07AGI2005

A g r i c u l t u r a l I n n o v a t i o n s

P o l y c u l t u r e a n d R e s e r v o i r R a n c h i n g : S u s t a i n a b l e

A q u a c u l t u r e S t r a t e g i e s f o r P a d d l e f i s h ( P o l y o d o n

s p a t h u l a ) P r o d u c t i o n

Inside this fact sheet:

# Introduction

# Paddlefish

# Polyculture of Paddlefish and Catfish

# Reservoir Ranching

# Reservoir Ranching Demonstration

# Summary

# SARE Research Synopsis

# References

SARE Agricultural Innovations are based on

knowledge gained from SARE -funded projects.

Written for farmers and agricultural educators,

these peer -reviewed fact sheets provide practical,

hands -on information to integrate well -researched

sustainable strategies into farming and ranching

systems. The articles are written by project

coordinators and published by SARE.

South, Midwest and North Central regions of the

United States. Temperate climates globally.

G E O G R A P H I C R A N G E :

F a c t S h e e t Practical applications for

s u s t a i n a b l e a g r i c u l t u r e

PDF available at www.sare.org/publications/factsheet/pdf/07AGI2005.pdf

Sustainable Agriculture Research & Education

Steven D. Mims and Richard J. Onders

Aquaculture Research Center, Kentucky State University

Reservoir ranched paddlefish.

Introduction

A

quaculture is the farming and caring of aquatic organ-

isms including fish, mollusks, crustaceans and aquatic

plants under individual or corporate ownership. Aquacul-

ture has been almost entirely responsible for the expansion

of available food fish since 1988, with production doubling

in inland waters over the last decade. However, the major-

ity of the expansion in aquaculture production is from

Asian countries, largely from China.

Aquaculture in the United States ranks 11th in the world

in terms of total production and value. As a result, the

United States imports a majority of its aquatic foods,

which contributes to our nation’s trade deficit as well as an

uncertainty of supplies and product quality (1). Further,

aquaculture in the United States is expected to face strong

competition from both the continued growth of imports of

aquacultural products globally and from domestic poultry

and livestock industries (1). Species diversification, mod-

ernization of traditional production systems, and the devel-

opment of innovative production methods should be prac-

ticed to increase efficient use of water resources and lower

production costs (2).

Traditional aquacultural species in pond culture are expen-

sive because of the high costs for land, pond construction

and feed. To compete, the U.S. must produce high -value

species in production systems that use existing water more

efficiently, minimize waste of nutrients, maximize the use

of natural foods derived from solar energy (i.e. photosyn-

thesis), enhance water quality, and increase fish productiv-

ity of existing waters (3). The purpose of this fact sheet is

to describe two production systems, polyculture and reser-

voir ranching, that show promise of becoming popular

(Introduction continued on page 2)

S u s t a i n a b l e S t r a t e g i e s f o r P a d d l e f i s h S A R E 2

methods for increasing fish production and profits in inland

waters compared to a traditional monoculture system. We

also examine the usefulness of paddlefish as a high -value,

emerging species that grows well in polyculture with channel

catfish or in reservoir ranching.

Paddlefish

Paddlefish, closely related to sturgeons, are filter feeders

throughout most of their life and the only member of the

family Polyodontidae on the continent (4). Paddlefish have a

mostly cartilaginous skeleton guaranteeing no bones in the

meat. Paddlefish grow rapidly, up to 0.75 pounds/month,

and can be easily harvested by seining or gill netting. Paddle-

fish reproduction can be induced with hormones to propa-

gate; and fingerlings can be raised intensively up to stocker

size of more than 12 inches in the same season. Mature fe-

male fish (about 20 to 70 pounds) can produce about 15 per-

cent of their body weight in roe (3 to 10 pounds). However,

there are some disadvantages to paddlefish and their produc-

tion. They have poor tolerance for low dissolved oxygen (
ppm), and show handling stress when water temperatures are

higher than 70 o F. Artificial propagation and fingerling pro-

duction are complex procedures and fingerlings are vulner-

able to bird predation (5).

Paddlefish have long been an alternative to sturgeon as a

source of meat and caviar. Formerly abundant in the Missis-

sippi River basin and adjacent Gulf Coast drainage, natural

populations of paddlefish were commercially harvested for

their high -valued, boneless meat and roe sold as caviar. Con-

tinued loss and alteration of natural spawning habitat, or-

ganochlorine (i.e. chlordane and PCB) contaminants, and

overexploitation by commercial fishing are believed to be the

main reasons for declining populations.

The listing of sturgeon and paddlefish species by the United

Nations Convention on International Trade in Endangered

Species (CITES) greatly restricts the importation of sturgeon

products from the Caspian Sea area, the major source for the

world’s supply of caviar and sturgeon meat products. As a

result, there is an increasing gap between the demand and

supply of those products. In some markets, wild -caught pad-

dlefish have been substituted for sturgeon because of their

similarity in taste and quality. Producing cultured paddlefish

in the United States would help to meet the consumer de-

mand and, at the same time, reduce the pressure on natural

paddlefish/sturgeon populations.

