Series 101. North Central Regional 

Aquaculture Center, Publications Office, Iowa State 

University, Ames. 

108 NCRAC Culture Series 101- Walleye Culture Manual 
Call, J. E. 1996. Pond production of fingerling walleye at Garrison Dam National Fish Hatchery. 

Pages 109-1 10 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture Series 101. 

North Central Regional Aquaculture Center Publications Office, Iowa State University, Ames. 

Pond Production of Fingerling Walleye at 

Garrison Dam National Fish Hatchery 

John E. Call, U.S. Fish L? Wildlife Service, PO. Box 530, Riverdale, N. D. 58565 

Introduction 

The Garrison Dam National Fish Hatchery, located in 

central North Dakota, has been operated by the U.S. 

Fish and Wildlife Service since 1964 for the production 

of sport fishes. Up to 10 million walleye fingerlings are 

produced annually. Northern pike, hybrid walleye, 

largemouth bass, paddlefish, rainbow trout, and salmon 

are also cultured. The hatchery is situated below the 

dam of Lake Sakakawea, which serves as its primary 

water source (Figure 1). There are sixty-four 1.5-acre 

(0.61-ha) ponds. All ponds are equipped with outside 

kettles for fish harvest. This report describes contemporary procedures used at Garrison Dam National Fish 

Hatchery to produce walleye fingerlings. 

Culture 

walleye eggs are obtained from wild stocks at Devils 

Lake and Lake Sakakawea in mid-April. At this time of 

year, the hatchery water supply is approximately 35°F 

(2"C), and must be heated by boilers to provide more 

suitable water temperature for egg incubation. Manipulating water temperatures, however, enables us to 

control the length of egg incubation. Lengthening the 

walleye incubation interval to as much as 40 d allows us 

to double crop some rearing ponds, producing both 

northern pike and walleye fingerlings in tandem in the 

same rearing ponds, because northern pike spawn 

earlier in the year than walleye, and northern pike 

fingerlings require a relatively short rearing period. 

Extendmg the walleye egg incubation period allows us 

to raise a crop of northern pike fingerlings in a pond, 

drain and refill the pond, and then restock it with 

walleye fry. Although egg survival may be reduced for a 

40 day incubation, the loss is a small price to pay for 

enabling us to double crop ponds. 

Pond filling and egg hatching are coordinated by using 

a spreadsheet which predicts hatching dates based on 

cumulative temperature units. Pond filling begins 

approximately May 6, at which time the water temperaFigure 1. One unit of 1.5 acre (0.61 ha) ponds at Garrison 

Dam National Fish Hatchery as viewed from dam. 

ture is near 50°F (1 0°C) and prolonged periods of cold 

weather are normally past. 

Pond fertilization is based on information gathered by 

trial and error over 30 years. For many years alfalfa hay 

was chopped and added to the ponds. It performed well 

as a fertilizer, but was labor intensive to handle and 

spoiled quickly in storage when rained on. In 1992, we 

switched to alfalfa meal. The small particle size allows 

rapid decomposition and it does not plug screens during 

pond draining. Additionally, because it is stored in a 

bin, there is no spoilage. A grain box mounted on a 

trailer is used to transport the alfalfa meal to the ponds. 

The meal is broadcast onto the pond surface by an 

auger projecting out over the pond as the truck is slowly 

driven along the &ke (Figure 2). 

Fertilization begins immediately after pond filling using 

133 lbs/acre (1 18.6 kg/ha) of alfalfa meal/application. 

Ponds are fertilized once every 3 d. Fertilization is 

discontinued 7 d before the anticipated draining date. 

Pond fertilization schedules are generated by a computer program. Dissolved oxygen levels are monitored 

closely. If dissolved oxygen levels fall below 5 mg/l at 

sunrise, when measured 1 ft (30 cm) above the pond 

NCRAC Culture Series 101 - Walleye Culture Manual 109 
Chapter 5 - WaIley Fingerling Culture in Drainable Ponds 

Figure 2. Alfalfa meal broadcast onto the pond surface at 

the Garrison National Dam Fish Hatchery. 

bottom, fertilization ceases until oxygen levels recover. 

The maximum amount of organic fertilizer that can be 

safely used without oxygen depletion will be influenced 

by many factors, such as water temperature, natural soil 

fertility, cloud cover and the amount of phytoplankton 

present. However, no attempt is made to adjust fertilization based on plankton, pond color or other criteria. In 

1995, cost of alfalfa meal for pond fertilization was 

about $75.00/acre ($1 85.00/ha) 

Walleye fry, 1-2 d old, are stocked 9 d after the pond 

has started to fill with water. Fry are enumerated by 

water displacement (220/ml) and are transported to the 

pond in 5-gal (1 8.9-L) buckets which are equipped with 

a stone diffuser through which oxygen is bubbled 

Figure 3. Catch basin used at the Garrison National Dam 

Fish Hatchery for collecting walleye fingerlings discharged directly from 16 in (40 cm) pipe from the pond. 

during transport. Stocking rate varies from 166,000- 

200,00O/acre (410,000-494,000/ha). 

The culture period for walleye fingerlings is normally 

29 d, but abnormal water temperatures can alter the 

culture period by as much as a week. As the anticipated 

draining time approaches, fish are sampled by seining 

every 3 d to determine fish size and condtion. When 

fish reach 1.25 inches (32 mm) total length, the pond is 

drained (Figures 3 and 4). However if sampling 

indicates that the fish have not grown, a food shortage 

probably exists, and the pond is drained before fish 

condition deteriorates further. We believe that survival 

after &stribution is determined as much by fish con&- 

tion as it is by fish size. Average production for the last 

3 years has been 136,000/acre (336,00O/ha) of 1,70O/lb 

(3,744kg) fingerlings. Average survival for the same 

period was 76%. As the pond bottom is exposed during 

the draining process, it is seeded with annual rye grass 

using a broadcast seeder at the rate of 33 lbs/acre (37 

kg/ha). This is done to increase soil organic matter and 

to help control soil erosion. 

Information gathered during the growing season is 

stored in a database. We have found ths to be a 

convenient way to not only record information but to 

analyze the production data. 

Top View 

‘Dam boards 

/ 

ScreP 

Outlet 

Figure 4. Schematic of catch basin shown in Figure 

3. Area A is the turbulent section which receives 

water from the pond. Area B is less turbulent and 

water leaves by passing through screens (Area B). 

Dam boards are used to set water depth in the kettle 

and may be removed for complete draining. For 

harvesting the fish, the inlet water is turned off and 

a crowder screen is used to force the fish out of A 

into B. 

110 NCRAC Culture Series 101- Walleye Culture Manual 
Wawronowicz, L. J., and W. G. Allen. 1996. Walleye fingerling production techniques in drainable 

ponds on the Lac du Flambeau Indian Reservation. Pages 11 1-1 13 in R. C. Summerfelt, editor. 

Walleye culture manual. NCRAC Culture Series 101. North Central Regional Aquaculture 

Center Publications Office, Iowa State University, Ames. 

WaI leye Fingerling Production Techniques 

in Drainable Ponds on the Lac du Flambeau 

Indian Reservation 

Larry J. Wawronowicz and Willis G. Allen, Lac du Flambeau Tribal Natural Resource Department, FO. Box 67, 

Lac du Flambeau, WI. 54538 

zroduction 

urface waters on the Lac du Flambeau Indian 

Reservation support a subsistence and sports fishery 

with walleye being the primary target species for 

harvest. Based on adult walleye population and recruitment estimates conducted during the spring and fall, the 

number, size, and lakes to be stocked with pond-reared 

walleye are determined. The purpose of the paper is to 

describe the techniques used by the Tribal Fish Culture 

Program for rearing walleye from fry to 1.75-2.25 in 

(44.5-57.2 mrn) fingerlings in drainable ponds. The 

reservation is located in north-central Wisconsin, 

approximately 80 miles (128 km) northwest of Wausau. 

The 92,000 acres (36,800 ha) of reservation land has 

20,000 surface acres (8,000 ha) of water in 158 lakes 

and 34 miles (54.7 krn) of creeks, rivers, and streams. 

Description of ponds 

The ponds are 0.25-0.75 acres (0.1-0.3 ha) in size and 

are either lined with clay or HDPE plastic. The 12 

ponds used in the program are 8.5 acres (3.4 ha) of 

which six, 0.5 acre (0.2 ha) ponds, are plastic lined. 

Average pond depth is 4.0 ft (1.2 rn) with 34 acre-ft 

(41,942 m3) of water available for walleye production. 

Pond levee slopes are either 2: 1 or 4: 1 with 20 ft (6.1 

m) levee crowns. The water supply is groundwater or 

lake water. The groundwater can be supplied to the 

pond at a rate of 1,000 gpm (3,790 Wmin ) and lake 

water at 2,600 gpm (9,854 Lhin). Lake water temperature ranges 40"-79°F (4.4"-26.1 "C) during the production season and the groundwater is constantly 50°F 

(10°C). Both the groundwater and lake water have 

methyl orange alkalinity ranges from 20-70 ppm (mg/ 

L) calcium carbonate, respectively. Soil associated with 

the watershed is Rubicon sand which has a pH ranging 

4.5-6.0 and an organic matter content of 0.5-1 .O%. 

Pond preparation and fertilization 

Pond preparation begins in the fall for the next production season. All ponds are left dry over winter. This 

consolidates the bottom, aides in disease control, and 

eliminates unwanted fish and plants. The earthen ponds 

are allowed to seep dry, rather than being rapidly 

drained, to simulate natural conditions that trigger 

cladocerans and copepods to produce resting eggs. The 

eggs survive the winter and contribute to the initial 

zooplankton present in the spring when the ponds are 

filled. Levees are repaired along with any plumbing 

problems and pond bottoms that are not plastic lined are 

planted with rye grass. The rye grass aides in erosion 

control and adds to the fertilization regime. In midApril, the earthen ponds are disked to break down the 

rye grass and to aerate the soil. Rye grass is disked to 

breakup clumps of rye grass which may serve as 

starting sites for benthc algae. The ponds are partially 

filled about 4 weeks before walleye fry are stocked. 

Initially, the ponds are fertilized and filled to about one 

third the pond volume. This allows the water to warm 

faster which speeds up the establishment of zooplankton. Surface water from Pokegama Lake is used to fill 

the ponds, which is the same water source used to hatch 

the walleye eggs. We are able to observe the zooplankton in the unfiltered hatchery water, When the zooplankton are observed, water from Pokegama Lake is 

again pumped to the ponds to capitalize on the plankton 

in the lake water. An addtional one thrd of the pond is 

filled when we first see the plankton in the hatchery 

water and the final one third is added when the walleye 

eggs start to hatch. 

