Sunfish Culture Guide

In cooperation with USDA\CSREES   NCRAC Culture Series

North Central Regional Aquaculture Center
Sunfish Culture Guide

Editors

Joseph E. Morris, Iowa State University

Charles C. Mischke, Mississippi State University (formerly with Iowa State University)

Donald L. Garling, Michigan State University

A publication of the North Central Regional

Aquaculture Center (NCRAC)

In cooperation with

United States Department of Agriculture

Cooperative State Research, Education, and Extension Service (CSREES)

Grant 94-38500-0048

North Central Regional Aquaculture Center

NCRAC Culture Series 102 (First Edition, 2002)
Sunfish Culture Manual ii NCRAC Culture Series
NCRAC Culture Series Sunfish Culture Manual iii

The North Central Regional Aquaculture

Center (NCRAC) was formed in February

1988. It is one of five regional aquaculture

centers administered by the U.S. Department

of Agriculture (USDA).

The mission of these centers is to support

aquaculture research, development,

demonstration, and extension education to

enhance viable and profitable U.S.

aquaculture production that will benefit

consumers, producers, service industries, and

the American economy.

They work together within the broader,

integrated aquaculture program of the USDA

to promote a well-developed sustainable

aquaculture industry in the USA. NCRAC

programs are jointly administered by Michigan

State University (MSU) and Iowa State

University (ISU). The Director’s office is located

at MSU; the Associate Director is at ISU.

North Central Regional Aquaculture Center

The NCRAC serves 12 states in the Midwest:

Illinois, Indiana, Iowa, Kansas, Michigan,

Missouri, Minnesota, Nebraska, North Dakota,

Ohio, South Dakota, and Wisconsin. It relies

on leaders in the aquaculture industry for

direction in its programs. The Industry Advisory

Council (IAC) sets priorities.

A Technical Committee, researchers, and

extension specialists work with the IAC to

formulate program priorities. Regional

programs are meshed with the other Centers

to avoid duplication.

Research teams and extension aquaculture

specialists from regional universities and

public agencies develop and execute work

plans to investigate priority problems identified

by the IAC. A Board of Directors oversees the

administration and management of NCRAC’s

programs.

Questions about NCRAC programs may be directed to:

Dr. Ted R. Batterson, Director

North Central Regional Aquaculture Center

Department of Fisheries and Wildlife

Michigan State University

East Lansing, MI 48824

Telephone: 517-353-1962

Fax: 517-353-7181

E-mail: batters2@pilot.msu.edu

The NCRAC Publications Office at ISU serves as the outlet for regional aquaculture

communications. The Associate Director of NCRAC is in charge of this office.

Dr. Joseph E. Morris, Associate Director

North Central Regional Aquaculture Center

Department of Natural Resource Ecology and Management

124 Science Hall II

Iowa State University

Ames, IA 50011-3221

Telephone: 515-294-5280

Fax: 515-294-7874

E-mail: jemorris@iastate.edu
Sunfish Culture Manual iv NCRAC Culture Series
NCRAC Culture Series Sunfish Culture Manual v

Sunfish Culture Guide

A project of the North Central Regional

Aquaculture Center (NCRAC)

Editors

Joseph E. Morris

Charles C. Mischke

 and Donald L. Garling

Series Editor: Joseph E. Morris, Associate Director

North Central Regional Aquaculture Center (NCRAC)

Production: IDEA (Information Development ~ Expanding Awareness), ISU Extension

26 Curtiss, Ames, Iowa 50011, 515-294-8802, www.idea.iastate.edu

Layout Editor: J.K. Eckhart, Write Image, Inc.

North Central Regional Aquaculture Center

NCRAC Culture Series 102 (First Edition, 2002)
Sunfish Culture Manual vi NCRAC Culture Series

Table of Contents

North Central Regional AquaCulture Center ..................................................... iii

Credits ................................................................................................................ v

Table of Contents .............................................................................................. vi

Preface ............................................................................................................. vii

Chapter 1: Historical Background................................................................... 1–3

Chapter 2: Spawning Behavior and Early Life History ................................. 4–11

Chapter 3: Culture Methods ....................................................................... 12–18

Chapter 4: Brood Stock Management ........................................................ 19–24

Chapter 5: Hybridization ............................................................................. 25–28

Chapter 6: Water Temperature Influences on Survival and Growth ........... 29–30

Chapter 7: Industry Status.......................................................................... 31–33

Chapter 8: Production of Polyploid Sunfish ................................................ 34–40

Chapter 9: Fee-Fishing............................................................................... 41–47

Chapter 10: Calculating Chemical Treatments ........................................... 48–57

Chapter 11: Common Sunfish Parasites .................................................... 58–68

Chapter 12: Collecting Fish Samples for Disease Diagnosis ..................... 69–78

References ................................................................................................. 79–83

Appendix A: Chapter Notes .............................................................................. 84

Appendix B: Contacts for Additional Information .........................................85-86

Appendix C: Abbreviations, Acronyms, Common Names ...........................87-88

Index...........................................................................................................89–91

Note: Footnoted text indicates chapter notes, which are located in Appendix A.

Chapter notes provide additional explanation and contact information.
NCRAC Culture Series Sunfish Culture Manual vii

P r e f a c e

 With the growing interest in aquaculture over the past three

to four decades, there is an increasing need to evaluate and

develop different fish species for aquaculture. Because of

the interest in species other than trout or catfish, coupled

with the limited availability of compiled information on other

species, the North Central Regional Aquaculture Center

(NCRAC) decided to develop culture manuals on potential

aquaculture species.

The purpose of the NCRAC culture series is to provide an

assemblage of current information regarding the culture of a

specific fish species. The guides are written in a style useful

to all levels of expertise, from the novice to the expert culturist.

Editor R.C. Summerfelt completed the Walleye Culture

Manual, Culture Series 101, which is available from NCRAC.

The Sunfish Culture Guide, Culture Series 102, is the second

in the series. The Yellow Perch Culture Guide will be the third

guide in the series.

The Sunfish Culture Guide, which focuses on Lepomis spp.,

is organized so that each chapter can stand alone. Culturists

with different interests and levels of expertise can use all or

any part of the guide. Consequently, some repetition of

information was unavoidable; however, we believe that

repetition will not cause readers undue distraction.

Measurements are given in both metric and English units.

The metric system greatly simplifies calculations, but many

culturists are more comfortable using the English

measurement system. For readers not familiar with scientific

abbreviations, Appendix C contains a chart of common

abbreviations.

References cited within the text are listed at the end of the

manual. Readers with a strong interest in certain topics are

encouraged to refer to these references for more in-depth

information.

Your editors,

Joseph E. Morris, Charles C. Mischke, and Donald L. Garling
Sunfish Culture Manual viii NCRAC Culture Series

A c k n o w l e d g e m e n t s

The Sunfish Culture Guide is the result of

collaborative efforts of the North Central

Regional Aquaculture Center (NCRAC)

extension members and work groups. Work

on the NCRAC sunfish project was made

possible through grants from the U.S.

Department of Agriculture-Cooperative State

Research Education and Extension Service

(USDA-CSREES).

NCRAC funded participants in the sunfish

project included: Bruce A. Barton, University

of South Dakota; Fred P. Binkowski, University

of Wisconsin-Milwaukee; Paul B. Brown,

Purdue University; Donald L. Garling,

Michigan State University; Robert S. Hayward,

University of Missouri; Terrence B. Kayes,

University of Nebraska-Lincoln; Christopher

C. Kohler, Southern Illinois UniversityCarbondale; Jeffrey A. Malison, University of

Wisconsin-Madison; Joseph E. Morris, Iowa

State University; Douglas B. Noltie, University

of Missouri; Robert J. Sheehan, Southern

Illinois University-Carbondale; Robert C.

Summerfelt, Iowa State University; and James

R. Triplett, Pittsburgh State University. Charlie

Stevens was industry advisory council liaison

and Joseph E. Morris was extension liaison.

Non-funded collaborators of the sunfish

project included: Denzil Hughes, Fountain

Bluff Fish Farms, Illinois Department of

Conservation; Jim Frey, Ron Johnson, and

Myron Kloubec, Missouri Department of

Conservation; Tribal Council; and the National

Biological Service.

We are grateful to those reviewers and

organizations who took time out of their busy

schedules to give us constructive input on this

publication.

Disclaimer

The views expressed in this guide are those

of the authors and do not necessarily reflect

those of the USDA or any of its sub agencies.

Photo Credits

The editors thank Sterling K. Johnson (Texas

A&M University) for the use of his photographs

to depict various fish diseases. We also

acknowledge and thank the following

individuals who contributed photos for this

publication:

Ø Gary Atchison, Iowa State University

Ø Joseph Morris, Iowa State University

Ø Charles Mischke, Iowa State University

Ø Glenda Dvorak, Iowa State University

Ø Bruce Hinrichs, Iowa State University

Ø Clay Pierce, Iowa State University

Ø LaDon Swann, Mississippi-Alabama

Sea Grant Consortium

Questions regarding specific photos used in

this Guide should contact Joseph Morris, Iowa

State University, Department of Natural

Resource Ecology and Management, 124

Science II, Ames, Iowa 50011,

jemorris@iastate.edu.
Historical Background

Sunfish are important elements to the environmentalhealth of ponds and streams. Certain species have

been popular research subjects, key to pond stocking,

and important forage bases. Sunfish are now under

consideration for their potential suitability in commercial

scale aquaculture production.

This chapter explains:

• The term sunfish

• Early research

• Sunfish importance

• Aquaculture potential

1

Sunfish Culture Guide NCRAC Culture Series 102

Historical Background
NCRAC Culture Series 102 Sunfish Culture Guide 1

Chapter 1 Historical Background

Historical Background

Authors: C. C. Mischke and J. E. Morris, Iowa State University

The Term Sunfish

The term “sunfish” refers to any of thirty

sunfish species in the Centrarchidae family

(Pflieger 1975). Centrarchids are strictly a

North American fish family that includes bass

(Micropterus spp.), bream (Lepomis spp.), and

crappie (Pomoxis spp.).

Characteristics

Members of the Centrarchidae family have

deep bodies, laterally compressed. The

anterior portion of their dorsal fin consists of

spiny rays; the posterior portion consists of soft

rays. The pelvic fins of sunfish are located

directly beneath the pectoral fins.

Manual focus

This guide focuses on the Lepomis species

of sunfish. Most available literature to date

deals with the bluegill and redear sunfish, but

the information could apply to most of the

Lepomis species. Basic production practices

are the same for pure sunfish species as for

their hybrids (Dupree and Huner 1984).

Early Research

The first studies

dealing with sunfish, as

with most fish, were

observational studies that

noted their basic

biological activities.

Breder (1936) was one of the first researchers

to extensively observe the habits of the North

American sunfish.

Sunfish Importance

Sunfish and sunfish hybrids have several

characteristics that make them suitable

candidates for aquaculture production. They may

be well suited to such temperate regions as the

North Central Region (NCR), where there is a

shorter growing season and cooler water

temperatures. However, further research is

needed to establish the culture of these fish

as a viable aquaculture enterprise.

As with any aquaculture venture, sunfish

aquaculture must be approached cautiously, with

considerable planning, and careful research.

Assessment of market opportunities should be

part of the evaluation, as it is with all potential

aquaculture enterprises.

Spawning nests of sunfish.

1
Sunfish Culture Guide 2 NCRAC Culture Series 102

Chapter 1 Historical Background

Bluegill sunfish

The bluegill is the most abundant sunfish, and

widespread introduction has increased its range

in North America, Europe, and South Africa

(Pflieger 1975; Carlander 1977). They are

abundant in ponds, lakes, and slow-moving

streams. Bluegill are intolerant of chronic high

turbidity and siltation; they thrive in warm, clear

waters where aquatic vegetation or other cover

is present (Pflieger 1975).

Redear sunfish

Redear sunfish, frequently referred to as the

“shellcrackers,” typically live near the bottom

of lakes and ponds, mainly eating snails. They

have a rapid growth rate and are usually larger

than the bluegill,

commonly reaching 267

mm (10.5 in.) (Pflieger

1975; Tomelleri and

Eberle 1990).

Green sunfish

Green sunfish are

widely distributed and

adaptable to a wide range

of conditions, for

example: high turbidity,

low dissolved oxygen,

and high alkalinity

(Childers 1967; Tomelleri

and Eberle 1990).

This wide tolerance

usually results in their

overpopulation and the

suppression of other sunfish populations.

Key pond and research components

Specific species of sunfish have been key

components in farm ponds throughout the U.S.

They have been stocked extensively in ponds

as forage fish for largemouth bass and as sport

fish (Swingle 1946; Dupree and Huner 1984;

McLarney 1987).

Bluegill are popular research subjects. They

are especially used for toxicology studies (Eaton

1970, 1974; Benoit 1975; Sandheinrich and

Atchison 1989; Coyle et al. 1993; Little et al. 1993),

but also for ecology studies on foraging

behavior (Li et al. 1985; Butler 1988; Ehlinger

1989; Gotceitas and Colgan 1989, 1990).

Because bluegill are an important forage base

and are so wide spread, fishery biologists

frequently sample them to determine a pond’s

balance and its structure.

There is continuing interest in and intensive

culturing and marketing of sunfish and their

hybrids for pond stocking and food fish

production.

Aquaculture Potential

For a fish species to be suitable for

aquaculture production

on a true commercial

scale, it

needs to meet both

marketing and biological

criteria (Webber and

Riordan 1976).

Sunfish, especially

bluegill and their

hybrids, seem to have

the potential to become

a very commercially

viable and marketable

aquaculture product.

Marketing criteria

Marketing criteria

include appearance,

texture, and consumer

recognition. Bluegill have a good to excellent

flavor and slightly soft texture, which makes

them acceptable to a large number of

consumers (McLarney 1987). Their flesh is

firm, white, and flaky; since the flesh has little

fat, most sunfish meat may be kept frozen for

long periods (Becker 1983).

Sunfish are highly respected as food fish and

bluegill are referred to as “bread and butter

fish” (Becker 1983). Bluegill and other sunfish

are among the most highly recognized fish

Bluegill is the most abundant

sunfish, and thrives in warm,

clear waters with vegetation.

Redear grow rapidly and are

larger than bluegill.

Green sunfish are adaptable

to a wide range of

conditions.
NCRAC Culture Series 102 Sunfish Culture Guide 3

Chapter 1 Historical Background

species. This improves their marketability.

Biological criteria

Biological criteria include acceptance of

artificial feeds (Ehlinger 1989), temperature

tolerance (Heidinger 1975), good growth rates

(Krumholz 1946; Breck 1993), and the ability

to spawn repeatedly (Banner and Hyatt 1975;

Stickney 1985).

Because sunfish and sunfish hybrids possess

many desirable characteristics for aquaculture

production, there is increased interest in

developing culture techniques.

Research is currently conducted on all aspects

of sunfish culture, from out-of-season spawning

to grow-out, and finally to marketing.

Summary

Interest in sunfish has progressed from merely

observational studies of basic biological

information to an interest in intensive and

extensive culture practices.

Because sunfish possess desirable production

characteristics, research is now conducted in

all areas of sunfish aquaculture.

Sunfish possess strong

commercial qualities for

aquaculture.

Notes
Spawning Behavior &

Early Life History

Sunfish species have a number of similar breedinghabits. Different morphological characteristics provide

allow a wide variety of hybrid development. Research into

these habits gives breeders a better understanding of

what aspects of the spawning and development process

help ensure reproduction success.

This chapter explains:

• Nest building

• Behavioral studies

• Spawning habits

• Hatching and growth

• Larval development

2

Sunfish Culture Guide NCRAC Culture Series 102

Spawning Behavior

cues for species recognition. Similarities in spawning habits
NCRAC Culture Series 102 Sunfish Culture Guide 4

Chapter 2 Spawning Behavior and Early Life History

Spawning Behavior and Early Life History

Authors: G. D. Dvorak, J. E. Morris, and C. C. Mischke, Iowa State University.

Behavioral Studies

Many observational studies of sunfish spawning

behavior have been conducted (Breder 1936;

Hunter 1963; Erickson 1967; Keenleyside 1967;

Avila 1975; Smith 1975; Clarke et al. 1984).

Sunfish were found to be more aggressive when

crowded into small areas, regardless of sex or

season (Erickson 1967; Avila 1975).

Adequate spacing is necessary to induce bluegill

reproductive behavior under intense

environmental conditions, according to Bryan et

al. (1994).

Species recognition between bluegill and

pumpkinseed is based on morphological

characteristics and could act as a behavioral

isolating mechanism (Keenleyside 1967).

Childers (1967) found it necessary to remove

the opercula tabs of male redear sunfish when

crossing them with female bluegill.

Clarke et al. (1984) investigated the courtship

sequences in pure and hybrid crosses of

bluegill and pumpkinseed. They found that

male behavior was influenced by the

behavior and species of the female present,

and that females of different species

signaled males differently. They concluded

that species discrimination is based on

differences in courtship behavior.

Signal value of certain acts varies with the

partner species present. Avila (1975) compared

the nesting behavior of male bluegill in

surrounded nests [three adjacent occupied nests

< 60 cm (24 in.)] and peripheral nests [nests that

were separated from adjacent nests by

>60 cm (24 in.)]. Peripheral males displayed

more reproductive behavior (92%) than

surrounded males (76%).

Nest Building

In the wild, sunfish are nest builders in shallow

waters and their reproductive habits are

remarkably uniform. All sunfish spawn in the late

spring or early summer when water

temperatures approach 20–29o

C (68–84oF)

(Breder 1936).

Male sunfish generally appear first at the

spawning sites and construct nests along the

shoreline in unshaded areas (see below) that

have maximum exposure to sunlight (Hunter

1963; Avila 1975). Using his tail, the male sweeps

a nest using tail undulations (caudal peduncle),

making a shallow circular depression in the soft

mud or gravel bottom of quiet shallow water.

Sunfish nests consist of depressions 5–15 cm

(2–6 in.) deep and approximately 30 cm (12 in.)

in diameter, constructed in water 0.3–1.5 m

Nesting site. Sunfish prefer shallow water to build their

nests. These waters are warmer than are the deeper

waters.

2
Sunfish Culture Guide 5 NCRAC Culture Series 102

Chapter 2 Spawning Behavior and Early Life History

(1–5 ft) deep (Becker 1983). Most sunfish are

colonial nesters, which means they construct

nests in densely packed aggregations (Gross and

MacMillan 1981).

Often different species can be found nesting

together in the same colony (Childers 1967). A

bluegill colony is usually comprised of

40–50 nests within a radius of 18–21 m (20–23

yd) (Becker 1983).

Spawning

During the spawning season, males become

brilliantly colored, which helps attract females.

Additionally, tail sweeping and rim circling

behaviors have value both to attract females and

threaten other males (Avila 1975). After

construction, the male circles the

nest and produces courtship calls

consisting of a series of grunts

(Avila 1975; Gross and MacMillan

1981; Becker 1983).

The courtship behavior of male

sunfish closely resembles their

aggressive behavior (Breder

1936). A female ready to spawn

(gravid female) does not

reciprocate this aggressive

behavior and remains stationary,

which may serve as a signal to the male.

Once a female is attracted to the nest,

however, the male circles and guides the

female into the nest where the eggs are then

deposited and fertilized.

During spawning, the female reclines to one

side and the pair swims side by side in a tight

circle over the nest. As the female releases her

eggs, the male fertilizes them. When sunfish

eggs are fertilized, they become water hardened

and adhere to the material on the nest bottom.

Female sunfish can produce from 2,000–

25,000 eggs per spawn. More than one female

may deposit eggs in a single nest (Avila 1975;

Becker 1983).

After eggs are deposited, the male chases the

female out of the nest. The males defend the

nests from predators and fan the nest to keep

the eggs aerated and clean of debris, guarding

them until the fry begin to swim.

Hatching and Growth of Fry

 Eggs usually hatch from 2–6 d after

fertilization, depending on species, photoperiod

(number of light hours), and temperature.

Bluegill eggs hatch in 2–3 d, (Smith 1975;

Beard 1982) but redear sunfish eggs hatch in

6–10 d (Childers 1967). As photoperiod and

temperature are increased, hatching time is

decreased (Toetz 1966).

Larval sunfish remain in the bottom of the nest,

protected by the male and receiving nutrients

from their yolk sacs until the swim-up stage.

The critical stage in their

development is when

larvae switch from

endogenous to exogenous

feeding—when they no

longer rely on their yolk

sacs and must obtain food

from the environment for

energy.

During this critical stage,

nutrients from the yolk sac

are depleted, and the

larvae’s mouth becomes more fully developed.

The larval fish will starve if they do not begin

feeding during this critical stage.

Swim-Up Times

Swim-up times for sunfish vary with the species

and the temperature. Times range from 2 d posthatch for green sunfish (Meyer 1970; Smith 1975)

to 3–7 d post-hatch for bluegill (Meyer 1970; Toetz

1966; Smith 1975; Mischke 1995; Mischke and

Morris 1997) and 3 d post-hatch for redear

sunfish (Meyer 1970).

Meyer (1970) reported swim-up age for bluegill

as 3 d post-hatch at a constant temperature of

21°C (70°F). Toetz (1966) and Bryan et al. (1994)

reported bluegill larvae swim-up at 4 d post-hatch

at 23.5°C (75°F) and 26°C (79°F), respectively.
NCRAC Culture Series 102 Sunfish Culture Guide 6

Chapter 2 Spawning Behavior and Early Life History

Childers and Bennett (1961) reported that

bluegill larvae reach swim-up at 5–6 d post-hatch

at 21°C (70°F). Mischke (1995) and Mischke and

Morris (1997) reported bluegill swim-up to be 7 d

post-hatch in the 21–25°C (70–77°F)

temperature range.

Redear larvae swim-up in 3 d post-hatch at 21o

C

(70o

F) (Meyer 1970), whereas green sunfish

have been reported to swim-up in two d posthatch at 21oC (70oF) and at 25oC (77oF).

Additionally, green sunfish fry typically have a

greater total length at hatching and swim-up than

other sunfish (Taubert 1977).

The first prey items for larval sunfish must be

small enough to fit into their mouth. Toetz (1966)

reported the mouth gape of larval bluegill at the

onset of exogenous feeding to be 230–270 μm

(0.009–0.011 in); hence the first prey items must

be smaller than this for sunfish larvae to

consume it.

If sunfish survive the critical stage in the wild

and begin feeding, their first food consists of small

zooplankton rotifers, early instar stages of

cladocerans and copepod nauplii.

Sunfish growth is rapid, and as mouth size

increases, they begin selecting

larger plankton prey, such as

cladocerans (Siefert 1972). As the

fish grow larger, they feed mainly

on aquatic insects, small crayfish,

and other small fish (Carlander

1977; Stickney 1985).

Larval Development

Larvae form identification is

essential to studies of food habits,

age, and growth of larvae (Meyer

1970). However, studies of larval

sunfish development have been

limited to specific species and

mainly address such meristic

features as: myomere counts

(muscle filaments), pigmentation,

and ray development (Meyer 1970;

Taubert 1977).

Morgan (1951) provides a detailed description

(with diagrams) of larval bluegill development.

Duwe (1952, 1955) describes the development

of the swim bladder in green sunfish and bluegill.

Childers (1967) described some larvae features

for all crosses between bluegill, green sunfish,

and redear sunfish, but these are limited to prehatching events (i.e., hatching percentages,

length at hatch). Smitherman and Hester (1962)

compared meristic characters of hybrid sunfish

to their parentals.

Dvorak (1997) made detailed observations of

larval hybrid sunfish development. In Table 2.1,

he describes the early development of the female

green sunfish x male bluegill (GxB)

hybrid larvae reared at a mean temperature of

21.5o

C (70.7oF).

Table 2.2 (end of this chapter) shows a

comparison of larval development for other

sunfish reported by additional researchers.1

Prior to hatching, the transparent embryo

encircles the yolk sac (Figure 2.1). A single oil

globule can be seen in the yolk sac. Additionally,

the optic capsule is developed but not pigmented.

