Satterfield, J. R. Jr., and S. A. Flickinger. 1996. Collection and care of broodfish. Pages 63-69 in 

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

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

Collection and Care of 

Broodfish 

James R. Satterfield, Jr., Colorado Division of Wildlife, 6060 Broadwax Denver, Colorado 802 16 and 

Stephen A. Flickinger, Department of Fishery and Wildlife BiologL: Colorado State University Fort Collins, 

Colorado 80523, USA 

Introduction 

Culture of walleye has traditionally involved collection of wild broodstock from public waters (Nickum 

1978; Richard and Hynes 1986). This differs from 

production of many other important sport fish such as 

channel catfish and rainbow trout, where captive 

broodstock are normally used (Piper et al. 1982). 

Collection of wild broodstock can often be a limiting 

factor in an agency’s ability to meet walleye production 

needs (Satterfield 1992). Fish farmers desiring to raise 

walleye may encounter complex legal restraints to 

procure fertilized eggs from wild fish. Thus, collection 

of sufficient wild broodstock is vital to overall success 

of many walleye management and culture programs 

throughout the US. 

Besides collecting sufficient fish to meet production 

needs, other important objectives of broodfish collection include: maximizing operation efficiency in terms 

of cost and labor; maintaining a positive public image; 

minimizing impacts on walleye populations and 

nontarget fish species; and conducting operations which 

minimize hazards to personnel and the public. To fulfill 

these objectives, careful planning and attention to detail 

are required. Because no two spawning sites are 

identical, site-specific fish collection techniques are 

often needed. 

The objectives of tlvs chapter are to provide biologists 

and culturists with a broad overview of broodstock 

collection and handling techniques. We hope information provided will be of particular use to state game and 

fish agencies and to fish farmers beginning new walleye 

Present address: Montana Fish, Wildlife and Parks, 1420 East 

Sixth Avenue, Helena, Montana 59620-0701 

culture programs. It is also hoped that well-established 

programs may find in this report methods and ideas that 

will improve their walleye production efforts. 

Collection of wild broodstock 

In the U.S., most walleye broodstock are collected 

from public waters. Of the case studies in this chapter, 

only one state, Pennsylvania, reported conducting 

operations on a closed water (Harvey and Hood 1996). 

Certainly, it is advantageous to conduct operations on 

closed waters, thus alleviating concerns for fish theft, 

net and equipment vandalism, and user conflicts. 

However, walleye broodstock collection usually occurs 

in large lakes and reservoirs which contain adequate 

walleye populations to allow collection of large 

volumes of eggs and milt. Such waters are rarely 

privately owned and are usually open to the public. 

Rules and regulations 

Application of some simple regulations at spawning 

sites can greatly reduce potential conflicts between 

fisheries personnel and anglers, boaters, or other 

resource users. The most common problem at many 

spawning sites is interference in netting operations, 

both accidental and intentional. Fishing in the vicinity 

of nets by bank and boat anglers should be discouraged, 

if necessary, through regulations. Anglers often lose 

hooks and lures in nets, creating a dangerous situation 

for spawning personnel. This can be minimized, if 

necessary, by closing public access to specific shoreline 

areas that are heavily netted. Closures may be enforced 

for the duration of spawning operations or may be for 

specific daily hours, such as from late afternoon to early 

NCRAC Culture Series 101 - Walleye Culture Manual 63 
morning, when nets are actually deployed. Temporary 

wakeless zones can also be established to avoid 

dangerous traffic around netting sites; these regulations 

will also reduce damage to nets by boaters. 

Such regulations are most practical when netting sites 

are concentrated, as along dam rip-rapping, inlet areas, 

or windswept shoals. When collection efforts are too 

dispersed for closures, nets should be well marked with 

highly visible, fluorescent buoys, and signs should be 

placed on adjacent shoreline areas and at key access 

points such as boat ramps to notify and educate the 

public regarding spawning operations. Despite all of the 

above efforts, sometimes a night watchperson is 

necessary. 

In addition to posting or closing netting sites, it is also 

necessary to provide personnel with facilities to spawn 

fish, dock boats, and store equipment which are closed 

to the public. Such sites should be secure, provide 

comfortable working conditions, and facilitate efficient 

operations. A review of case studies by Jorgensen 

(1 996), Colesante (1 996), and Harvey and Hood (1 996) 

will reveal many useful innovations for selecting 

spawning sites. 

Capture techniques 

Most states rely primarily on trap-netting or gill-netting 

to collect walleye broodstock (Huet 1970; Krise and 

Meade 1986). Another gear that is often overlooked, but 

which can be effective for collecting walleye in certain 

situations, is boat-mounted electrofishing (Priegal 1970; 

Satterfield and Fliclunger 1995a). The effectiveness of 

different types of collection are site specific (Hayes 

1983; Hubert 1983). 

Trap-netting, when practical, is probably the most 

desirable gear for collection of walleye broodstock. 

Deployment and fish retrieval is much less labor 

intensive than with gill nets, and mortality of collected 

fish is minimal (Dumont 1990; Langer 1994). 

Satterfield and Flickinger (1 995a) also indicated that 

male walleye collected by trap-netting yield more 

semen per fish than when collected by gill-netting, 

presumably because of minimal handling of captured 

fish. 

Size and construction of trap nets varies among states 

where ths gear is commonly used, and it is influenced 

by number and size of fish typically caught, size of 

crew available to deploy and retrieve nets, and shoreline 

slope and configuration. Colesante (1 996) reports the 

use of trap nets with 6.0 ft (1 -83 m) square frames. 

Conversely, trap nets as small as 3.0 ft (0.93 m) have 

been effectively used in Colorado (Satterfield 1992). 

Obviously, larger trap nets require more labor and 

larger boats than smaller trap nets. Trap nets with bar 

mesh about 0.75-1.5 in. (1.9-3.8 cm) and centermounted, single leads of up to 130 ft (40 m) are 

typically used. 

Trap nets are often set perpenhcular to shore on dam 

rip-rap, points, inlet areas, and other locations where spawning walleye concentrate. 

As a rule of thumb, trap nets are placed in 

deep enough water to barely cover the top of 

the front frame (Figure 1). Length of lead 

will vary, dependmg on depth of trap-net set 

and shoreline slope. Leads are attached to 

shore by use of natural structures such as 

logs or brush; fence posts temporarily placed 

on shore also make good attachment points. 