Since 1980, many different fertilization programs were 

tried before it was decided that organic fertilization was 

the best alternative. The amount of fertilizer used 

largely depends on pond fertility, weather conditions, 

NCRAC Culture Series 101 - Walleye Culture Manual 111 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

number and size of the fish, and the quality and quantity 

of the zooplankton population. Generally, we apply 

1,175 lb/acre (1,335 kgha) of alfalfameal and 118 lb/ 

acre (I 34 kgha) of Torula yeast. The fertilization 

program usually begins by applying approximately ?4 

the total amount of fertilizer required when the pond is 

first filled, and subsequent applications are weekly, 

each about % of the total amount of fertilizer required 

age of the fry and the condition of the zooplankton 

population. We stock three-d-old fry, or fry that are 

strong enough to swim to a light located at the head end 

of a fry tank. Walleye fry are stocked at a rate of 

120,000 fry/acre (300,000 fryha). 

What constitutes a desirable zooplankton population? A 

subjective judgment, based on experience of the pond 

during the production season (Table 1). 

Table 1. Application rates Ib/acre 

meal and Torulas yeast during 

season. 

(kg/ha) of Alfalfa 

the production 

manager has been our guide. This is based on relative 

1 st 2nd 3 rd 4th 5th Total 

Alfalfa meal a 587.5 146.88 146.88 146.88 146.88 1175.0 

(524.0) (131.0) (131.0) (131.0) (131.0) (1048.0) 

Torulas yeast 59.0 14.75 14.75 14.75 14.75 118.0 

(52.6) (13.2) (13.2) (13.2) (13.2) (105.4) 

Total 646.5 161.63 161.63 161.63 161.63 1293.0 

(576.7) (144.2) (144.2) (144.2) (144.2) (1153.5) 

a The initial application of alfalfa meal equals % of the total amount of fertilizer required, subsequent applications equal '/B of the total amount of alfalfa meal required. The same proportions 

are used for application of the Torulas yeast. 

Alfalfa meal is broadcasted evenly around the pond 

with a scoop made from a one gallon milk container. 

Because Torulas yeast is a very fine powdery substance, 

it is applied as a slurry formed by mixing it in 50 gal 

(190 L) of water. The yeast and alfalfa meal are 

distributed evenly around the pond. 

Monitoring of zooplankton 

The ponds are monitored for zooplankton before and 

after the fry are stocked. Zooplankton are collected by 

using a 80 micron mesh net with a mouth diameter of 8 

in (203 mm) and a length of 20 in (508 mm). The net is 

extended from a fiberglass pole and pulled through the 

pond for approximately 20 ft (6.1 m). Sampling areas of 

the pond will vary, but the windward side of the pond is 

usually sampled. The pond manager is responsible for 

determining the quantity and quality of the zooplankton 

populations before stocking and during the rearing 

season. Subsequently, the hatchery and pond managers 

make the decision when fry are stocked based on the 

abundance, size, and species 

composition of the zooplankton determined by daily 

monitoring of the ponds. In 

general, at the time of 

stocking, copepods and 

rotifers of various sizes 

should be abundant, and only 

a moderate number of 

daphnids (water fleas). As the 

rearing season progresses, 

there should be more 

daphnids than copepods and 

chironomid larvae as well. 

The condtion of the zooplankton is also noted. The 

biologist looks for the 

presence of egg or embryos in 

the zooplankton and the 

relative size composition of 

the zooplankton. These observations provide the pond 

manager the information required to know if more 

fertilizer is necessary to maintain the zooplankton 

population. If, for example, the relative abundance of 

copepods is decreasing compared with previous 

samples, and there are no large-bodied cladocerans 

present, and the zooplankton that are present are not 

reproducing, the pond manager would fertilize if 

oxygen concentrations at sunrise are adequate (>5 mg/ 

L). If oxygen concentrations are less than 4 ppm 

(mg/L), and the weather is predicted to be cloudy, hot, 

and with little or no wind, the ponds should not be 

fertilized because the additional fertilizer will result in 

decreased oxygen concentration when the fertilizer 

begins to decompose. 

Monitoring oxygen and pH 

We monitor oxygen concentrations at sunrise using an 

oxygen meter. Samples are usually collected at the 

deepest area of the pond at mid-depth. On occasion, all 

112 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 7 

ponds will be sampled more thoroughly to determine if 

there is oxygen and temperature stratification. The most 

critical interval for low oxygen is from mid-June to July 

when the walleye are harvested. The rearing volume 

may be reduced by half when oxygen stratification 

occurs, with oxygen concentrations of <2 ppm (mg/L) 

from the pond bottom to mid-depth. If low oxygen 

concentration or stratification occurs, we draw-off the 

bottom water and replace it with aerated cooler lake 

water or cold groundwater. 

Because our ground and lake water have low alkalinity 

(Le., buffering capacity), the pH is monitored in the 

morning, afternoon, and after dark to spot pH changes 

occurring as a consequence of photosynthesis and 

respiration. Water samples for pH monitoring are 

collected at mid-depth and at the surface. Changes in 

pH were a preliminary concern when we lined the 

ponds with plastic liners because we thought that if the 

soil was covered, the buffering capacity of the water 

would be changed, however, we found that pH readings 

in the lined ponds were not substantially different from 

that of the clay lined ponds. 

Monitoring fingerlings and aquatic insect 

control 

we do not actively sample walleye to determine 

growth rates or condtion factors during the production 

season. Growth, con&tion, and density are casually 

observed and noted daily. Generally, walleye fingerlings 

can be observed near flowing water during the daylight 

hours, 14 d after stocking. At 14 d, the fingerlings are 

approximately 0.75 in (19.1 mm) and can be easily 

ob served. 

When necessary, to control air-breathing piscivorous 

aquatic insects, a portion of a mixture of 3 gal (1 1.4 L) 

of fuel oil and 1 qt (0.95 L) of 30-weight motor oil is 

applied to the surface of the pond. Ponds should not be 

treated until fish are at least 12-14 d old, which avoids 

affecting swirnbladder inflation. 

Harvest methods 

Eve fyke nets and a seine are used to harvest 

fingerlings from the ponds. The fyke nets are 

made of '/s in (3.2 mm) mesh, with 4 ft gates (1.2 

m), and 3 ft (0.9 m) diameter hoops; they are 

used with a 25 ft (23 m) lead. The seine has !4 in 

(3.2 rnm) mesh, it is 300 ft (275 rn) long x 8 ft 

(7.3 rn) deep. Fingerlings are crowded toward the 

water supply line by seining '/2 to % of the pond. 

Fyke nets are set in the un-seined portion of the 

pond. The pond is slowly drained while fresh 

water is added. Seining and setting of the nets 

occur in the morning and the nets are checked 

every 3 h. Two floating boxes are used to place 

the walleye fingerlings in when removed from the 

nets. The boxes, which look like a jon boat with 

two bows, are approximately 3 x 4 x 1 ft (0.9 x 

1.2 x 0.3 m) and are constructed so the bottom 

and the 3 ft (0.9 m) sides are screened to allow 

for water exchange. Water is exchanged by 

simply moving the boxes through the water. 

When all nets are harvested, the boxes are floated 

to a pond side site where the length, number of 

fisMb, and total weight of the fish harvested are 

determined. The fish are transferred to a hauling 

truck and transported in a 1.0% saline solution to 

reduce physiological stress. Because the tribal 

government does not allow the use of herbicides 

and the ponds do not have catch basins, our 

harvest method was initially designed to harvest 

walleye in ponds that had aquatic vegetation 

problems. The method proved to be so effective 

and easy on the fish under poor harvest conditions, we now use this method all the time. 

Yield 

Typically we raise walleye to 2 in (51 mm) in 40 

d. Given a size of 7 mm at hatching, the growth 

rate is about 0.043 in/d (1.10 mdd). The 

fingerlings range 417-450 fisldlb (917-990 fish/ 

kg) at harvest. Annual survival to 2.0 in (51 mm) 

is variable; it ranges from 30-75%. 

NCRAC Culture Series 101 - Walleye Culture Manual 113 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

114 NCRAC Culture Series 101- Walleye Culture Manual 
Culver, D. A. 1996. Fertilization procedures for pond culture of walleye and saugeye. Pages 11 5- 

122 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture Series 101. North 

Central Regional Aquaculture Center Publications Office, Iowa State University, Ames. 

Fertilization Procedures for Pond Culture of 

Walleye and Saugeye 

David A. Culver, Department of Zoology, The Ohio State University, I735 Neil Avenue, Columbus, OH 432 10- 

Introduction 

Our research on fertilization and stoclung strategies 

for walleye production ponds was stimulated by the 

unacceptable variation in the survival and growth of 

walleye fry to stockable-sized fingerlings in the ponds. 

Some of this variability is the result of low dissolved 

oxygen and/or high ammonia and pH. In many cases, 

the fish ponds developed a blue-green phytoplankton 

bloom with little or none of the edible and most useful 

algae for zooplankton, particularly if low N:P ratio 

fertilizers are used (Helal and Culver 1991). The 

zooplankton on which the fish depend also has been 

shown to vary profoundly in abundance, with an abrupt 

decline often occurring after a clear-water period 4 or 5 

weeks after the ponds are filled, forces fish to switch to 

feedmg on chironomids. An addtional problem is that 

large mats of filamentous algae often float to the 

surface just before ponds are scheduled to be drained. 

As water levels drop during draining, fish often hide 

under these mats and are smothered. Mats also collect 

in the kettle areas where fingerlings are being netted out 

of the ponds and are dfficult to separate from the fish. 

Clearly, research on suitable fertilizers must be directed 

toward the water quality and the algae and zooplankton 

produced, not simply correlated with fish production 

results. 

While different abiotic (e.g., light, temperature) and 

biotic factors (e.g., food availability, competition, 

predation) have been found to regulate zooplankton 

abundance and thus fish growth in ponds, the most 

convenient variables to manipulate in managing 

hatchery ponds are: 1) amounts, timing and types of 

fertilizer inputs; 2) stoclung schedules relative to pond 

filling times; and 3) the number of fish stocked. In 

determining the best strategies to use in Ohio hatchery 

ponds for culturing walleye and saugeye we have thus 

concentrated on these variables. Our approach has been 

to apply the results of research on lakes to suggest how 

plankton production might be optimized for fingerling 

production rather than to simply associate fish yield 

with various fertilization and stockmg regimens. For 

example, when we tested various N:P ratios by fertilization with a combination of inorganic and organic 

fertilizers (Qin et al. 1995), and varied the number of 

days between the time when ponds were filled and the 

fry are stocked, we measured nutrient concentrations, 

phytoplankton composition and abundance, zooplankton composition and abundance, and fish diets from 

stomach content analysis throughout the production 

season in replicated pond treatments. We then interpreted the results in light of published results of 

eutrophication and trophic dynamics research in lakes. 

Findmgs from limnological research involving &fferent 

trophic levels that are applicable to problems in 

managing fish ponds include the following: 

1) Small algae, most easily eaten by crustacean 

zooplankton, grow best when the inorganic 

nitrogen to reactive phosphate (N:P) ratio in the 

pond is above 7: 1 by weight. 

2) Algae favor ammonia over nitrate as a N source. 

3) N:P ratios < 7: 1 often favor nitrogen-fixing bluegreen algae (Helal and Culver 1991), many of 

which are filamentous (inedible by many zooplankton) andor may produce toxins harmful to 

fish and zooplankton. 