Figure 2.1. Fertilized sunfish eggs just prior to hatching contain the fish

embryo, which encircles the yolk sac.
Sunfish Culture Guide 7 NCRAC Culture Series 102

Chapter 2 Spawning Behavior and Early Life History

The blood is clear and can be seen circulating

around the yolk and into the heart; the heart beats

rapidly. The embryo moves vigorously in a

shivering-like manner until the egg membrane

suddenly ruptures and the larvae are set free.

Post-hatch Times

Within 24 h of hatching, the eyes become

pigmented (Figure 2.2). A single, circular oil

globule is located posterior in the round yolk sac.

The intestine can be seen from the yolk sac to

the anus. Within 24 h, the notochord, myomeres,

and median finfold develop.

The G x B hybrid larvae are 4.2 mm (0.016 in.)

mean total length (TL) and very inactive at this

stage. The heart is clearly seen located in front

of the yolk sac.

Blood pigmentation is light pink and can be

seen moving throughout the body and around

the tail and anus.

2–3 days

Larvae are 4.5 mm (0.18 in.) TL by 2 d posthatch. The eyes and blood become more

darkly pigmented. The otolith is clearly seen,

the median finfold is still present, and pectoral

fins are visible. The larvae intestine has also

widened.

By 3 d, larvae are 4.9 mm (0.19 in) TL (Figure

2.3) and the medial finfold and yolk sac becomes

reduced. The yolk sac is more oblong and the

larval body is long and slender.

Up to this point, there is no pigmentation on the

larvae itself although there is blood pigmentation.

4–5 days

At 4 d post-hatch, the lower jaw begins to form

and the mouth of the larvae becomes indented;

however, it is not opened to the gut. Total length

at this stage is 5.3 mm (0.21 in.).

The pectoral fins get longer and start beating.

However, movement of the larvae is minimal due

to the weight of the remaining yolk sac.

Table 2.1. Developmental observations of GxB larvae reared to swim-up at 22oC (71oF)

listed by days post-hatch (dph).

d ) ph L s ength mm (in Observation

1 ) 4.2(0.16 Blood and eyes pigmenting; inactive; intestine seen from yolk sac to anus;

median finfold present; heart visible

2 ) 4.5 (0.18 Eyes and blood more darkly pigmented; pectorals develop; intestine

widens; larvae are more active

3 ) 4.9 (0.19 Pectorals continue developing; median finfold and yolk sac begin reducing;

yolk sac is more oblong

4 ) 5.3 (0.21 Lower jaw forming; mouths begin indenting; pectorals developing and

beating

5 ) 5.6 (0.22 Mouths begin opening weakly; pigmentation above yolk sac; tail becoming

more heterocercal and starting to beat

6 ) 5.9 (0.23

Pigmentation over yolk sac increasing; pectorals beating rapidly; yolk sac

almost gone but single oil globule remains; tail more heterocercal; anal fin

begins forming; some larvae have full undulatory movements

7 ) 6.1 (0.24 Gas bladder inflated; free swimming; mouth gape was 0.30 mm (0.01 in)
NCRAC Culture Series 102 Sunfish Culture Guide 8

Chapter 2 Spawning Behavior and Early Life History

Larvae measure 5.6 mm (0.22 in.) by 5 d.

Pigmentation above the yolk sac begins

developing. The pectorals continue getting longer

and the larvae beat them rapidly.

Their mouths begin to open weakly and their

tail starts to become heterocercal (i.e., develop

two unequal lobes) and to beat.

6–7 days

At 6 d post-hatch, larvae pigmentation above

the yolk sac increases. The pharyngeal arches

are observable and the pectorals are long and

beat rapidly. The larvae begins to move about.

The mean TL for the larvae at this stage is 5.9

mm (0.23 in.). The yolk sac almost disappears,

but the single oil globule remains (Figure 2.4).

The tail now becomes more heterocercal and

the anal fin begins forming. Some larvae have

full undulatory body movements.

Larvae inflate their gas bladders and swim

by 7 d. They have a mean TL of 6.1 mm (0.24 in.).

Their mouth gape is 0.30 mm (0.012 in.), which

is larger than the mouth gape of 0.23–0.27 mm

(0.009–0.011 in.) reported by Toetz (1966) for

larval bluegill at the free swimming stage.

Etnier (1971) reported that G x B hybrid juveniles

have larger mouths than parentals.

Intestine

Figure 2.3. Sunfish fry 3 d post-hatch have a reduced

yolk sac and begin to acquire a long and slender

body shape.

14 days

Figure 2.5 shows larvae at 14 d post-hatch.

The swim bladder is prominent, dark, and

circular. Notice that the median fin fold is still

present but greatly reduced.

Food can be seen in the stomach and intestine.

Additionally, pigmentation begins to develop on

the head and body.

28 days

By 28 d post-hatch, the

median fin fold is gone and

rays are developed in the

caudal fin of the GxB

larvae (Figure 2.6).

The larvae are still quite

transparent at this stage,

but rows of pigmentation

can be seen along the

body and in patches on

the head. Notice that the

swim bladder is still dark

and prominent at this Figure 2.2. Within 24 hours after hatching, the eyes of hybrid sunfish larvae become

pigmented and various other structures are clearly observable.

Eye

Heart Yolk Sac

Notocord

Oil

Globule

Myomere
Sunfish Culture Guide 9 NCRAC Culture Series 102

Chapter 2 Spawning Behavior and Early Life History

Figure 2.5. At 14 d post-hatch sunfish fry actively feed,

have a prominent swim bladder and are developing

pigmentation.

Figure 2.6. Sunfish fry 28 d post-hatch are still transparent,

but actively feed and swim.

stage.

Summary

Even though the various sunfish species

have similar spawning habits, there are

different morphological characteristics that act

as cues for species recognition.

Because sunfish have similar spawning

behavior, they are relatively easy to cross with

one another, thereby producing a wide variety

of hybrids. However, because of the

morphological differences of some species,

such steps as ear flap removal may need to

be taken to facilitate spawning.

Sunfish have a rapid early development from

spawning to swim-up relative to other species.

Most sunfish species hatch 2–6 d after spawning

and swim-up 2–7 d after hatching.

The mouth gape of sunfish is very small;

therefore, larvae require proportionately small

food particles at the critical stage when they

switch from endogenous to exogenous

feeding. If they are unable to take in the food,

they will not survive.

Notes

Figure 2.4. Hybrid sunfish fry by 6 d post-hatch have almost

entirely lost their yolk sac and begun to swim about.

Yolk Sac
NCRAC Culture Series 102 Sunfish Culture Guide 10

Chapter 2 Spawning Behavior and Early Life History

Table 2.2. Developmental observations made by other researchers on pure strain

bluegill, green sunfish and GxB hybrids listed by days post-hatch (dph).

B e luegill Larvae

d ) ph L s ength mm (in O r bservation Autho

0 ) 3 (0.1 Morgan 1951

0 ) 2-4(0.1-0.2 Taubert 1977

0 ) 3-4 (0.1-0.2

Alimentary canal; continuous finfold, pectoral fins, optic

vesicles and lens of eye present; heart beating; blood

red; single oil globule within yolk sac

Toetz 1966

0 ) 4-5 (0.2 Childers 1967

1 ) 3 n -4 (0.1-0.2 A 6 nus clearly ope Toetz 196

2 ) 4-6 (0.2 Alimentary canal open from above yolk sac to anus;

mouth not open but jaws present and move weakly

Toetz 1966

3 ) 5-6 (0.2

Mouth open; mouth gape 0.13 mm (0.005 in); jaw

moves weakly; swim bladder present; pectoral fins

beating

Toetz 1966

3 ) 5 p -6 (0.2 S 0 wim-u Meyer 197

3 ) 6 d (0.2 N 0 o chromatophores on top of hea Meyer 197

4 ) 4-5 (0.2

Alimentary canal open from pharynx to mouth; mouth

gape 0.20 mm (0.008 in); continuous finfold reducing,

except tail

Toetz 1966

~ ) 4 5 g (0.2 B 0 ecame free swimmin Meyer 197

5 ) 5-6 (0.2 Larvae free swimming; oil globule in anterior of yolk;

mouth gape 0.23 mm (0.009 in) Toetz 1966

6 ) 5-6 (0.2 Taubert 1977

6 ) 5-6 (0.2 Yolk almost gone; "pin heads" large head and narrow

trunk; pigment cells; mouth gape 0.24 mm (0.009 in) Toetz 1966

7 ) 5-6 (0.2

Yolk gone except for a tiny oil globule; pelvic fin

present; swim bladder black; mouth gape 0.27 mm

(0.011 in)

Toetz 1966

8 ) 5 (0.2 Morgan 1951

8 ) 5-6 (0.2 Tiny oil globule still present; swim bladder dark; lens of

eye orange; mouth gape 0.29 mm (0.011 in) Toetz 1966

9 ) 5-6 (0.2 Oil globule gone; swim bladder pigmented; mouth gape

0.33 mm (0.013 in) Toetz 1966
Sunfish Culture Guide 11 NCRAC Culture Series 102

Chapter 2 Spawning Behavior and Early Life History

Notes

Table 2.2 cont’d

G e reen Sunfish Larvae

0 ) 4 s (0.02 E 7 yes pigmented; pectoral fin bud Taubert 197

0 ) 5 (0.02 Childers 1967

6 ) 6 g (0.02 F 7 ree swimmin Taubert 197

9 ) 5 (0.02 Caudal rays developing; profuse spotting with small

concise chromatophores on top of head Meyer 1970

7 p (0.03) A 0 nal and dorsal rays started to develo Meyer 197

8 d (0.03) A 0 ll fin rays develope Meyer 197

F e emale Greenfish x Male Bluegill Hybrid Larvae

0 ) 3 ) (0.01 Weighed 0.15 mg (0.000005 oz

Mischke and

Morris 1998

0 ) 5 (0.02 Childers 1967
Culture Methods

Sunfish have not been cultured on a large scale,so there is limited information regarding the best

culture methods. Out of several different culture methods

evaluated, pond culture is the most popular method.

However, research continues to explore the best type of

sunfish and most effective culture method for aquaculture.

This chapter explains:

• Pond culture

• Cage culture

• Indoor larvel fish production

• Fry care and feeding

3

Sunfish Culture Guide NCRAC Culture Series 102

Culture Methods
NCRAC Culture Series 102 Sunfish Culture Guide 12

Chapter 3 Culture Methods

Culture Methods

Authors: C. C. Mischke, J. E. Morris, and R. L. Lane, Iowa State University.

Pond Culture

Most sunfish aquaculture production to date

has been extensive production of bluegill in small

ponds and lakes. Adult sunfish are stocked and

allowed to spawn naturally in ponds. Generally,

young are raised in the same ponds as the adults

(Stickney 1985).

Ponds for specific species

Ponds used for production of a specific sunfish

species must be carefully maintained to avoid

interbreeding with

other sunfish, a

common trait in this

family.

Water from surface

sources must be

filtered through

a sock-type filter

consisting of Saran

cloth to prevent the

introduction of

undesirable fish (ca.

300–μm opening).

Some aquaculturists

prefer to use ponds

with a maximum depth

of 0.9–1.5 m (3–5 ft), however, keeping some

shallow areas at least 0.3 m

(1 ft) in depth (Higgenbotham et al. 1983).

Water temperature

Brood fish are stocked before water

temperatures reach 21°C (69.8°F). According to

McLarney (1987), adult sunfish should be

stocked in the winter at a rate of 250/ha

(100/acre). A stocking rate of 100 pairs/ha

(40 pairs/acre) has also been suggested (Dupree

and Huner 1984; Engelhardt 1985). Stocking 2

yr old fish at a ratio of one male to one female

has been successful (Dupree and Huner 1984;

Stickney 1985).

Food requirements

When culturists use good

pond culture techniques,

sunfish fry are able to obtain

their food requirements from the

natural production in the pond

(e.g., insects and zooplankton).

Brood fish, on the other hand,

should be fed with a

supplemental pellet feed from

diameter (Dupree and Huner

1984).

A definite protein requirement

has not been set for sunfish;

however, it is assumed that

protein estimates of sunfish

brood stock fall between

rainbow trout and channel catfish.

Often in pond sunfish grow-out, producers

depend on such natural organisms as

zooplankton and benthic organisms, for the main

food source (Figure 3.1).

3

Ø Filter surface water

Ø Varying water depth

Brood Fish Stocking

Considerations

Ø Winter stocking

Ø Supplement diets

3.2 to 6.2 mm (1/8 to 1/4 in.) in
Sunfish Culture Guide 13 NCRAC Culture Series 102

Chapter 3 Culture Methods

However, these natural food sources can

become quickly depleted at high fish densities.

Producers should consider using supplemental

diets to enhance growth in any high-density

sunfish pond production.

 Using higher protein feeds (>35% ) may

improve growth and production potential of

hybrid sunfish (green sunfish female x bluegill

male)Tidwell et al. (1992). The NCRAC (1998)

is in the process of determining dietary

requirements for grow-out of bluegill and hybrid

sunfish. The dietary phosphorus requirement of

hybrid sunfish (GxB) is < 0.5% of the dry diet.

Also, both bluegill and GxB hybrids grow best

when fed diets containing at least 10% dietary

lipid in the form of fish oil.

Work with hybrids in recirculating systems and

in ponds suggests that when the formulated diet

supplies virtually all the nutrition, optimum crude

protein levels are >40%.

However, when fish are grown in ponds and

natural food is available, a dietary crude protein

level of 36% is considered adequate for

maximum mean harvest weight.

Food conversion ratio

Specific growth rates (SGR) and food

conversion ratios (FCR) are commonly used in

aquaculture to express growth and feed

conversion, respectively. When fish growth rates

are exponential, as typically occurs

over short intervals of time, instantaneous rates

should be used to express growth (Busacker et

al. 1990).

SGR (%/d) = (ln Wt – ln Wi

)/T) X 100.

Where: Wf = mean weight at the end of the

period

Wi = mean weight at the

beginning of the period

T = time in days of the period

The working formula is expressed as:

FCR = [weight of feed fed (g)/live weight

gain (g)].

The inverse function of this equation is referred

to as feed efficiency.

SGR and FCR measurement studies

To date, the majority of sunfish studies

involving measurements of SGR and FCR have

dealt exclusively with hybrids.1

 Tidwell et al.

(1992) and Webster et al. (1992) reported SGR

values of 1.98 and 2.6, respectively. Both studies

used small fish (3–5 g).

Webster et al. (1997) reported lower SGR

values for larger fish ( >20 g). An SGR value of

0.37 was reported for large fish stocked in ponds

for the summer growing season (Tidwell et al.

1994). The SGR values for sunfish should

increase with genetic modification and enhanced

culture methods.

Webster et al. (1992) reported FCR values of

3.72 and 3.87 at 32 and 38% crude protein,

respectively, using smaller fish (3–4 g). Webster

et al. (1997) reported slightly higher FCR values

for larger fish ( >20 g). High FCR values were

reported for large fish stocked in ponds for the

summer growing season (Tidwell et al. 1994). Figure 3.1. The typical method of sunfish production has

been by use of small ponds.
NCRAC Culture Series 102 Sunfish Culture Guide 14

Chapter 3 Culture Methods

Stocking rate

NCRAC (1998) suggested the stocking rate

for grow-out of hybrid sunfish is 12,355–17,279

fish/ha (5,000–7,000 fish/acre). The accepted

food size for sunfish is 227–340 g (1

/2 – 3/4 lb).

Sunfish generally require more than 2 years

to reach this size.

Only one stocking rate is given for pond growout. The best results occur when the first year

stocking density is relatively high and then

reduced to a much lower second year density

for final grow-out.

Cage Culture2

In areas where regular pond culture is not

practical, cage culture (Figure 3.2) may be a

viable option. Irregularly shaped ponds,

quarry pits, or other bodies of water that

cannot be seined easily are all possible

areas that may be conducive to cage culture.

According to Morris and Edwards (1991),

sunfish must meet these desired species

characteristics for cage culture:

Ø Fast growth

Ø Tolerance of crowded conditions

Ø Good growth in regional environments

Ø Native to region

Ø Market value

Cage culture advantages

There are certain advantages to cage culture.

One of the most important is that many types of

water resources can be used that would not

otherwise be practical for fish production.

Fish harvesting and management are also

greatly simplified. Cage culture requires a

relatively low initial investment and allows the

continued use of the pond for sport fishing or

culture of other species (Masser 1988; Morris

and Edwards 1991).

Cage culture also eliminates unwanted fish

reproduction. Sunfish cannot spawn in cages

that are suspended off the bottom. Therefore,

more uniform fish size and more accurate

inventories are possible.

When fish are grown in cages, they are able

to use some of the pond’s natural productivity,

but not as much as free-roaming fish.

Therefore, the protein requirement for cage

cultured sunfish is between that of pond cultured

fish and fish cultured in recirculating systems.

Stocking rates

Stock fingerling sunfish at 10 cm (4 in.) or larger

and grade for uniformity in size.

Ø 500 sunfish fingerlings can be stocked in a

0.12 X 0.12 X 0.12 m (4 X 4 X 4 ft) square

cage.

Ø 2000 sunfish can be stocked in a 0.24 X

0.24 X 0.12 m (8 X 8 X 4 ft) cage

(Masser 1988).

Ø 200 fish/m3

 (6 fish/ ft3) can be cage

stocked (NCRAC 1998).

The best results usually occur when first year

stocking densities are reduced for the second

year final grow-out.

Figure 3.2 Cage culture is used well in a

variety of ponds.
Sunfish Culture Guide 15 NCRAC Culture Series 102

Chapter 3 Culture Methods

Indoor Larval Fish Culture

Although previous sunfish

production has been mostly extensive

in ponds, there has been success in

obtaining fry through some intensive

laboratory culture methods.

Regardless of where sunfish brood

stocks are held (ponds, cages, or

tanks), their gametes can be stripped

and fertilized in the hatchery.

Childers and Bennett (1961) hand

spawned mature gametes from fish

into petri dishes. Eggs were stripped

from one or more mature females into

damp petri dishes followed by

stripping milt from one or more males

onto the eggs (Figure 3.3).

After mixing milt and eggs, water was added,

and a 2 min interval allowed for fertilization to

take place.

Fertilized eggs were then carefully

placed into clean petri dishes containing aged

tap water and allowed to water harden. Next,

the petri dishes of fertilized eggs were rinsed

with water and placed in aerated aquaria.

Childers and Bennett reported that fertilization

occurred with several thousand eggs from

various intergeneric crosses (i.e., crosses of

different species of sunfish; hybrids). No hatching

rates were given.

Toetz (1966) conducted intensive studies on

the larval rearing of bluegill. 3 To acquire

gametes, he captured wild bluegill and hand

spawned the eggs into petri dishes. The testes

of the males were extracted and cut up in a watch

glass. Water was added, and the suspension

then added to the eggs.

Toetz (1966) reported as high as 79% hatch

when mature eggs were taken from the

posterior-medial portion of the ovaries.

Temperature and photoperiod

Childers and Bennett (1961) successfully

induced bluegill and their hybrids to produce

gametes through manipulation of temperature

and photoperiod. Banner and Hyatt (1975)

induced bluegill to spawn by manipulating the

temperature and photoperiod and by presenting

conspecifics (males and females of the same

species).

Bluegill exposed to a 16 h light: 8 h dark

photoperiod at 25°C (77°F) released gametes

when stripped.

Figure 3.3. One method of reproducing sunfish in the laboratory is to

hand-spawn mature gametes from the sunfish into petri dishes.

Recirculating systems are gaining popularity for fish

production in areas where water resources are limited.
NCRAC Culture Series 102 Sunfish Culture Guide 16

Chapter 3 Culture Methods

The presence of male bluegill greatly increased

female ovarian development. Also, nest digging

activities increased when a sharp fluctuation in

temperature interrupted ambient conditions

appropriate for spawning.

Other experiments have been successful in

artificially reproducing sunfish using similar

methods (Smitherman and Hester 1962;

Merriner 1971; Smith 1975).

Bryan et al. (1994) manipulated temperature

and photoperiod and introduced artificial

spawning nests to induce courtship and

spawning of bluegill in the laboratory. After

spawning, males were allowed to defend the

nests for 12 h. Nests were then removed and

placed into 38-L (10 gal) flow-through aquaria.

At 26°C (79°F), eggs hatched in 36 h.

Larval sunfish were transferred to rearing

chambers at 3 d post-hatch and fed Artificial

Plankton Microcapsules® (Argent Chemical

Laboratories, Redmond, Washington). At 9 d

post-hatch, brine shrimp was fed 3 times daily.

However, no survival rates were given.

Mischke and Morris (1997) developed a

protocol for handling brood stock and out-ofseason spawning for intensive culture of sunfish.

They induced natural spawning of adult bluegill

in the laboratory through the manipulation of

temperature and photoperiod (Figure 3.4).

Brood fish spawned multiple times on artificial

nests (Figure 3.5). After spawning, the nests

were transferred to a hatching tank and the eggs

were allowed to hatch. Once hatched, larval fish

were removed from the nests and transferred to

aquaria for swim-up (Figure 3.6).

Larval sunfish require brine shrimp for an initial

period before offering commercial diets.

Increased growth rates and fry survival occurred

when brine shrimp were fed for longer periods.

Fry Care and Feeding 

If sunfish fry are held in aquaria while they

absorb their yolk sacs, they should be siphoned

from the aquaria before they

reach swim-up. Bluegill larvae reach swim-up

at 7 d post-hatch, so they should be siphoned

from the aquaria just before this time

(Mischke 1995).

Larvae may then be transferred to rearing

chambers or tanks held at 25°C (77°F), the

preferred growth temperature of larval bluegill

(Beitinger and Magnuson 1979; Bryan et al.

1994), and offered feed.

Figure 3.5. Artificial nests are used for out-of-season

spawning of sunfish in indoor tanks.

Figure 3.4. Out-of-season spawning of bluegill brood stock

can be successful in indoor tanks.
Sunfish Culture Guide 17 NCRAC Culture Series 102

Chapter 3 Culture Methods

The critical stage in larvae sunfish development

is from 4–9 d after hatching, since they switch

from endogenous (energy derived internally from

the yolk sac) to exogenous (external) feeding

(Toetz 1966; Smith 1976).

During this critical stage, nutrients from the yolk

sac are utilized and the sunfish’s mouth opens.

The larval fish will starve if they do not begin

feeding at this stage (Figure 3.6).

Food size

Proper feed for larval sunfish must be small

enough that the fish can physically handle it.

Toetz (1966) reported the mouth gape of larval

bluegill at the onset of exogenous feeding to be

230–270 μm (0.009–0.011 in.). First food items

must be smaller than this for sunfish to consume

it.

The mouth gapes of redear sunfish and

pumpkinseeds are very close to that of the

bluegill. The mouth gapes of warmouth, green

sunfish, and longear are larger.

Sunfish that survive the critical stage in the wild

will begin feeding. Their first food consists of

small plankton, including rotifers and copepod

nauplii (Figure 3.7). Growth is rapid and as the

mouth size increases they begin selecting larger

prey items (Siefert 1972).

Commercial feed

When intensively culturing sunfish fry, a

commercial feed <250 μm (0.01 in.) should be

used as the first feed, and progressively larger

feeds offered as the sunfish grow. When

changing to larger feed sizes, mix the larger feed

with the smaller sized feed for a couple of

feedings to allow the fish to adapt to the larger

feed size.

Bryan et al. (1994) transferred larval sunfish to

rearing chambers at 3 d post-hatch and fed

Artificial Plankton Microcapsules® (Argent

Chemical Laboratories, Redmond, Washington).

At 9 d post-hatch, brine shrimp were fed to the

fish 3 times daily. No survival rates were given.