Figure 1. Trap-net deployed for collecting walleye broodstock. 

The principle disadvantage of trap nets is that 

their use is confined to a relatively narrow 

range of depth and bottom slope configurations. Trap nets do not work well in water 

deeper than about 12 ft (3.7 m) because fish 

will usually swim over the lead and avoid 

capture. Trap nets also function poorly in 

locations with large broken rocks, because 

64 NCRAC Culture Series 101- Walleye Culture Manual 
fish will swim under leads. Bottom configuration must 

be fairly flat or trap nets will have a tendency to twist, 

especially if strong crosswinds develop. 

Trap-netting usually begins in March or April when 

surface temperature approaches 40°F (4.4"C ). Because 

fish are rarely injured when captured in trap nets, it is 

not necessary to check them as often as gill nets which 

require daily removal of fish to minimize mortality to 

walleye and other fish. Use of gill nets requires more 

frequent inspection of nets than does trap nets, but gill 

nets are easier to move and are less expensive (Dumont 1990). 

Gill-netting is a useful alternative for 

collecting walleye broodstock in waters 

where trap-netting is impractical. Gill-netting 

is particularly useful in lakes with steeplysloped bottoms or extended reaches of riprap or rocky shoreline. When fish are 

dispersed or concentrations have not been 

identified, gill nets can sample a wider range 

of depths than trap nets or electrofishing. 

the gill net should just reach the surface (Figure 2). Gill 

nets set in this manner prevent fish from swimming 

over the top of the net or detecting the net before 

capture by encountering loosely bunched layers of net. 

When an extended reach of shoreline is to be netted, 

gaps between the ends of gill nets should be minimized 

to prevent fish from avoidmg capture by swimming 

between nets (Figure 3). 

Gill nets are usually set in the late afternoon and 

retrieved shortly after sunrise. To further reduce fish 

As with trap nets, construction of gill nets is 

normally tailored to individual spawning 

sites. Factors influencing gill-net specifications include; average size of adult walleye 

present; depth and slope of netting sites; and 

nontarget fish species present. Gill nets are 

normally constructed of multifilament mesh 

to reduce injury to fish and are often dyed to 

reduce visibility and improve catch rate 

(Jester 1977). A common mesh size for gill 

nets is 2.0 in (5.1 cm) bar mesh, which is a 

useful size for collecting walleye 15 to 30 in 

(38.1 to 76.2 cm) total length. If larger males 

are in short supply, it may be necessary to 

use smaller mesh 1.5 in (3.8 cm) to capture 

first-time spawning walleye. A typical net 

depth for capturing broodsize walleye is 6.0 

ft (1.83 m) and net lengths may range from 

about 150 to 300 ft (45.8 to 91.6 m). 

Figure 2. Gill-net set at proper depth to maximize capture of 

walleye broodstock. Note that float-line of gill-net just reaches the 

surface. 

For walleye broodstock collection, gill nets 

are often set parallel to dam rip-rap or other 

rocky, windswept shore areas in water about 

6.0 ft (1.83 m) deep. Ideally, with the lead 

line resting on the bottom, the float-line of 

Figure 3. Series of gill nets set perpendicular to rip-rap on dam 

NCRAC Culture Series 101 - Walleye Culture Manual 65 
mortality, some states (e.g., Iowa) check nets periodically throughout the evening to reduce the time captured fish are in the gill nets (Jorgenson 1996). However, it has been our experience that this is unnecessary 

as long as water temperature does not exceed 50°F 

(10°C). In many waters, gill net operations must be 

suspended after water temperature exceeds ths point, 

not only to avoid high mortality rates, but also because 

capture of nontarget fish species may increase. 

Gill-netting is labor-intensive. Nets must be checked 

daily to minimize fish mortality and must be removed 

from the water being netted, so that debris can be 

removed and the nets can be reset. Broodstock collections involving gill-netting require scheduling of a 

morning and an evening shift of personnel to deploy 

and retrieve nets, whereas trap-netting or electrofishing 

operations require only one shift. 

Both gill-netting and trap-netting are passive sampling 

methods that rely on movement of fish to facilitate 

capture. Electrofishing, on the other hand, is an active 

gear which can be effective when fish are not moving 

(Satterfield 1992). Electrofishing is probably not 

suitable as a primary means of collecting broodstock, 

but it can be useful for augmenting trap nets or gill nets, 

and it is effective for collecting male walleye 

(Satterfield and Flickinger 1995a). 

Night electrofishmg has been conducted for several 

years by the Colorado Division of Wildlife to collect 

walleye at the Marston Reservoir in Denver (Satterfield 

1992). Electrofishing is performed with boat-mounted 

gear powered by a 5,000 watt generator through a 

variable voltage pulsator to deliver 200-300-v DC. It 

has been our experience 

at Marston Reservoir 

and other waters, that 

walleye are more 

vulnerable to electrofishing at night as they 

migrate into shallow 

water when light levels 

are reduced (Satterfield 

and Flickinger 1995a). 

Depending on water 

clarity, walleye may be 

collected in water up to 

10 ft (3.0 m) with the 

use of extended dip-net 

handles. Walleye concentrated in inlet areas are 

particularly susceptible to electrofishng, and additional 

fish can also be collected by electrofishing parallel to 

shoreline at depths of 3.28-10 ft (1-3 m). 

We are unaware of any evidence that electrofishmg 

damages eggs or milt of walleye or any other fish 

species (Maxfield et al. 1971; Walker et al. 1994). 

Personnel employed as netters on electrofishing boats 

rarely collect nontarget species (Langer 1994). 

Care of broodstock 

Proper care of broodstock is a vital element in successful spawning operations. Fish may be held for several 

days after capture, as when green females are held until 

maturation or when ripe males are reused for consecutive days. Improper care may lead to hgh mortality. 

Fish loss during spawning operations can impact 

walleye populations when a large number of adult fish 

are collected. High mortality of walleye can also lead to 

public relation problems. 

Transportation of fish to spawning site 

Proper care of broodstock begins when fish are removed from nets and transported to spawning sites. 