4) Under low phosphate concentrations, small algae 

species (edible) are competitively favored relative 

to large green and blue-green filamentous species. 

Many large algae also store phosphorus in times 

of abundance in polyphosphate granules and then 

can supply daughter colonies for weeks. 

5) Cladoceran production is enhanced by a high 

abundance of edible algae but these algae are 

overgrazed when cladocerans persist in high 

densities causing clearwater periods (Qin and 

Culver 1995a,b). 

NCRAC Culture Series 101 - Walleye Culture Manual 115 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

6) In the absence of fish predation, Daphnia suppresses copepods and smaller cladocerans such as 

Bosmina through competition for food (Culver et 

al. 1984). 

7) Planktivorous stages of walleye and saugeye 

preferentially select large crustaceans, with 

copepods being preferred over cladocerans. 

8) Under lower edible algal availability during 

clearwater periods, crustacean zooplankton 

reproduction rates decline, making them numerically more susceptible to fish predation (Wu and 

Culver 1994). 

A number of Ohio hatchery production problems have 

been addressed using limnological strategies. We 

highlight five of these problems below, along with the 

means for their solution. 

1) Maintaining an adequate abundance of copepods 

and cladocerans for fish growth and survival: We 

encouraged growth of small algae (diatoms, 

coccoid greens, flagellates) for growth using 

liquid inorganic fertilizers once per week to 

achieve an inorganic N:P ratio of 20: 1 by weight, 

with no more than 30 pg phosphate-PL. The ratio 

began changing immedately upon fertilization, 

but we restored it to 20:l once per week. We 

stocked fish at 4-5 d of age and filled ponds at the 

same time using reservoir water. High densities 

(over 50/1) of zooplankton were not necessary to 

provide adequate food for fry at stoclung. Walleye 

consumption per day per fish was very low 

initially and increased exponentially with time 

(Madon and Culver 1993). The zooplankton 

bloom grew along with the walleye’s appetite, 

and we avoided overgrazing by Daphnia by 

stocking sufficient fish to prevent overabundance 

of Daphnia in week 4 or 5 (Culver et al. 1984). 

2) AvoiQng lvgh ammonia concentrations in the 

ponds, especially during the clearwater phase 

during week 4 or 5: We measured nutrients in 

ponds once a week and fertilized up to a target 

inorganic P concentration and N:P ratio, rather 

than using one fixed fertilizer amount. 

3) AvoiQng low oxygen concentrations: We used no 

organic fertilizers. For each unit of photosynthetically-produced biomass, one unit of oxygen is 

released to the water; for each unit of heterotrophcally produced biomass, one unit of 

oxygen is consumed. 

4) Avoiding large filamentous green and blue-green 

algae: We maintained a low phosphate concentration, favoring those algae (mostly small species) 

whose phosphate uptake mechanisms become 

saturated at low concentrations. Addition of large 

amounts of fertilizer at one time, especially when 

ponds are filled, favored large filamentous 

phosphorus storers, so we fertilized often with 

small amounts of N and P. We restored the N:P 

ratio in the pond to 20: 1 once per week to 

minimize growth of nitrogen-fixing filamentous 

blue-greens. Also, we found many filamentous 

greens and blue-greens grew heterotrophically on 

the bottom of the pond, especially in those ponds 

to which organic fertilizers such as alfalfa meal 

had been added. When ponds cleared up, these 

algae were still rich with phosphorus from the 

sedments and were able to photosynthesize 

sufficiently to produce oxygen bubbles which 

caused them to float up to surface just when we 

wanted to harvest fish. Another genus, 

Hydrodictyon, did not float up, but it acted as a 

mini-gill net, killing fry and even fingerlings. 

Heavy fertilization at the clearwater period would 

also favor this species. After a suitable fertilization regimen was identified, we adjusted the 

density of stocked fish to obtain the optimum 

trade-off among zooplankton abundance, fish 

size, and numbers produced. 

Application to hatchery ponds in Ohio 

walleye and saugeye production research was performed at the Hebron, Senecaville, and St. Mary’s state 

fish hatcheries (total of 80 drainable ponds) in Ohio. All 

three hatcheries draw water from mesotrophic or 

eutrophic reservoirs, with significant agricultural 

activity in the watersheds. Dependng upon weather, 

there can be tremendous differences in the nutrient 

concentrations in the water used to fill the ponds, from 

essentially no inorganic nitrogen or reactive phosphate 

to as much as 0.25 mg N/L as ammonia and 1.2 mg N/L 

as nitrate. In this last case, rainfall occurred at St. 

Mary’s, OH, just after many farmers had fertilized their 

fields. Water sources for all three hatcheries have total 

alkalinity values of 80-1 11 mgL as CaCO,. Reservoirs 

usually have spring blooms of phytoplankton and 

diverse populations of zooplankton at the time ponds 

are filled. 

116 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 5 

Pond sizes and shapes differ among the hatcheries, with 

Hebron and S enecaville having primarily inhvidually 

fillable and drainable 1 acre (0.4 ha) rectangular ponds 

averaging 3 ft (I m) deep, whereas St. Mary’s ponds 

vary from 0.1-7 acres (0.04-2.8 ha) in size, and many 

are arranged as groups of three ponds served by a single 

fill valve with two ponds fillable only by sequential 

overflow from the pond with the fill valve. All three are 

in turn drained by underground pipes feeding a single 

concrete harvesting kettle. Ponds at St. Mary’s are 

currently under renovation to make them more uniform 

in size and to provide individual control of filling and 

draining. 

Filling is delayed until just before fry are ready to be 

stocked so that the abrupt plankton decline that occurs 

4-5 weeks after ponds are filled will occur as late into 

the production season as possible. Lake water is passed 

through a filter, either a 0.01 in (0.25 mm) mesh metal 

microstrainer (Hebron), a sand filter (Senecaville), or 

0.01 in (0.25 mm) mesh screens in each pond (St. 

Mary’s) to remove eggs of fish such as gizzard shad or 

common carp as the ponds are filled. Previously, saran 

sack filters (0.02-0.03 in, 0.5-0.7 mm mesh size) were 

fastened over inlet pipes for each pond. In order to 

maintain known nutrient inputs, no adhtional water is 

added after the ponds are filled except to make up for 

evaporation losses. 

Brood stock and fry production 

Fry stocked in the ponds are produced in jar hatcheries 

managed cooperatively among the three hatcheries to 

optimize use of spawning runs of walleye in Salt Fork 

and Senecaville Lakes (early, 1 April) and the Maumee 

River and reefs of Lake Erie (later, 17-18 April) and 

water temperatures available for running the jar 

hatcheries and for filling the ponds. Hebron warms up 

first, followed by Senecaville, and then St. Mary’s. 

Numbers of fry that are stocked are estimated by 

counting a measured volume of settled fry in a cylinder, 

and by then generating estimates of volumes of fry 

needed to obtain the desired stoclung densities in the 

ponds, typically 180,00O/acre (445,00O/ha). Increasing 

attention is being given to avoiding introduction of 

zebra mussels into the hatchery with eggs and milt from 

Lake Erie. Zebra mussels may someday become 

established in the hatcheries due to introduction from 

fishing boats trailered between sites such as Lake Erie 

and the reservoirs that are used to fill the ponds, so the 

hatcheries are being monitored for zebra mussel adults, 

veligers, and settling juveniles. 

Fertilization of the ponds 

we use liquid nitrogen and phosphorus fertilizers from 

agricultural suppliers exclusively. For nitrogen fertilization, we use 28:O:O which is a combination of urea and 

ammonium nitrate. All hatcheries now use phosphoric 

acid (0:54:0) as a phosphorus source. We cannot infer 

the N:P ratio of a dry fertilizer directly by the N:P:K 

ratio, since in this notation the N is percent weight as N, 

the P is as P,O,, and the K is as K,O. For liquid 

fertilizers, one needs not only the percent N and P per 

weight of fertilizer but also the specific gravity (weight 

per volume) of the fertilizer to determine the expected 

N and P content per volume. Furthermore, none of the 

agricultural fertilizers we have purchased contained 

exactly the amounts of N and P expected. Nevertheless, 

for planning purposes, 28:O:O fertilizer has about 4 lb 

N/gal (480 g NL) (half as urea), and phosphoric acid is 

about 3.3 Ib P/gal (396 g PL). A typical 1-1.2 acre 

(0.4-0.5 ha) pond with no inorganic nitrogen or reactive 

phosphate will receive 1.3-1.6 gal (5-6 L) of the former 

and 10 fl oz (300 ml) of the latter. We have also used 

10:34:0 liquid fertilizer (ammonium phosphate) plus 

28:O:O to obtain the desired additions, but the calculations are simpler using phosphoric acid and 28:O:O. 

Hatchery staff have reported no difficulties working 

with concentrated phosphoric acid, provided care is 

exercised, and they appreciate the much smaller 

volumes that need to be used. Measurements must be 

accurate: there is a big difference between the response 

of the algae to 30 pg (i.e., IO fl oz/ac, 750 ml/ha) and 

60 pg/L of phosphate (Le., 20 fl oz/ac, 1500 ml/ha). 

We analyzed each batch of all fertilizers, since we 

commonly find contamination, as well as variation in 

strength. For example, one batch of 28:O:O had 0.24 lb 

P/gal (29 g P/L) as a contaminant, which not only 

complicated the computations, but would have resulted 

in adding 2.2 times the intended phosphorus dose had 

1.3 gal (5 L) of it been added. To measure the ammonia 

and nitrate concentration of the 28:O:O and phosphorus 

fertilizers, we first diluted them to 1 :200,000 or 

1 :300,000 with ammonia-free (run through a cation 

exchange column) double-distilled water and then 

analyzed the &luted solution with ion-specific electrodes for ammonia and nitrate respectively (see below). 

Urea content is typically analyzed by measurement as 

NCRAC Culture Series 101 - Walleye Culture Manual 117 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

ammonia after treatment with urease, a procedure used 

by all hospitals to measure blood and urine for urea-N 

content. This test can measure urea accurately over the 

range of 0.01-2 g/L urea N, so we only dilute fertilizer 

samples 1 : 1,000 before submitting them to local 

hospitals, who either perform the analyses free or for a 

small fee. Note that they report urea as mg N/dl 

(deciliter or 100 ml), not liter. We &lute phosphoric 

acid to 1 :2, 1 :3, and 1 :4 million with double distilled 

water before analysis to test for consistent results in the 

range for which the ammonium molybdate method is 

accurate. 