Mischke and Morris (1998) transferred larval

bluegill to rearing chambers at 7d post-hatch and

conducted several feeding studies. They found

that larval bluegill would not digest commercial

feeds at the onset of exogenous feeding.

However, feeding brine shrimp nauplii (newly

hatched brine shrimp) (Figure 3.8) for 14 d and

then weaning larvae to Fry Feed Kyowa® B250 (Biokyowa, Incorporated, Tokyo, Japan)

increased survival rates to approximately 43%.

Comparisons

If sufficient land or water resources are not

available, a recirculating system may be a

Figure 3.6. Aquaria like these are used to hold the sunfish

fry until they absorb their yolk sacs and are able to accept

such feeds as brine shrimp.

Figure 3.7. Larval bluegill begin feeding at 7 d post-hatch

and must have adequate food supplies of the right size at

this stage or the fish will starve.
NCRAC Culture Series 102 Sunfish Culture Guide 18

Chapter 3 Culture Methods

viable means of sunfish grow-out.

Recirculating systems usually use tanks for

production; therefore, much less land is

required than for pond culture.

Also, recirculating systems use a fraction of

the water that would be needed for pond

culture. Through reuse and treatment of water,

recirculating systems use <10% of the water

required by ponds to produce similar yields

(Losordo et al. 1992).

There are, however, higher fixed costs

associated with recirculating systems than with

pond production systems (e.g., pumping costs

and oxygenation). Recirculating systems

require a higher level of management than

pond production systems.

Unlike pond production, a truly complete diet

is required for sunfish in recirculating systems.

Crude protein levels required for recirculating

are estimated to be > 40% (NCRAC 1998).

Stocking densities for sunfish grow-out in

recirculating systems have not been

adequately determined at this time.

Summary

Even though pond culture is the most common

culture method for sunfish (both for spawning

and grow-out), there are many culture methods

available. Sunfish may be suitable for growout in cages and recirculating systems. There

are also encouraging results of intensive, outFigure 3.8. Culturing brine shrimp to feed to first-feeding

sunfish can increase survival rates.

of-season spawning techniques for sunfish in

the laboratory.

A combination of these methods may be

desirable; for example, use out-of-season

spawning in a recirculation system and then

grow-out in cages or ponds.

Individuals should choose culture methods most

suited to production needs and geographic area.

Land, labor, and capital restraints must also be

considered.

Very specific requirements for feeding and

stocking for first and second year grow-out are

not yet available, but the general values given

here can be used as a starting point and refined

for individual requirements.

Notes
Brood Stock Management

Careful sunfish brood stock management is essentialto ensure quality of stock and the highest level of

reproduction. The purity of a particular brood stock species

begins with careful selection and identification of the fish,

depth and filtration of ponds, and amount and size of feed

provided. Research into hormone use may reveal ways to

maintain desired production levels.

This chapter explains:

• Field collection methods

• Species and sex determination

• Pond management

• Hormone research

4

Sunfish Culture Guide NCRAC Culture Series 102

Brood Stock Management
NCRAC Culture Series 102 Sunfish Culture Guide 19

Chapter 4 Brood Stock Management

Brood Stock Management

Authors: C. C. Mischke and J. E. Morris, Iowa State University

Field Collection Methods

The type of field method used to collect

species depends on the individual and the

collection purpose. Each type, however,

requires the proper equipment and diligence.

There are three major collection types:

Ø Electro fishing

Ø Trap nets

Ø Seine nets

Nets

Sunfish brood stock collected using electro

fishing equipment, trap nets, seine nets (Figure

4.1) or other types of nets, require proper

permits that are acquired from natural

resource agency personnel.

It is important to make certain the proper

steps are taken and any permits necessary

are acquired.

Anesthetize net-captured fish immediately in 19

L (5 gal) of water with 1.5 g (0.05 oz; 80 ppm) of

Finquel® (Argent Chemical Laboratories,

Redmond, Washington).

Electro fishing

Place fish captured by electro fishing in fresh

water and allow them to recover from the stress

of electro fishing for approximately 1/2 h before

anesthetizing.

After capture, brood stock can be stripped of

gametes (eggs and milt) and either released or

kept for future brood stock. Keep in mind that if

Finquel® is used, there is a 21-d withdrawal time

for bluegill >7.6cm (3 in.) in length.

Egg and sperm collection

When fish are stripped of gametes on site,

remove the fish from the anesthetic and dry the

urogenital pore with a soft cloth to prevent the

anesthetic from interfering with fertilization.

Then strip the eggs from ripe females into a

damp glass petri dish by applying gentle pressure

on the abdomen. Immediately fertilize the eggs

by stripping the milt from one or more males

directly onto the eggs.

After stripping the eggs and milt:

Ø Return the fish to the pond.

Ø Swirl petri dish vigorously to mix gametes.

4

Figure 4.1. Seining is one possible method of sunfish

brood stock acquisition if proper permits are obtained.
Chapter 4 Brood Stock Management

Sunfish Culture Guide 20 NCRAC Culture Series 102

Ø Wait 2 min to allow fertilization to take

place (Childers and Bennett 1961).

Ø Pour the fertilized eggs (in lots of 200–

300) into clean glass petri dishes filled

with aged tap water.

Ø Allow approximately 15 min for the eggs

to water harden.

Once the eggs water harden:

Ø Wash the fertilized eggs by lowering

and raising the petri dishes 4–5 times

in a large beaker of dechlorinated tap

water.

Ø Place petri dishes in aquaria with gentle

aeration after washing, or

Ø Add enough water to each petri dish to cover

the fertilized eggs, and

Ø Replace the water approximately 6 times

each day during incubation.

Transportation

If the adult sunfish are kept for future brood

stock, take care in their transport and

acclimation to their new environment.

Fish should be transported in water with

plenty of oxygen and 1% NaCl (uniodized salt)

to reduce osmoregulatory (physiological

regulation of internal water/solute

concentration) stress.

Once fish arrive at the holding facilities, they

must be acclimated to the different water

chemistry and temperature. Do this by slowly

exchanging hauling water with system water.

Species and Sex Determinations

It is very important to identify different sunfish

species, especially when trying to produce

hybrids. Table 4.1 contains characteristics of the

most common sunfish.

Identification of hybrid sunfish can be difficult

because hybridization results in fish with multiple

species characteristics. Pflieger (1975) and

Tomelleri and Eberle (1990) provide keys,

description, and illustrations for more specific

identification of sunfish species.1

Physical identification

Identifying the brood stock sex is critical when

producing any hybrid to ensure stocking proper

male to female ratios.

The ease of sexing brood fish is a function of

the time of year. As with most fish, the sunfish

are more easily sexed during the breeding

season.

As the spawning period nears, the males take

on distinctive, brilliant spawning colors, and

milt is usually easy to express from the vent

(Dupree and Huner 1984).

Females have a much fuller and rounder

abdomen than males during the breeding

season (Figure 4.2).

A mature male bluegill’s urogenital opening

usually terminates in a small, funnel-shaped

pore (McComish 1968). The area around the

opening tends to be darkly pigmented. These

features help to identify male from female.

Figure 4.2. Observations of the urogenital openings

of adult sunfish can help to determine the sex of

the fish.
NCRAC Culture Series 102 Sunfish Culture Guide 21

Chapter 4 Brood Stock Management

According to Brauhn (1972), male bluegill

characteristics include:

Ø Square, heavily pigmented opercula lobe

Ø Black pigmented gular area

Ø General dark cast to the body

Ø Definitive spot at the posterior base of

dorsal fin

The female’s urogenital opening resembles a

small, swollen doughnut-like ring, probably the

result of a slight eversion of the urogenital tract

(McComish 1968).

According to Brauhn (1972), other female

characteristics include:

Ø Rounded, less pigmented opercula lobe

Ø Yellow pigmented gular area

Ø General light appearance to the body

Ø Reduced spot at the posterior base of

dorsal fin.

Extraction identification

Another method of sexing brood fish is probing

for eggs (extraction identification). First, use

Table 4.1. Key to sunfish identification. (Adapted from Pflieger 1975)

W htuomraW htuomraW htuomra G neer

S hsifnuS hsifnuS hsifnu

R r aedeR r

S hsifnuS hsifnuS hsifnu

P - nikpmuP -nikpmuP -nikpmu

s dee

L r aegnoL raegnoL raegno

S hsifnuS hsifnuS hsifnu B lligeulB lligeulB lligeul

S seicepS seicepS seicep Lepomis

gulosus

Lepomis

cyanellus

Lepomis

microlophus

Lepomis

gibbosus

Lepomis

megalotis

Lepomis

macrochirus

R htuoMevitaleR htuoMevitaleR htuoMevitale

S ezi L e egra L l gra S l lam S e lam M l taredo lamS

P niFlarotceP niFlarotceP niFlarotce S d dnuor,troh L d etniop,gno L d etniop,gno S d nuor,troh etniop,gnoL

G srekaRlliG srekaRlliG srekaRlli L t rednels,gno S t uots,troh S k uots,troh S r ciht,troh ednels,gnoL

R f onigraMraeR fonigraMraeR fonigraMrae

B lliGynoB lliGynoB lliGyno

C e r voC e r

,draH

elbixelfni elbixelf,nihT ,kcihTelbixelfni T e elbixelfni,nih lbixelf,nihT

E palFraE palFraE palFra

deppiT

thgirbhtiw

nider

gnideerb

selam

htiwkcalB

hsitihw

nigramwolley

htiwkcalB

redrobhsitihw

tnenimorpdna

der/egnaro

tops

reveN

,degnolorp

deroloc-thgil

redrob

ylbaredisnoC

detagnole kcalbyleritnE

B eziSdnakcaB eziSdnakcaB eziSdnakca

C noitaroloC noitaroloC noitarolo

-evilohciR

htiwnworb

suoremun

nworbkrad

sgnilttom

neerg-hsiulB

dlaremehtiw

wolleydna

snoitcelfer

ronedloG

evilo-thgil

neerg

ronedloG

evilo-thgil

neerg

neerg-eulB

htiwdelkceps

dnawolley

dlareme

-evilokraD

htiwneerg

dnadlareme

yssarb

snoitcelfer

B ylle

C noitaroloC noitaroloC noitarolo

thgiL

wolley

wolleyelaP

etihwro

otwolleY

wolley-egnaro

otwolleY

wolley-egnaro

otwolleY

egnaro

hsiddeR

egnaro

O r eht

C scitsiretcarahC scitsiretcarahC scitsiretcarah

nisirideR

hctap,eye

nohteetfo

eugnot

eulbyvaW

nosenil

keehc

Distinct b al ck

b ol tc ih n

oesab f os ft

od rsal fin
Chapter 4 Brood Stock Management

Sunfish Culture Guide 22 NCRAC Culture Series 102

gentle pressure on the abdomen, palpating

from the middle of the abdomen back to the

vent.

The fish is a male if milt (white liquid) is

expelled from the urogenital opening. If no milt

appears, the fish is probably a female; check

with a capillary tube to be certain.

A 1.1–1.2 mm (0.043–0.047 in.) wide

capillary tube 5–10 cm (2–4 in.) in length

should be used (Figure 4.3). Hold the fish

upside down and gently insert the capillary

tube through the urogenital opening.

Once the capillary tube is inserted:

Ø Angle it back towards the tail and slightly to

one side.

Ø Gently insert the tube through the oviduct

and into the ovary.

Ø Use gentle force and slightly twirl the tube

back and forth to help insertion.

Ø When the tube is inserted, place a finger

over the end of the tube and remove it.

If eggs are seen in the tube, the fish is a female.

If no eggs are present and no milt was seen from

palpation of the abdomen, then a certain sex

determination cannot be made, and the fish

should not be used.

Pond Management

Because interbreeding is common in this fish

family, it is important in sunfish brood stock

management to not hold brood fish in ponds

that are contaminated with other sunfish.

Therefore, ground water should be used for

filling sunfish ponds; or, if surface water is

used, it should be filtered to prevent

introduction of undesirable fish.

Filtration and depth

A common and simple method of filtration of

surface waters is the use of a Saran® or nylon

sock filter. The filter material should have

approximately the same size mesh as

mosquito netting to prevent admission of larval

fish into the pond. Due to the small mesh size,

daily to weekly cleaning is required (McLarney

1987). Also, before filling and stocking brood

fish ponds, ponds should be dried thoroughly

and all depressions treated with an appropriate

fish toxicant.

The preferred depth of brood fish ponds is from

0.9–1.5 m (3–5 ft) with some shallow areas 0.3

Male and female green sunfish. The male often

appears smaller. The female shows the typical

swollen, doughnut like ring.

Figure 4.3. Insertion of a capillary tube into the sunfish

urogenital opening is the most reliable method for sexing

adult fish.

Capillary Tube
NCRAC Culture Series 102 Sunfish Culture Guide 23

Chapter 4 Brood Stock Management

m (1 ft) in depth (Higgenbotham

et al. 1983). Fish should be

stocked at a rate of 100 pairs/

ha (40 pairs/ acre) and a ratio

of one male to one female

(Dupree and Huner 1984;

Engelhardt 1985; Stickney

1985).

Food size and amount

It is important for brood stock

to be in good physical condition

for maximum spawning success. High quality

dry feeds should be fed several times daily.

When >225 kg/ha (200 lbs/acre) standing

crop is maintained, brood fish should be

offered a pellet feed 3.2–6.2 mm (1/8–1/4

in.) in diameter to supplement available

natural feed, according to Dupree and Huner

(1984). A floating feed is preferred to a

sinking feed because floating feed allows the

producer to observe fish on a regular basis.

The amount of feed depends on the water

temperature. When temperatures are above

21°C (70°F), feed brood stock 5–7 times per

week at a rate of 3% of the standing crop.

At temperatures from 13–21°C (55–70°F),

feed the brood stock on alternate days at a

rate of 1–2% of the standing crop; and when

water temperatures are <13°C (55°F) do not

feed the brood stock (Dupree and Huner

1984).

Hormonal Injections

The use of hormones , pending INAD approval,

could also be useful for induction of sunfish

spawning. A small amount of research has been

done in this area; however, its priority may

increase in the future.

The United States Food and Drug

Administration (USFDA) has recently approved

Chorulon®, an HCG product, as a new animal drug

for male and female brood fish under the direction

of a licensed veterinarian (NCRAC 1999).

Neal (1961) injected bluegill with combinations

of human chorionic gonadotropin (HCG) and

mammalian follicle stimulating

hormone (FSH). Results

showed that FSH alone did

not increase gonadal weight,

but gonadal weight did

increase using a FSH-HCG

combination.

Additional findings

Other research on sunfish

should be applicable to bluegill.

Sneed and Dupree (1961)

injected gravid green sunfish

with a thyroid-stimulating hormone (TSH), HCG,

and acetone-dried buffalo pituitaries.

Three injections of 225 international units (IU)

of HCG combined with 2, 3, and 5 units of TSH

per pound of body weight resulted in the ovulation

of the fish. However, it was found that HCG or

pituitary extract alone would not cause ovulation.

Leutinizing hormone-releasing hormone (LHRH) in other fish has been used at the rate of 0.1

mg/kg (0.0000015 oz/lb) of fish body weight

(Argent Chemical 1975), but a specific amount

for bluegill was not given.

The hormone was injected into the

intermuscular tissue, but the hormone alone did

not cause the fish to reproduce. The careful

combination of photoperiod, water, temperature,

and proper nutrition was also required.2

Mischke et al. (2001) noted success in

spawning both bluegill and hybrid sunfish using

HCG hormone Chorulon

approved for male and

female brood fish!

Floating feed allows the

producer to observe fish

on a regular basis.
Chapter 4 Brood Stock Management

Sunfish Culture Guide 24 NCRAC Culture Series 102

both a combination of water temperature

and photoperiod.

Summary

Because sunfish species are so similar, the

species and sex of the fish is extremely important

when managing brood stock of sunfish. Sunfish

species can be determined using various keys.

Sex of sunfish is best determined during the

spawning season by probing with capillary

tubes. In general, sunfish do spawn

quite readily; however, there has been research

on hormonal injection to facilitate gamete

production.

Notes
Hybridization

Hybridization is increasingly recognized as aviable part of fish management and aquaculture

production. Fertility considerations, growth rates, and

and use in pond management.

This chapter explains:

• Hybrid importance

• Historical hybrid research

• Hybrid production methods

 5

Sunfish Culture Guide NCRAC Culture Series 102

Hybridization

vigor give hybrids a potential advantage as a food fish
Chapter 5 Hybridization

NCRAC Culture Series 102 Sunfish Culture Guide 25

Hybridization

Authors: C. C. Mischke, G. D. Dvorak, and J. E. Morris, Iowa State University

Hybrid Importance

Hybrids are increasingly recognized as

important to overall fish management.

Centrarchid sunfish hybrids (Figure 5.1) show

potential for aquaculture and fishery

management because:

Ø Sunfish are extremely fecund, each female

producing an average of 80,000 eggs/year

in several successive spawns (Carlander

1977).

Ø Sunfish communities can become

overpopulated and stunted quickly.

Many hybrid sunfish are used to control

population through:

Ø Their reduced reproductive potential.

¡ The result of skewed sex ratios

¡ Predominately males

Ø Their abnormal reproductive behavior.

¡ (Krumholz 1949; Childers and

Bennett 1961; Heidinger and Lewis

1972; Lewis and Heidinger 1971).

Hybrid sunfish also exhibit:

Ø Hybrid vigor with improved growth.

¡ (Childers 1967; Kurzawski and

Heidinger 1982; Brunson and

Robinette 1983; Engelhardt 1985)

Ø High acceptance of artificial feeds.

¡ Lewis and Heidinger 1971; Brunson

and Robinette 1983; Tidwell et al.

1992)

Ø Greater tolerance to cooler water and

poor environmental conditions.

¡ Heidinger 1975; Brunson and

Robinette 1983)

Ø High vulnerability to angling.

¡ (Kurzawski and Heidinger 1982;

Engelhardt 1985; Brunson and

Robinette 1986).

These characteristics make hybrid sunfish

good candidates for aquaculture, especially in

the Midwest.

Figure 5.1. Common sunfish hybrids include

the various crosses between bluegill (top) and

green sunfish (bottom).

5
Chapter 5 Hybridization

Sunfish Culture Guide 26 NCRAC Culture Series 102

Historical Hybrid Research

The earliest research on

stocking hybrid sunfish for

population control was done by

Ricker (1945). He found female

redear sunfish x male bluegill (RxB) resulted

in only 2% females, good growth rates, and

excellent stocking in small ponds.

Krumholz (1949) also observed that in small

ponds stocked with hybrid sunfish, RxB hybrids

exhibited faster growth and were relatively

heavier for their length when compared to

parental stocks.

Childers and Bennett (1961) completed

crosses between bluegill, redear sunfish, and

green sunfish. They found:

Ø Female bluegill x male

green sunfish (BxG)

produced significant

numbers of F1 offspring

naturally.

Ø Female green sunfish x

male redear sunfish

(GxR) will produce

significant numbers of F1

offspring naturally.

Ø Only female redear

sunfish x male green

sunfish (RxG) F1

 hybrids exhibited a 50:50

sex ratio.

Ø All others had >70% males.

They found female green sunfish x male bluegill

(GxB), RxB, and the female bluegill x male redear

sunfish (BxR) F1

 hybrids did not reproduce.

Heidinger (1975) investigated the growth of

hybrid sunfish (GxB) at low temperatures [<15°C

(59°F)] when stocked with channel catfish. He

found that, in all cases, hybrid sunfish gained

weight while channel catfish lost weight.

Heidinger concluded, on the basis of temperature

requirements, hybrid sunfish are better adapted

for colder climates than channel catfish.

In Mississippi, Brunson and Robinette (1983)

looked at hybrid sunfish growth at low

temperatures for 112 d with an average

temperature of 10.4°C (50.7°F). They compared

winter growth of young-of-the-year bluegill to

that of the GxB hybrid. They found that hybrids

had increased weight and length compared to

bluegill; they also outgrew bluegill by a ratio

of approximately 2:1.

Intermediate characteristics

The intermediate nature of hybrids has

been reported in several studies. Etnier

(1971) collected female green sunfish x male

pumpkinseed hybrids and GxB hybrids and

their parental species from three lakes in

north-central Minnesota. He found that both

hybrids had larger mouths and larger food

organisms in their stomach than either the

bluegill or pumpkinseed,

but not green sunfish.

Green sunfish have larger

mouths than either bluegill or

pumpkinseed. The female

pumpkinseed x male bluegill

hybrid was found to be

intermediate in many meristic

measurements, including their

pharyngeal arches and teeth

(Heckman 1969). Smitherman

and Hester (1962) found

intermediate characteristics of hybrids between

all crosses of bluegill, redear sunfish, and the

redbreast sunfish.

Reproduction findings

Increased growth rate is primarily attributed

to the reduced fertility of hybrids, which also

helps to eliminate the overpopulation

frequently associated with sunfish populations

(Krumholz 1949; Childers 1967). With less

energy diverted to reproduction, more energy

can then be used for growth.

Hybrid sunfish

production

began in 1945.
Chapter 5 Hybridization

NCRAC Culture Series 102 Sunfish Culture Guide 27

Some F1 hybrids were fertile (Ricker 1945;

Laarman 1979), but they typically showed low

fecundity and highly skewed sex ratios, which

limits their reproductive potential. The fecundity

of bluegill females was reported to be 280

times greater than GxB F1

 hybrid females

(Laarman 1979).

Some hybrids were reproductively isolated

from their parental species. Brunson and

Robinette (1987) attempted to backcross F1

GxB hybrids with females of each parental

species in both ponds and the laboratory but

were unsuccessful.

In the lab experiment, fertilization was

accomplished, but the embryos failed to

survive. They concluded that gametes of the

hybrids might not have been compatible with

parental gametes.

Hybrid Production Methods

There are two methods used to produce hybrid

sunfish: stripping and fertilizing eggs in the

hatchery (Figure 5.2) or stocking parent

species and allowing them to spawn, usually

in ponds.

Method 1

Childers and Bennett (1961) and Smitherman

and Hester (1962) described this laboratory

method for stripping and fertilizing eggs:

Ø Select females of the desired sunfish

species containing mature gametes.

Ø Hand spawn them into damp, glass petri

dishes. Note:

¡ Petri dishes must be glass in order

for this technique to work properly.

¡ Fish are considered to contain

mature gametes if their eggs or milt

are easily extruded using gentle

pressure on the abdomen.

Ø Dip the petri dishes into clean,

de-chlorinated water.

Ø Shake vigorously to remove excess water.

Ø Hold females with their vents over the petri

dishes and strip by gentle stroking motions

with the fingers on either side of the

abdomen toward the vent.

Ø After eggs are stripped into the petri

dishes, strip milt from one or more males

onto the eggs using the same stroking

motions used for stripping the eggs.

When milt and eggs are stripped:

Ø Mix by vigorously swirling the petri dish.

Ø After mixing, add de-chlorinated water.

Ø Allow 2 min for fertilization to occur.

Ø Place the fertilized eggs into clean glass

petri dishes containing aged tap water, and

Ø Allow the eggs to become water hardened

(ca. 15 min).

Ø Wash the eggs by raising and lowering the

petri dish several times in a container of

aged tap water. Note:

¡ Fertilized eggs adhere to the petri

dishes.

¡ Non-fertilized eggs will not.

Ø Place the petri dishes of fertilized eggs into

aerated aquaria.

Hatch time

Eggs should hatch from 41–46 h after

fertilization, depending on the photoperiod and

temperature. As the amount of light and

temperature are increased, hatching time is

decreased (Toetz 1966).

Figure 5.2. Stripping and fertilizing eggs in the laboratory is

a common method of hybrid sunfish production.
Chapter 5 Hybridization

Sunfish Culture Guide 28 NCRAC Culture Series 102

Method 2

The second method of producing hybrid

sunfish is to stock parent species in empty

ponds. To prevent contamination with

undesirable sunfish:

Ø Dry the spawning pond thoroughly.