Tubs placed in boats or vehicles should be large enough 

to hold ample fresh water to avoid stress. The number 

or weight of walleye that can be safely transported from 

netting to spawning sites will depend on water temperature, travel time, and the overall condition of the fish 

(Stickney 1983). Water used for transporting fish should 

have 0.5% sodium chloride. During daylight operations, 

tanks should be covered because walleye are stressed 

from bright light. 

Table 1. Summary of walleye milt production 

from multiple daily strippings at Marston 

Reservoir spawning operat ion, Denver, 

Colorado, 1991. Modified from Satterfield 

and Flickinger (1 995a). 

Stripping Fish (N) Fresh milt Milt/fish 

(m L) (m L) 

First 154 48 1 3.1 

Second 154 20 1 1.3 

Third 149 81 0.5 

Tanks should be aerated, 

and pure oxygen can 

also be delivered via an 

airstone. If boat transportation time is 

lengthy, particularly 

with large loads of fish, 

it may be necessary to 

periodically exchange 

water in the holding 

tanks. Surface foam in 

hauling tanks is an 

indication of excessive 

66 NCRAC Culture Series 101- Walleye Culture Manual 
mucous waste and 9.0 I- a sign that life support systems for 

transported fish are compromised (Davis 1961). 

Holding broodstock at spawning site 

After fish are transported to the spawning site, they are 

usually segregated by sex, and females are sorted into: 

green and ripe groups. Females which are gravid but do 

not yield eggs with gentle abdominal pressure are 

defined as green, while ripe females are fish that can be 

easily stripped. At some sites, fish arc held in cages 

which are secured in about 3.28 ft (1 m) of water so that 

cages are accessible to project personnel in chestwaders. If fish theft is a concern, cages may be locked 

and placed in deeper water, but a boat will be necessary 

to add and remove fish. 

Several cages will be needed if males arc to be reused 

and/or green females are held until maturation. Cages 

should be clearly labeled to ensure fish are placed in the 

proper cage. Cages should be covered to provide fish 

with shade and should be located so that adequate fresh 

water circulates through cages. Cages should be 

anchored sufficiently to withstand strong winds. 

When spawning is to take place in the hatchery, 

removal and sorting of walleye is more automated and 

less labor-intensive. Obviously, this is preferred for 

operations which will be conducted in specific waters 

for many years. However, there may be a need to use 

more portable operations when evaluating new spawning sites or when traditional waters are not producing 

satisfactory results. 

Spa wning broodstock 

Authors of the case studies for this chapter emphasized 

that ripe females should be spawned as soon after 

collection as possible to avoid egg loss. Green females 

may be held for up to about 3 d to allow for maturation, 

but females that do not ripen by this time are released. 

Maturation of green females may be accelerated under 

controlled conditions by holding them in slightly 

warmer water. Some research has also been conducted 

on the use of hormonal injections to ripen females, but 

this technique is still experimental (see Heidmger et al. 

case study Chapter 2). 

Many culturists report that males come into sexual 

maturity prior to females and taper off while females 

are still ripe (Figure 4; Satterfield 1992). Males are also 

stripped as soon as possible to avoid loss of milt. Thus, 

I 

Y= 8.387 - 2.62~ 0 r=-0.70 

5.0 4.0 :i 

0 1.0 2.0 3.0 4.0 

Sex Ratio (M:F) 

Figure 4. Relationship between 

walleye sex ratio (M:F) and temperature at Marston Reservoir. 

Denver, Colorado in 1991. Modified from Satterfield (1 992). 

male walleyes may be in short supply near the end of 

spawning operations. However, stripped males may be 

held and reused. When sufficient numbers of males are 

not available to meet spawning needs, males may be 

held for a second stripping, which provides about 40% 

as much semen as the first, without affecting quality of 

the semen (Table 1 ; Satterfield and Flickinger 1995a). 

However, holding fish for a third stripping is inefficient 

as the third stripping produces only about 16% as much 

milt as the first stripping. Use of extenders or 

cryopreservation of walleye semen should be considered when semen is in short supply (Moore 1995) 

Captive broodstocks 

Use of captive walleye broodstocks will eventually 

become commonplace for private culturists. The ability 

to select for desirable genetic traits and to alter time of 

spawning will offset the negative aspects of space and 

maintenance costs. Domestication will be desirable for 

commercial production for out-of-season spawning. 

Guidelines for genetic selection are described in texts 

on fish genetics (Kapuscinslu and Jacobson 1987, Tave 

1986). 

NCRAC Culture Series 101 - Walleye Culture Manual 67 
It seems to be impractical to maintain a captive walleye 

broodstock using natural forage. Consequently, the 

chapters on feed-training and on raising fish to food 

size, as well as Nagle’s case study (1996) on captive 

broodstocks, should be read. Typically, research on 

broodfish nutrition receives little attention, and therefore culturists should expect to encounter some nutritional problems (too much body fat is a common one) 

for many years. 

Summary 

Effective collection of wild broodstock is an essential 

part of a successful walleye spawning operation. 

Thorough planning is critical to ensure adequate 

equipment and labor are available. State game and fish 

agency personnel working on public waters should give 

attention to projecting a professional image and 

insuring safe conditions for both fishery workers and 

the public; implementation of temporary closures and 

other restrictions may be necessary to avoid userconflicts and unsafe conditions. 

A variety of gear is available for collection of 

broodstock. When starting new operations it may be 

necessary to evaluate several types of gear to determine 

which type is most suitable for a particular aquatic 

habitat. In some instances, a combination of gear such 

as gill nets and trap nets may be most useful. For 

established operations, some augmentation of existing 

collection techniques may further optimize operation 

efficiency. 

Collected broodstock should be treated carefully to 

maximize spawn-taking potential and to avoid longterm damage to walleye populations. Fish should be 

removed as quickly as possible from collection gear, 

hauled at an appropriate density to a spawning site, and 

monitored throughout the entire spawning process to 

insure a high survival rate of fish after they are returned 

to the habitat where they were captured. 

Ref e re n ces 

Colesante, R. T. 1996. Collection of walleye broodstock, 

egg take, incubation, and fry production at the 

Oneida Fish Cultural Station. Pages 71-74 in R.C. 

Summerfelt, editor. Walleye culture manual. NCRAC 

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

Ames, Iowa. 