Immediately after the pond fills, we raise the inorganic 

concentration to 600 pg/N/L and P to 30 pg PO,-P/L, 

and then maintain this concentration each week 

thereafter using the appropriate volumes of nitrogen and 

phosphorus fertilizers. This requires first measuring the 

ammonia, nitrate, and phosphate concentrations in each 

pond. We use ion-specific electrodes for ammonia and 

nitrate and the acid molybdate/stannous chloride 

method for phosphate (APHA et al. 1980). The ammonia method requires a digital pH meter that can be read 

in millivolts, an ion-specific ammonia electrode (e.g., 

ORION 951201), a magnetic mixer, &lute standards of 

50-1,000 pg NH,-NL made fresh each week in 

distilled, ammonia-free deionized water, an alkaline 

ionic strength adjusting solution (e.g., ORION 95121 l), 

and the solution for filling the electrode. Nitrate 

requires the same meter, a nitrate electrode (e.g., 

ORION 930700), a reference electrode (e.g., ORION 

900200 plus solutions), standards, and an ionic strength 

solution called Nitrate Suppressor Solution (e.g. , 

ORION 930710). The suppressor solution is both a pH 

buffer and a solution to remove interfering ions. For 

example, it contains silver sulfate to precipitate chloride 

ion, sulfamic acid to remove nitrite, a buffer at pH 3.00 

to remove bicarbonate and carbonate, and alum to 

complex organic acids. Instead of using the recommended 10 ml suppressor solution plus 10 ml sample or 

standard, we use 5 ml of suppressor and 15 ml of 

sample or standard (or even 2 ml + 20 ml) as this gives 

a greater millivolt response per mg nitrate. 

Phosphate is measured using acid molybdate and either 

stannous chloride or ascorbic acid methods (APHA et 

al. 1980) using a spectrophotometer or colorimeter. We 

prefer the stannous chloride method because it is more 

sensitive and allows for correction for turbidity. We 

have found a Klett-Summerson colorimeter with a 4-cm 

light path to be less expensive than a spectrophotometer, but quite effective. 

Complete equipment, glassware, stock solutions, and 

supplies for these analyses are available from scientific 

supply houses such as VWR and Fisher Scientific, and 

cost about $5,000. Some effort was required to find a 

source of distilled water low enough in phosphate to 

give low blanks and accurate standards. Analyses for 30 

ponds requires one person-day, although our staff 

usually divides up the tasks of sample collection, and 

nitrogen and phosphorus analyses among three persons. 

Once the N and P concentrations of fertilizer and ponds 

are known, we use them and the volume of each pond at 

the current water level to calculate the amounts of N 

and P fertilizers to add to each pond that week to 

restore phosphate to 30 pg/L and inorganic N to 600 

pgL using the following formulas: 

1. Vpf = (30-PP) VP 

Pf x 1000 

where: Vpf = volume of phosphorus fertilizer needed 

(L); Pp = phosphorus concentration measured in pond 

(pg PL); Vp = volume of water in the fish pond (m’); 

Pf = phosphorus concentration of fertilizer (g PL); and 

1,000 is the combined conversion factors between L 

and m3 and between pg and g. 

(30-Pp) Nf 

Pf 

2. Na = 

where: Na = nitrogen added by ammonium phosphate 

fertilizer (pg NL); Pp = phosphate concentration 

measured in the pond (pg PL); Nf = nitrogen concentration of ammonium phosphate fertilizer (g NL); and 

Pf = phosphate concentration of ammonium phosphate 

fertilizer (g PL). If phosphoric acid is used as the 

phosphorus source, this calculation is not required. 

3. Vnf = (600-Np-Na) Vp 

where Vnf = volume of nitrogen fertilizer needed (L); 

Np = inorganic nitrogen concentration (NO,-+NH,+) in 

the pond (pg NL); Na = nitrogen added to the pond by 

P fertilizer from equation 2 (pg NL); Vp = volume of 

the pond (m?); Nf = nitrogen concentration of fertilizer 

(ammonia plus nitrate plus urea (g as NL)); and 1,000 

again is the combined conversion factors between L and 

m3 and between pg and g. The calculations of nitrogen 

and phosphorus fertilizer to be added are made assumNf x 1000 

118 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 5 

ing that either phosphoric acid or ammonium phosphate Biological moni t ori n g 

(10:34:0) is the P fertilizer form and that neither is the 

phosphoric acid contaminated with nitrogen, nor is the 

nitrogen fertilizer (28:O:O) contaminated with phosphorus. 

As noted above, we only use liquid inorganic fertilizer. 

The progress of the seasonal bloom of algae was 

followed with weekly algal counts or more frequent 

measurements with a Secchi disk (Figure 1). The data 

in Figure 1 are from St. Mary's hatchery in 1990 from 

group of ponds stocked at two &fferent fish densities. 

Secchi transparency can be seen to decrease and then 

Not only does organic fertilizer contribute to 

oxygen problems (Qin and Culver 1992, 

1995b; Qin et al. 1995), but it is also not 

possible to alter the relative amounts of N and 

P in organic fertilizer (Culver 1991), nor is it 

possible to know with certainty when or where 

the N and P contained in organic fertilizer will 

be released into the pond. Inorganic fertilizers 

are also less expensive than organic fertilizers. 

In 1993, phosphoric acid cost $412/metric ton, 

and $90 purchased sufficient fertilizer to 

supply all three hatcheries for the season. 

Nitrogen fertilizer (28:O:O) cost $150 per 

metric ton, or about $400 for the season for all 

three hatcheries. Adding 90 lbs (40 kg) alfalfa 

meal to a single 1 acre (0.4 ha) pond (equivalent to addmg 10 mgL) for each of 6 weeks 

cost $69 for the season. Inorganic fertilizer 

cost an average of $490/80 = $6.13/pond for 

the season. 

Liquid fertilizer is added to the tank of an 

agricultural sprayer that is attached to a tractor 

and diluted with 50 gal (200 L) of pond water, 

and the solution is sprayed over the surface of 

the pond as the tractor travels along the dam. 

Some practice is required to time tractor speed 

to spray the entire contents of the tank in one 

pass. Measuring out the fertilizer went quickly 

using carboys with spigots for dispensing the 

phosphoric acid and larger polyethylene tanks 

with valves for the nitrogen fertilizer. In 

practice, the N and P are depleted by the next 

week in most ponds. More than half of our 

ponds needed the full 600 pg/L N or 30 pg/L P. 

If pond concentrations of N (or P) exceeded 

the target of 600 (or 30) pgL, no fertilizer of 

that form was added until the concentration 

dropped below the target level. 

Figure 1. Comparison of high and low fish stocking density effects on various parameters in 

i norgan ical ly-fert i lized ponds (2 per treat men t) 

at the St. Mary's State Fish Hatchery, 1990. 

100 

80 

g 60 

5 40 

20 

0 

a 

4 

x 

0 10 20 30 40 

I .6 

1.4 

1.2 

rn1 

0.6 

E 0.4 

0.2 

0 

: 0.8 - 

0 10 20 30 40 

h 

I 

. Algae .;A -.I 1.. I 

0 10 20 30 40 

la 

16 

14 d 

?I2 

10 

8 

6 

a 

0 10 20 30 40 

10 1 I 

9.8 

9.6 

I 9.4 

9.2 

9 

8.8 

8.6 

e 

0 10 20 30 40 

0.4 

- 0.3 0 

v 

.cI 

g 0.2 .- 

5 0.1 

0 

0 IO 20 30 40 

2500 1 rI 

0 10 20 30 40 

Hollow squares = high fish density (21 6,00O/acre, 540,00O/ha), Filled 

squares = low fish density (1 04,00O/acre, 260,00O/ha). Secchi disc 

transparencies after day 32 were to the bottom of the pond, or about 1 m. 

Walleye biomass is shown as mean individual wet weights from twiceweekly samples of 10 or more fish seined from each pond. 

NCRAC Culture Series 101 - W a l l e y e C u l t u r e Manual 119 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

increase as imperfect evidence of an algal bloom that 

builds and declines as a result of a zooplankton bloom 

that occurred in the ponds. The dynamics of the algae 

and zooplankton can also be followed by their indirect 

effects on water chemistry. For example, oxygen 

declined throughout the season as the algae declined. 

Lower algae abundance resulted in lower photosynthesis, resulting in lower oxygen concentration. The pH 

tends to be high when photosynthesis is high and 

declines later in the season. Measurements of N and P 

are shown for the initial conditions and for subsequent 

weeks, 6 d after each fertilizer adhtion. When algal 

abundance becomes low, added nitrate, ammonia, and 

phosphate will be left over the next week when analyses 

are performed (e.g., day 38), since there are insufficient 

algae to assimilate what we add plus what is released by 

decomposition and animal excretion (Qin et al. 1995). 

Here, analysis of N and P in the ponds is particularly 

important, since hatchery managers may see an increase 

in Secchi transparency, assume that addtional fertilizer 

was required, and then overfertilize the ponds. 

Fish growth is monitored weekly, and the pond draining 

is influenced by whether growth exceeds 1 mdd, 

apparent condtion of the fish, and whether they are > 

25 mm. Fish are usually harvested when they are 30-40 

mm; larger fish are easier to harvest, as they are less 

likely to be pressed against the screens on the kettle by 

Figure 2. Total harvest of percid fingerlings from St. 

Mary’s, Hebron, and Senecaville Hatcheries, OH, 

1987-1 994. 

the draining currents. Growth is affected by stocking 

density, but it is difficult to follow this through the 

season, since survival is not 100% and one cannot know 

with certainty when mortality occurred. If we assume 

that most mortality occurs the first week after stocking, 

however, we can compare growth of fish living at 

different densities using their abundance at harvest. 

Walleye and saugeye attained larger size at harvest 

densities below 32,00O/acre (80,000ha). Above that 

density, however, fish size at harvest stays constant (at 

about 0.3 g wet weight) up through at least 144,000/ 

acre (360,00O/ha). A constant fish size at harvest with 

increasing harvest numbers implies that greater yield 

occurred at higher harvest numbers, which was indeed 

the case, We found walleye yield (kg/ha) = 24.2 + 

0.0002 HD, where HD is the harvest density in number 

of fish/ha (Culver et al. 1993). A similar regression for 

saugeye was Yield = 12.6 + 0.0003 HD. 

Improving survival was a major goal of our project, and 

this has been achieved: The percent of ponds at the 

Hebron hatchery with e 10% survival declined from 

55% to 0%. For ponds at the St. Mary’s hatchery, which 

were used to illustrate results in this paper, survival 

varied from 46-86%, and the mean was 63%, over a 

range of stoclung densities from 100,000-240,000 fry/ 

acre (248,000-596,000 fry/ha). Average survival across 

all ponds among the three hatcheries in 1991 was 64%, 

12 

IO 

.=8 - 

E 

-6 

S 

.- 0 

U 

v) 

; a4 

z 

2 

0 

A 

1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 

Rectangles = walleye. Triangles = saugeye. Circles = total percids. 

with a yield of 86,000 fingerlingdacre 

(215,00O/ha), and a wet weight of 61 lbs/ 

acre (68 kgha) (Culver et al. 1993). 

These improvements in survival and yield 

have been reflected in both walleye and 

saugeye culture. Since 1986, the greatest 

demand for stocking in state waters has 

been for saugeye, so the increase in overall 

production due to the adoption of our 

fertilization, filling, and stocking regimen 

is reflected primarily in the production of 

saugeye (Figure 2). The same pond 

management protocol has been used for 

both taxa, and their growth and survival 

rates did not hffer (Culver et al. 1993, Qin 

et al. 1994). 