Extensive water resources suitable for growing paddlefish

exist in the United States, including millions of acres of pri-

vate and public reservoirs throughout the United States built

for flood control management and/or hydroelectric produc-

tion. Most of those reservoirs are managed exclusively for

sport fish. However, if paddlefish were permitted to be

stocked at 10 fish/acre in just 2,000 acres/year and with a 75 -

percent harvest rate, it is predicted that enough meat and cav-

iar per year (after an initial waiting period of at least seven

years) could be produced to impact the economy by as much

as $7 million a year. Further, with catfish production being

the largest segment of U.S. aquaculture, there are over

175,000 acres of existing catfish ponds in the southern region

(1) where paddlefish could be raised also.

High feed cost is one of the major factors limiting the income

of catfish farmers. However, excess feed and excrement from

catfish make these ponds nutrient -rich and abundant with

zooplankton. Polyculture of catfish with a filter feeding spe-

cies such as paddlefish could take advantage of the zooplank-

ton in catfish ponds to increase the fish yield per acre without

adding to the feed cost. Though bighead carp, a filter -feeding

fish native to China, have been introduced into catfish ponds

and have demonstrated yields of 300 -500 kg/ha (6), meat from

this species is not well accepted by American consumers be-

cause it has small bones and a strong fish taste, causing a low

market value for this product. However, paddlefish, a native

filter feeding species, provides a more valuable meat with no

bones, a mild flavor and a firm texture (5).

Polyculture of Paddlefish and Catfish

Polyculture of paddlefish with channel catfish is a system

designed for producing yearly harvest of paddlefish for meat.

Paddlefish should be stocked large enough so as not to be

preyed on by the catfish. In production ponds, more than 12

Polycultured paddlefish.

S u s t a i n a b l e S t r a t e g i e s f o r P a d d l e f i s h S A R E 3

inches is the recommended size. In catfish fingerling ponds,

less than 12 inches is suitable.

Since paddlefish feed on natural zooplankton, there is a cer-

tain carrying capacity of fish that can be grown per surface

area of the pond based on the amount

of natural food present. Ponds that are

more than five years old typically have

an established food base favorable to

paddlefish; newer ponds should be as-

sessed before stocking. For example, in

Kentucky, we had an average fish sur-

vival of 29 percent in ponds that were

only two years old as opposed to 75

percent in ponds that were six years or

older. Paddlefish stocked at 100 fish/

surface acre should exhibit a growth

rate of about 0.5 pounds/month produc-

ing 5 - to 6 -pound fish in a year with

about a 75 -percent survival rate.

Paddlefish can be harvested using the same net or “seine” as

catfish. Seines are typically large enough to encircle the entire

area of the pond. In the middle of the seine, there is an attach-

ment known as the “sock,” which is 10 to 15 feet long and

allows the fish to congregate. Socks are of different mesh sizes

to permit the grading of fish, allowing small fish to be re-

leased back into the pond and larger fish to be harvested and

processed. During this grading process, paddlefish can be

easily removed by hand sorting. The fish are relatively docile,

and the paddle provides a convenient handle to catch the fish.

In catfish fingerling ponds, using a seine with one -inch mesh

will permit the release of small catfish and only retain the

paddlefish. Paddlefish can be held in holding nets in the pond

then loaded onto hauling truck for transport to the processing

plant.

Catfish ponds are not recommended for growing mature fe-

male paddlefish for roe. Catfish ponds present a higher level

of risk for caviar production than reser-

voir ranching due to possible mortality

from frequent handling of the paddlefish

during catfish harvest or low dissolved

oxygen (
ducers have taken the risk and have been

successful in producing caviar and meat

by careful water quality management

and infrequent harvests. Farmers who

have raised paddlefish for several years

in the same pond use gill nets to selec-

tively remove only the paddlefish. Gill

nets of four -inch mesh or larger will usu-

ally not catch catfish, and the paddlefish

are easy to remove alive. This method

is easy, but the gear may need special

permitting by state officials for use as aquaculture harvesting

equipment.

See table 1 for a comparison of two production strategies for

paddlefish.

Advantages and Disadvantages of Polycul-

turing Paddlefish with Channel Catfish

Paddlefish between 5 and 6 pounds grown with catfish in

ponds should increase production yields by 300 -500 pounds

as well as profit margins between $100 to $200/acre compared

to growing only catfish in ponds. Paddlefish are docile and

relatively easy to harvest and sort from catfish. Farmers have

Pond Polyculture with Catfish

Reservoir Ranching

Product(s)

Meat

Meat and Caviar

Stocking

100 Fish/acre

5-10 Fish/acre

Culture Duration

12 Months

7-9 Years (sexual maturity)

Potential Revenue

$100 -200/acre 1

$500 -1000/acre 2

Table 1. Biological and Economical Comparison of Paddlefish Polyculture with Channel

Catfish and Reservoir Ranching: Two Sustainable Production Strategies.