Davis, H.S. 1961. Culture and diseases of game fishes. 

University of California Press, Los Angeles. 

Dumont, S.C. 1990. Evaluation of standardized fish 

sampling procedures in coldwater impoundments. 

Master’s thesis, Colorado State University, Fort 

Collins. 

Harvey, J. E., and S. E. Hood. 1996. Collection and 

spawning of walleye broodfish and incubation of 

fertilized eggs. Pages 25-28 in R.C. Summerfelt, 

editor. Walleye culture manual. NCRAC Culture 

Series 101. North Central Regional Aquaculture 

Center Publications Office, Iowa State University, 

Ames, Iowa. 

Hayes, M.L. 1983. Active fish capture techniques. Pages 

123-146 in L.A. Nielsen and D.L. Johnson, editors. 

Fisheries techniques. American Fisheries Society, 

Bethesda, Maryland. 

Heidinger R. C., B. L. Tetzlaff, and R. C. Brooks. 1996. 

Hormone induced spawning of walleye. Pages 59-62 

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

NCRAC Culture Series 101. North Central Regional 

Aquaculture Center Publications Office, Iowa State 

University, Ames, Iowa. 

Hubert, W.A. 1983. Passive capture techniques. Pages 

95-122 in L.A. Nielsen and D.L. Johnson, editors. 

Fisheries techniques. American Fisheries Society, 

Bethesda, Maryland. 

Huet, M. 1970. Textbook of fish culture: breeding and 

cultivation of fish. Fishing News (Books) Ltd., 

Far n h a m , S u rre y, En g I and , 

Jester, D. B. 1977. Effects of color, mesh size, fishing in 

seasonal concentrations, and baiting on catch rates 

of fishes in gill nets. Transactions of the American 

Fisheries Society 106: 43-56. 

Jorgensen, W. 1996. Wild broodstock collection in Iowa. 

Page 77 in R.C. Summerfelt, editor. Walleye culture 

manual. NCRAC Culture Series 101. North Central 

Regional Aquaculture Center Publications Office, 

Iowa State University, Ames, Iowa. 

Kapuscinski, A.R., and L.D. Jacobson. 1987. Genetic 

guidelines for fisheries management. Minnesota Sea 

Grant Research Report No. 17, University of Minne68 NCRAC Culture Series 101- Walleye Culture Manual 
sota, Duluth. 

Krise, W.F., and J.W. Meade. 1986. Review of the 

intensive culture of walleye. Progressive FishCulturist 48:81-89. 

Langer, G. J. 1994. Evaluation of the Colorado Division 

of Wildlife’s warmwater fish sampling protocol. 

Master’s thesis, Colorado State University, Fort 

Collins. 

Maxfield, G.H., R.H. Lander, and K.L. Liscom. 1971. 

Survival, growth, and fecundity of hatchery-reared 

rainbow trout after exposure to pulsating direct 

current. Transactions of the American Fisheries 

Society 100:546-552. 

Moore, A. 1996. Use of semen extenders for walleye. 

Pages 51-53 in R.C. Summerfelt, editor. Walleye 

culture manual. NCRAC Culture Series 101. North 

Central Regional Aquaculture Center Publications 

Office, Iowa State University, Ames, Iowa. 

Nagel, T. 1996. Development of a domestic walleye 

broodstock. Pages 75-76 in R.C. Summerfelt, editor. 

Walleye culture manual. NCRAC Culture Series 101. 

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

Nickum, J.G. 1978. Intensive culture of walleyes: the 

state of the art. American Fisheries Society Special 

Publication 11:187-194. 

Piper, R.G., 1.6. McElwain, L.E. Orme, J.P. McCraren, 

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

management. U.S. Department of the Interior, Fish 

and Wildlife Service, Washington, D.C. 

Priegal, G.R. 1970. Reproduction and early life history 

of the walleye in the Lake Winnebago Region. 

Technical Bulletin 45, Wisconsin Department of 

Natural Resources, Madison, Wisconsin. 

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

manual. Ontario Ministry of Natural Resources, 

To ro n t 0. 

Satterfield, J.R., Jr. 1992. Walleye semen collection, 

preservation , and storage. Doctoral dissertation, 

Colorado State University, Fort Collins. 

Satterfield, J.R., Jr., and S.A. Flickinger. 1995a. Field 

collection and short-term storage of walleye semen. 

Progressive Fish-Culturist 57: 182-1 87. 

Satterfield, J.R., Jr., and S.A. Flickinger. 1995b. Factors 

influencing storage potential of preserved Walleye 

semen. Progresive Fish-Culturist 57: 175-1 81 

Stickney, R.R. 1983. Care and handling of live fish. 

Pages 85-94 in L.A. Nielsen and D.L. Johnson, 

editors. Fisheries techniques. American Fisheries 

Society, Bethesda, Maryland. 

Tave, D. 1994. Genetics for fish hatchery managers, 2nd 

edition. AVlNan Nostrand Reinhold, New York. 

Walker, M.K., E.A. Yanke, and W.H. Gingerich. 1994. 

Use of electronarcosis to immobilize juvenile and 

adult northern pike. Progressive Fish-Culturist 

56:237-243. 

NCRAC Culture Series 101 - Walleye Culture Manual 69 
70 NCRAC Culture Series 101- Walleye Culture Manual 
Colesante, R. T. 1996. Collection of walleye broodstock, egg take, incubation, and fry production 

at the Oneida Fish Cultural Station. Pages 71-74 in R. C. Summerfelt, editor. Walleye culture 

manual. NCRAC Culture Series 101. North Central Regional Aquaculture Center Publications 

Office, Iowa State University, Ames. 

Collection of Walleye Broodstock, Egg 

Take, Incubation, and Fry Production at the 

Oneida Fish Cultural Station 

Richard T: Colesante, New York State Department of Environmental Conservation, Oneida Fish Cultural 

Station, Constantia, New York 13044 

Introduction 

Since 1897, walleye have been collected by hatchery 

crews on Oneida Lake to obtain gametes for fry 

production to meet needs for fishery management in 

New York State. This case study describes techniques 

used to collect broodfish, obtain eggs and semen and 

produce fry at the New York State Department of 

Environmental Conservation Oneida Fish Cultural 

Station. 