Ø Treat all depressions with approved fish

toxicants before filling and stocking with

brood fish.

Filtration process

Water from surface sources must be filtered to

prevent introduction of undesirable fish. As

discussed in Chapter 4, a common and simple

filtration method of surface waters is use of a

Saran® or nylon “sock” filter.

The filter material should have approximately

the same size mesh as mosquito netting to

prevent admission of larval fish because of the

small mesh size, daily to weekly cleaning is

required (McLarney 1987).

Area required

Dupree and Huner (1984) found that ponds

<0.4/ha (1/acre) in area are preferable for

hybrid production. After the pond has been

properly prepared:

Ø Select mature male and female sunfish.

Ø Stock them into the ponds.

Stock parent fish at a 1:1 ratio of males to

females suggest Dupree and Huner (1984) and

Engelhardt (1985).

They also suggest stocking rates of:

Ø 100 pairs/ha (40 pairs/acre) for small

brood fish.

Ø 75 pairs/ha (30 pairs/acre) for large

brood fish.

Spawning temperatures

Spawning activity begins when the water

temperature reaches:

Ø 21°C (70°F) for green sunfish.

Ø 24°C (75°F) for redear sunfish.

Ø 27°C (80°F) for bluegill. 

Spawning continues as long as the

temperature remains above these levels

(Dupree and Huner 1984).

Summary

There is interest in production of hybrid

sunfish because of the potential reduction in

fecundity, generally due to skewed sex ratios

of some sunfish crosses. Hybrids can also

show hybrid vigor and grow faster than either

parent species.

Many sunfish crosses have been considered;

however, the most common crosses are

between bluegill and green sunfish, and bluegill

and redear sunfish.

Ponds less than one acre

are preferred for hybrid

production!

Notes
Water Temperature

Influences on Survival

& Growth

Various experiments show that external environmentsprofoundly affect fish body temperature. In turn, this

affects all growth components for fish considered for

aquaculture.

This chapter explains:

• Environmental effects

• Growth and survival rates

 6

Sunfish Culture Guide NCRAC Culture Series 102

Water Temperature
NCRAC Culture Series 102 Sunfish Culture Guide 29

Chapter 6 Water Temperature Influences on Survival and Growth

Water Temperature Influences on Survival and Growth

Authors: C. C. Mischke and J. E. Morris, Iowa State University

Environmental Effects

Fish are poikilothermic animals, which means

that their body temperature fluctuates with the

external environment; therefore, temperature

profoundly affects their physiology.

All components of growth are influenced by

temperature (Kitchell and Windell 1968; Beitinger

and Magnuson 1979), including:

Ø Food consumption

Ø Digestion rate

Ø Maintenance

Ø Metabolism

Ø Specific dynamic action

Ø Effective food conversion

Consequently, most fish species have an

optimum temperature for growth and survival.

Temperature ranges1

Research shows that temperature affects fish

both in fertility and growth rates. Researchers

report the optimal temperature range for sunfish

is 20–30°C (68–86°F) (Breder 1936; Banner and

Hyatt 1975; Carlander 1977). Most sunfish spawn

when temperatures are within this range

(Carlander 1977).

Growth rates for sunfish generally increase as

temperatures increase up to approximately 30°C

(86°F). They decrease as temperatures increase

above 30°C (86°F) (Carlander 1977; Lemke

1977; Beitinger and Magnuson 1979).

Growth and Survival Rates

Temperature affects fish capacity to survive and

grow. The highest mean specific growth rate

(2.35%/d) occurred at 30°C (86°F) from

bluegill grown for 30 d at 2°C (4°F)

temperature increments from 20–36°C (68–

97°F) reported Lemke (1977).

Growth of bluegill is the greatest at 31°C

(88°F), but not significantly different from fish

at 25°, 28°, and 31°C (77°, 82°, and 88°F)

according to Beitinger and Magnuson (1979).

Temperature not only affects sunfish growth,

but also impacts survival. Bluegill eggs hatch

at temperatures ranging from 23–34°C (73–

93°F).

Banner and Van Arman (1973) successfully

hatched bluegill eggs at 34°C (93°F), but 50%

mortality occurred. They also reported eggs

Sunfish prefer to build nests in the warmer temperatures

of shallow waters. Optimal water temperature for sunfish

fertality and growth is 20–30°C (68–86°F).

6
Sunfish Culture Guide 30 NCRAC Culture Series 102

Chapter 6 Water Temperature Influences on Survival and Growth

at different temperatures had a maximum

percent hatch at 22°C (72°F) in one

experiment and a maximum percent hatch at

24°C (75°F) in a second experiment.

Fry have a greater thermal tolerance range

than eggs, and juveniles have a greater

thermal tolerance than fry or eggs (Banner and

Van Arman 1973). Wrenn et al. (1979) found

a hatching success mean of 95% (range 76–

99%) for bluegill eggs within the 23–34°C (73–

93°F) temperature range.

Summary

Water temperature has a profound influence on

fish ability to spawn, grow, and survive. Optimal

growth of sunfish is reported to be at water

temperatures of 18–23oC (64–73oF). These

temperatures have the most positive influence

on all components of fish physiology.

Notes

Water temperature

affects sunfish ability to:

Ø Spawn

Ø Grow

Ø Survive
Industry Status

Currently, a limited number of aquacultureproducers exist. The industry has plenty of room

for new producers. However, more information needs

to be available on the most successful aquaculture

production techniques.

This chapter explains:

• Industry status

• Locations

• Primary markets

7

Sunfish Culture Guide NCRAC Culture Series 102

Industry Status
NCRAC Culture Series 102 Sunfish Culture Guide 31

Chapter 6 Water Temperature Influences on Survival and Growth

Industry Status

Authors: C. C. Mischke and J. E. Morris, Iowa State University

Industry Status

Sunfish culture, on a commercial scale, is a

very small industry at this time. Because the

number of sunfish producers is small, the

industry is wide open for new producer entry.

As the global world shrinks and the population

expands, new food sources and production

methods are needed.

Most common sunfish species

Bluegill is the most commonly raised sunfish

species for a number of reasons talked about

in-depth elsewhere in this guide. These prolific

fish are also adaptable to environmental

conditions and lend themselves well to certain

hybrid varieties.

Most common culture methods

Pond culture is currently the most commonly

used culture method. However, cages,

raceways, and recirculating systems are also

used.

According to a 1999 NCRAC survey, a variety

of sunfish species and hybrids are cultured, but

bluegill remains the most commonly cultured

sunfish species. Most sunfish culture occurs

from the Midwest east and south.

Locations

Very few producers are located in western

United States. Table 7.1 summarizes the current

number of sunfish producers reported by the

Aquaculture Buyer’s Guide (Aquaculture

Magazine 1999).1

Of the listed producers of sunfish, most were

located in Texas.

The North Central Regional Aquaculture

Center (NCRAC) conducted a survey of state

aquaculture contacts to determine the number

of sunfish producers in each state, the specific

species produced, the culture methods used, the

most commonly used markets, and the prices

received. Table 7.2 gives the number of

producers in each state.

As with the Aquaculture Buyer’s Guide listing,

most of the commercial sunfish producers are

located in Texas and Wisconsin. Many of the

surveys were not returned, but it is clear that the

sunfish industry is small and very dispersed

throughout the U.S.

Primary Markets

The primary market for sunfish is sport-fish

stocking and fee-fishing operations. Some states

did report a market for food fish, bait, and scientific

research use.

Summary

There are a small number of sunfish producers

in the U.S., with the majority located in Wisconsin

and Texas. Because of the relatively small

number of sunfish producers, there is ample

opportunity for entry into the industry by new

aquaculture producers.

However, the limited number of producers

means there is limited information on proven

production techniques on a commercial scale.

7
Sunfish Culture Guide 32 NCRAC Culture Series 102

Chapter 7 Industry Status

Shrinking world + expanding population = need

for new food sources that are:

Ø Plentiful

Ø Practical

Ø Profitable

Species Cultured Number of States

with Producers

Total Number of

Producers

B 1 luegill 3 56

G 78 reen Sunfish

R 6 edear 1 52

P 44 umpkinseed

L 45 ongear

C 51 oppernose 1

H 8 ybrid Bluegill*

F 4 ingerlings 13

M 4 arket Size 5

H 1 ybrid Sunfish* 1 13

*The specific species cross was not given.

Table 7.1. The number of states in the U. S.

with sunfish producers and the total

number of sunfish producers as listed in

the 1999 Aquaculture Buyer’s Guide,

Aquaculture Magazine.

Notes
NCRAC Culture Series 102 Sunfish Culture Guide 33

Chapter 7 Industry Status

Table 7.2. The number of commercial sunfish producers,

reported by state aquaculture extension specialists and

aquaculture coordinators, 1999.

NR = state aquaculture specialists did not respond to survey.

State

Number of

Commercial

Producers

State

Number of

Commercial

Producers

A 4a labama M R ontan N

A 0a laska N R ebrask N

A 1a rizona N R evad N

A R rkansas N New

Hampshire

0

C R alifornia N y N 1 ew Jerse

C 0o olorado N 0 ew Mexic

C R onnecticut N k N 0 ew Yor

D 0 elaware

North

Carolina

7

F 0a lorida N R orth Dakot N

G R eorgia N o O 3 hi 4

H 0a awaii O R klahom N

I 0 daho 2 n O R rego N

I R llinois N a P R ennsylvani N

I 0d ndiana R 0 hode Islan

I 2 owa

South

Carolina

0

K 8a ansas S 0 outh Dakot

K 3e entucky T 6 ennesse

L 8s ouisiana T 5 exa 7

M 0h aine U 2 ta

M 0 aryland 2 t V 0 ermon

M R assachusetts N a V 1 irgini

M 7 ichigan 2 n W 0 ashingto

M R innesota N a W 3 est Virgini

M R ississippi N n W 0 isconsi 8

M 0 issouri 2 g W R yomin N
Production of Polyploid Sunfish

Polyploid sunfish are those with three or more full setsof chromosomes rather than the usual two. This type

of sunfish has the potential to overcome current barriers

limiting sunfish use in aquaculture.

This chapter explains:

• Sunfish aquaculture positives and negatives

• Overcoming obstacles

• Polyploidy, triploid, and tetraploidy induction techniques

8

Sunfish Culture Guide NCRAC Culture Series 102

Polyploid Sunfish
NCRAC Culture Series 102 Sunfish Culture Guide 34

Chapter 8 Production of Polyploid Sunfish

Production of Polyploid Sunfish

Authors: D. L. Garling, P.D. Wilbert, A.R. Westmaas, and S.M. Miller, Michigan State University;

R. Sheehan, P. S. Wills, and J.M. Paret, Southern Illinois University—Carbondale

Sunfish Aquaculture

Many factors make sunfish strong

aquaculture candidates for commercial

production in the Midwest. The bluegill sunfish

is the most frequently pursued game fish in

the United States, particularly by first time

anglers and youth. Sunfish are also desirable

as a food fish in Midwest markets.

Positive characteristics

Sunfish brood stock are

easy for culturists to

acquire in high numbers, in

contrast to such species as

the walleye and striped

bass. Less experienced

culturists find that sunfish

readily spawn in ponds,

which is in contrast with

other types of fish. Sunfish

are also not inclined to be

cannibalistic, like the

striped bass and walleye.

A number of sunfish species and hybrids are

known to readily accept pellet feeds, which is

important for survival. Sunfish also exhibit fast

initial growth and steady growth at lower

temperatures than channel catfish, which is

an important characteristic for production in

cooler regions. Sunfish are raised in the

Midwest for pond stocking and in limited

numbers for food fish.

Negative characteristics

Despite these important positive attributes of

sunfish, several factors have slowed progress

towards widespread commercialization of

these fish for the food fish market.

The development of a food fish production

industry has been impeded because sexual

maturation occurs prior to the attainment of

marketable sized fish. Sexual

maturation leads to slow, inefficient

growth and uncontrolled

reproduction. These same

problems affect their value as a

sport fish in recreational ponds.

Sunfish hybrids

To limit reproduction in bluegill

sunfish, fish culturists developed

sunfish hybrids. The most

commonly available sunfish hybrid

is a cross between the green

sunfish female and the bluegill

male.

The first generation (F1) of this cross,

although sexually fertile, is predominantly

male. In some populations, males comprise

greater than 95% of the population; but this

number can vary greatly (Table 8.1). However,

production of second-generation (F2

) progeny

can occur despite skewed sex ratios.

This hybrid can also back cross with parental

species. A considerable amount of energy that

could go into growth is expended in such

8

Polyploid sunfish could

overcome barriers

limiting sunfish in

aquaculture.
Sunfish Culture Guide 35 NCRAC Culture Series 102

Chapter 8 Production of Polyploid Sunfish

prespawning behaviors as nest building and

aggressive territoriality among males. These

behaviors may affect the density at which

sunfish can be reared.

Overcoming Obstacles

Induced polyploidy in sunfish could potentially

overcome many current obstacles to the

development of food fish aquaculture in the

Midwest. Polyploidy refers to the condition of

having three or more full sets of chromosomes

instead of the two found in normal diploids

(Table 8.2). Triploid fish produce few, if any,

sperm or eggs because they have three instead

of the normal two sets of chromosomes.

Induced triploidy in other species resulted in

fish with reduced testes and ovaries

development and delayed sexual maturation.

If triploid sunfish exhibit similar characteristics,

problems associated with the onset

of sexual maturation before attaining market

size, such as the loss of dietary energy to

gonadal development and spawning

behaviors, will diminish.

Efficient growth

Efficient growth through sexual maturation is

especially important for sunfish because the

market value greatly decreases for fish less

P e loidy Term C nx ell Typ

h m aploid e 14 gg or sper 2

d s iploid b 28 ody cell 4

t s riploid b 32 ody cell 7

t s etraploid b 46 ody cell 9

Table 8.2. Ploidy terminology where n is the

number of complete sets of chromosomes

and x is the number of chromosomes for

the bluegill sunfish.

than 0.51 kg (0.33 lb). Induced triploidy could

promote good growth and feed conversion

through market size.

Induced triploidy could overcome problems

of uncontrolled reproduction since few, if any,

triploid individuals produce sperm or eggs. Any

sperm or eggs produced usually fail to create

viable young. Ponds that contain only triploid

bluegill sunfish would, consequently, not stunt

as a result of overpopulation.

Tetraploidy was induced in a variety of fish,

including the bluegill sunfish, rainbow trout,

Table 8.1. Literature reported sex ratios of GxB hybrids.

C e ross B s roodstock Sourc % e Male Referenc

M 1 ichigan 8 ) Hubbs and Hubbs (1933

M 7 ichigan 8 ) Laarman (1973

C 7 entral Illinois 9 ) Childers and Bennett (1961

G s x B S 0 outhern Illinoi 8 ) Ellison and Heidinger (1978

T 8 exas 6 ) 6-7 Crandall and Durocher (1980

M 5 ississippi 9 ) Brunson and Robinette (1987

B s x G C 0 entral Illinoi 6 ) 4-7 Childers (1967

S 1 outhern Illinois 7 ) Lewis and Heidinger (1971
NCRAC Culture Series 102 Sunfish Culture Guide 36

Chapter 8 Production of Polyploid Sunfish

and tilapia. Tetraploid trout crossed with

diploids produce viable offspring at lower

survival levels than crosses between normal

diploids. However, triploid trout produced by

tetraploid x diploid crossings out performed

triploid trout produced by heat shocks.

Under ideal production conditions, tetraploid

bluegill sunfish can be used to produce

triploids through tetraploid x diploid crosses,

eliminating the need to treat eggs separately.

Polyploidy Induction Techniques

Michigan State University (MSU) and

Southern Illinois University-Carbondale (SIUC)

worked jointly (funded by the NCRAC) to

develop methods to induce and evaluate

polyploidy in bluegill sunfish and its hybrid with

green sunfish.

MSU researchers were the first to produce

triploid and tetraploid bluegill using cold shocks.

SIUC researchers were the first to produce

triploid hybrid sunfish.

They subsequently produced triploid bluegill

using hydrostatic pressure shocks and refined

flow cytometry methods that facilitate ploidy

determinations in larval sunfish.

SIUC researchers evaluated several shock

types, magnitudes, and durations and found that

hydrostatic pressure shocks were superior to

temperature shocks: Pressure shocks

produced high survival (>90%), 100% triploidy,

and no deformed fish.

Methods recently developed at Iowa State

University (ISU) reliably reproduce bluegill

sunfish out-of-season. They are then reared

from hatch to juvenile size under laboratory

conditions (Mischke and Morris 1997, 1998).

These advances significantly enhanced the

commercial potential for sunfish production.

Three Chromosomes Sets

Triploids possess three rather than two sets of

chromosomes and are created by interrupting

the process of meiosis. Meiosis is the type of

first cell division that results in production of either

Table 8.3. Polyploidy induction techniques for sunfish.

1

 t/p = temperature or pressure used in the stock treatment

2

 rtc = % survival relative to control = (treatment survival/control survival) X 100

S y pecies Ploid Method, Initiation,

t/p1

, Duration

%

Induction

% Survival

rtc2, Stage

Reference

Largemouth

Bass

3N

pressure,

5 min, 55,158 kPa

(8000 psi), 1 min

1 h 00 55, prehatc

Garrett et al.

(1992)

B N luegill 3

pressure,1-1.5 min,

55,158 kPa (8000

psi), 5 min

1 h 00 72, hatc

Westmaas

(1992)

B N luegill 4 cold, 40 min, 7.5oC

(45.5oF),15 min

4 d 0 < ) 1, 17-12 Miller (1995

Hybrid Sunfish

(B x G) 3N

pressure, 2 min,

48,264 kPa (7000

psi), 4 min

1 h 00 90, hatc

Wills et al.

(1994)

W N hite Crappie 3 cold, 5 min 5oC

(41oF), 60 min

7 h 2-92 33-40, hatc

Baldwin et al.

(1990)
Sunfish Culture Guide 37 NCRAC Culture Series 102

Chapter 8 Production of Polyploid Sunfish

eggs or sperm.

The second meiotic division of the egg is

completed shortly after a sperm enters an egg.

Since fertilization is external in sunfish,

application of a treatment to inhibit the second

meiotic division is possible.

The second meiotic division may prevent any

process that causes depolymerization of

microtubules essential to formation of the spindle

apparatus. The spindle apparatus separates the

chromosomes during the second meiotic division.

Various treatments have been used to inhibit

the second meiotic division, including cold

shocks, chemical treatments, hydrostatic

pressure, and heat shocks.

The resulting egg has two identical sets of

maternal chromosomes. Subsequent fertilization

of the egg creates a 3N triploid individual with

three or a triploid set of chromosomes.

Triploid Induction Techniques

The most effective treatments used to produce

triploid sunfish are pressure shocks (Table

8.1). The pressure shock units used by most

researchers are based on a design originally

used by Dasgupta (1962).

A hydraulic press with a pressure gauge applies

the desired pressure to a treatment vessel. The

pressure unit treatment vessels consist of a

cylinder and piston constructed by a machine

shop.

The vessel used at MSU was:

Ø A stainless steel cylinder 14 cm (5.5 in.) in

length, with an outer diameter of 5 cm (2

in.) and a 3.8 cm (1.5 in.) inner diameter.

Ø A 10.8 cm x 1.27 cm (4.2 x 0.5 in.) stainless

steel base welded to the bottom of the

cylinder for stability (Figure 8.1).

Ø A solid brass piston 17.8 cm (7 in.) in length.

Ø Compression maintained from two rubber

‘O’ rings around the base of the piston.

A hole drilled up through the center of the

piston had a release valve at the top that could

be opened to allow air to escape. This also

released pressure on the apparatus when a

Figure 8.1. Applying pressure in the production of

triploids.

treatment was complete. Decompression

speed of the press was nearly instantaneous.

Materials required

Sunfish must be hand spawned prior to shock

treatments. Sunfish collected from ponds during

the spawning season or induced to spawn

in tanks should be checked for ripeness just

before spawning.

Fish are ripe if they release eggs or milt when

gentle pressure is applied to their sides just in

front of the vent using a thumb and forefinger.

The following materials are needed :

Ø A small glass dish.

Ø Pasteur pipette and pipette bulb (available

from a scientific supply house).

Ø Soft cloths (e.g., undershirts).

Ø Stopwatch.
NCRAC Culture Series 102 Sunfish Culture Guide 38

Chapter 8 Production of Polyploid Sunfish

Ø Equipment to incubate the treated eggs.

Ø Press and treatment vessel.

Hand spawning technique

Begin hand spawning by gently drying the

genital areas of both the male and female fish.

Apply gentle hand pressure to:

Ø The sides of the female to expel eggs onto

a dry glass container.

Ø Obtain milt in the same way from two males

for each female spawned.

Ø Collect the milt with a Pasteur pipette and

pipette bulb.

As soon as the milt is added to the eggs in

the glass container:

Ø Gently stir.

¡ Fertilization time is arbitrarily noted

as when eggs and sperm are mixed.

¡ This time determines when to apply

pressure shocks.

Ø Start the stopwatch at this time.

The process

After milt is applied to the eggs, slowly add

water to the eggs to activate the sperm and

wash out excess milt.

As soon as the eggs are washed or just prior to

the pressure treatment:

Ø Pour the fertilized eggs (Figure

8.2), with approximately 15 ml

of water, into the pressure

cylinder.

Ø Place the piston into the

cylinder and:

¡ Make certain the valve is

open.

¡ Press it down into the

cylinder until water comes

out of the valve opening.

¡ Close the valve.

Ø Place the treatment vessel

under the hydraulic press.

Ø Use initiation time, pressure,

and treatment duration

(recommended in Table 8.3).

Ø Release the press pressure on the piston.

Ø Open the cylinder valve after the shock

treatment time is complete.

The eggs can then be incubated as for outof-season spawning or in incubation chambers

(Mischke and Morris 1998).

Cold Shock Treatments

Cold shock treatments (tetraploid induction)

are the only treatments used successfully to

induce tetraploidy in the bluegill sunfish. Cold

shock treatments are applied using a water

bath maintained at the treatment temperature.

Bluegill are first:

Ø Spawned

Ø Eggs fertilized

Ø Eggs washed (described above)

Fertilized eggs are poured into treatment/

incubator chambers prior to starting the cold

shock treatment.

Materials required:

Two-piece chambers can be cut from sections

of PVC pipe. Each chamber should be

approximately 5 cm (2 in.) in length by either 7.62

(3 in.) or 6.35 cm (2.5 in.) in width.

Figure 8.2. Fertilized sunfish eggs being prepared for pressure treatment.
Sunfish Culture Guide 39 NCRAC Culture Series 102

Chapter 8 Production of Polyploid Sunfish

Using silicone:

Ø Attach fine mesh screen (420 mm (0.016

in.) to one end of each 5 cm (2 in.) long

pipe piece.

Ø Leave the other end open.

Ø Place the larger diameter cup over the

smaller cup containing eggs to create a

closed chamber.

These materials allow water to pass through

the chamber, but retain the eggs and the newly

hatched fry.

The process

The most effective cold shock treatment used

to produce tetraploid bluegill was a 15-min

application at a temperature of 7.5o

C (59oF)

40 min after fertilization.

After completing the shock treatment interval:

Ø Remove the incubation chambers from

the cold water bath.

Ø Place in an incubation unit (Figure 8.3).

The chambers can be placed in a commercial

Heath-type drip incubator or an up-welling

bucket incubator. An up-welling bucket

incubator can be made from:

Ø Two buckets the same size (19-liter (5-

gal) buckets are easiest to use).

Ø Cut out the bottom of one bucket, leaving a

1.3 centimeter (1/2 in.) lip around the edge.

Ø Attach a round piece of fiberglass

replacement screening to both sides of

the lip using silicone cement.

Ø Drill a hole in the side of the second

bucket, just above the bottom.

Ø Glue a male hose adapter into the hole

using silicone cement.

Ø Place the screen-bottomed bucket tightly

into the hose adapted bucket.