Our filling, stocking, and fertilization 

regimen has resulted in a 1 0-fold increase 

in total production of percids by the Ohio 

120 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 5 

state hatchery system since 1987 (Figure 2) without an 

increase in personnel. The actual increase in fish 

produced per acre (hectare) is about 5-fold7 since some 

of the increase represents the use of more ponds. 

Weekly chemical analyses and fertilization require 

more time than previous regimens, but more reliable 

water quality has decreased the need for intervention 

during low oxygen occurrences. Discontinuing the use 

of alfalfa hay and meal has, in turn, decreased labor and 

material costs, while increasing survival of fish. More 

reliable production has decreased the number of ponds 

needed to meet production goals. 

These techniques may need to be adjusted for other 

locations where lower or higher inorganic carbon 

content (alkalinity), warmer or colder water temperatures (ours ranged from 52-73"F, 11-23"C), or differently-shaped ponds might alter the dynamics of the 

system. For example, we use lower phosphorus additions in our deep ponds and in lakes. Still, chemical and 

biological monitoring of the production season and high 

stocking density have successfully decreased the 

variability among ponds, while increasing the number 

and weight of fish produced per acre. 

Acknowledgments 

This study was initiated at the suggestion of Robert F. 

Carline in 1980, and the work was done with the 

assistance of four doctoral students, Jianguang Qin, 

Sharook Madon, Ralph Vaga, and Hamdy Helal, plus 

numerous student assistants. The cooperation and 

support of Jim Stafford and staff of the Hebron Hatchery, Dick Chittum and staff of the St. Mary's Hatchery, 

and Pat Keyes and staff at the Senecaville Hatchery is 

gratefully acknowledged. They were tolerant and 

patient at their busiest times, and risked several years' 

walleye and saugeye production to our experiments, and 

ultimately improved on our methods to set new production records. This study was funded through Federal 

Aid in Fish Restoration, Project F-57-R, Study 14, from 

the Ohio Department of Natural Resources, Division of 

Wildlife, the U.S. Fish and Wildlife Service, and The 

Ohio State University. 

References 

APHA (American Public Health Association, American 

Water Works Association, and Water Pollution 

Control Federation). 1980. Standard methods for the 

examination of water and waste water. 15th ed. 

Washington, DC. 

Culver, D. A. 1991, Effects of the N:P ratio in fertilizer for 

fish hatchery ponds. Verhandlungen lnternationale 

Vereinigung fur Theoretische und Angewandte 

Limnologie 24: 1503-1 507. 

Culver, D. A., S. P. Madon, and J. Qin. 1993. Percid 

pond production techniques: timing, enrichment, and 

stocking density manipulation. Journal of Applied 

Aquaculture 2(3/4):9-31. 

Culver, D. A., R. M. Vaga, and C. S. Munch. 1984. Effect 

of size-selective fish predation on the reproductive 

output of Cladocera in hatchery ponds. 

Ve r h a n d I u n g e n I n t e r n at i o n al e Ve re i n i g u n g f u r 

Theoretische und Angewandte Limnologie 221 636- 

1639. 

Helal, H., and D. A. Culver. 1991. N:P ratio and plankton 

production in fish ponds. Verhandlungen 

I n t e r n at i o n a I e Ve rei n i g u n g f u r T h eo ret i sc h e u n d 

Angewandte Limnologie 24:1508-1511. 

Madon, S. P., and D. A. Culver. 1993. Bioenergetics 

model for larval and juvenile walleye: an in situ 

approach using experimental ponds. Transactions of 

the American Fisheries Society 122:797-813. 

Qin, J., and D. A. Culver. 1992. The survival and growth 

of larval walleye (Stizostedion vitreum) and trophic 

dynamics in fertilized ponds. Aquaculture 108:257- 

276. 

Qin, J., and D. A. Culver. 1995a. Effect of larval fish and 

nutrient enrichment on plankton dynamics in experimental ponds. Hydrobiologia (in press). 

Qin, J., and D. A. Culver. 1995b. Effect of young-of-theyear walleye (Percidae: Stizostedion vitreum) on 

plankton dynamics and water quality in ponds. 

Hydrobiologia 297:217-227. 

Qin, J., D. A. Culver, and N. Yu. 1994. Comparisons of 

larval walleye and saugeye (walleye x sauger hybrid) 

growth and impacts on zooplankton in experimental 

ponds. Progressive Fish-Culturist 56:91-99. 

Qin, J., D. A. Culver, and N.Yu. (1995) Effect of organic 

fertilizer on heterotrophs and autotrophs and on 

water quality management in ponds. Aquaculture and 

Fisheries Management (in revision). 

NCRAC Culture Series 101 - Walleye Culture Manual 121 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

Qin, J., S. I? Madon, and D. A. Culver. 1995. Effect of 

larval wal I eye (Stizostedion vitreum) and fertilization 

on the plankton community: Implications for larval 

fish culture. Aquaculture 130:51-65. 

Wu, L., and D. A. Culver. 1991. Age-0 yellow perch 

(Perca flavescens) dietary ontogeny in the western 

basin of Lake Erie: Effect of midsummer decline in 

zoo p I an kt o n pop u I at i o n s . Ve r h an d I u n g e n I n t e r n ationale Vereinigung fur Theoretische und Angewandte 

Limnologie 242366-2370. 

Wu, L., and D. A. Culver. 1992. Ontogenetic diet shift in 

Lake Erie Age-0 yellow perch: A size-related response to zooplankton density. Canadian Journal of 

Fisheries and Aquatic Sciences 49:1932-193 

Wu, L. and D. A. Culver. 1994. Daphnia dynamics in 

western Lake Erie: Regulation by algal limitation and 

young-of-year fish predation. Journal of Great Lakes 

Research 20537-545. 

122 NCRAC Culture Series 101- Walleye Culture Manual 
Flowers, D. D. 1996. Fingerling production in drainable ponds at White Lake Fish Culture Station. 

Pages 123-128 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture Series 

101, North Central Regional Aquaculture Center Publications Office, Iowa State University, 

Ames. 

Fingerling Production in Drainable Ponds 

at White Lake Fish Culture Station 

David D. Flowers, Ontario Ministry Of Natural Resources, White Lake Fish Culture Station, RR2 Sharbot Lake, 

Ontario, CANADA, KOH 2PO 

Introduction 

white Lake Fish Culture Station (hereafter referred to 

as White Lake) is operated by the Ontario Ministry of 

Natural Resources (OMNR) and is presently the only 

government hatchery in the Province that raises 

walleye. In 1982, a new Provincial initiative established 

a Community Fisheries Involvement Program (CFIP). 

Under this program many walleye culture projects were 

begun as partnerships between community groups and 

local OMNR districts. Most of the walleye stocked in 

Ontario during the last 10 years have come from 

community operated ponds. 

In recent years, a considerable amount of research and 

experimentation has been devoted to pond culture at 

White Lake. Walleye have been stocked at different 

densities in culture ponds to examine its effects on prey 

density and on walleye growth and survival. Other 

studies have compared various fertilization regimens 

using organic and inorganic fertilizers and examined 

their effects on pond dynamics and 

walleye growth. These studies have 

helped government and CFIP hatcheries 

manage ponds more effectively for 

fingerling production. 

This case study describes pond management techniques 

used at White Lake that have evolved from traditional 

culture methods used in Ontario and from research 

findmgs at White Lake and elsewhere. 

Pond management techniques 

white Lake has ten small ponds for walleye production that have a combined total surface area of 2.6 acres 

(1.05 ha). Six ponds were designed as replicates for 

experimental work, each has a surface area of 0.1 acre 

(0.04 ha), mean depth of 3 ft (0.91 m) and a volume of 

0.28 acre-ft (345.4 m3). The remaining four ponds are 

designated production ponds (Figure 1). They have 

larger surface areas (0.4-0.6 acres, 0.16-0.24 ha) and 

are more variable in shape and depth (mean depth 2.5- 

3.4 ft, 0.76-1.04 m). Although pond stoclung and 

fertilization rates are often based on surface area, at 

White Lake, these parameters are based on pond 

In Ontario, pond culture begins in May 

when fry are stocked into fertilized 

ponds. Fry feed on zooplankton and 

insect larvae for 6 to 8 weeks and grow 

to 1.6-2.4 in (40-60 mm) by early July. 

At that time, they are usually harvested 

and stocked in local lakes, or brought 

indoors for further intensive culture using 

artificial feeds. Some CFIP groups have 

been quite successful supplementing 

ponds with minnows to extend the 

growing season and produce larger 

fingerlings. Figure 1. Production ponds at White Lake. 

NCRAC Culture Series 101 - Walleye Culture Manual 123 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

40 - 

30 - 

20 - 

10 - 

volume using acre-ft (volume of water covering 1 acre 

(0.4 ha) to the depth of 1 ft (0.3 m)) as the standard unit 

of measure. Pond volume should be considered when 

determining how many walleye can be stocked in a 

pond, especially when using small ponds having similar 

surface areas, but significantly dfferent volumes. 

Studies at White Lake have used surveyed pond volume 

measurements to more accurately determine stockmg 

rates for ponds of different sizes (i.e., for fish density 

studies) and to help standardize fertilization rates and 

phosphorus inputs between ponds. 

There are many factors that affect annual 

variation in pond production. Variability in 

water quality and uncontrollable parameters, 

such as the weather, cause problems when 

trying to maintain adequate zooplankton 

populations. In addition, cohort competition and 

cannibalism will limit the consistency in 

fingerling size and numbers produced from 

ponds. While there is little we can do to compensate for poor weather, good pond management practices are essential to consistent 

fingerling production. 

Pond prepara tion 

Many of the ponds at White Lake are used to 

raise salmonids over the winter, however, they 

are completely drained in the spring and left dry 

for at least 10 d before refilling. Drying stabilizes the pond substrate, reduces aquatic 

vegetation growth and facilitates the oxidation 

of accumulated fecal matter and excess feed. 

The water source for the ponds at White Lake is 

from a natural mesotrophic lake. The inflow to 

each pond is fitted with a retaining screen to 

prevent the entrance of undesirable fish during 

initial filling. Ponds are filled at least 2 weeks 

prior to walleye introductions to ensure adequate time for zooplankton development. Inflows are 

usually shut off during the culture period to prevent 

hlution of nutrients, but minimal flows may be used to 

offset evaporation and seepage. 

Initial pond stocking densities 

The stocking rate for White Lake ponds has traditionally been 50,000 fry/acre-ft (40.5 fry/m3)). In 1988 

ponds were stocked at 3 densities (24,670, 49,340 and 

74,010 fry/acre-ft; 20,40 and 60 fry/m3), to study the 

effects on walleye growth and survival. In 1988, 

survival from stocking to harvest during a 6-week 

culture period was not affected by stoclung density, 

however, size at harvest was density-dependent (i.e., 

fish were smaller in ponds stocked at the higher 

densities). Growth differences began to appear after 

week 3 (Figure 2) and at 6 weeks fingerlings harvested 

from low density ponds weighed 40% more than 

fingerlings from high density ponds (Table 1). This 

study suggests that at high fish densities competition 

for space and food would limit walleye growth and 

will ultimately lead to significant cannibalism and 

density -dependent mortality. 