Oneida Lake is the largest inland lake within New York 

State. It is a shallow 50,000 acre (20,234 ha) lake with a 

mean depth of 22 ft (6.7 m). The lake is annually 

stocked with 102 million walleye fry (2,040 fry/acre, 

5,04O/ha) which contribute to the adult population that 

averages 10 fish/acre (25 fish/ha). Hatchery efforts at 

broodstock collection deal with this population. 

The water supply for the Oneida Fish Culture Station 

comes from Scriba Creek, a major tributary to Oneida 

Lake. Generally, hatchery water is 24°F (1.1 -4.4”C) 

warmer than lake water during the spawning period; 

this source of warmer water is very useful in handling 

“hard or green” female walleyes. 

Spawning season 

Oneida Lake is completely covered with ice from 

December-January through March-April. Ice normally 

leaves the lake during the first two weeks in April. As 

soon as ice is gone, trap nets are set. If ice leaves the 

lake in early-mid March, a test net is set. Spawning 

activity usually begins during the last week of March or 

early April when lake temperatures approach 40°F 

(4.4”C). Photoperiod appears very important in the 

timing of spawning; water temperature appears to be an 

immediate stimulus to initiate spawning activity only 

when “the time” is correct. 

The length of the walleye spawning run in Oneida Lake 

is determined by many factors. A cold spring can 

extend the spawning period by a few days and the 

converse is also true. If the ice is gone by late March or 

early April, a 14 d spawning period is common; if ice 

out is later, spawning may last only 7-10 d. During the 

last 20 years, the annual walleye egg requirement for 

the hatchery has been about 320 million eggs. This 

target has been met every year except one. Typically, 

eggs must be collected for the entire spawning period. 

Collection of broodstock 

Oneida Lake trap nets, designed and built by hatchery 

staff, are used to collect adult fish. The nets are made 

with 0.75 in (1.9 cm) bar, 1.5 in (3.8 cm) stretch, nylon 

webbing placed on 4 ft (1 .2 m) or 6-ft (1.8 m) frames 

(Figure 1). The net is equipped with wing (2), leader 

(I), and crib (1) anchors which stabilize the net even 

during periods of high wind and wave action. The nets 

are generally set at the mouth of Scriba Creek and 

selected locations withm 0.75 mi (1.2 km) in each 

direction of the mouth. Nets are set within 0.25 mi (0.4 

km) of shore in water 6-8 feet (I 3-2.4 m) deep. The 

leader of the net, usually between 100-1 50 ft (30.5- 

45.7 m) long, generally extends toward, but does not 

reach, the shore. Netting sites have been standardized 

by hatchery crews over the years and are generally 

associated with rocky shoals or points along the lake. 

Fifteen to 24 nets are set each spring. Walleye in 

Oneida Lake spawn on shoals and in tributaries; netting 

operations collect fish from all locations. Normally, 

between 30,00040,000 adult walleyes are netted and 

transported to the hatchery each year. 

Trap nets are tended each day. Fish are removed from 

nets and transported by boat to the hatchery in live cars. 

Live cars are rectangular fiberglass tubs, 2.75 x 4.1 x 

NCRAC Culture Series 101 - Walleye Culture Manual 71 
Chapter 3 - Collection and Care of Broodfish 

1.5 ft (0.8 x 1.2 x 0.5 m) (width x length x depth), 

containing approximately 30 gal (1 13.6 L) of water. 

There is no aeration or treatment of the water in the live 

cars. Early in the spawning run, over 90% of the fish in 

a net will be walleye; as the run progresses and water 

temperature increases, other species of fish become 

prevalent. At the hatchery, the live car is hoisted by a 

mechanical lift and moved along a rail to a sorting 

table. The live car is lowered onto the table and each 

walleye is sexed and spawning condition is determined; 

the live car commonly holds up to 200 adult walleye. 

Males, ripe females (ready to strip that day), and hard 

(green) females are placed in separate fiberglass 

holdmg tanks. The hatchery has 32 tanks, 25 x 4 x 2.3 ft 

(7.6 x 1.2 x 0.7 m), for use during this phase of the 

Figure 1. Frame diagram of Oneida Lake Trap net. 

132 ft leader 

I 

I 

I 

I 

I 

I 

I Leader 

operation. Generally, up to 500 adults will be held in a 

tank, volume near 200 ft3 (5.7 m3), with a flow of 

approximately 80 gpm (5.0 L/sec). Tanks are not 

covered and fish are exposed to low light (~140 lux) 

conditions while being held in the hatchery. 

Spawning 

Ripe females are stripped the day they are captured. 

Hard females netted on previous days are checked daily 

and, if they have become ripe, they are stripped. If the 

hatchery had to rely only on ripe fish captured from the 

lake, the production goal would never be met. It is the 

ripening of hard females that are collected from the lake 

that supplies more than 50% of our eggs. Hard females 

Wing jack 

I 

are held for up to 3 d; normally 60-80% of 

these fish become ripe. The typical temperature hfference between the lake and the 

hatchery's water supply is 24°F (1.1-4.4"C), 

which probably stimulates these fish to ripen 

in the hatchery. Under unusual situations, a 

cold front can cause the stream temperature to 

be less than the lake; when this happens, few 

females ripen. Hard females are generally held 

no longer than 3 d. If they have not ripened, they 

are released. 

After sufficient ripe walleyes are accumulated in 

the hatchery, stripping crews are established. 

Each crew consists of 3 people, one stripping 

females, another stripping males, 

and a third stirring eggs and adding 

water to the bowl containing eggs 

and sperm. Eggs and sperm are 

stripped into fiberglass bowls with 

a volume of 6.5 gallons (24.6 L); 

eggs are fertilized using the wet 

method. One pint (0.5 L) of water, 

is placed in the bowl; eggs and sperm 

\ 

Outside wing 

float Or lead 

Outside heart 

Inside wing 

are added simultaneously while 

additional water is added as needed to 

make a slurry of eggs, sperm and water. In 

the egg fertilization process, male and 

female fish are generally used in a 1 : 1 

ratio. Early in the spawning run, gametes 

Inside heart 

Funnel 

6 Crib ft 

- I - - rF Crib brail from 15 females and 15 males are stripped 

into a bowl; later in the run, when some 

females may be partially spent, gametes 

from 20 females and 20 males are used. 