Ø Connect a water line to the male hose

adapter to pass water through the screen

and incubation chambers.

Ø During incubation, supply the unit with

26o

C (79oF) water.

Ø Keep the flow at approximately 1.5 liters/

min (ca. 0.4 gpm).

Figure 8.3. Triploid eggs being placed in an incubator for

hatching.

Fry culture

Transfer the fry to ponds for grow-out to

market size after they are 14–28 d posthatch. For best grow-out results, process

intensive fry (larval) culture as described by

Mischke and Morris (1998).

Ploidy Testing

Bluegill fry can be tested for ploidy at 7–12 d

post-hatch (shortly after yolk absorption) using

a flow cytometry ploidy analysis technique

developed at MSU. At least five fry from each

shock treatment should be tested for ploidy.

Unfortunately, ploidy level determination by

flow cytometry is expensive.
NCRAC Culture Series 102 Sunfish Culture Guide 40

Chapter 8 Production of Polyploid Sunfish

Ortho Cytofluorograph Analysis for Cellular

DNA Content of Fixed Cells with DNA Doublet

Discrimination program to compile and analyze

sunfish ploidy data.

MSU provides sample preparation and ploidy

determination protocols to commercial

laboratories, along with the equipment

necessary to run ploidy analysis, and may, on

a limited basis, run ploidy analysis of fry at

cost.

Blood samples of larger bluegill can be used to

determine ploidy by flow cytometry, karyotyping,

or the use of a Coulter-counter with channelizer

(Ihssen et al. 1990).

Summary

The production of 100% triploids is very

important for food fish producers and

recreational fisheries managers, since even

a few normal diploid fish would result in

unwanted reproduction.

The laboratory techniques using pressure

shocks to induce triploidy in sunfish can be

used to eliminate uncontrolled reproduction

and make sunfish more suitable for

commercial food fish production. It may also

make them more valuable for sale in the

recreational fisheries market.

The development of procedures for tetraploid

induction may decrease labor costs for triploid

Lepomis production, while ensuring 100%

triploidy. The determination of whether induced

triploidy and tetraploidy can be done

commercially to confer more rapid growth,

more efficient growth, or both, are key factors.

These keys still require research to determine

the cost to benefit ratio for induced triploidy.

Notes
Fee-fishing

Fee-fishing ponds and lakes provide multiple benefits tothe community as a whole, to fish culturists, and to the

owners/operators. A successful fee-fishing business must

be carefully planned and operated to be truly rewarding to

the operator and the angler.

This chapter explains:

• Fee-fishing ponds

• Successful fee-fishing business characteristics

• How to start a fee-fishing business

• Follow up information

9

Sunfish Culture Guide NCRAC Culture Series 102

Fee-fishing
NCRAC Culture Series 102 Sunfish Culture Guide 41

Chapter 9 Fee-Fishing

Fee-Fishing

Author: D. L. Garling, Michigan State University

Fee-Fishing Ponds

Fee-fishing ponds, also called catch-out

ponds or pay lakes, are usually small, heavily

stocked bodies of water containing one or

more kinds of fish. The type of fish stocked in

these ponds depends on pond conditions.

Cold-water ponds are normally stocked with

trout; warm-water ponds are usually stocked

with channel catfish or channel catfish with

hybrid sunfish.

Ponds stocked with largemouth bass, or

largemouth bass and bluegill, do not usually

supply the harvest rate necessary for a

successful fee-fishing business.

Ponds should also be stocked with catchable

size catfish or be located in areas where fishing

opportunities are limited. A warm-water pond

Figure 9.1. Fee fishing operations get the majority of their

business from families with young children.

can be stocked with a hardy fish, such as carp,

and managed on a “fish-for-fun” basis.

Operators of fee-fishing ponds may charge:

Ø A basic fee for 1/2 or 1 d of fishing.

Ø A basic fee for each pound or inch of fish

caught (high quality fish).

Ø Both for the fishing privilege and the fish

caught.

Facilities may include:

Ø Snack bar

Ø Picnic facilities

Ø Bait and tackle shop

Ø Boat rentals

Ø Public rest rooms

Ø Parking

The Fee Angler

A 1975 survey of Michigan fee-fishing operators

indicated that the majority of customers (75%)

were composed of families with young children

(Figure 9.1). Other customers were usually

individual adult males or special groups (e.g., the

Rotary Club or Boy Scout Troops).

When asked what the most important

characteristics of a fee-fishing operation was for

them, Virginia fee anglers ranked their

9
Sunfish Culture Guide 42 NCRAC Culture Series 102

Chapter 9 Fee-Fishing

preferences for return and enjoyment as:

Ø Manager’s attitude (ability to deal effectively

with people)

Ø Water quality

Ø Natural area beauty

Ø Companionship

Ø Fish size

Ø Facilities

Ø Ease of access

Ø Number of fish caught

Ø Weather

Ø Privacy

Fee anglers do not rank catching fish high

on their priority list; probably because they

expect to catch fish while at a catch-out pond.

They may rank other factors higher than

catch rate or size of fish caught, but no feefishing pond will remain in business long if its

customers fail to catch fish!

Successful Business Characteristics

The most common characteristic of a

successful fee-fishing business is providing a

desirable family outing.

Parents are satisfied if their children catch

quality fish in a reasonable length of time,

usually without regard to cost.

Scenic

Ponds should be located in a “natural” area

screened from urban distractions. Trees are

effective screens when placed between roads,

parking areas, and other evidences of man

and the actual fishing area.

Fee-fishing areas should include picnic

facilities (e.g., tables, benches, trash

receptacles) and public rest rooms.

Youth attraction

Fee-fishing facilities can also succeed when

planned as an amusement park with such

youth attractions as playground equipment.

Most successful fee-fishing areas are located

within 80.5 km (50 mi) of population centers with

50,000 or more people or near other types of

public attractions.

People skills

Most importantly, the fee-fishing operator

must be willing and able to work with people.

It is essential to be polite and courteous even

under the most difficult situations (for example,

being awaken at 5:00 AM for bait).

The best advertisement for a successful

business is word of mouth from satisfied,

repeat customers. Other forms of advertising,

such as road signs and brochures at tourist

stops, can help attract a first time fee-fishing

angler and help launch a business.

The friendly, helpful operator will bring

customers back!

How to Start a Fee-Fishing Business

Starting a fee-fishing business requires solid

planning and objective thinking. It requires

research into time, pond location, type of fish,

and legal considerations.

Also consider:

Ø Site selection and beautification

Ø Pond construction

Ø People management

Ø Pond management

Ø Advertisement and information

Ø Liability insurance and legal assistance

Ø Economic analysis & average return

Business Characteristics

Ø Courteous operator

Ø Fish catch

Ø Scenic location

Ø Youth attractions

Successful Effective
NCRAC Culture Series 102 Sunfish Culture Guide 43

Chapter 9 Fee-Fishing

Site selection1

The best site for profitable fee-fishing is a

pond within 80.5 km (50 mi) of a population

center of >50,000. The site should be in a

peaceful, natural setting with easy access. It

must have an adequate supply of high quality

water to facilitate holding large numbers of fish.

Springs and wells are the most desirable

sources of water. Rivers and streams are less

desirable because they can be a source of

unwanted fish, fish diseases, silt from runoff,

and may flood the pond.

Ground water may be an acceptable source

of water if a well or spring to maintain water

quality supplements it.

Surface runoff is usually not a desirable water

source for fee-fishing ponds since water

availability and pond level then becomes

seasonal, fluctuating with the rainfall.

Runoff water can also carry sediment and

nutrients into a pond, which encourages

excessive and unwanted aquatic plant growth.

Pond construction

Before construction, check with your state’s

Conservation or Natural Resources Agency

to determine what permits are required.

Ø Permits may be required to buy and sell

game fish.

Ø Pond-building permits may be required,

depending on the:

¡ Location of the pond.

¡ Water source.

¡ Character of the waterway receiving

the pond effluent.

The Natural Resource Conservation Service

provides information and technical assistance

in pond construction and design.

Follow the guidelines established by the U.S.

Department of Agriculture, Natural Resource

Conservation Service to construct ponds.

Site beautification

It is important to locate the fee-fishing pond

in a pastoral, natural setting.

After pond site selection:

Ø Develop a plan to show the location of the

pond(s) and other facilities (e.g., snack bar,

rest rooms, parking lot, and picnic tables).

Ø Include landscape features in the plan.

Ø Ensure that all trees, shrubs, and power

lines are at least 6–9 m (20–30 ft) away

from the pond bank to avoid snagged

fishing tackle.

Ø Avoid natural screens of deciduous trees,

like poplars, to prevent leaf litter in ponds,

unless the trees are on the leeward side

of ponds or coniferous trees screen them.

¡ Place deciduous trees no closer than

their maximum mature height.

¡ Plant these behind a windbreak of

conifers to avoid unwanted fall leaf

litter in the pond.

Ø Use fast growing conifers for an effective

natural screen between the ponds,

parking lots, roadways, and buildings.

SAFETY

FIRST!

Safety

To promote pond safety, maintain one or more

safety stations around the pond. A safety station

consists of:

Ø A pole with a connected rope and floatation

device that can be thrown to someone

who inadvertently falls into the pond.

Ø A clear site line should also be maintained

between the pond and the pond operator’s

location.
Sunfish Culture Guide 44 NCRAC Culture Series 102

Chapter 9 Fee-Fishing

Pond management

Fee-fishing pond management differs from

recreational pond management and lake

management. The goal of fee-fishing is to provide

adequate numbers of catchable fish to clientele,

rather than sustained fishing recreation over time.

Stock the ponds with catchable size fish when

needed rather than stocking just once or twice

each year.

Stocking considerations

Rainbow trout (Oncorhynchus mykiss) are

usually stocked in cold-water ponds [summer

temperatures do not exceed 21oC (70oF)]

because they are easier

to catch than brown trout

(Salmo trutta) and more

hardy than brook trout

(Salvelinus fontinalis).

Supplies of catchable

sized rainbow trout that

are >23 cm (9 in.) are

also easier to locate

than supplies of

catchable brook or

browns. Warm water

ponds are generally stocked with catchable

sized channel catfish >30 cm (12 in.) or hybrid

sunfish >15 cm (6 in.).

Although bluegill, crappie, perch, bullhead,

northern pike, and walleye can be stocked in

larger recreational fee-fishing lakes, they should

not be stocked in small fee-fishing ponds.

Bluegill, crappie, perch, and bullhead often

overpopulate and stunt in small ponds and lakes.

Northern pike and walleye eat large amounts of

fish and only produce reliably fishable populations

in lakes >16 ha (40 acre).

Wild fish should never be stocked in fee-fishing

ponds or lakes because they can introduce

parasites and diseases.

Stock fee-fishing ponds with enough fish to

ensure a good catch rate. However, stocking

very high densities of fish may result in crowded

conditions, which leads to disease outbreaks.

Sick or dying fish are not good advertisements

for a fee-fishing pond.

Actual stocking rates of catchable size fish

depend on how quickly they are caught. It also

depends on the operator’s ability to maintain

water quality through aeration and the addition

of water from springs or wells.

Feeding considerations2

It may be necessary to feed the fish; however,

feeding fish should be avoided unless you

have the ability to run water through the pond

to remove excess nutrients added by uneaten

feed and fish wastes.

Even if the fish did eat

all of the feed, a

significant amount of

food can be converted

into fish wastes.

Excess nutrients from

feed and fish waste

leads to excessive plant

growth. This makes

fishing difficult and the

area unattractive. If

feeding is necessary to

maintain the weight and health of fish, it is

better to feed:

Ø No more than once a day or every

other day.

Ø Only at rates the fish can completely eat in

a few minutes.

Ø Use floating feed to visually determine if the

fish are actively eating the feed.

Use available resources

Use every resource available for greater

chance of success. The Fisheries and Wildlife

specialist for a State’s Cooperative Extension

Program, for example, can provide additional

information on cold water and warm water

pond management for fishing and weed

control. They can also provide a list of

commercial fish sources, and assistance in

controlling fish predators.

Stock ponds as needed—or you won’t stay in

business long!
NCRAC Culture Series 102 Sunfish Culture Guide 45

Chapter 9 Fee-Fishing

People management

People management is as important as fish

management when operating a fee-fishing

business. Remember that fee anglers rank the

manager’s attitude and ability to work with

people as their highest preference in selecting

a fee-fishing pond.

Advertisement and information3

Active forms of advertisement (TV, radio,

newspapers) may be necessary to initially

attract customers to a fee-fishing pond. Later,

passive advertisements, such as road signs

(where allowed) and word of mouth, are generally

sufficient to attract local customers.

Pamphlets distributed at tourist stops (highway

rest stops, restaurants, and motels) or through

your state’s Travel Bureau can help in attracting

vacationers.

Some state Travel Bureaus or

regional Chambers of Commerce

print travel guides with local

attraction advertisements.

Advertisements should always

include:

Ø Directions to the area

Ø Facilities available

Ø Activities available

Ø Operation schedule (season, days, and

hours open)

Ø Species available

Ø Fees

Once fee anglers arrive, use signs to clearly

direct customers to parking areas and points

of information.

Prominently post prices for fishing and other

services (fish cleaning and bagging) to avoid

confusion and later misunderstandings. Clearly

post all rules.

Generally, fee-fishing businesses prohibit

swimming for liability reasons. Businesses that

stock catchable size fish usually require that

all fish caught are kept by the person to avoid

hooking mortality.

Prominently post:

Ø Prices

Ø Fishing regulations

Ø Activity rules

Rules and Regulations

Additional suggestions

A snack bar and bait and tackle shop can

serve as a focal point to provide:

Ø Information

Ø Additional services

Snack bars and/or bait and tackle shops are

significant sources of additional income to the

fee-fishing operator and promote goodwill.

Distributing a free pamphlet (such as How To

Fish) at the snack bar with the fee-fishing

business name, location, and schedule of

operation acts as an advertisement as well as

demonstrating goodwill.

The pamphlet can explain how to have an

enjoyable day at the pond, provide fishing tips,

and encourage repeat customers.

Posting photos of customers with impressive

catches tends to bring them back

with friends to show off the

pictures and then to point out

where they landed “the big one!”

Photos can also boost the

expectations for a good catch and

a good time for the incoming

anglers.

Property care

Place numerous trash receptacles around the

snack bar, picnic area, and ponds to reduce litter

problems. Make certain that the cans are

covered and emptied often to limit attracting flying

pests like bees and flies, which customers will

certainly notice.

Since a fee-fishing business is often operated

close to the owner’s home, it is important to

make private areas off limits to customers.

Clearly identify areas open to fee-fishing and

associated activities and those off-limit in order

to protect privacy and keep goodwill.

Liability insurance and legal assistance4

Liability insurance is an absolute necessity to

protect a fee-fishing business against

unforeseen accidents. Some states have laws

that limit a landowner’s liability. For example,
Sunfish Culture Guide 46 NCRAC Culture Series 102

Chapter 9 Fee-Fishing

Michigan Act. No. 110 (House Bill 4202) may

limit liability for individual landowners operating

a fee-fishing business.

Sections 3 and 4 of the law limit the liability of

a landowner, tenant, or leasee. A person who

paid a fee to fish on their land and were injured

can sue them, but only if all of the following

situations occurred:

Ø The injuries were caused by an

unreasonably risky, harmful condition;

Ø The owner, etc. knew or should have known

of the condition;

Ø The owner, etc. failed to make

the condition safe or to warn

the person of the condition;

Ø The injured person did not

know or had no reason to

know of the condition.

Insurance companies that are

experienced in covering outdoor

recreation businesses should be

contacted to determine the cost

and coverage available before

going into business.

Incorporating the business

Additional liability protection and

certain tax advantages may be afforded by

incorporating. Including only the pond area

and associated facilities as part of

the corporation assets may be a

benefit.

Economic Business Analysis

Before beginning any business venture, it is

wise to research the possibility of success.

Michigan can serve as an example of the

economics of a fee-fishing business in the north

central region.

In 1975, 50 Michigan fee-fishing businesses

were surveyed. The 34 respondents were

located throughout the state. Almost all of the

operations were family-run, provided a

supplemental source of income, and required

little or no part-time help.

For analysis, the operations were then

divided into small or large operations based

on their annual gross incomes.

Only large operations provided the primary

source of income for their owners.

Average Dollar Return

Average returns to labor,

management, and investment were

low for both sizes of operations. The

average annual return of a small

operation was not sufficient to cover

annual operating costs when labor

and management costs (fair

wages to owner or owner’s family)

were included in the calculations.

Although large operators had

greater returns overall, they still

provided low returns to labor and

to management.

It was found that the average

return of investment for both small

and large businesses were

negative. However, while all the

businesses provided income to the

owner, not all of the individual

businesses had negative returns.

Location, facilities, management, and other

factors affected the returns to fee-fishing

operators.

Unfortunately, insufficient data were collected

to estimate the optimum size of a fee-fishing

operation. But in 1975, an initial investment of

at least $30,000 for fee-fishing firms was

estimated to “break even” under average

circumstances.

This estimate should be increased to current

dollar equivalents for planning purposes.

Follow Up Survey

A 1991 follow-up survey indicated that slightly

<40% of licensed Michigan fish growers had feefishing operations. Approximately 9% of all

licensed fish growers surveyed were involved in

fee-fishing only and 11% were primarily involved

$

$

Consider cost

and return before

investing!
NCRAC Culture Series 102 Sunfish Culture Guide 47

Chapter 9 Fee-Fishing

in fee-fishing operations.

Rainbow trout were the

most commonly used fish

species, although some

growers provided brook or

brown trout, catfish, bluegill,

or largemouth bass.

Most fee-fishing operators

did not charge an entrance

fee, but did require that all

fish caught be purchased,

priced either by the inch or pound. Most operators

provided cleaning, bagging, and icing of fish

caught; but few provided additional services such

as farm tours, refreshments, tackle, or

souvenirs.

In the south, additional services have been

found to generate significant income for the

fee-fishing operator.

Only a few Michigan operators aggressively

advertised their business. Most relied on wordof-mouth advertising or repeat customers.

The primary competition for fee-fishing

operations was from public access

recreational fisheries (lakes and rivers) and

other types of family-oriented recreation.

Summary

Fee-fishing lakes are becoming a popular

means of income, especially around heavily

populated urban areas where there are limited

opportunities to fish.

Fee-fishing lakes can provide the fish culturist

with a different channel to market fish.

Obviously, the costs and estimated returns

for a fee-fishing business should be carefully

considered before any investments are made.

With the proper location, management, and

facilities, a fee-fishing business can be

rewarding and profitable to the operator.

Notes
Calculating Chemical

Treatments

Disease recognition and treatment for fish isessential for maintaining healthy stock and

maximizing investment. Treatment requires the ability

to accurately calculate rates for approved chemicals

in easy-to-use formulas.

This chapter explains:

• Disease and mortality causes

• Drug and chemical treatment overview

• Pond/tank treatment calculations

• Measurement facts

• Conversion factors

10

Sunfish Culture Guide NCRAC Culture Series 102

Chemical Treatments
NCRAC Culture Series 102 Sunfish Culture Guide 48

Chapter 10 Calculating Chemical Treatment

Calculating Chemical Treatments

Authors: M. Riche and D. L. Garling, Michigan State University

Disease and Mortality Causes

Diseases are a common problem in fish

culture. The best method for controlling

disease problems is prevention. Disease

prevention includes:

Ø Providing good water quality.

Ø Minimizing handling stress.

Ø Using only clean and disinfected

equipment.

Ø Using a good quality, correctly stored

feed.

Despite careful and conscientious prevention

efforts, however, disease problems can still

occur. When a problem occurs, it is important

to quickly identify and treat the problem.

Four RECOUP steps used in treating a

disease can help prevent its reoccurrence.

Die-off rates

When mortalities do occur, the rate at which

fish die can be used for an initial disease

diagnosis. Generally, fish death rates follow

one of three patterns:

Ø Rapid <1–2 d

Ø Slow for a few days then a rapid die-off

Ø Slow rate over a long period of time

Die-off causes

If fish die-off occurs within 1–2 d, they are

most likely dying as a result of an

environmental disaster (e.g., lack of oxygen

or lightening) or a toxic chemical.

Death due to lack of oxygen in a pond occurs

most often just before sun up when the levels

of oxygen are lowest in the pond. The largest

fish die first.

If a large number of all sizes of fish die,

especially after a thunderstorm, your pond may

have been struck by lightening. Fillet a few of

the dead fish. If there are areas of bleeding

along the backbone, the fish may have died

from electrocution.

If fish die as a result of a toxic chemical, the

smallest fish die first because their metabolism

is faster than that of larger fish. The faster

metabolism of small fish results in quicker

uptake of a toxic chemical.

Fish dying slowly for a few days, followed

by a rapid die-off within 1 or 2 d, are most

likely the victims of a virulent virus or

bacteria. A fish health specialist is required

for a specific identification of the cause and

treatment recommendation.

Contact the aquaculture extension specialist,

State Department of Agriculture aquaculture

10

R E C O U P

Reduce stressors (e.g., low DO, high ammonia,

high or low temperatures)

Correct pathogen identification (e.g., parasite,

bacteria, and virus)

Use safe and appropriate treatments

Prevention
Sunfish Culture Guide 49 NCRAC Culture Series 102

Chapter 10 Calculating Chemical Treatment

coordinator, or state aquaculture association

to find a fish health specialist.

Bacterial infections generally result from

stress. If the stress causing the virulent

bacterial infection is identified and corrected

(e.g., low oxygen, silty water, rapid temperature

changes, or heavy parasite load), the severity

of die-off may be reduced.

If fish die at a slow rate over a long period of

time (weeks or months), they are most likely

dying as a result of:

Ø Prolonged stress from poor water quality.

Ø Too low or high a temperature.

Ø Large daily temperature changes.

Ø A low virulent bacteria or virus.

Ø A heavy parasite load.

This type of slow die-off pattern may correct

itself if the fish are dying due to water quality

problems caused by too many fish in the

system. The causes of a slow die-off, however,

are most often the stressors types that lead to

more rapid die-offs from virulent bacteria.

Consequently, it is important to quickly identify

and correct the cause of the die-off.

Drug/Chemical Treatments Overview

Drug and chemical treatments should only

be given after stress has been reduced and

the disease causing pathogen identified.

Safe and appropriate treatments kill the

pathogen without

harming fish. There

is often a small

difference in the

drug amount that

kills the pathogen

and the amount

harmful to fish.

Feed treatments1

Medicated fish feeds are available to treat

bacterial diseases for specific fish species. The

U.S. Food and Drug Administration is currently

reviewing reports on permitting the use of

these feeds to treat bacterial diseases in other

It is crucial to

calculate the correct

amount of federally

approved chemicals

to use.

WARNING!

species of fish under the supervision of an

attending veterinarian.

Until rules are developed for the extra-label

use of medicated fish feeds, they can only be

used to treat fish listed on the feed label.

Pond/Tank Treatment Calculations

To calculate the correct amount of chemical

to use, find out what pathogen you are dealing

with and the chemical dose that will kill it.

“Dose” refers to the strength of the treatment.

To calculate a safe and appropriate dose,

measure the area of the pond or tank and the

volume of water the fish are in. Always check

calculations twice, since small errors can result

in dead fish. It is particularly important to be

careful where decimals are used. Calculate:

Ø Area

Ø Water volume

Ø Correct amount

Calculate the area

The area of most ponds and tanks is

determined by using equations for the area of

a circle, rectangle, or right triangle. The area

of irregular shaped ponds is determined by

dividing the pond into smaller areas that

resemble these shapes.

The smaller areas are calculated and added

together to get the total area. Figure 10.1

shows these equations.