/ + High Medium 

01 

1 2 3 4 5 Harvest 

'ooo] (b) 

800 * 

600 - 

1 2 3 4 5 Harvest 

Week 

Figure 2. Weekly changes in (a) mean total lengths and (b) 

mean weights of walleyes in ponds stocked with low (20 

fish/m3), medium (40 fish/m3) and high(60 fish/m3) densities 

of larval walleyes. From Fox, M.G. and D.D. Flowers. 1990. 

Effects of fish density on growth, survival and food consumption by juvenile walleyes in rearing ponds. Transactions of the American Fisheries Society 1 19:112-I 21, 

Fertilization 

Trahtional pond fertilization methods in Ontario have 

centered on the use of organic fertilizers such as 

soybean meal (solid content - 7.7% N, 0.7% P, 2.0% 

K) for extensive pond culture. White Lake ponds are 

fertilized at least 2 weeks prior to stocking fry to 

ensure adequate time for zooplankton development. 

They receive a large initial application of dry soybean 

meal (applied to the pond bottom immehately before 

filling) at a rate equivalent to 4 times the weekly rate 

124 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 5 

Table 1. - Summary of measurements (means with ranges in 

parentheses) of juvenile walleyes harvested from ponds 

stocked at low (20 larvae/m3), medium (40 larvae/m3), and 

high (60 larvae/m3) densities at the White Lake Fish Culture 

Station Ontario, in 1988.= 

Stocking Density 

Measurement Low Medium High 

Total length (mm)a 

Weight (mg)" 

Final Density 

(nu m be r/m 3, 

Percent Survival 

Biomass (g/m3) 

Condition facto rb 

Number of ponds 

48.9 

(47.8-49.6) 

788 

(71 1-832) 

14.4 

(1 0.5- 1 5.7) 

71.8 

(62.3-78.3) 

11.3 

(8.3-1 3.4) 

0.637 

(0.62-0.65) 

3 

43.0 

(40.3-45.8) 

565 

(447-683) 

31.5 

(27.9-35.1) 

78.7 

(69.7-87.7) 

18.2 

(1 5.7-20.6) 

0.630 

(0.62-0.64) 

2 

41.3 

(39.0-43.0) 

470 

(397-51 8) 

41.4 

(39.4-42.7) 

69.0 

(65.7-71 .l) 

19.7 

(1 5.6-22.6) 

0.650 

(0.61 -0.70) 

3 

a Standardized for 44-d-old fish; fish were harvested over a 3-d period when they were 44-46 d 

old. 

Condition Factor = 1 O5 (~eight,g)/(length,mm)~. 

prey items for pond fingerlings, 

but soybean meal alone has not 

always been effective in production of zooplankton populations. 

Inorganics , with high phosphate 

levels, have proven effective 

supplements to our standard 

fertilization practices. They 

stimulate the production of 

phytoplankton, which, in turn, 

increases densities of zooplankton species that are preyed upon 

by walleye. Present production 

targets for White Lake require 

summer fingerlings that average 

consistently achieve this target 

size with good survival rates it is 

often necessary to use inorganic 

fertilizers. Experimental studies 

at White Lake have shown that 

using a combination of soybean 

meal and inorganic fertilizer has 

helped increase walleye growth 

and production from culture 

ponds. Table 2 summarizes the 

results of a fertilization experi908-454/1b (2,000-1,000/kg). TO 

(Le., about 392 lbs/acre-ft, 140 g/m3). The standard 

weekly application rate is 98 lbs/acre-ft (36 g/M"), 

equivalent to 2.8 mg N/L and 0.25 mg P/L. During the 

culture period soybean meal is pre-weighed for each 

pond, mixed with water and then placed in large 

containers near the culture ponds to ferment. When 

spread along the shallow, near-shore areas of the pond 

this fertilizer helps stimulate the production of 

chironomids and larger invertebrates. It is an 

excellent soil condtioner. Soybean fertilization 

rates are reduced to 73 lbs/acre-ft (27 g/rn3) 

when inorganic supplements are used (to be 

ment at White Lake in 1990. Walleye in ponds given 

inorganic supplements grew faster and were almost 

twice the weight of those in the control ponds (soybean 

meal only) at harvest. Improved fingerling growth was 

apparently due to higher production of Daphnia which 

persisted longer in ponds given inorganics. 

Table 2 - Juvenile walleye harvest from a fertilization experiment at White Lake in 1990 (standard 

deviation in parentheses)? 

discussed). Any ponds that held salmonids 

during the previous winter are not given a large Treatment Mean 

initial application of fertilizer because of the 

accumulated nutrients from fecal matter and (n=3) Supplement (n=3) 

excess feed. Instead, these ponds are fertilized 

using the standard weekly application rate 

is terminated one week prior to fish harvest. 

Va r i a b I e Soybean Only Soybean + Inorganic 

Mean length (mm) 42.9 (3.0) 51.5 (2.1) 

P rodu ct i o n ( g/m3) 10.2 (3.8) 

during the culture period. All pond fertilization Mean weight (mg) 486 (64) 933 (1 22) 

7.2 (0.8) 

Survival (%) 49.3 (3.3) 35.9 (21 .l) 

0.63 (0.06) 0.68 (0.07) Soybean meal fertilization increases chironomid Condition factor (K) 

production which are one of the most important a Modified from Fox et al 1992 

NCRAC Culture Series 101 - W a l l e y e C u l t u r e Manual 125 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

A commercially formulated granular fertilizer (8% N, 

32% P,O,, 16% K,O) is applied at 23.6 lbs/acre-ft (8.7 

g/m3), which is equivalent to 0.7 mg NL and 2.8 mg P/ 

L per week. Inorganic fertilizer is placed in large, 

screened floating trays in the middle of the pond where 

it dissolves quickly. 

Problems in using inorganic fertilizers, include midday 

oxygen supersaturation, and high pH (>9.0) readings. 

High phosphorus levels in pond water discharge may 

also exceed environmental guidelines for hatchery 

effluent. Oxygen deficiencies associated with overfertilization and cloudy weather account for most of the 

problems encountered in our ponds. 

General pond maintenance and monitoring 

Pond culture programs have often been developed using 

a trial-and-error approach. Successful, fish production 

depends on calculated and planned pond management 

strategies. Production programs should have predctable 

results, when based on accurate record keeping and 

diligent monitoring procedures. 

Water quality sampling. Alkalinity and pH are 

determined before stocking fry and once a week 

thereafter, usually in the early afternoon. White Lake 

ponds have an approximate alkalinity of 100-1 20 mg/L 

and the normal range for pH is from 7.5-8.5. Oxygen 

and temperature readings are taken near the outflow of 

each pond before sunrise. These measurements are 

recorded at least twice weekly for all ponds. Pond 

temperatures range from 57°F (1 4°C) when fry are 

stocked, to 77°F (25°C) by early July when ponds are 

harvested. The average pond temperature throughout 

the culture period is 68°F (20°C). If oxygen levels drop 

below 4 mg/L inflows are increased and/or fertilization 

rates reduced. Supplemental aeration systems are used 

to prevent critically low oxygen levels and help improve 

nutrient cycling within ponds (Figure 3). 

Prey monitoring and fish sampling. Zooplankton are 

carried into White Lake ponds during initial filling, 

which is from a mesotrophic lake. These zooplankton 

provide a seed stock for future development. Visual 

observations during the day or at night, can easily 

confirm presence or absence of adequate zooplankton 

numbers without elaborate routine sampling. Stomach 

analysis of pond-raised walleye at White Lake have 

shown that chironomids are a very important component of the diet. Final emergence of chironomids from 

ponds late in the culture period often causes prey 

shortages and predctable growth reductions for 

fingerlings 

Figure 3. Experimental ponds at White Lake with supplemental 

aeration. Granular inorganic fertilizers are placed in floating trays in 

the middle of the pond and soybean meal is spread in the shallow 

water along the shoreline. The black steel drum at the rear of the 

picture holds fermenting soybean meal. 

A reduction in abundance of zooplankton 

or benthic invertebrates often reduces 

walleye condition. Routine weekly fish 

sampling is essential to assess fish con&- 

tion and to help forecast potential harvest 

dates. Walleye condition at White Lake is 

assessed weekly beginning at week 3. A 

small number of fingerlings (20-40) are 

seined from each pond, measured and 

weighed. If collected fish appear emaciated 

or if large numbers of cannibals appear, an 

early harvest is considered. If walleye 

continue to grow and if there is weight 

gain from week to week then pond culture 

continues. No weight gain for more than 2 

consecutive weeks often indicates low prey 

abundance. Under these conditions walleye 

become more cannibalistic and ponds 

should be harvested quickly to ensure 

reasonable survival. 

126 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 5 

Aquatic vegetation and insect control. Chemicals are 

not used to control aquatic vegetation at White Lake 

and applying gas or oil to pond surfaces, to control 

predacious aquatic insects, is prohibited at this facility. 

Floating, filamentous algae are usually raked from the 

ponds during drawdown procedures. Regular draining 

with long fallow periods helps reduce the growth of 

rooted aquatic vegetation and prevents major insect 

problems. 

Fingerling harvest and handling procedures 

All ponds at White Lake have a partial concrete bottom 

that is exposed when water levels are reduced. This 

makes it easier for staff to walk on the bottom of the 

ponds and effectively use seines to harvest fingerlings. 

Final harvest occurs 6 to 8 weeks after stockmg. After 

harvest, fingerlings are placed in large tanks where they 

are separated from aquatic insects, tadpoles, algae and 

other organic matter. To reduce fingerling stress during 

Table 3 - Summary of production results for ponds at White Lake Fish Culture Station, 

Ontario. Values represent mean data for the period 1991 -1 994 (ranges in parentheses). 