Bridle 

72 NCRAC Culture Series 101- Walleye Culture Manual 
Collection and Care of Broodfish - Chanter 3 

Typically, Oneida Lake walleye yield 40,000 to 50,000 

eggsBowls full of eggs are carried to the water hardening 

area where the eggs are stirred, using 3-in (7.6-cm) 

paint brushes. When four bowls are available, the 

fertilized eggs are poured into a 20 gal (75.7 L) tub 

containing 5 gal (18.9 L) of a 400 ppm tannic acid 

solution to remove the adhesiveness of the eggs. Eggs 

in the tannic acid solution are continuously stirred for 

2.5 min. The eggs are decanted and the remaining egg 

slurry is stirred and egg clumps are broken up (as 

needed) by hand. Fresh water is added and decanted 

from the tub two more times, and eggs are stirred and 

clumps of eggs are broken up by hand each time. The 

tub is filled for a third time with fresh water, and the 

eggs are allowed to water harden for up to 1 h. About 

every 15 min during water hardening, eggs are stirred 

briefly by hand. 

lncu bat ion 

Typically 320-350 million walleye eggs are collected 

annually. There are 13 jar batteries capable of holdmg 

910 McDonald type incubation jars. After water 

hardening, the water in the tub is decanted and 3 qts 

(2.9 L) of eggs are placed in each jar. Water flow 

through the jar is about 1.5 gpm (5.7 Lpm) for the first 

2-3 d, slowed to 1 .O gpm (3.8 Lpm) for the majority of 

the incubation period and increased to 1.5 gpm 5.7 

Lpm) at hatching. During incubation, eggs are treated 

every other day with a 1:600 (1,667 ppm) formalin 

solution for 15 min to control fungus. 

Periodically during incubation, dead eggs are siphoned 

from jars. Dead eggs accumulate at the top of each jar 

as incubation progresses. Siphoned eggs (which always 

include some live eggs) are placed in jars and allowed 

to roll and separate. When this “hospital” jar is siphoned, dead eggs are then discarded and live eggs are 

retained. 

Eggs are incubated in creek water at ambient temperatures. The temperatures vary from 40-65°F (4.4- 

18.3”C) during the incubation period, but they may vary 

as much as 10°F (5.6”C) in a 24 h period. Typically 

incubation lasts about 21 d; however, in some years, 

incubation can take as few as 15 d or as many as 30 d. 

Generally, the longer the incubation period, the poorer 

the survival of eggs. Percent eye-up is determined by 

sampling 20% of the jars (randomly selected) on each 

battery, remeasuring the surviving eggs, and expanding 

this estimate for each battery and for all batteries. 

Normal yearly eye-up average is 80436%; however, 

during periods of long incubation, eye-up may be as 

low as 70-75%. 

Hatching can begin as early as 270°F (1 32.2”C) 

temperature units and usually peaks by 400°F 

(204.4”C) temperature units. Fry swim from jars, travel 

through an open drain system on the jar battery and 

drop into a holdng tank. The holding tank is 25 x 4 x 

2.3 ft (7.6 x 1.2 x 0.8 m), 210 ft’(5.9 m’), with a single, 

50-meshY stainless steel, barrier screen. A “T” shaped 

bubbler, made of 0.5 in (1.3 cm) PVC, is placed near 

the bottom of the screen and along its length. Drilled 

% in (0.32 cm) holes release air towards the screen. Air 

is produced by two high-volume, low-pressure air 

pumps. The bubbler prevents egg shells and fry from 

accumulating on the screen which could limit the 

discharge of water. Water flow through individual 

batteries and holding tanks during hatching is between 

70-100 gpm (18.5-26.4 Lpm). 

As walleye fry accumulate in holding tanks, samples 

are taken to establish volumetric dsplacement values 

for inventory at stocking. Generally, between 200-230 

newly hatched fry will displace 1 ml of water. Attempts 

are made to stock fry within hours of hatching, but 

many times this is not possible because of scheduling 

difficulties. All fry are stocked prior to the initiation of 

feeding (usually 3-5 d). If held beyond this time, 

cannibalism would occur in crowded holding tanks. 

Total fry production from the hatchery ranges between 

150-200 million. About thirty bodies of water are 

stocked with the hatchery-spawned fry each spring. 

Netting 30,000-40,000 adult walleye and collecting 320 

million fertilized eggs in a 7-14 d period demands 

efficiency. The program at the Oneida Fish Cultural 

Station has evolved over 100 years. Improvements in 

egg handling techniques and modem fish moving 

equipment have reduced manpower requirements by 

one third. Table 1 summarizes broodstock collection, 

egg take, and fry production during the 1993 and 1994 

production seasons. Each year of hatchery operation 

results in improvements in efficiency, which should 

continue over the ensuing production seasons. 

NCRAC Culture Series 101 - Walleye Culture Manual 73 
Chapter 3 - Collection and Care of Broodfish 

Table 1. Broodstock collection, egg take, and fry 

production summary for 1993 and 1994 at the 

New York State Department of Environmental 

Conservation Oneida Fish Cultural Station. 

1993 1994 

Date lake was first ice-free 

Date first net set 

Total nets set 

First day tended 

Total net days 

Last day tended 

Hatchery temperature: 

Mean 

Range 

Lake temperature: 

Mean 

Range 

Total walleye collected 

Males 

Females (hard) 

Females (ripe) 

Females (spent) 

Females stripped 

Males stripped 

Ave rag e eg gslfe m al e 

Date first eggs taken 

Date last eggs taken 

Date of first hatching 

Incubation days 

Incubation temperature: 

Mean 

Range 

Total eggs taken 

Estimated eye-up percentage 

Total fry stocked 

411 2 

411 2 

20 

411 3 

9 

412 1 

48°F 

(8.9"C) 

39-51 "F 

(3.9-1 0.6"C) 

41 "F 

(5°C) 

37-43°F 

(2.8-6.1 "C) 

38,977 

26,337 

10,583 

1,546 

1,511 

7,421 

7,421 

50,209 

411 5 

412 1 

513 

20 

55.7"F 

(1 3.2%) 

4557°F 

(7.2-1 3.9"C) 

372,600,000 

80.4% 

152,086,000 

411 7 

411 7 

20 

411 8 

7 

4/24 

47°F 

(8.3%) 

42-52°F 

(5.6-1 1.1 "C) 

41 "F 

(5°C) 

38-43°F 

(3.3-6.1 "C) 

34,645 

22,925 

7,362 

1,290 

3,086 

7,920 

8,451 

42,420 

411 8 

4/25 

4/30 

15 

53.6"F 

(12.0%) 

46-64°F 

(7.8-1 7.8"C) 

336,000,000 

88.5% 

202,000,000 

74 NCRAC Culture Series 101- Walleye Culture Manual 
Nagel, T. 1996. Development of a domestic walleye broodstock. Pages 75-76 in R. C. Summerfelt, 

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

Center Publications Office, Iowa State University, Ames. 