Calculate the water volume

A pond or tank without water coming in or

going out is called static. Water volume in a

Facts to Remember

Area of rectangle = length x width

Area of circle = radius2

 x 3.14 (π)

radius = diameter

1 acre = 43,560 square feet

1 acre-foot = 1 acre of water

1 foot deep

2
NCRAC Culture Series 102 Sunfish Culture Guide 50

Chapter 10 Calculating Chemical Treatment

static pond or tank is the amount of water

under the area calculated. It is determined by

multiplying the area by the water depth. In a

pond, use average water depth (Figure 10.2).

Calculating the volume of water in a flowthrough system is more complicated. The

water leaving the tank must also be included

in the volume for calculating the dose. The

water flowing out removes some of the

chemical previously added.

To keep the same dose during the entire

treatment, the amount of chemical leaving with

the water must be replaced. In a flow-through

system, you must know the flow rate. Flow rate

is the amount of water leaving a tank or pond

in 1 min.

The flow rate is determined by measuring the

amount of time it takes to fill a 5 gal bucket

with the incoming or outgoing water. It is

expressed as:

5 gal/min to fill = gal per min

Calculate the correct amount

The chemical dose to use is usually given as

the weight or amount of chemical to apply in a

certain amount of water. There are a number

of ways the weight and volume are given.

To reduce the chance of using too much or

too little chemical, it is best to change

weights and volumes into familiar units with

conversion factors.

For example, if you are more familiar with

pounds than kilograms, convert the

kilograms to pounds (conversion factors and

conversion tables are given at the end of

this chapter).

Percent Active Ingredient

Before measuring any chemical, read the

label carefully. It is important to note the

percent active ingredient.

The percent active ingredient is the amount

of chemical actually doing the work.

Example: The chemical formalin is a

mixture of water and formaldehyde.

Rectangular Pond 250 ft

500 ft

Area = 500 ft x 250 ft = 125,000 ft2

Expressed as:

125,000

 43,560

= 2.9 acres

Circular Pond

Area = 1502 x 3.14 = 70,650 ft2

Expressed as:

Acreage = 70,650

43,560 = 1.6 acres

Diameter = 300 ft

70 ft

80 ft

Area 2

Area 1

200 ft

90 ft

Area 1 = 80 ft x 70 ft = 5,600 ft2

Area 2 = 200 ft x 90 ft = 18,000 ft2

Pond Area = 5,600 + 18,000 = 23,600 ft2

Expressed as:

Acreage = 23,600

43,560 = 0.5 acres

Irregular Shaped Pond

Figure 10.1. Areas for rectangle, circle, and right triangle.
Sunfish Culture Guide 51 NCRAC Culture Series 102

Chapter 10 Calculating Chemical Treatment

Formalin can be 37% formaldehyde with

63% water or 20% formaldehyde with

80% water. The percent of formaldehyde

is the percent active ingredient.

Since only the formaldehyde does the work,

it is necessary to use a correction factor so

the right amount of active ingredient is used.

The easiest way to calculate the dose is with

the following equation:

D = V x K x CF x AI

Where: D = Dose

V = water volume

K = amount needed to kill pathogens

CF = conversion factors

AI = (100%)/(% active ingredient)

Some sample calculations are given below.

For ease of discussion, English units will be

used for many of the samples.

Scenario 1: Pond Treatment.

After 4 d of early morning dissolved oxygen

readings you are happy to see the dissolved

oxygen is back to saturation.

Although you didn’t lose any fish when the

dissolved oxygen was low, the fish are acting

like the dissolved oxygen is still low.

A gill parasite is present in some of the sicker

fish examined. A positive identification

indicates the parasite is Trichodina.

You know formalin is effective against

Trichodina but you also know it will decrease

the dissolved oxygen if there is high level of

organic matter in the pond. However, you need

to take action.

Steps to take:

1. Checking with the state extension agent

to ensure formalin is safe and legal, you

decide to treat your 4 acre pond.

Treatment: Formalin is 37% active

ingredient (stock solution)

Treatment Rate: 15 ppm (using

Formalin as 100% dosage)

Pond with irregular bottom

1. Measure the depth at several uniformly

spaced points.

2. Add these values together and divide by

the number of depth readings.

Example: Depth in feet:

A = 6

B = 10

C = 8

D = 5

E = 3

F = 6

 38

Average depth = 38 ft = 6.3 ft

 6

Calculating Depth and Water Volume

Pond with uniform slop on bottom

Maximum pond depth = 15 ft

Depth = 1/2 (maximum depth) = 15 =7.5 ft

 2

If the surface area on pond is 3 acres, the

volume = 3 acres x 7.5 ft = 22.5 acre-feet

Figure 10.2. Area and volume for a regular shaped pond.

*A *B *C

*D *E *F

Pond with irregular bottom
NCRAC Culture Series 102 Sunfish Culture Guide 52

Chapter 10 Calculating Chemical Treatment

It looks like “ich,” so you collect a few for

diagnosis. The diagnosis indicates you were

right; your fish have “ich”, (Ichthyopthirius). The

buyer said he doesn’t want diseased fish.

You know there is a way to correct the

situation. Steps to take:

1. You determine chemical A is effective in

treating Ich. Checking with the state

extension agent to ensure the chemical

is safe and legal, you treat your pond.

Treatment: Chemical A is 20% active

ingredient.

Treatment Concentration: 25 ppm;

repeat every 5 d as needed.

2. You measure the pond and determine the

following dimensions (Figure 10.3):

The pond is an irregular shape. The best way

calculate the area is to:

Ø Divide the pond into two regular areas

Ø Calculate each area

Ø Add the two areas together to get the total

pond area

Area A is the area of a right triangle,

measured as (Length x width)/2, or:

 (100 ft x 200 ft)/2 = 20,000 ft2

Area B is the area of a rectangle and

Figure 10.3. Area and volume of an irregular-shaped pond.

the correct conversion factor to change

the area to acres.

The conversion factor indicates there

is 43,500 ft2

 in every acre.

Pond area is now measured as:

180,000

 43,500

4. You now calculate the volume of water

under the area. The measurements

indicate the average depth is 7 ft.

Volume of water is measured as area

of pond x average depth, or:

4.13 acres x 7 ft

= 28.9 acre-feet (A-ft)

5. You calculate the dose or amount of

formalin to use. The dose is the amount

of formalin to get 15 ppm of active

ingredient.

Using the equation:

D = V x K x CF x AI

You get: 28.9 A-ft x 15 ppm x (0.33

gal / 1.0 A-ft) x 1 = 143 gal

Treatment: The dose is 143 gal of

formalin (37% active ingredient) in

28.9 ac ft of water.

Scenario 2: Irregular Shaped Pond

A buyer is interested in purchasing bluegill

stocked in your 0.20 ha (0.5 acre) pond last

fall. However, you notice that the bluegill have

white patches on their skin.

2. You measure the pond and determine the

following dimensions (Figure 10.2):

Pond area is measured as Length x

width, or:

600 ft x 300 ft = 180,000 ft2

3. You are more comfortable using acre

instead of thousands of sq ft, so you use

= 4.13 acres
Sunfish Culture Guide 53 NCRAC Culture Series 102

Chapter 10 Calculating Chemical Treatment

measured as (Length x width), or:

60 ft * 200 ft = 12,000 ft2

Total area of the pond is measured

as Area A + Area B, or:

20,000 ft2

 + 12,000 ft2 = 32,000 ft2

3. You now calculate the volume of water

under the area. The measurements

indicate the average depth is 6.5 ft.

Volume of water is measured as Area

of the pond * average depth, or:

32,000 ft2

 * 6.5 ft = 208,000 ft3

4. After volume is determined, calculate the

dose or amount of chemical A to use.

The dose is the amount of chemical

A to get 25 ppm of active ingredient.

Using the equation:

D = V x K x CF x AI

You get: 208,000 ft3 x 25 ppm x (1.04

fl oz/1,000 ft3

) x (100%/20% active

ingredient) = 27,040 fl oz

5. It is easier to measure gallons than

27,040 fl oz, so you convert to gallons.

The conversion factor indicates there

is 128.0 fl oz in each gal.

Figure 10.4. Area and volume of a rectangular tank.

27,040 fl oz x (1.0 gal / 128.0 fl oz)

= 211.25 gal

Treatment: The dose to use is

211.25 gal of chemical A in 208,000

ft3 of water.

Scenario 3: Static bath in a tank.

After coming back from a fish culture

workshop, your nephew tells you he doesn’t

think the fish like the new food you bought

before you left. Even though they didn’t eat,

he kept feeding them because he thought they

would get hungry.

The tank water looks brown, so you turn up

the water flow and the water clears. When the

water clears, you notice the fish have white to

pinkish patches of slime on their skin.

A diagnosis identifies the parasite Epistylis

on their skin and gills. You are afraid to use

formalin because the gills are already

damaged. You find out salt (sodium chloride)

is effective against Epistylis.

1. Checking with the state extension agent,

you learn salt is a low priority regulatory

drug and may be used for treatment.

Treatment: Salt (sodium chloride)

Treatment Concentration: Static bath

of 1% salt for 10–30 min.

2. A static bath requires turning off the water.

After providing aeration to the tank, you

take the measurements. The tank has the

following dimensions (Figure 10.4).

Area of the tank is measured as

length x width, or:

7.62 m x 1.52 m = 11.58 m2

3. You calculate the water volume under the

area. The water depth is 0.62 m.

Volume of water is measured as area

of the tank x depth of water, or:

11.58 m2

 x 0.62 m = 7.18 m3
NCRAC Culture Series 102 Sunfish Culture Guide 54

Chapter 10 Calculating Chemical Treatment

4. After determining the volume, calculate

the salt dose to use. The dose is the

amount of salt to get a 1% solution, which

is the same as 1 lb of salt for every 100 lb

of water.

5. To determine the amount of salt to use,

convert the volume to pounds of water.

The conversion factor indicates there

are 2,201.5 lb of water in each m3.

Using the equation:

D = V x K x CF x AI

You get: 7.18 m3

 x (1 lb of salt / 100

lb of water) x (2,201.5 lb/m3

) x (100%/

100% active ingredient) = 158 lbs

Treatment: The dose to use is 158 lb

of salt or 7.18 m3

 of water.

Scenario 4: Flow through bath in a tank.

The bluegills in your circular tanks are

swimming slowly near the top of the tank. For

a week you have been trying to reduce the

ammonia level in your recirculating system.

Some of the fish are swallowing air and the

gill covers won’t close normally.

Your fish have been diagnosed as having

bacterial gill disease with tissue swelling. After

 Figure 10.5. Volume of a circular tank.

flushing the tank with freshwater, you contact

the state extension agent. The agent informs

you salt is a low priority regulatory drug.

1. You decide to treat the fish with salt to kill

the bacteria and soothe the gills. The fish

are having difficulty getting enough

oxygen, however, so you don’t want to

turn the water off. Therefore, you choose

to treat them with a flow-through bath.

Treatment: Salt (sodium chloride)

Treatment Concentration: 1%

solution for 1 h.

To maintain the 1% solution for the

entire hour, you need to keep adding

salt to replace the salt flowing out with

the water.

2. Calculate the volume of the tank (Figure

10.5) to find the flow rate of water leaving

the tank.

Area is measured as 3.14 x (distance

from center to edge) 2 , or:

3.14 x 6 ft x 6 ft = 113 ft 2

Volume is measured as area * depth

of the water, or:

113 ft 2

 x 4 ft = 452 ft 3

Treatment application: 1.0% solution

is the same as 1 lb of salt in every

100 lb of water.

3. Salt is most easily measured in pounds.

Convert the volume of water into pounds

of water. A cubic foot of water weighs

62.43 lb (refer to the Conversion Chart

at the end of this chapter).

Using the equation:

D = V x K x CF x AI

You get: 452 ft 3 x (1 lb of salt/100 lb

of water) x (62.42 lb of water/1.0 ft3

)

X (100%/% active ingredient) =282

lb of salt
Sunfish Culture Guide 55 NCRAC Culture Series 102

Chapter 10 Calculating Chemical Treatment

The initial dose is 282 lb of salt in 452

ft 3 of water. Then:

Ø Drop the water level about 0.5 ft.

Ø Add 282 lb of salt.

Ø Allow the water to come up to the

original level.

¡ This allows the salt to dissolve before

it begins to leave the tank.

Ø Allow additional salt when the water

begins to flow out of the tank.

¡ This replaces the salt leaving with

the water.

4. First calculate the flow rate to determine

the amount of additional salt needed.

You determine it takes 16 sec to fill a

5 gal bucket with the incoming water.

5. Calculate the flow rate (gallons per

seconds), which is:

(5 gal/16 s) x (60 s/1 min)

= 18.8 gal/min

Knowing the flow rate allows you to calculate

how much salt will leave the tank during the

treatment and how much salt to replace.

Since the tank contains 1.0 lb of salt for every

100 lbs of water, convert the gallons of water

leaving the tank to pounds of water leaving

the tank. Each gallon of water weighs 8.32 lb

(see Conversion Chart). With these factors,

calculate the amounts needed.

6. Use the following equation to calculate the

salt leaving the tank:

(18.8 gal/1.0 min) x (8.32 lb of water/

1.0 gal) x (1.0 lb of salt/100.0 lb of

water) = 1.6 lb of salt/1.0 min

Treatment: For a 1 hr treatment, you

need an additional (1.6 lb of salt/1.0

min) x (60 min/1.0 h) or:

96 lb of salt/1.0 h of treatment

Use an automatic delivery device to

deliver:

96 lb of salt at 1.6 lb of salt/min

Summary

Disease is a common problem in fish culture.

When a problem occurs it is vital to recognize

it immediately, seek professional advice, and

quickly treat the problem. Implementing the

RECOUP steps can resolve the problem,

reduce stress, and limit loss.

Calculating a safe and appropriate dose will

kill the pathogen without harming the fish.

Calculations should always be checked twice

for accuracy since small errors can result in

dead fish.
NCRAC Culture Series 102 Sunfish Culture Guide 56

Chapter 10 Calculating Chemical Treatment

Useful Conversions

1 liter (l) of water

= 1 kilogram (k)

= 2.205 pounds (lb)

1 milliliter (ml) or

cubic centimeter (cm3

) of water

= 1 gram (g)

= 0.0353 ounce (oz)

1 gallon (gal) of water

= 8.34 pounds (lb)

= 3.785 kilograms (kg)

1 cubic foot (ft3

) of water

= 62.36 pounds (lb)

= 28.29 kilograms (kg)

1 fluid ounce (fl oz)

= 1.043 ounces (oz)

= 29.57 grams (g)

1 parts per million (ppm)

= 1.226 grams per acre/foot (g/acre/ft)

= 0.0283 grams per cubic foot (g/ft3

)

= 2.718 pounds per acre/foot

 (lb/acre/ft)

= 0.0038 grams per gallon (g/gal)

= 0.0000623 pounds per cubic foot

 (lb/ft3

)

1 cubic foot per second (ft3

/sec)

= 448.83 gallons per minute (gal/min)

= 26,930 gallons per hour (gal/h)

= 646,320 gallons per day (gal/d)

= 1.699 cubic meters per minute

 (m3

/min)

= 101.93 cubic meters per hour (m3

/h)

= 2446 cubic meters per day (m3

/d)

1 percent solution

= 38 grams per gallon (g/gal)

= 1.3 ounces per gallon (oz/gal)

= 0.622 pounds per cubic foot of water

 (lb/ft3

/H20)

1 acre

= 43,560 square feet (sq ft)

= 208.7 x 208.7 feet (ft)

= circle diameter 235.5 feet (ft)

1 acre per foot

= 1 surface area 1 foot deep

= 43,560 cubic feet (ft3

)

= 2,718,144 pounds (lb)

= 1,233.49 cubic meters (m3

)

= 325,851 gallons (gal)

Rotenone applications = 3 ppm

General dilution formula:

Desired concentrations x desired

volume/concentration of stock solution

= volume of stock solution to dilute to

the desired volume.
Sunfish Culture Guide 57 NCRAC Culture Series 102

Chapter 10 Calculating Chemical Treatment

U n nit G e rai O d unc P m oun M m illigra G m ra Kilogra

G 13 rain 0 3 .002 0 8 .00014 6 8 4. 0 5 .064 0.00006

O 5 unce 41 5 37. 0 0 .062 2 5 8,35 2 4 8.3 0.028

P 0 ound 7 6 ,00 11 0 4 6 53,59 4 6 53. 0.453

M 4 illigram 0 6 .015 0 2 .0003 0 11 .00000 0 1 .00 0.00000

G 3 ram 1 3 5.4 0 2 .035 0 0 .002 1 11 ,00 0.00

K 0 ilogram 1 7 5,43 3 5 5.2 2 0 .20 1 0 ,000,00 1 1 ,00

Conversion of Weight Units

U h nit I t nc F d oo Y r ar M r illimete C r entimete Mete

I 13 nch 0 8 .083 0 0 .027 2 0 5.4 2 4 .54 0.025

F 2 oot 11 3 0 8 .333 3 8 04. 3 8 0.4 0.304

Y 6 ard 331 4 9 4 14. 9 4 1.4 0.914

M 4 illimeter 0 3 .039 0 1 .003 01 1 .001 0 1 . 0.00

C 7 entimeter 0 8 .398 0 9 .032 0 0 .010 1 11 0.0

M 7 eter 3 1 9.3 3 6 .28 1 0 .093 1 0 ,00 1 1 0

Conversion of Length Units

Conversion of Volume Units

U n nit G t allo Q t uar Pin

Fluid

Ounce

Cubic

Foot

Cubic

Inch M r illiliter Lite

Cubic

Meter

G 1 48 8 allon 1 7 2 0 0 .133 2 4 31. 3 5 ,785. 3 8 .78 0.0037

Q 5 uart 0 122 .2 3 4 0 5 .033 5 6 7.7 9 6 46.3 0 5 .94 0.0009

P 5 int 0 5 .12 0 16 . 1 7 0 8 .016 2 8 8.8 4 3 73.1 0 7 .47 0.0004

Fluid

Ounce

0 3 .0078 0 5 .031 01 4 .062 0 5 .0010 1 3 .80 2 6 9,57 0 3 .029 0.0000

Cubic

Foot 7 2 .481 2 4 9.9 5 5 9.8 918 57. 1 7 ,72 2 2 8,31 2 2 8.3 0.0283

Cubic

Inch 0 3 .0043 0 6 .017 0 1 .034 0 8 .554 0 19 .0005 1 4 6.3 0 6 .016 0.00001

M 6 illiliter 0 6 .0002 0 1 .0010 0 8 .002 0 5 .033 0 0 .00003 0 11 .06 0 1 .00 0.00000

L 2 iter 0 7 .264 1 4 .05 2 1 .113 3 3 3.8 0 2 .035 6 0 1.0 111 ,00 0.00

Cubic

Meter

3 7 64.2 1 3 ,05 2 0 ,11 3 3 3,81 3 0 5. 6 0 1,00 1 0 ,000,00 1 1 ,00
Common Sunfish Parasites

Parasites, which are commonly found in fish,can become a real problem in aquaculture

production—affecting fish health, pond stability,

and marketability. Knowledge and prevention remain

the most effective tools. The Federal Food and Drug

Administration (FDA) regulates all drugs used for fish

diseases.

This chapter explains:

• Parasites and hosts

• Chemical treatments

• Prevention

• Parasite groups

• Parasite characteristics and effects

11

Sunfish Culture Guide NCRAC Culture Series 102

Sunfish Parasites
NCRAC Culture Series 102 Sunfish Culture Guide 58

Chapter 10 Calculating Chemical Treatment

11

Common Sunfish Parasites

Authors: T. Sampson, Michigan Department of Natural Resources, Fish Division and D. L. Garling,

Michigan State University

Parasites and Hosts

Parasites depend on other organisms, called

hosts, for survival. They may be found inside

the host (endoparasites) or around the host

(ectoparasites). Parasites affect their hosts in

various degrees, ranging from mild irritation to

mortality.

Some parasites require several different hosts

to complete their life

cycle. The particular host

associated with the adult

parasite is commonly

referred to as the final

host or definitive host.

Other hosts that occur in

the life cycle are called

intermediate hosts; these

hosts may include other

fish, snails, and birds.

Parasitic indications

Although careful pond

maintenance reduces

the risk of parasites,

they may still occur from a number of sources.

General signs of parasitic infection include:

Ø Gulping at the surface

Ø Flared gills

Ø Flashing

¡ In an effort to remove an irritation on

the skin, fish will attempt to rub the

irritated area against the side or

bottom of a raceway.

¡ This exposes the shiny underbelly,

which gives the appearance of a

flash of light.

Ø Lethargic behavior, off feed, or laying on

the bottom

Ø Excess mucus production, fin erosion, or

skin lesions

Ø Tremors

These symptoms may be associated with

other diseases, so it is best to

get the advice of an expert for

the cause.

Chemical Treatments for

Fish Infected with

Parasites

In the past, chemical

therapeutics were used to

eliminate fish parasites. Over

the years, however, laws

changed and some of the

chemicals used in

aquaculture were found to be

either harmful to humans or

harmful to the environment.

To insure human safety, the U.S.Food and

Drug Administration (FDA) must approve all

chemicals used as treatments for parasites

and diseases, either added to water for direct

treatment or added to feeds.

Drugs must be specifically labeled for

aquaculture use. To insure safety and drug

efficacy, culturists should follow all label

directions and warnings. Currently, few

chemical therapeutics are approved for use in

Parasites affect fish health, pond

stability, and marketability!
Sunfish Culture Guide 59 NCRAC Culture Series 102

Chapter 11 Common Sunfish Parasites

aquaculture. Of the approved drugs, only

formalin is effective against fish parasites.

Use of low priority drugs1

The FDA also permits the use of low

regulatory priority aquaculture drugs. This

means the FDA reviewed these types of

compounds and determined them to be new

animal drugs of low regulatory priority. As a

result, the FDA determined that several of

these “low priority” drugs can be used to

combat parasites.

This designation does not mean that the FDA

has officially approved these substances for

use, even though the expectation of

detrimental effects is low. It does mean that

these compounds must be used under specific

guidelines and tolerances established by the

FDA. Among these compounds are:

Ø Acetic acid

Ø Garlic (whole form)

Ø Magnesium sulfate

Ø Sodium chloride

These were used successfully to treat some

parasitic infestations.

Under certain conditions authorized by FDA,

unapproved new animal drugs may be used

in conformance with the terms of an

Investigational New Animal Drug (INAD)

application. Additional information on

approved, low regulatory priority and INADs

can be obtained from the FDA Center for

Veterinary Medicine.

Chemically treating large

scale culture ponds is not

practical. Focus instead

on maintaining good

water quality and

following good cultural

practices.

Prevention

The best “treatment” is proper cultural

practices that prevent parasitic infestations

from occurring. Among these practices are:

1. Eliminate predators and intermediate

hosts such as other fish, snails, herons

and kingfishers.

2. Use a water source with high quality water

that is free of fish.

3. Quarantine any new fish for a period

sufficient to determine if they are carrying

any parasites.

4. Maintain low rearing densities to reduce

stress in the fish. High rearing densities

facilitate rapid transmission of diseases

when they do occur.

5. Maintain good water quality by monitoring

dissolved oxygen content. The dissolved

oxygen content of rearing water should

be between 90 and 100% saturation.

Reduce the amount of organic matter in

ponds that removes oxygen as it decomposes.

Parasite Groups

A variety of fish parasites exist, but many of

these can be listed in ten major types.

These include:

1. Protozoa—single celled animals.

2. Monogenetic Trematodes—flukes with

posterior organs of attachment.

Ø Simple life cycles involving only one

host.

Ø Primarily external parasites found on

the gills, skin, and fins.

3. Digenetic Trematodes—flukes with a

mouth and ventral suckers.

Ø Complex life cycles involving

intermediate hosts.

Ø Adults are generally internal

parasites found in the intestine,

throat, stomach, gall bladder, and

urinary bladder.

Ø Young stages, called metacercariae,

are found in the skin, muscle, eyes,

and internal organs.
Chapter 11 Common Sunfish Parasites

NCRAC Culture Series 102 Sunfish Culture Guide 60

4. Cestodes (Tapeworms)—worms with

flattened, segmented bodies.