Pond Pond size Number 

~ 

2a 

2b 

5a 

5b 

5c 

5d 

3 

4 

6 

7 

(acres) (acre-ft) stocked 

0.1 

0.1 

0.1 

0.1 

0.1 

0.1 

0.4 

0.5 

0.5 

0.6 

0.28 

0.28 

0.28 

0.28 

0.28 

0.28 

1.37 

1.23 

1.61 

1.71 

10,200 

10,200 

10,200 

10,200 

10,200 

10,200 

67,560 

60,640 

79,480 

84,560 

Days in 

pond 

S u rvi va I 

(“w 

36.5 

43.0 

40.7 

40.7 

40.7 

40.7 

47.0 

48.0 

44.0 

47.0 

73.9 

(61.8-86.1) 

90.5 

60.1 

(26.1 -86.5) 

88.7 

(86.0-91.2) 

87.5 

(81.8-96.9) 

89.8 

(84.1 -1 00) 

53.9 

(20.6- 75.3) 

57.6 

(28.0-80.4) 

60.0 

(43.8-76.5) 

29.8 

(5.0-64.0) 

Harvest 

Production 

(IW 

Survey 

yearsa 

0.31 

0.64 

0.61 

0.70 

1.19 

0.58 

0.56 

0.57 

0.51 

0.66 

35.4 

44.8 

44.6 

47.9 

59.5 

46.0 

43.2 

43.8 

39.0 

48.5 

5.3 

(4.2- 6.5) 

12.9 

7.8 

(3.8-1 0.6) 

13.9 

(1 1.2-1 7.8) 

22.7 

(9.7-37.3) 

12.0 

(1 1.2-12.7) 

47.0 

(1 5.4-71.4) 

51.9 

(1 3.2-1 00.2) 

57.1 

(23.7-1 30.0) 

26.0 

(1 2.6-54.7) 

91,93 

93 

91 -93 

91 -93 

91 -93 

91 -93 

91 -93 

91 -94 

91 -94 

91,92,94 

a Production data is reported only for those years where consistent stocking rates were used in the ponds; i.e.. 37,000 fry/acre-ft (30/ 

m3) for experimental ponds (0.1 acres, 0.04 ha) and 49,340 fry/acre-ft (40/m3) for production ponds (0.4-0.6 acres, 0.16-0.24 ha). 

NCRAC Culture Series 101 - Walleye Culture Manual 127 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

clean up, tank water temperatures are adjusted below 

ambient conhtions and light levels are reduced. We 

have found that walleye held for 24 h after seining are 

in much better shape for transport and stocking, than 

improve production. During the period 1991-1994, the 

mean survival from fry to fingerlings in White Lake 

ponds was >60% (Table 3) and the total annual production was about 200,000 summer fingerlings that average 

walleye harvested and stocked on the same day. 908-454Ab (2,000-1,000/kg). 

Summary 

White Lake ponds are intensively managed for production of fingerling walleyes. Fertilization rates and initial 

stock densities arc high and supplemental aeration 

systems are used to improve nutrient cycling and 

prevent oxygen problems. Research stuhes at this 

facility have shown that stocking densities can be 

adjusted to maximize numbers or size of fish produced 

from ponds. Other studies have provided insight into 

use of inorganic fertilizers and organic fertilizers to 

References 

Fox, M.G. and D.D. Flowers, 1990. Effects of fish density 

on growth, survival and food consumption by juvenile 

walleyes in rearing ponds. Transactions of the 

American Fisheries Society. 1 19:llZ-121. 

Fox, M.G., D.D. Flowers and C. Watters. 1992. The 

effect of supplementary inorganic fertilization on 

juvenile walleye (Stizostedion vitreum) reared in 

organically fertilized ponds. Aquaculture 10627-40. 

128 NCRAC Culture Series 101- Walleye Culture Manual 
Wright, G. M. 1996. Walleye culture in a 1 00-acre drainable pond in northern Michigan. Pages 

129-130 in R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture Series 101. North 

Central Regional Aquaculture Center Publications Office, Iowa State University, Ames. 

Walleye Culture in a 100-acre Drainable 

Pond in Northern Michigan 

Gregory M. Wright, Sault St. Marie Tribe of Chippewa Indians, Nunns Creek Fishery Enhancement FacilitH 

HC 4 7 Box 8 IOU, Hesel, MI 49745 

Introduction 

The ChippewdOttawa Treaty Fishery Management 

Authority stocks about 350,000 fingerling walleyes into 

the three upper Great Lakes (Huron, Michigan, and 

Superior) annually to create a commercial fishery for 

walleye in an area where no significant walleye 

populations existed in the past. About 250,000,2-inch 

(5.1-cm), fingerlings are stocked in late June to early 

July, and from late September to early November, about 

100,000 advanced fingerlings, 6-7 in (15.2-17.8 cm), 

are stocked. Because survival of the small fingerling has 

been poor, increased effort is now given to rearing and 

stocking more advanced fingerlings. This case study 

describes procedures used at Nunns Creek Fishery 

Enhancement Facility to raise advanced fingerling 

walleye. 

The pond 

Advanced fingerlings are raised in a 1 00-acre (40.5- 

ha) drainable pond. The pond was built about 30 years 

ago by constructing a 2,000-ft (610-m) earthen dam 

across a small intermittent stream. The pond is filled 

each year with runoff from spring rains and snow melt. 

The pond bottom is primarily clay with little organic 

material. Nearly 40% of the pond has standing or 

floating timber. The pond has a maximum depth of 12 ft 

(3.7 m), and about 75% is 4-6 ft (1.2-1.8 m) deep. The 

surrounding watershed is a mix of maple forest wood 

lots and hay fields. 

Stocking 

Fry are stocked by the third week of May when water 

temperature is about 52°F (1 1OC). About three million 

fry are stocked annually (25,000 fry/acre, 61,775 fry/ 

ha). Predation from brook sticklebacks, are regarded as 

the major cause of fry mortality. By mid June, walleye 

are about 1.0-1.2413 (25-30-mm) in length. Walleye fry 

feed primary on zooplankton until mid-July. The pond 

has zooplankton densities that range from 7 1 to 3,3 12/ 

qt (75-3,500/L). Daphnia populations range from 4.7 to 

237/qt (5-25OL). By the second week of July, however, 

walleye begin to forage on fish, which is mainly small 

stickleback, but other prey include fathead minnow, 

finescale dace, pearl dace, golden shiner, leeches, and 

crayfish. 

Fert ilizat ion 

Inorganic fertilizer (urea) is applied throughout the 

culture period to develop phytoplankton needed to 

sustain the zooplankton populations. The pond is 

fertilized with urea (46:O:O). Urea is applied by placing 

perforated 50-lb ( 22.7-kg) bags on floating cribs that 

are distributed throughout the pond. About 10 bags are 

placed on the cribs every other week. A total of 4,000 

lbs (3568 kg) of fertilizer (i.e., 400 lbs/acre, 357 kg/ha) 

is applied during the growing season. 

Harvest 

Pond draining begins in early August and, depending 

in the local precipitation, it usually is completed by the 

end of October. In the first part of the harvest interval, 

the fish range in size from 3-5 in (7.6-12.7 cm), the 

larger fish are not harvested until the final draw down, 

and then they are usually harvested at night. 

During draining, water and fish flow through a 16-in 

(40.6-cm) pipe into a seine box and finally into a 

holding/harvesting tank (Figure 1). Most water flowing 

into the seine box drains off, but fish are deflected into 

a 6-ft (1 3-m) diameter holdmgharvesting tank. This 

NCRAC Culture Series 101 - Walleye Culture Manual 129 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

system is currently being upgraded with a perforated 

aluminum seine box and much larger harvesting tank. 

When the pond drains down to the bottom, the water 

quality is poor because of high suspended solids, and 

low dmolved oxygen. However, in 1994, a 4-in (10.2- 

mm) well was installed to help maintain water quality 

in the holdmgharvesting tank. The well water is passed 

through a packed column to degas and oxygenate 

before entering the harvesting tank. The addition of 

cold, well-oxygenated water has helped reduce the 

stress on the fish. 

Summary 

This pond culture system produces IOO,OOO (1 ,OOO/ 

acre), 6-7-in (1 5.2-17.8-cm) walleye with minimal 

inputs for fertilizer and little labor. The fallen and 

standing timber seems to facilitate fish production. The 

major liability of this culture system is the heavy 

predation by brook stickleback on newly stocked 

walleye fry. To eliminate this problem, in 1995, a 10 

acre (4.1 ha) nursery pond was constructed. The nursery 

pond is located up stream of the production pond. The 

nursery pond will be stocked with fry and they will be 

raised to about l-in (25-mm), then the pond and fish 

will be drained into the larger pond. 

Figure 1. Schematic diagram of connection between the pond and the external seine box 

where walleye are harvested. 

Side view 

I la+ gate ytrol ,, -/ Overflow pipe I Aluminium seine box 

(20 x 3 x 3 ft) 

1/4 x 1 in hardware cloth ''Ii! funnel -. ,^ .~ 

Pond Earthendam \ - 

7 

I 

16" Steel drain pipe 

4" PVL outttaw 

Discharge water 

6 ft diameter steel tank cut in half 6 

- 

ft diameter ~L~~, La,lK 

25 ft long I 6 ft tall 

6" PVC pipe Stream bed 

I Top view , 

I I Solid steel funnel - 

I I 

I It 4------ ------ I 

1 Holding tank Down stream 

- 

water flow 

/ 

Overflow pipe 

Fish netting platform 

130 NCRAC Culture Series 101- Walleye Culture Manual 
Raisanen, G. 1996. Culture of advanced fingerling walleye in Minnesota ponds. Pages 131-134 in 

R. C. Summerfelt, editor. Walleye culture manual. NCRAC Culture Series 101, North Central 

Regional Aquaculture Center Publications Office, Iowa State University, Ames. 

Culture of Advanced Fingerling Walleye in 

Minnesota Ponds 

Gregg Raisanen, Aquaculture Department, Alexandria Technical College, 160 1 Jefferson St., Alexandria, MN 

56308 

Introduction 

Tradtionally, fingerling walleyes are raised by 

stocking fry (1-3 days posthatch) into fertilized ponds 

from which fingerlings are harvested 25-45 d later 

when they reach about 2-in (5.0-cm) long. Most 

fingerlings are stocked into lakes and reservoirs for 

population enhancement. This method of production is 

currently being used by both state and federal agencies 

across the country. Because the survival rate of 2-in 

(5.0-cm) fingerlings that are stocked in natural and 

artificial lakes is highly variable, in the 196Os, the 

Minnesota Department of Natural Resources 

(MNDNR) recognized the need for the stocking of 

larger fingerlings, 4-9-in (10.2-22.9-cm), especially 

when they are stocked into waters with larger predator 

populations. There is also a market for larger fingerlings by lake associations and angler clubs and the 

private sector is currently producing fish to meet this 

need. 

To produce larger fingerlings, pond-cultured walleye 

must be provided forage fish, or they can be moved 

from ponds to tanks where they can be trained (habituated) to eat formulated feed. Governmental and private 

hatcheries that raise advanced fingerlings in drainable 

ponds usually harvest the 2-in (5.0-cm) fish and then 

transfer a known number back into ponds at a lower 

stocking rate, 10,000- 15,000/acre (24,700-37,050 ha), 

and feed the fish fathead minnows until they are 

harvested in the fall. Although this method is successful 

in the production of advanced fingerling fish, it may be 

cost prohibitive in the private sector. The price for 

forage fish (usually fathead minnows) range from $0.50 

to $3.00/lb wholesale which means there is a production cost of $2.00 to $12.00/lb ($0.90-$5.45/kg) of 

fingerlings produced if a 4: 1 food conversion ratio is 

obtained. The cost for minnows to raise a 5-in (12.7- 

cm) fingerling will range from $0.08 to $0.48 per 

fingerling. When the cost of pond construction, pond 

filling, management, harvesting, and fry is added, the 

current market value of fingerlings would be less than 

production costs. 