Development of a Domestic Walleye 

Broodstock 

Tim Nagel, London Fish tiatcherx Ohio Department of Natural Resources, Division of Wildlife, London, Ohio 

43140 

Introduction 

This case study summarizes 20 years of breeding at the 

London Fish Hatchery, London, Ohio, to develop a line 

of domestic walleye broodstock. This project was 

initiated to develop a line of fish that were less excitable 

and that were more easily trained to accept pelleted 

feed. Some aspects of this program have been described 

(Nagel 1985,1991). 

Acquisition of P, generation and production 

and culture of F, generation 

Fertilized eggs were obtained from wild broodstock 

captured from the Pymatuning and Mosquito Reservoirs 

in northeast Ohio in the spring of 1975, 1976, and 1977 

(Table 1). It is thought that the original source of 

walleye in these reservoirs was Lake Erie. Wild 

broodstock that were spawned were designated as the 

parental (P,) generation. There were three year classes 

(1975, 1976, and 1977) of P, broodstock. 

The fertilized eggs were transported to the London Fish 

Hatchery where they became the F,-generation. This 

was the first generation of broodstock in the breeding 

program to be cultured at the London Hatchery. There 

were three F,-generation year classes (1975, 1976, 

1977). F,-generation fish were raised in 0.1 -acre (0.04 

ha) earthen ponds until they were 1.4-1.5 in (3 1-38 

mm), and were transferred to covered 5O-ft' (1,421 L) 

troughs with internal lighting where they were trained 

to accept a formulated &et (W- 16) using procedures 

developed at the London Hatchery from 1972-1975 

(Nagel 1976). Solenoid-actuated feeders were used to 

dispense feed hourly from dawn to dusk. Hand feeding 

at dusk was also used, because it can reduce the 

acclimation period. 

After 2 weeks, fingerlings were restocked in a 0.1-acre 

(0.04 ha) pond and were fed a floating trout chow. Each 

year class was stocked in a separate pond. A floating 

diet was used to observe feeding behavior and to 

prevent overfeedmg, something which can occur when 

using a sinking pellet. Fish were fed just before sunrise 

and after sunset. Feeding was done daily, but only 

during crepuscular periods. Feed-trained fish were 

cultured in the ponds until they were 4 years old. 

Males matured at 3 years, while females matured at 4-5 

years. Brood fish averaged 3 lbs (1.36 kg). When water 

temperature reached 48°F (9"C), most males had an 

abundance of milt. However, most ceased semen 

production within 7- 10 d. Four to 5-year-old females 

that were gravid ripened within 3-5 d. After harvest, 

fish were sexed, and males that were producing semen 

were placed in divided troughs up-water from gravid 

females. Fish were easily stripped 3-5 d after harvest, 

and hormonal injections were not needed. 

Production of F, F, and F, generations 

F,-generation fish were spawned in 1979-1983 to 

produce five year classes of F,-generation walleye 

(1979,1980,1981,1982, and 1983). The 1975 and 

1976 F,-generation year classes were spawned in 1979 

to produce the first (1 979) year class F,-generation fish. 

F,-generation fish were cultured as described above. 

However, hatching success of the 1979 year class was 

poor. 

This process was repeated to produce the F, and F, 

generations. F,-generation fish were spawned in 1984 

and 1986-1989 to produce five year classes of F,- 

generation walleye (1984, 1986, 1987, 1988, and 1989). 

F,-generation fish were spawned 1990-1994 to produce 

five year classes of F,-generation fish (1990, 1991, 

1992, 1993, and 1994) (Table 1). The year classes 

within each generation were not produced by the same 

parents or by the same parental generation year class. 

NCRAC Culture Series 101 - Walleye Culture Manual 75 
Chapter 3 - Collection and Care of Broodfish 

During this breeding program, 13.2 million eggs were 

produced, more than 200,000 pond-raised fingerlings 

were trained to accept pelleted feed, and 4,000 feedacclimated walleye were raised as broodstock. Percent 

hatch was 50-60%. 

The breedmg program has been terminated; as of fall, 

1995, only 100 brooders were at the station. All other 

brood fish were stocked or used in experiments. 

Benefits of domestication 

To date, the only success with producing fry under 

intense culture conditions at the London Hatchery has 

been by using fry produced from London strain 

broodstock. In one year, 1.5 million eggs were produced from 4-year-old brood fish. Prior to 1980, 

maximum survival to 4.9 in (12.5 cm) was 40-50%. 

Survival of F,-generation fish increased to 90%. 

less excitable during the course of the breeding project. 

During the dusk feedmg, walleye swam towards me 

immediately upon my arrival at the ponds. Brood fish 

did not have to be induced to spawn, and even spawned 

in the ponds for several years. 

References 

Nagel, T. 1976. Intensive culture of fingerling walleyes 

on formulated feeds. Progressive Fish-Culturist 

38190-91. 

Nagel, T. 1985. Development of a domestic walleye 

broodstock. Progressive Fish-Culturist 47:121-122. 

Nagel, T. 1991. Artificial propagation of walleye. Pages 

259-261 in NCRAC-91. Proceedings of North Central 

Aq uacu I t u re Conference, Kal am azoo, Michigan, 

March 18-21, 1991, North Central Regional Aquaculture Center, Michigan State University, East Lansing. 

During the 20-year domestication process, changes in 

walleye behavior were observed. The fish became far 

Table 1. Breeding history of London strain walleye broodstock development program. Fish were developed from broodstock captured from 

Pymantuning and Mosquito Reservoirs, Ohio. 