Ø The head usually has suckers or

hooks.

Ø Adults are generally found in the

intestine.

Ø Juvenile forms are found in other

internal organs as well as the

intestine.

5. Nematodes (Roundworms)—thin,

elongated worms with a cylindrical

shaped body.

Ø Adults are usually found in the

intestinal tract.

Ø Some are external found outside the

rectum, skin and muscles.

Ø Larval stages are found in various

internal organs.

6. Acanthocephala (Spiny Headed Worms)—

worms with flattened or cylindrical bodies.

Ø Possess a hook bearing appendage

(proboscis) with which it attaches to

its host.

Ø Adults are generally found in the

intestine with larval forms found in

the liver.

7. Copepods— external parasites.

Ø Found on the gills, skin, and fins.

Ø They may be louse like, worm like, or

grub like.

8. Leeches— external parasites.

Ø Attaches to the host with suckers.

Ø Suckers may be larger or smaller

than their body diameter.

9. Glochidia—larval clams encapsulated in

the fins and gills of the host.

10. Fungi—plant-like organisms that lack

chlorophyll. Best Practice

Ø Proper culture treatments

Ø Good water quality

Ø Limit fish stress

Ø Reduce bird & snail

populations

Parasite Characteristics and Effects

Parasites left unrecognized and untreated

create a serious problem that may seriously

affect any investment return for the

aquaculture operator.

Following are tables listing the most common

parasites, their:

Ø Causative agents

Ø Characteristics

Ø Effects

Ø Treatments

Ø Prevention

Ø Effects on humans

The family these parasites belong to heads

each set of tables and Figures 11.1–11.4

shows specific types of these parasites.

Parasites affect

pond stability

There are 10 major types of

parasitic groups.
Sunfish Culture Guide 61 NCRAC Culture Series 102

Chapter 11 Common Sunfish Parasites

C n hilodon

Causative Agent A single celled animal of the genus and species Chilodonella cyprini.

Characteristics

An oval shaped body 50-70 μm (0.002-0.003 in.) in length. Individuals can

only be seen with magnification although colonies may be seen on the fish

as blotchy gray areas.They are capable of movement due to fine hairs

called cilia that cover their body.

Chilodon are capable of movement due to fine hairs called cilia that cover

their body. Chilodonella reproduces on the fish by dividing in half. It

produces a resistant cyst that can survive through periods of unfavorable

environmental conditions. It is most frequently observed when fish move

into shallow water to spawn.

Effects

Large infestations of Chilodonella cause fish to become lethargic, lie on

their sides or rise to the surface, and may lead to death. Infestations on

the gills cause the fish to secrete large amounts of mucous, which impairs

respiration.

Treatments

A 1 h bath in a 250 mg/l (0.033 oz/gal) formalin solution, where possible.

1% salt solution may also be used.

Prevention

Avoid high concentrations of organic material in rearing ponds.

R d educe crowding and maintain good water quality by monitoring dissolve

oxygen content.

E . ffects on Humans Not harmful to humans

Family = Protozoa—Single Cell Animals

E s pistylis

C . ausative Agent A single celled animal of the genus Epistylis

Characteristics

A microscopic protozoan with cilia for movement.

This parasite is generally found on the skin, fins, and gills of fish. It is most

common during summer in water with high organic content. Lesions

appear as short, slimy, fungus-like growths.

Effects

Hemorrhaging may occur at the site of attachment. The sites of

hemorrhages are susceptible to secondary bacterial infections. Heavy

infestations can cause large mortalities.

Treatments

A 1 h bath in a 200 mg/l (0.027 oz/gal) formalin solution, where possible.

A 15 min bath in a 2% salt solution is effective in controlling this parasite

but not practical in large scale pond culture.

In ponds, treatments with potassium permanganate have been shown to

provide some relief.

Prevention

Avoid high concentrations of organic material in rearing ponds.

R d educe crowding and maintain good water quality by monitoring dissolve

oxygen content.

E . ffects on Humans Not harmful to humans
Chapter 11 Common Sunfish Parasites

NCRAC Culture Series 102 Sunfish Culture Guide 62

I ) chtyobodoiasis (Costia)

Causative Agent

A single celled animal of the genus Epistylis.

The parasite ranges in size from 10-20 μm (0.0004-0.0008 in.) in length by

5-10 μm (0.0002-0.0004 in.) wide.

Characteristics

Ichtyobodo lives on the skin and gills of fish utilizing sloughed epithelial

cells from the fish for food.

Generally, the fish and the parasites live in a state of symbiosis where

neither adversely affects the other. Under situations of environmental stress

or poor health, the fish's immune system may become compromised,

allowing the parasites to reproduce at an immense rate to the point where

they begin attacking live cells.

Ichtyobodo is most active when water temperature is between 10-25o C

(50-77o F) and cannot survive in temperatures >30o C (86o F). Ichtyobodo

is transmitted from fish to fish either in its adult form or as an encysted

form.

Fish in poor health or exposed to such environmental stressors as low

dissolved oxygen, overcrowding, or some other pathogen are more

susceptible to epizootics than those living in a more favorable

environment.

Effects

Fish may become lethargic and go off feed. They may be seen "flashing"

or rubbing against the side or bottom of a pond or tank in an attempt to

alleviate the irritation. A thickening of mucus may appear on areas of the

body most heavily affected.

Treatments

Several chemical therapeutics are available for small rearing units where

fish are easily accessible.

Among these are: 1-min dip in a 2-5% solution of acetic acid and a 1-2

min dip in a 3-5% solution of sodium chloride.

Prevention

When possible, quarantine any new fish prior to placing them in with

existing fish when possible. Avoid any water source with wild fish

population, maintain optimum water quality, and reduce crowding.

E . ffects on Humans Not harmful to humans
Sunfish Culture Guide 63 NCRAC Culture Series 102

Chapter 11 Common Sunfish Parasites

Figure 11.1. White Spot (Ich) is the largest protozoan found

on fish.

White Spot on the

skin, fins, and gills.

W ) hite Spot (Ich)

Causative Agent An external protozoan of the genus and species Ichthyophthirius

multifiliis (Figure 11.1). It is the largest protozoan found on fish.

Characteristics

Adults appear as white spots up to 1 mm (0.04 in.) in diameter within the

epithelial layers of the skin, fins, and gills of fish.

Upon maturity, the adult leaves the fish host and becomes enclosed in a

cyst. Within the cyst it divides and multiplies to produce 400-2,000 young.

When water conditions are favorable, the young (metacercariae) leave the

cyst and become free swimming until they find a fish host. If they do not

find a fish host within a few days they die.

Depending on the water temperature, the entire life cycle takes from 4 d to

3 wk. Ich is most active when water temperature is between 15-24o

C (60 -

75o

F).

Effects

Fish may become lethargic and lie on the bottom of the pond. They may

be seen "flashing" or rubbing against the side or bottom of a pond or tank.

Treatments

Heavy infestations affecting all fish may not respond to chemical

therapeutics and may result in severe mortality.

Treatment with formalin at 15-25 mg/l (0.002-0.003 oz/gal) in ponds for 5-7

d may work if started when Ich is first seen. If possible, raise water

temperature to 29o

C (85oF) for 3 wk.

C n aution: Formalin may also kill algae, which could lead to lowered

dissolved oxygen levels in ponds, especially at elevated temperatures.

Prevention

Quarantine any new fish prior to placing them in with existing fish when

possible. Avoid any water sources with wild fish populations,

maintain optimum water quality, and reduce crowding.

E . ffects on Humans Not harmful to humans
Chapter 11 Common Sunfish Parasites

NCRAC Culture Series 102 Sunfish Culture Guide 64

Notes

T a richodina

Causative Agent A single celled animal of the genus Trichodina. There are several species.

Characteristics

A microscopic saucer shaped protozoan with cilia at each end of the cell.

It attaches to fish by means of an adhesive sucking disk on its underside.

T o r f ichodina reproduces both sexually and through binary fission. The presence

this parasite is usually an indication of poor water quality and/or too high a

r . earing density

Effects

Large infestations of Trichodina cause fish to become lethargic, lie on their

sides or rise to the surface, and may lead to death.

Infestations on the gills cause the fish to secrete large amounts of mucous,

which impairs respiration and often leads to a secondary bacterial infection.

Treatments A 1 h bath in a 250 mg/l (0.033 oz/gal) formalin solution, where possible.

Prevention

Avoid high concentrations of organic material in rearing ponds, reduce

crowding, and maintain good water quality by monitoring dissolved oxygen

content.

E . ffects on Humans Not harmful to humans
Sunfish Culture Guide 65 NCRAC Culture Series 102

Chapter 11 Common Sunfish Parasites

Family = Trematodes—Flukes

Prevention helps ensure

profitability and smoother

sailing!!

B ) lack Spot (Black Grub)

C . ausative Agent Encysted larval flukes of the genus Uvulifer spp

Characteristics

Black pigmented cysts approximately 1 mm (0.04 in.) in diameter slightly

raised from the skin, fins, mouth, or flesh of fish.

The life cycle begins when the adult fluke living inside the intestine of a

Kingfisher produces eggs that are released in the feces. The eggs hatch

producing a free-swimming larva (miracidia) that must find a snail host

within several hours or die.

I e n the snail, the miracidia continues to develop and multiply. They leave th

snail as free-swimming larvae (cercariae) that must find a fish host within

several hours or die.

Once they enter the fish a cyst is formed around the parasite, which

remains with the fish until a Kingfisher eats it, where it then continues to

develop into an adult fluke.

Effects

In general, even heavy infestations of these parasites do relatively little

damage to the fish. There is some evidence that heavily infested juvenile

fish may experience excessive blood loss, physiological stress, and even

death. Also, fish with heavy infestations on the eyes may become blind.

T . reatments No chemical treatment

Prevention

Removal of intermediate hosts (snails and Kingfishers) will disrupt the life

cycle of this parasite. Copper Sulfate (CuSO4) applied to a pond at a rate

of 1.0 ppm, kills algae and reduces snail populations. Removal of roosting

places around a pond discourages Kingfisher predation.

E . ffects on Humans Not harmful to humans
Chapter 11 Common Sunfish Parasites

NCRAC Culture Series 102 Sunfish Culture Guide 66

Y b ellow Grub and White Grub

Causative Agent

Encysted larval digenetic trematodes of the genera Clinostomum spp.

(Yellow Grub) (Figure 11.2) and Posthodiplostomum spp. (White Grub)

(Figure 11.3).

Characteristics

Whitish or yellow pigmented cysts about 1-2 mm (0.04-0.08 in.) in

diameter slightly raised from the skin, fins, mouth, or flesh of fish (may also

occur in visceral organs).

Y e ellow grub life cycle

T e he Yellow Grub life cycle begins when the adult fluke (grub), living insid

the throat of such wading birds as egrets or herons, produces eggs that

wash out of the bird as it eats. The white grub life cycle begins when the

adult fluke (grub), living inside the intestine of such wading birds as egrets

or herons, produces eggs that are released from the bird through its feces.

Y s ellow and white grub eggs

The eggs hatch, producing free-swimming larvae (miracidia) that must find

a snail host within several hours or die. In the snail, the miracidia continue

to develop and multiply.

They leave the snail as another free-swimming larvae (cercariae) that must

find a fish host within several hours or die. Once they enter the fish, a cyst

is formed around the larval parasite (metacercariae). The parasite

remains with the fish until eaten by a heron or egret where it continues to

develop into an adult.

Effects

Generally, even heavy infestations of these parasites do relatively little

damage to the fish. Infestations of these flukes do affect the marketability

by making the fish aesthetically unpleasing and difficult to sell as food.

Treatments

Several chemical treatments reduce infestations in laboratory research,

although these chemicals are expensive and currently not approved for use

by the US FDA.

Prevention

Removal of intermediate hosts (snails and wading birds) disrupts the life

cycle of these parasites. Copper Sulfate (CuSO4

) applied to a pond at a

rate of 1.0 ppm, for algae control, reduces snail populations and removal

of roosting places around ponds discourages heron and egret predation.

E . ffects on Humans Not harmful to humans
Sunfish Culture Guide 67 NCRAC Culture Series 102

Chapter 11 Common Sunfish Parasites

Figure 11.2. The yellow cysts identified the Yellow Grub

parasite that begins life inside the throat of wading birds.

Figure 11.3. The white cyst identifies the White Grub

parasite that begins life in the intestine of wading birds.

B m ass Tapeworm

Causative Agent A cestode of the genus and species Proteocephalus ambloplitis.

Characteristics

The adult tapeworm may grow to a length of 300-400 mm (12-16 in.). It

fixes itself to the intestinal wall of the final host (commonly bass and

sunfish) by means of muscular suckers on its head.

The body of the tapeworm consists of numerous segments called

proglottids. Each proglottid has its own reproductive system. When a

proglottid is filled with eggs, it breaks away from the body of the tapeworm

and is passed from the fish into the water.

The water dissolves the casing of the proglottid and the eggs are

released. In order for the life cycle to continue, certain copepod

crustaceans (the first intermediate host) must eat the eggs.

In the body of the crustacean, the eggs hatch and develop into a larva

called a procercoid. Once the crustacean is eaten by another fish (the

second intermediate host), the procercoid larva bores through the wall of

the digestive tract and invades the visceral organs of the fish such as the

liver, spleen, or reproductive organs.

The life cycle comes full circle when a bass or sunfish (the final host) eats

the fish containing the procercoid larva, which then attaches to the intestine

and develops into adult tapeworms.

Effects

Large infestations of Proteocephalus ambloplitis can cause nutritional

deficiencies leading to fish sterility and death.

T . reatments No approved chemical therapeutic

Prevention

Use parasite free brood stock. Avoid using a water source with wild fish

that may be infected.

E . ffects on Humans Not harmful to humans
Chapter 11 Common Sunfish Parasites

NCRAC Culture Series 102 Sunfish Culture Guide 68

Figure 11.4. Fish lice have a clear, gelatinous disc shaped

body with eight legs and a small tail and are visible to the

naked eye.

Summary

There are several common parasites of

sunfish that may occur in culture situations.

However, because there are so few approved

chemicals for treatment of parasites in

aquaculture, the best “treatment” of parasites

is through prevention.

Maintaining good water quality, reducing bird

and snail populations, and limiting fish stress,

greatly reduce parasite outbreaks.

A ) rgulus (Fish Lice)

Causative Agent A monogenetic fluke of the genus Argulus (Figure 11.4).

Characteristics

A clear, gelatinous disc shaped body with eight legs and a small tail.

Visible to the naked eye they generally grow to between 7-10 mm (0.3-0.4

in.). It has two hooks for attaching itself to a fish and a proboscis between

its eyes, which it forces under the scales and into the skin. It feeds by

sucking the fish's blood.

Mating takes place in late spring and summer. The female deposits her

eggs along the sides of a pond in long, flatish tubes. Females die after

egg deposition and the eggs hatch in about a month. After hatching, the

young will mate and attach themselves to a fish host.

Effects

Heavy infestations can cause large mortalities. This parasite is also

suspected as a carrier of viral infections.

Treatments

A 1 h bath in a 200 mg/l (0.027 oz/gal) formalin solution where possible. A

15-min bath in a 2% salt solution is effective in controlling this parasite, but

not practical in large scale pond culture.

Prevention

Avoid high concentrations of organic material in rearing ponds, reduce

crowding, and maintain good water quality by monitoring dissolved oxygen

content.

E . ffects on Humans Not harmful to humans
Collecting Fish Samples for

Disease Diagnosis

Because disease can be common among fish, it isessential to recognize potential diseases and know

what steps to take. Knowledge of how to correctly collect

and ship samples of fish suspected of disease is vital for

an accurate and timely diagnosis.

This chapter explains:

• Disease management

• Locating a fish health specialist

• How to collect samples

• How to ship samples

• Forms to include

12

Sunfish Culture Guide NCRAC Culture Series 102

Disease Diagnosis
Chapter 12 Collecting Fish Samples for Disease Diagnosis

NCRAC Culture Series 102 Sunfish Culture Guide 69

Ø Quickly recognize the

beginning of a

problem.

Ø Correctly collect

samples.

Ø Correctly ship

samples.

Ø Provide timely and

accurate information

on the problem.

It is essential to:

12

Collecting Fish Samples for Disease Diagnosis

Authors: M. Riche and D. L. Garling, Michigan State University

Disease Management

Disease is a common problem in fish culture.

It can reduce hatchery efficiency and

production, which increases costs and reduces

profits. Disease occurs as a result of

interactions between the fish, pathogens, and

the environment. Disease outbreaks occur

when a fish’s resistance is lowered due to

stress caused by environmental fluctuations

and poor management practices (Figure 12.1).

Prevention requires a minimizing of

environmental fluctuations and practicing good

farm management. Daily observation of fish

behavior and feeding activity is necessary to

allow early problem detection so that an

accurate diagnosis and treatment can be

performed early.

Despite careful and conscientious

prevention, disease problems can still occur.

When a problem does occur, it is important to

catch and correct the problem quickly. A fish

culturist must have an existing plan to handle

the problem.

Sound strategy is knowing:

Ø The nearest fish health diagnostic

laboratory.

Ø How to collect diseased specimens.

Ø How to properly get the specimens to the

laboratory.

It is essential that a fish culturist and fish

health specialist work closely together. It is the

fish health specialist’s responsibility to make

Figure 12.1. Diseases occur in fish populations when three

ingredients are present: fish, a stressor, and a disease

organism. The shaded area in the figure indicates disease

when these three ingredients overlap.

Fish Stress

Disease Organism
Chapter 12 Collecting Fish Samples for Disease Diagnosis

Sunfish Culture Guide 70 NCRAC Culture Series 102

a timely and accurate diagnosis. It is the fish

culturist’s responsibility to provide the

specialist with the tools to do the job. Working

closely together increases the likelihood of a

quick, accurate diagnosis followed by

appropriate treatment.

For the fish health specialist to be effective

in treating the disease, it is essential for the

culturist to act quickly. A case history form

should accompany the diseased fish to the

laboratory. The form provides information

necessary for the fish health specialist to

provide a timely and accurate diagnosis.

Locating a Fish Health Specialist

Specific identification of the cause of fish

disease and treatment recommendations

usually require examination by a fish health

specialist. To find the nearest fish health

specialist, contact:

Ø An aquaculture extension specialist.

Ø State Department of Agriculture

aquaculture coordinator.

Ø State aquaculture association.

The fish culturist should always contact a fish

health specialist prior to bringing in or shipping

specimens. This ensures the laboratory can

handle the case in a timely and efficient

manner. The fish health specialist can often

suggest the most appropriate method for

shipping fish when they are contacted prior to

capturing the fish. This enhances the likelihood

of successful shipping and a more accurate

diagnosis.

How to Collect Samples

Collecting samples requires

more than just capturing

sick fish. It

requires

collecting and recording some

important observations and

information to help the fish

health specialists make a

diagnosis.

Prior to collecting fish specimens:

Ø Perform a water quality analysis.

Ø Use a pond side water quality kit to ensure

an adequate analysis.

Record mortality rates

Recording any daily mortality rates is an

important step in finding and understanding a

disease problem.

These records are valuable tools that provide

the fish health specialist important clues.

A pattern similar to curve one, where mortality

is rapid and approaches 100% within 1–2 d,

suggests mortality is due to a severe

environmental problem.

Problems associated with this pattern include:

Ø Low dissolved oxygen

Ø Temperature and pH

Ø Carbon dioxide

Ø High ammonia and nitrite levels

Ø Toxic chemical(s)

To help the fish health specialist determine

the cause of death, test the water for:

Ø Dissolved oxygen

Ø Carbon dioxide

Ø Conductivity and pH

Ø Temperature

Ø Ammonia and nitrite levels

Ø Alkalinity

Ø Hardness

Ø Biological oxygen demand (BOD)

Ø Total suspended solids (TSS), where

practical

Record the results on a case history form.

Use live fish

To enhance the chance of a quick and

accurate disease diagnosis, use live fish.

Submitting live fish for diagnosis allows the fish

health specialist to observe behavior and

clinical symptoms first hand.

Live fish can either be transported directly to

the disease diagnostic laboratory by the fish
Chapter 12 Collecting Fish Samples for Disease Diagnosis

NCRAC Culture Series 102 Sunfish Culture Guide 71

culturist, or shipped. Direct transport is the

preferred method, since the fish generally

arrive at the diagnostic laboratory more quickly

and in better condition than when shipped. This

method also allows the fish health specialist

to ask the culturist any relevant questions

regarding the disease incident.

Collecting live fish at the surface with a dip

net or cast net is the best method for capturing

diseased fish. Sick fish rarely eat, so using a

hook and line for collecting fish is usually

ineffective.

Similarly, fish caught in a seine are often

healthy and can lead to a misdiagnosis.

Dead fish collection

If live fish are not available, use dead fish,

but only if they have been dead <6 h. Fish

dead >6 h exhibit an increased tissue

decomposition, reduced parasitic loads, or can

contain bacteria that confuse the results.

Dead fish that do not have red gills, normal

coloring, or lack mucous are generally

unacceptable for diagnosis.

Collect water sample

When sending specimens to a disease

diagnostic laboratory, collect a water sample

in a clean, sealed jar or bottle at the same time

the fish are collected.

Before collecting the water sample, rinse the

container two to three times with the water to

be collected. Seal the container under water

being careful to eliminate any air bubbles.

Water samples are often helpful to a

specialist in making a diagnosis. Not all

disease diagnostic laboratories are equipped

to analyze water quality samples, however.

The fish health specialist or local extension

specialist can help locate a suitable water

quality analysis laboratory.

Collecting samples also requires collecting

and recording important observations and

information to help the fish health specialist

make a diagnosis.

These include:

Ø Gathering representative specimens

exhibiting clinical signs of disease.

Ø Collecting water samples.

Ø Recording any observations on a case

history form.

Shipping Samples

Fish can be sent to the fish health specialist

by a variety of methods. Contact the nearest

available fish health specialist for the best

shipment method.

 Contact the nearest available fish health

specialist for the best shipment method.

These include:

Ø Transporting or shipping live fish.

Ø Shipping fish on ice.

Ø Shipping frozen fish.

Ø Shipping fish fixed and preserved.

Remember to make certain the case history

form accompanies any fish to the diagnostics

laboratory to help the specialist.

Choosing specimens

When transporting or shipping sick fish,

select smaller individuals. Choose

representative fish that clearly exhibit clinical

signs of the disease.

Some clinical signs to look for include:

Ø Lethargy (lack of energy)

Ø Refusal to eat

Ø Erratic swimming

Ø Red or white spots

Ø Fungus

Ø Discoloration of skin, gills, or eyes

Ø Lesions or ulcers

Ø Fin erosion

Shipping methods

are important.
Chapter 12 Collecting Fish Samples for Disease Diagnosis

Sunfish Culture Guide 72 NCRAC Culture Series 102

Ø Cysts

Ø Internal or external parasites

Ø Hemorrhaging.

If the fish health specialist recommends

shipping freshly killed fish, the fish should be

euthanized prior to preparation for shipping.

The most common methods for euthanasia

are over anesthetization with tricaine

methanesulfonate (Finquel®), benzocaine, or

carbon dioxide.

To assist a fish health specialist make a

diagnosis, include 2–3 healthy fish for

comparison. Keep healthy fish separate from

diseased fish and clearly marked.

It is important to properly prepare fish for

shipping to maintain tissue integrity for an

accurate diagnosis.

Plastic bag shipments

When fish cannot be transported to the fish

health specialist directly, the next most

desirable method is to ship them live. It is

important to select specimens that will survive

since disease organisms quickly leave dead

fish. This can contaminate other fish and lead

to a misdiagnosis.

The specimens should be shipped in heavy

duty plastic bags. Double bagging is best to

reduce the risk of puncture or leakage. Then:

Ø Fill the bags with clean water

approximately 1/3 full to leave sufficient

room for oxygen addition.