In west-central Minnesota there are numerous winterkill ponds that are 5-150 acres (2-60 ha) which 

have mean depths of 4-1 2 ft (1.2-3.7-m). Because 

they winterkill, these ponds do not have a persistent 

sportfish population, and they are used for the production of baitfish and leeches by the private sector. Most 

are hghly productive, yields of baitfish are as high as 

1,000 lbs/acre (1,121 kgha); however, typical rates are 

closer to 250 lbs/acre (280 kgha). 

For the past 30 years, the MNDNR has used winterkill 

ponds to produce advanced walleye fingerlings. The 

ponds are usually stocked with fry at a rate of 5,000/ 

acre (12,355ha) in the spring and then harvested in the 

fall when water temperatures drop below 60°F 

(1 5.5"C). Survival of walleye fingerlings ranges from 

0-30% but average 3.5%. The target yield is 5-1 0 lbs 

fingerlingdacre (5.6-1 1.2 kg/ha) (MNDNR personal 

communication). The harvest of fingerlings is dependent upon survival and also on the percentage of the 

population that can be harvested. Survival is influenced by zooplankton populations, temperature, 

predator populations (other fish, birds, mammals, 

amphibians), forage fish populations, and water 

quality. 

In the private sector, the price of fry ranges from 

$0.01-0.02 each, thus, the extensive method of 

fingerling production as practiced by the Minnesota 

DNR would not be profitable because a survival rate of 

3.5% means the production costs for a 5-in (12.7 cm) 

fingerling is $0.28 to 0.57 each just for the fry used for 

stocking. Production costs would be much higher 

when labor, transportation, and forage are included. 

Moreover, the loss of baitfish production when the 

ponds are stocked with walleye fry has to be regarded 

as a production cost, because the reduced baitfish 

harvest is a real loss of income. 

NCRAC Culture Series 101 - Walleye Culture Manual 131 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

During the past three years at Alexandria Technical 

College we have been evaluating a two-step protocol 

where a combination of drainable and undrainable 

ponds are used to produce advanced walleye fingerlings. In this 2-step protocol we take advantage of the 

high fry survival in drainable ponds and the hgh 

forage production of the undrainable ponds. We are 

interested in evaluating the success of rearing walleyes 

in drainable ponds from fry to 2 in (50.8 mm) fingerlings, and then transferring known numbers of fish at 

desired densities to natural ponds for final rearing to 

advanced fingerlings. Specifically, we were interested 

in determining the percentage of stocked fingerlings 

that can be harvested, how the growth rate of fingerlings is influenced by stocking density, and the 

influence of pond size on these factors. 

Methods 

walleye fingerlings were raised during the summers 

of 1992, 1993, and 1994. Two drainable ponds were 

utilized. Pond 9 is 2 acres (0.81 ha) and pond 10 is 1 

acre (0.40 ha). The ponds were filled 10 d before 

stoclung. After filling, the ponds were fertilized with 

alfalfa meal twice-weekly at a rate of 100-200 lbs/ 

acre (1 12-224 kg/ha) per application. Fertilizer was 

added unless dissolved oxygen fell below 3 ppm in the 

morning. Total fertilizer added annually averaged 

1,500 lbs/acre (1,338 kg/ha). Fry were stocked at 

150,000 fry/acre (370,SOOha) in the one acre (0.40 

ha) pond and 75,000 fry/acre (185,25O/ha) in the two 

acre (0.81 ha) pond. Zooplankton was monitored biweekly by making a 20 ft (6.1 m) zooplankton net tow 

in three locations and pooling the three samples. Three 

sub-samples were counted using a circular plankton 

counting chamber. Zooplankton were identified and 

classified as rotifers, cladocerans, and copepods. 

Estimates of zooplankton density were calculated 

from these samples. 

Ponds were drained and the fish were harvested 30-40 

d after stocking. Fingerlings were netted, enumerated, 

and placed in a 0.5% salt solution in a hauling tank. 

Fingerlings were then transferred to the natural ponds 

for further culture. Five different natural ponds were 

used during the 3 years. Ponds utilized during the 

study had been leased by three different private fish 

growers in the Alexandna, MN area. Ponds were 

checked for fish populations prior to stocking using 

fyke nets. If adequate minnow populations were 

present, no additional stocking of forage was done. If 

test nets showed poor minnow populations present, the 

ponds were stocked with adult fathead minnows in the 

spring at the rate of 2 gal/acre (7.6 L/ha) 

Ponds were stocked with 400 to 3,800 fingerling 

walleyedacre (988-9,390/ha). Stoclung rate varied 

dependmg on pond size and the number of 2-in (5-cm) 

fingerlings available. Advanced fingerlings were 

harvested beginning the first week in October. Fyke 

nets (2-4 ft [0.61-1.2 m] diameter hoops, and one lead) 

were set perpenhcular to the shoreline. Nets were set at 

a rate of at least 1 netl4 acres (1 nevl.6 ha) of water. 

Nets were checked at least every other day, depending 

upon the catch rate. If the harvest rate was low, copper 

sulfate was applied at a rate of 0.5 ppm to stimulate fish 

movement, a common practice for capturing fish in 

undrainable ponds in Minnesota. Harvest normally was 

accomplished in a 2 week period. Fingerlings were 

transported in a OS% salt solution to a holdmg facility 

were they were counted, measured, and graded. 

Results and discussion 

Survival from fry to fingerlings in drainable ponds 

ranged from 21-75% (Table 1). Mean length at harvest 

was 2-in (5.0 cm) and ranged from 1.7-2.3 in (4.3-5.8 

cm). Although differences in survival and mean length 

at harvest between years could not be actually evaluated 

because of the variation in culture conhtions between 

years, length of the culture period and zooplankton 

densities seem to be the most important factors. In 1992 

and 1993, the fish were harvested after 30 d while in 

1994 the fish were harvested after 45 d (Figures 1 and 

2). Higher zooplankton populations in 1992 compared 

with 1994 may also have contributed to higher survival 

in 1992 than in 1994 (Figures 3 and 4). Cladoceran 

populations peaked right after stochng the fry in 1992 

and stayed at 500L until harvest. In 1994, cladoceran 

populations never reached as high a density and fell to 

low levels a week before harvest. This may be due to 

the high copepod population that was present in the 

pond during 1994. 

The harvest of 2-in to 5-in (50 to 127-mm) fingerlings 

grown in natural ponds ranged from 27-55% with a 

mean of 42% (Table 2). Pond E had a return rate of 

S2%, even though the pond has a high population of 

black bullheads. Mean length at harvest appears to be 

inversely related to the initial stocking rate, less than 

132 NCRAC Culture Series 101- Walleye Culture Manual 
Walleye Fingerling Culture in Drainable Ponds - Chapter 5 

1,200/acre stocking rate, 

produced the larger fingerlings. 

Although water temperatures 

were not taken, the mean air 

temperature was warmer in 1994 

than the other two seasons. 

Total harvest from fry to advanced fingerling ranged from 

10-23% with a mean of 19%. 

Fry purchased at $O.Ol/fry but 

actual cost of fry was $0.053 

($53/1,000) per advanced 

fingerling produced. Mean return 

was lower during the 1994 

season because of the low 

fingerling survival in the 

drainable ponds. Perhaps 

survival would have been greater 

if the fish had been harvested 

Table 1. Walleye fingerling production in Ponds 9 (2 acres, 0.81 

ha) and 10 (1 acre, 0.40 ha) at Alexandria Technical College. 

Fish Culture 

Year Pond Number Number Survival length days 

number stocked harvested (in) 

1992 9 150,000 83,000 55 1.8 35 

10 150,000 1 12,600 75 1.7 30 

1993 10 150,000 85,000 57 1.5 28 

1994 9 150,000 35,300 24 2.0 45 

10 150,000 31,443 21 2.3 40 

Totals 750,000 347,343 46 2.0 36 

sooner. If a mean survival rate of 60% can be obtained 

from fry to 2-in (5.0-cm) in drainable ponds and a 

harvest rate of advanced fingerlings average 42% of the 

stocked 2-in (5.0-cm) fingerlings, an overall return rate 

of 25% could be expected. This would result in fry cost 

of $0.04/advanced fingerling produced compared with 

$0.28/advanced fingerlings when fry are stocked 

directly into undrainable ponds. 

The two-step protocol allows the producer to take 

advantage of the hgh survival in the drainable ponds 

and the high productivity of the undrainable ponds. This 

results in lower fry and forage costs which may make 

the growing of advanced fingerling walleye more 

profitable. 

80 

70 

9 40 

$ 30 

20 I/) 

.- 

0 

\ 0 0 

\ 

2.5 1 

2i 

0.5 4 

”.------- / 

0 

/ 

0 

0 I I oJ I I I I I 

25 30 35 40 45 25 30 35 40 45 

Culture (d) Culture (d) 

Figure 1. Survival of walleye from fry to 2-in (5.0 

mm) fingerlings in relation to the number of culture 

days at Alexandria Technical College. Data are from 

ponds 9 and 10,1992-1994 (SeeTable 1). 

Figure 2. Mean length of walleye fingerlings harvested versus the number of culture days, Alexandria Technical College. Data are from ponds 9 and 

10,1992-1994 (SeeTable 1) 

NCRAC Culture Series 101 - Walleye Culture Manual 133 
Chapter 5 -Walleye Fingerling Culture in Drainable Ponds 

Table 2. Production of advanced fingerling walleye in natural ponds near Alexandria, 

MN, 1992-1 994. 

Year Pond Size Number Stoc ki ng Number Percent Fish 

(acres) stocked ratea harvested harvested length (in) 

1992 A 7 22,000 3,140 10,200 45 4.2 

B 10 38 , 640 3,860 12,264 31 4.8 

1993 B 10 32,000 3,200 8,656 27 4.0 

C 40 42 , 000 1,050 23,088 55 5.1 

1994 D 52 26,170 500 9 , 986 38 8.5 

E 80 31,443 400 16,344 52 5.5 

Totals 192,253 2,025 80,538 42 5.4 

a N/acre 

2500 

L 

-c. 

al 

.- 5 2000 v) 

_- 6 

1500 

P 

0 

0 1000 

a, 

5 500 

z 

cc 

L 

0 

- 

0 Cladocerans 

w Copepods 

o Rotifers 

- 

8 11 13 17 20 22 26 29 32 35 38 42 46 

Number of days after filling 

600 

a, 

$ 500 

.E 400 c 

(d 

300 

0 

.- - 

E 

9- : 200 

a, 

a 

3 

E 100 

z 

0 

0 Cladocerans 

Ro I Copepods 

o Rotifers 

8 13 16 21 23 27 29 34 36 40 43 

Number of days after filling 

Figure 3. The number of zooplankton per liter (MayJune 1992) in pond 10 with a stocking rate of 

150,000 walleye fry. 

Figure 4.The number of zooplankton per liter (MayJune 1994) in pond 10 with an initial stocking of 

150,000 walleye fry. 

134 NCRAC Culture Series 101- Walleye Culture Manual