Year Generation Description of mating 

year class 

1975 F1 (1975) P1 generation was wild broodstock 

1976 F1 (1 976) PI generation was wild broodstock 

1977 F1 (1 977) PI generation was wild broodstock 

1979 F2 (1 979) 1975, 1976 F1 year classes spawned 

1980 

1981 

F2 (1 980) 

F2 (1 981) 

1975, 1976, 1977 F1 year classes spawned 

1975, 1976, 1977 F1 year classes spawned 

1 982 F2 (1 982) 

1 983 F2 (1 983) 

1 984 F3 (1 984) 

1 986 F3 (1 986) 

1 987 F3 (1 987) 

1 988 F3 (1 988) 

1 989 F3 (1 989) 

1 990 F4 (1 990) 

975, 1976, 1977 F1 year classes spawned 

975, 1976, 1977 F, year classes spawned; F,-generation fish removed 

979, 1980 F2 year classes spawned 

980, 1981, 1982 F2 year classes spawned 

980, 1981, 1982, 1983 F2 year classes spawned 

981, 1982, 1983 F2 year classes spawned 

981, 1982, 1983 F2 year classes spawned; F2-generation fish removed 

984,1986, 1987, 1988, 1989 F3 year classes spawned 

1991 

1992 F4 (1 992) 1988, 1989 F3 year classes spawned 

1993 F4 (1 993) 1988, 1989 F3 year classes spawned 

1994 F4 (1 994) 1988, 1989 F3 year classes spawned 

F, (1 991) 1984, 1987, 1988, 1989 F3 year classes spawned 

76 NCRAC Culture Series 101- Walleye Culture Manual 
Jorgensen, W. D. 1996. Wild broodstock collection in Iowa. Page 77 in R. C. Summerfelt, editor. 

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

Center Publications Office, Iowa State University, Ames. 

Wild Broodstock Collection in Iowa 

Wallace D. Jorgensen, Spirit Lake Hatchery; 61 1 252nd Avenue, Spirit Lake, IA 51360 

Introduction 

This case study describes procedures used at the Spirit 

Lake Hatchery to collect walleye broodstock from 

natural lakes in northwest Iowa. The lakes range in size 

from 1,875 to 5,684 acres (759-2,300 ha). Because 

walleye in these lakes are not greatly attracted to 

flowing water at inlets or outlets, gill nets have been the 

most successful method for capture. After capture, fish 

are transported to the hatchery for stripping and 

fertilization. 

Procedures 

Ice cover leaves the lakes in northwest Iowa between 

late March and mid-April. However, the normal or 

average ice free condition of the lakes is April 8 to April 

11. After ice out, water temperatures are monitored 

daily and when temperatures reach 44-46°F (6.6-7.7"C) 

gill netting operations begin. 

Gill nets 

The gill nets we use are a multi-filament nylon gill net 

which are dyed brown. The netting is a size 104 nylon 

twine with a 2.5 in (6.4 cm) bar measure opening. 

These nets are 21 meshes (8.7 ft, 2.7 m) deep by 360 ft 

(1 10 m) long. Nets are tied on float and lead lines, 

placing three, 5 in (13 cm) stretch meshes per 4.5 in 

(1 1.4 cm) ties. A 2.5 in (6.4 cm) bar measure will 

capture walleye 16-32 in (40-81 cm). 

Ten, two-person crews set two nets each night at 7:OO 

p.m. Nets are lifted and fish removed at about 1O:OO 

p.m., the nets are reset and lifted again at 1 :00 a.m. The 

nets are removed after the 1:00 a.m. run. 

Each crew uses a 14-ft (4.3 m) aluminum boat for net 

placement and fish removal. Illumination is provided 

by a gas lantern secured to the top of a 5 ft (1.5 m) steel 

rod and the bottom fastened to the side rail of the boat. 

All nets are set perpendicular to the shoreline and then 

extended from the shore into deeper water. Water 

depths will range from 8 to 20 ft (2.4-6.1 m) deep at the 

outer end of the net. Nets usually will be set out from 

sand beaches, rockhbble shorelines and adjacent to 

rock points. 

Handling and transporting broodstock 

Fish are removed from the nets and placed in 20 gal 

(75.7 L) tubs of water located in the center of the boats. 

Crews change the water frequently, however, when 

large numbers of fish are captured, fish are placed in 4 x 

6 ft (1.2 x 1.8 m) by 1 in (2.5 cm) bar measure purse 

type live bags until the trucks arrive. 

Hatchery trucks transport fish from the lake sites to the 

hatchery (2-19 miles, 3.2-30.6 km). This is done after 

both the 1O:OO p.m. and 1:00 a.m. fish collection times. 

The tanks have a capacity of 1,400 gal (5,300 L). The 

water is oxygenated using liquid oxygen supplied from 

dewars on the truck. Normally the trucks are transporting up to 0.5 lb fish per 1 gal (60 gL) water. Lake, 

transport, and hatchery water temperatures range from 

46 to 56°F (7.7-13.3"C) during broodfish collection. 

A mo&fied isotonic saline solution is added to the 

water of the hauling tank. The saline solution consists 

of 4.3 lb (1.9 kg) sodium chloride, 0.17 lb (77 g ) 

potassium chloride, 0.1 1 lb (50 g) monopotassium 

phosphate, 0.09 lb (40.9 g) magnesium sulfate/lOO 

gallons (378 L) of water. 

Personnel at the hatchery sort and sex all fish and 

separate male, female, ripe female, and green female 

into individual tanks. Ripe females are defined as fish 

that will emit eggs from the ovaries with very slight 

pressure on the abdomen, and green females are fish 

that emit few or no eggs using the same technique. 

Green females are segregated by date of capture, and 

are checked every 24 hrs for ripeness. All stripped fish 

are transported back to the lakes in a saline solution. 

Dependmg on weather con&tions, all broodstock are 

captured within a 7 to 14 d period. Average broodstock 

needs are approximately 2,000 to 2,500 fish annually. 

We have found that post-spawning mortality is less than 

1 %. 

NCRAC Culture Series 101 - Walleye Culture Manual 77 
Chapter 3 - Collection and Care of Broodfish 

78 NCRAC Culture Series 101- Walleye Culture Manual