Ø Place 3–7 fish in the bag.

Ø Add pure oxygen to fill the bag.

Ø Ship the bags in a cooler or box.

¡ Cardboard boxes can be used, but

Styrofoam is preferred to reduce

changes in temperature.

¡ Pack crushed ice around the bags for

long trips.

Iced shipments

If the captured specimens are unlikely to

survive the trip to the disease diagnostic

laboratory, they can be shipped on ice.

Ø Place the fish in sealed bag without water

but on crushed ice.

¡ Shipping fish in water increases

tissue decomposition, potentially

confusing the diagnosis.

¡ No more than one fish should be

placed in a bag.

Ø Ship the fish in an insulated and sealed

container to prevent leaking.

Frozen specimen shipments

When live fish can’t be transported or

shipped immediately, they can be shipped

frozen. This method is less desirable than iced

specimens because thawing frozen

specimens destroys cells, making some

diseases hard to diagnose.

Freezing does not destroy bacteria, viruses,

and fungus, so their detection is still possible.

To ship the specimens:

Ø Contact the carrier about their regulations

regarding the shipment of packages

containing dry ice.

Ø Place diseased fish in a heavy duty bag

with a small amount of water and freeze.

Ø Cover the frozen fish (in the bag) with dry

ice in a well insulated container.

¡ A cooler

¡ Styrofoam box

Ø Include the case history sheet.

Ø Ship the specimens immediately after

packing.

¡ Samples remain frozen for 24–36 h.

When fish are thawed, coloration is lost. This

makes it important to record any unusual

coloration on the case history sheet before

freezing the sample.
Chapter 12 Collecting Fish Samples for Disease Diagnosis

NCRAC Culture Series 102 Sunfish Culture Guide 73

Preserved specimen shipments

This method is the least preferred method of

shipping fish to the fish health specialist. Some

diseases cannot be detected after preserving

the specimens in a fixative.

Bacteria, viruses, and fungus are killed by

fixatives and make their detection difficult. If

there is no other alternative, this method can

be used to determine some parasites and the

presence or absence of some bacteria (some

commonly used fixatives for preserving

specimens are listed in Table 12.1).

The best fixative for soft tissues, such as

organs, is the buffered formalin. For whole fish,

the preferred fixative is Bouin’s solution. When

preserving fish, it is best to use freshly

euthanized fish. It is important when

preserving freshly euthanized fish to:

Ø Use smaller fish

¡ They generally preserve better.

¡ They require less fixative.

Ø Place fish sized <5 cm (2 in.) directly into

the fixative.

¡ If fish >5 cm (2 in.) are used, cut

open the abdominal cavity to expose

the internal organs to the fixative.

Ø Use approximately 10 times more fixative

than tissue.

¡ A whole fish weighing 50 g requires

500 ml of fixative.

¡ A whole fish weighing 100 g requires

1,000 ml of fixative.

After 24–48 h:

Ø Carefully remove the fish from the fixative

and transfer to a 70% solution of alcohol.

¡ Ethyl alcohol is preferred.

¡ Either ethyl alcohol (ethanol) or

isopropyl alcohol can be used.

Ø Place the specimens in a heavy duty

sealed plastic bag containing the alcohol.

¡ Double bag to reduce the risk of

puncture or leakage.

Contact the carrier about their regulations

regarding the shipment of packages

containing alcohol.

Summary

Disease outbreaks reduce hatchery

efficiency and production, increase costs, and

reduce profits. Disease occurs as a result of

interactions between fish, pathogens, and the

environment. When a problem occurs, it is

important to catch and correct the problem as

quickly as possible.

The responsibility of the fish culturist is to:

1. Quickly recognize beginning problems.

2. Correctly collect samples.

3. Correctly ship the samples.

4. Provide timely and accurate information

regarding the problem.

The fish culturist and fish health specialist

who work closely together increase the

likelihood of a quick, accurate diagnosis,

followed by an appropriate treatment.

Note: A sample of the form to include with

your fish specimens is included at the end of

this chapter.

Bouin’s Solution

Saturated Pictric Acid 750 ml

Concentrated Formalin 250 ml

Galcial Acetic Acid 50 ml

Buffered Formalin

Concentrated Formalin 100 ml

Distilled Water 900 ml

Sodium Phosphate Monobasic 4.0 g

Sodium Phosphate Dibasic 6.5 g

Davidson’s Fixative

95% Ethyl Alcohol 300 ml

Concentrated Formalin 200 ml

Glacial Acetic Acid 100 ml

Distilled Water 300 ml

Table 12.1. Several different fixatives are commonly used

for preserving fish specimens.
Chapter 12 Collecting Fish Samples for Disease Diagnosis

Sunfish Culture Guide 74 NCRAC Culture Series 102

Laboratory Name:

Address:

Phone:

Case No.:

Date Rec’d:

Rec’d By:

For Laboratory Use Only

Case History Form

Owner Information

Owner’s Name:

Address:

Phone: (Home):

Phone (Farm):

General Information

Species:

Type of Culture System:

Source of Fish:

Feed Type and Amount (% BW/day):

Density Stocked:
Chapter 12 Collecting Fish Samples for Disease Diagnosis

NCRAC Culture Series 102 Sunfish Culture Guide 75

General Specimen Information

How many specimens are being submitted?

How are fish being submitted (live, iced, frozen)?

Were all the fish collected from the same tank or pond?

Date the fish were collected:

Is a water sample being submitted?

Describe how many fish are dying a day and how long they have been dying:

Is this a recurring problem?

When was the pond or tank stocked?

When was the last time the tank or pond was treated?

What was it treated with?

What was the concentration?

Yes No o o

Yes No o o

Yes No o o When did it last occur?

How often was it treated?
Chapter 12 Collecting Fish Samples for Disease Diagnosis

Sunfish Culture Guide 76 NCRAC Culture Series 102

Water Quality

Water Source:

Temperature:

pH:

Hardness (mg/L Ca CO3

):

Water Color:

Has the color changed recently?

Was there a change in weather?

Describe the change in the weather?

Flow (gpm):

Dissolved Oxygen (ppm):

Ammonia (ppm): Nitrate (ppm):

Alkalinity (mg/L CaCo3

):

Total Suspended Solids:

Yes No o o When did it change?

Yes No o o

Fish Behavior

Are fish eating?

Are fish listless?

Are fish flashing?

How long have fish been off feed?

Are fish swimming erratically?

Are fish swimming on their side?

Yes No o o

Yes No o o

Yes No o o

Are fish staying near the inlet, outlet, or aeration devices? Yes No o o

Yes No o o

Yes No o o
Chapter 12 Collecting Fish Samples for Disease Diagnosis

NCRAC Culture Series 102 Sunfish Culture Guide 77

Fine o

Fine o

Yes No o o

Disease Signs (Check those that apply)

Is there redness on the following:

Color of Gills:

Appearance of Gills:

Appearance of Fins:

Do the fish appear emaciated?

Are there sores or ulcers?

Are cysts present?

Are the eyes cloudy?

Are the eyes bulging?

Are there air bubbles in the skin, eyes, or fins?

Does there appear to be an excess of mucous?

Are there signs of fluid filled body cavity or bloating?

Is the body coloration normal?

Is there a white cottony growth on skin, gills, or fins?

Belly o Skin o Side o Fin o Mouth o None o

Dark Red o Bright Red o Pale o Grey o Brown o

Frayed o Uneven o Yellow Mucous o

Frayed o

Clubbed o

Eroded o Redness o Bloody o

Yes No o o

Yes No o o Where are they located?

Yes No o o Where are they located?

Yes No o o

Yes No o o

Yes No o o

Yes No o o

Yes No o o

Yes No o o How is coloration different?

Give a brief description of other clinical signs:
Chapter 12 Collecting Fish Samples for Disease Diagnosis

Sunfish Culture Guide 78 NCRAC Culture Series 102

Additional Comments:
References

NCRAC Culture Series 102 Sunfish Culture Guide 79

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Tidwell J.H., C.D. Webster, J.A. Clark, and M.W.

Brunson. 1994. Pond culture of female green

sunfish (Lepomis cyanellus) x male bluegill

(Lepomis macrochirus) hybrids stocked at 2

sizes and densities. Aquaculture 126:305-313.

Toetz D.W. 1966. The change from endogenous

to exogenous sources of energy in bluegill

sunfish larvae. Investigations of Indiana Lakes

& Streams 7:115–146.

Tomelleri J. and M. Eberle. 1990. Pp 167–193.

In: Fishes of the Central United States.

Lawrence, KS: University of Kansas Press.

Webber H.H. and P.F. Riordan. 1976. Criteria

for candidate species for aquaculture.

Aquaculture 7:107–123.

Webster C.D., J.H. Tidwell, L.S. Goodgame,

J.A. Clark, and D.H. Yancy. 1992. Effects of

protein level on growth and body composition

of hybrid sunfish (Lepomis cyanellus x

Lepomis macrochirus) reared in ponds.

Transactions of the Kentucky Academy of

Science 53:97–100.

Webster C.D., L.G. Tiu, and J.H. Tidwell. 1997.

Growth and body composition of juvenile

hybrid bluegill Lepomis Cyanellus x Lepomis

macrochirus fed practical diets containing

various percentages of protein. Journal of the

World Aquaculture Society 28:230–240.

West J.L. and F.E. Hester. 1966. Intergeneric

hybridization of centrarchids. Transactions of

the American Fisheries Society 95:280–288.

Westmaas A.R. 1992. Polyploidy induction in

bluegill sunfish (Lepomis macrochirus).

Master’s thesis, Michigan State University,

East Lansing.

Wills P.S., J.M. Paret, and R.J. Sheehan. 1994.

Pressure induced triploidy in hybrid Lepomis.

Journal of the World Mariculture Society

25:507–511.

Wrenn W.B., B.J. Armitage, E.B. Rodgers, T.D.

Forsythe, and K.L. Grannemann. 1979. Effects

of temperature on bluegill and walleye, and

SUNFISH GUIDE!

periphyton, macroinvertebrate, and

zooplankton communities in experimental

ecosystems. Washington, D.C.: U.S.

Government Printing Office. Environmental

Protection Agency EPA-600/3-79-092.

Tidwell J., C. Webster, and J. Clark. 1992.

Growth, feed conversion, and protein
Appendices

Sunfish Culture Guide NCRAC Culture Series 102

Appendices
NCRAC Culture Series 102 Sunfish Culture Guide 84

Appendix A

Chapter 9

1Obtain additional information on site

development for parks or campgrounds from

your state’s Cooperative Extension Service.

For example, Michigan Extension Service

Bulletin No. E-1252, Site Development

Process, provides valuable information on the

recreational site development process.

The Southern Regional Aquaculture Center

(SRAC) also has several publications on feefishing, SRAC Publications 479A-482.

2

The Fisheries and Wildlife specialist for your

State’s Cooperative Extension Program can

provide additional information on the

management of cold water and warm water

ponds for fishing, weed control, a list of

commercial fish sources, and assistance in

controlling fish predators.

3

Additional information on marketing your feefishing business is available from: Michigan

State University Cooperative Extension

Service Bulletin E-2409, Promoting fee-fishing

operations as tourist attractions.

4

Additional information on the benefits of

incorporating may be obtained from the your

state’s Cooperative Extension Service.

Chapter 10

1

Lists of approved drugs and chemicals that

are of low regulatory priority can be acquired

from your state aquaculture extension

specialist or on the Internet through the

AquaNIC (http://aquanic.org) home page.

Chapter 11

1

Access the FDA Internet homepage for more

information on drugs available for aquaculture

and INADs at:

http://www.fda.gov/cvm.

Appendix A: Chapter Notes

Chapter 2

1

 A number of researchers have observed and

verified the development of green sunfish and

bluegill larvae.

Chapter 3

1

 Tidwell et al. and Webster et al. studies are

excellent resources for information on the

measurements of SGR and FCR in hybrid

small fish.

2 Cage culture works well in ponds with

irregular shapes and can be lined up in a row

for efficiency of space.

3

 For further information on hatch rates and

larval rearing of bluegill, see Toetz (1966).

Chapter 4

1 For a more in depth look at species

characteristics through the last two decades,

read both Pflieger (1975) and Tomelleri and

Eberle (1990)’s studies.

2

 Hormones have only recently come into use

as an animal drug and hormonal use and

injections should only be done under close

supervision of a qualified veterinarian to avoid

serious damage.

Chapter 6

1

 Temperature plays an important role in every

aspect of aquaculture and can positively or

negatively affect sunfish survival,

reproduction, and growth. This can impact the

profitabality of an aquaculture venture.

Chapter 7

1

 If you are interested in aquaculture, contact

the NCRAC for the resource location nearest

to you. There are experts available to help you

get started and review with you options, pitfalls

to watch out for, and ways to help make your

business successful.
Appendix B

Sunfish Culture Guide 85 NCRAC Culture Series 102

This list of names and addresses for organizations and websites offer additional information on

aquaculture and fish health. These contacts can offer more in-depth resources for specific topics

related to sunfish culture.

Your particular state’s Fisheries Cooperative Extension Program or the North Central Regional

Aquaculture Center Contact (Table B.1) provides further information on many of the topics covered.

Ted Batterson, Director of the North Central Regional Aquaculture Center at:

Michigan State University

13 Natural Resources Building

East Lansing, MI 48824-1222

The associate director of the North Central Regional Aquaculture Center can be reached at:

Joseph E. Morris

Iowa State University

124 Science II

Ames, Iowa 50011-3221

An excellent source for general aquaculture information is the Aquaculture Network Information

Center (AquaNIC). The AquaNIC website contains valuable information and numerous resource

links. The AquaNIC web address is: http://aquanic.org.

Table B.1. Contacts for additional or specific information.

C e s ontact Name P s x ostal & Email Address T x elephone/Fax

M e r. Fred P. Binkowski Great Lakes WATER Institut

University of Wisconsin-Milwaukee

600 E. Greenfield Avenue

Milwaukee, WI 53204

sturgeon@csd.uwm.edu

(414) 382-1723

(414) 382-1700

Fax: (414) 382-1705

Mr. Jeffrey L.

Gunderson

Minnesota Sea Grant Extension Program

University of Minnesota-Duluth

2305 East 5th Street

Duluth, MN 55812

jgunderson@extension.umn.edu

(218) 726-8715

Fax: (218) 726-6556

D a r. Ronald E. Kinnunen Michigan State University - Upper Peninsul

702 Chippewa Square

Marquette, MI 49855-4811

kinnunen@msue.msu.edu

(906) 228-4830

Fax: (906) 228-4572

Appendix B: Contacts for Additional Information
Appendix B

NCRAC Culture Series 102 Sunfish Culture Guide 86

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llaHllaC-ytisrevinUetatSsasnaK

0061-60566SK,nattahnaM

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4375-235)319(

1865-235)319(:xaF

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9974-10475DS,needrebA

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0217-626)506(

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Table B.1 continued
Sunfish Culture Guide 87 NCRAC Culture Series 102

Appendix C

Appendix C: Abbreviations, Acronyms, Common Names

A r quaNIC Aquaculture Network Information Cente

B s OD Board of Director

o

C s degree of Celsiu

C e ES Cooperative Extension Servic

c r m centimete

d y da

o

F t degree Fahrenhei

F e CR Food Conversion Rat

F n DA Food and Drug Administratio

F . FO Freshwater Farms of Ohio, Inc

F g MA fish meal analo

ft, ft

2

, ft

3 foot, square foot, cubic foot

g ) gram(s

g ) al gallon(s

G h xB hybrid sunfis

h ) hour(s

h ) a hectare(s

H s ACCP Hazard Analysis Critical Control Point

I l AC Industry Analysis Counci

IAFWA International Association of Fish and

Wildlife Agencies

I r GF-1 insulin-like growth facto

i ) n. inch(es

I g NAD Investigational New Animal Dru

ISU Illinois State University

Iowa State University

J e SA Joint Subcommittee on Aquacultur

k ) g kilogram(s

L ) liter(s

l ) b pound(s

m, m2

, m3 meter, square meter, cubic meter

μm micrometer

m ) g milligram(s

m ) in minute(s

m ) L milliliter(s

M y SU Michigan State Universit

N r numbe

N s ADA New Animal Drug Application

N n CR North Central Regio

NCRAC North Central Regional Aquaculture

Center

N y DSU North Dakota State Universit

O n AA Ohio Aquaculture Associatio

O y SU Ohio State Universit

o ) z ounce(s

p n pm parts per millio

P y urdue Purdue Universit

R ) AC(s) Regional Aquaculture Center(s

R s AS recirculating aquaculture system
NCRAC Culture Series 102 Sunfish Culture Guide 88

Appendix C

S e GR specific growth rat

S e IUC Southern Illinois University-Carbondal

TC

Technical Committee (TC/E =

Technical Committee/Extension; TC/R

= Technical Committee/Research)

T h L total lengt

T s SS total suspended solid

U i M University of Missour

U a Mn University of Minnesot

U e SDA U. S. Department of Agricultur

U e SFWS U.S. Fish and Wildlife Servic

y d d yar

Y r OY young-of-the-yea

y ) r year(s

> n more tha

< n less tha

Other Abbreviations and Acronyms

C s ommon Names Scientific Name

Bluegill Lepomis macrochirus

Redear Lepomis microlophus

Green Sunfish Lepomis cyanellus

Pumpkinseed Lepomis gibbosus

Warmouth Lepomis gulosus

Longear Lepomis megalotis

Red Breast Sunfish Lepomis auritus

Common and Scientific Names of Sunfish
Sunfish Culture Guide 89 NCRAC Culture Series 102

Index

F

Fee fishing 31, 41, 42, 43, 44, 45, 46, 47

Feeds and feeding

3, 5, 6, 9, 12, 13, 16, 17, 18, 23, 25,

44, 48, 49, 53, 58, 69, 74, 76

Fertilization 5, 15, 19, 20, 27, 37, 38, 39

Fingerlings 14

Flukes 59, 65

Forage 2

Formalin 50, 51, 52, 53, 59, 73

Fry 5, 6, 8, 9, 15, 16, 17, 30, 39, 40

G

Gametes 15, 19, 27

Green sunfish 2, 5, 6, 10, 11, 13, 17, 23, 25,

26, 28, 34, 36

Grow-out 3, 12, 13, 14, 15, 18, 39

Growth 2, 3, 5, 6, 13, 14, 16, 17, 25, 26, 29,

30, 34, 35, 40, 43, 44, 77

H

Hatching 5, 6, 7, 8, 9, 15, 16, 17, 27, 29, 30,

36, 39

Heart 7, 8

History 1, 4, 26, 70, 71, 72, 74

Hormones 23, 24

Hybrid 1, 2, 3, 4, 6, 7, 8, 9, 10, 13, 14, 15, 20, 23,

25, 26, 27, 28, 31, 34, 35, 36, 41, 44

Hydrostatic pressure 36, 37

I

Industry 31, 34

Insects 6, 12

Intensive culture 2, 15, 16, 17, 39

Intermediate host 58, 59

Intestine 7, 8, 59, 60, 67

Investment 14, 46, 47, 60

K

Karyotyping 40

A

Acanthocephala 60

Acclimate 20

Acetic acid 59, 73

Anesthetic 19

Angler 34, 35, 41, 42

B

Bass tapeworm 67

Behavior 2, 4, 5, 9, 25, 35, 58, 69, 70, 76

Biology 1, 2, 3

Blood 7, 40

Brine shrimp 16, 17, 18

Brood stock 12, 15, 16, 19, 20, 22, 23, 24, 34

Brook trout 44

Brown trout 44, 47

Buffalo 23

Business 41, 42, 45, 46, 47

C

Cage culture 14

Capillary tube 22, 24

Carp 41

Catch-out 41, 42

Catfish 12, 26, 34, 41, 44, 47

Centrarchid 1, 25

Cestodes 60

Chromosomes 35, 36, 37

Cladocerans 6

Commercial feed 17,

Courtship 4, 5, 16

Crappie 1, 44

Crayfish 6

Cytometry 36, 39, 40

D

Digenetic trematode 59

E

Ecology 2

Economics 46

Embryo 6, 7, 27

Exogenous 5, 6, 9, 17, 18

Eyes 7, 8, 59, 71, 77

Index
Index

NCRAC Culture Series 102 Sunfish Culture Guide 90

L

Laboratory culture 15, 16, 18, 27, 36, 40

Largemouth bass 2, 41, 47

Larvae 5, 6, 7, 8, 9, 15, 16, 17, 18, 22,

36, 39, 60

Liability 42, 45, 46

Light 5, 15, 21, 27, 58

M

Marketing 2, 3

Meiosis 36

Meristic 6, 26

Metacercariae 59

Micropterus 1

Milt 15, 19, 20, 22, 27, 37, 38

Monogenetic trematode 59

Mortality 29, 45, 48, 58, 70

Mouth gape 6, 8, 9, 17

Myomere 6, 7, 8

N

Nests 4, 5, 16, 29

Nematodes 60

Northern pike 44

Notochord 7

Nutrients 5, 17, 43, 44

O

Oil globule 6, 7, 8

Oncorhynchus mykiss 44

Out-of-season 3, 16, 18, 36, 38

Osmoregulation 20

Ovaries 15, 16, 22, 35

Overpopulation 2, 25, 26, 35, 44

Ovulation 23

P

Parasites

44, 48, 49, 51, 53, 58, 59, 60, 67, 68, 71,

72, 73

Pay lakes 41

People management 42, 45

Perch 44

Phosphorus 13

Photoperiod 5, 15, 16, 23, 24, 27

Pigmentation 6, 7, 8, 9

Plankton 6, 16, 17

Polyploid 34, 35, 36

Pomoxis 1

Pond management 22, 42, 44

Prey 6, 17

Probing 21, 24

Production 1, 2, 12, 13, 14, 15, 18, 23, 24, 26,

27, 28, 31, 33, 34, 35, 36, 37, 40, 39, 58, 69,

73, 78

Protein 12, 13, 14, 18

Protozoa 59, 61, 63

Pumpkinseed 17

R

Rainbow trout 12, 35, 44, 47

Recirculating system 13, 14, 15, 18, 31, 54

Redbreast sunfish 26

Redear sunfish 1, 2, 4, 5, 6, 17, 26, 28

Reproduction

1, 4, 14, 17, 23, 25, 26, 33, 34, 35, 40

Rotifers 6, 17

Roundworms 60

S

Salmo trutta 44

Salt 20, 53, 54, 55

Salvelinus fontinalis 44

Sexing 20, 21, 22, 23

Sodium chloride 53, 54, 59

Spawning 3, 4, 5, 9, 12, 15, 16, 18, 20, 23, 24,

27, 28, 29, 30, 34, 35, 37, 38, 76, 77

Sperm 19, 35, 37, 38, 78

Spiny headed worms 60

Stocking 2, 12, 14, 15, 16, 18, 19, 20, 22, 23, 24,

26, 27, 28, 31, 34, 44

Stripping 15, 19, 27

Survival 16, 17, 18, 29, 30, 34, 36, 58

Swim bladder 6, 8, 9

Swim-up 5, 6, 7, 9, 16
Sunfish Culture Guide 91 NCRAC Culture Series 102

Index

T

Tanks 15, 16, 17, 18, 37, 49, 54

Tapeworms 60

Temperature 1, 3, 4, 5, 6, 12, 15, 16, 17, 20, 23,

24, 26, 27, 28, 29, 30, 34, 36, 38, 39, 44,

48, 49, 70, 72, 76

Temperature shock 36

Tetraploid 35, 36, 38, 39, 40

Testes 15, 35

Tilapia 36

Trematodes 59, 65

Triploid 35, 36, 37, 39, 40, 76, 77, 78

U

Urogenital 19, 20, 21, 22, 23

W

Warmouth 17

Weight 7, 13, 23, 26, 44, 50, 57

Y

Yolk sac 5, 6, 7, 8, 9, 16, 17

Z

Zooplankton 6, 12