1Based on 75% survival, fingerling purchased at $3 each, and meat sold as whole fish at $1/lb.

at the pond bank. 2Based on 50 -75% of the fish harvested, at least 3 females/acre, 4 pounds of roe/female and

caviar sold at $100/lb.

Polycultured paddlefish.

S u s t a i n a b l e S t r a t e g i e s f o r P a d d l e f i s h S A R E 4

reported better water quality such as lower ammonia and ni-

trite levels with paddlefish stocked in catfish ponds. Test

markets have demonstrated a strong acceptance for paddlefish

meat, which provides a new fish product for market diversifi-

cation.

There are some disadvantages to using paddlefish in polycul-

ture with catfish. Large numbers of stocker fingerlings (>12

inches) are currently not available. Because of the limited

supply, prices of fingerlings are high (> $3). Paddlefish can

not tolerate low dissolved oxygen (
nerable to bird predation, especially at night, when the fish

has a tendency to swim near the water surface. Markets are

not well established because of lack of consistent supplies of

cultured paddlefish.

Reservoir Ranching

Reservoir ranching is an extensive, sustainable, non -polluting

production system in which young fish (more than 12 inches

in length) are stocked into lakes or reservoirs, permitted to

forage on the natural food supply and harvested (7). They can

be harvested as a meat fish after two or more years, or be per-

mitted to grow to maturity of seven to nine years and har-

vested for their meat and roe. Paddlefish are usually over 10

pounds after two years, and females will usually reach matur-

ity when the fish is over 30 pounds. To catch meat fish, 4 - to

5-inch bar mesh gill nets will catch 10 - to 30 -pound fish. For

catching mature females usually over 30 pounds, 6 -inch bar

mesh nets are best suited. Gill nets should be 150 feet long

and 18 to 24 feet deep. They should be set perpendicular to

the shore and left overnight if the water temperature is below

50 oF. When the water temperature is over 50 oF, nets need to

be checked every couple of hours to prevent fish mortality.

Paddlefish can be stocked in lakes and reservoirs that are

managed for sport fishes such as hybrid striped bass and wall-

eye. They should not be stocked in reservoirs stocked with

striped bass or tiger muskie, large predator fish that could

consume them or

could get entan-

gled in gill nets at

harvest. This sys-

tem is very eco-

nomical for pad-

dlefish caviar pro-

duction, requiring

only the purchase

of young fish, an

existing body of

water, seven to

nine years of

waiting for sexual

maturity and

harvesting.

Reservoir Ranching Demonstration

A reservoir ranching demonstration was implemented in 1996

using a private 68 -acre “strip pit” reservoir (surface -mined for

coal in the mid -1950s) in southern Indiana. Four hundred

paddlefish were initially stocked. In the winter of 2004, 6 -

inch bar mesh gill nets (about a total of 900 feet) were set for

two 24 -hour periods. About 200 paddlefish averaging 33

pounds were captured. The fish were processed, providing

about 1.75 tons of whole -dressed (de -headed and eviscerated)

fish and 180 pounds of processed caviar. Another harvest

from this reservoir in the winter of 2006 will be attempted to

further assess survival. Initial cost of fish was $1,200 and har-

vest/processing costs were $3,600. Gross revenue was over

$35,000 for the caviar sold at $150/pound and meat sold at

$2.50/pound.

Pros and Cons of Reservoir Ranching in

Large Reservoirs (>2000 acres)

Use of large reservoirs could permit large numbers (i.e.

20,000 fish in 2,000 acres) of paddlefish to be stocked for

grow -out. At least half of the fish could be females, which

Reservoir ranched paddlefish.

Harvest rate

Mature fish

No. of Fish 1

Captured

Gross Revenue 2 Returns above Vari-

able Cost 3

25%

5,000

$1435,000

$1,391,500

50%

10,000

$2,599,000

$2,339,100

75%

15,000

$3,885,000

$3,496,500

Table 2. Potential Revenue from Paddlefish Harvested from a Hypothetical 2,000 -acre Reservoir.

1 50% of the fish are predicted to be mature females with about 4 pounds of processed caviar. 2 Based on fillet meat@ $5.99/lb and caviar@$100/lb. 3 Fish and harvest costs are predicted to be about 10% of the gross revenue .

S u s t a i n a b l e S t r a t e g i e s f o r P a d d l e f i s h S A R E 5

would assist in generating revenue from a domestic supply of

high -quality meat and caviar (table 2). Paddlefish will not

reproduce in static water, so the number of fish would never

increase.

Small family

farms could

produce and

supply

young pad-

dlefish for

stocking a

local reser-

voir. More-

over, aqua-

culture in-

frastructure

such as the

hatchery

and process-

ing plant could increase employment in

rural areas. At harvest, large mesh gill

nets (6 inches in bar mesh) that are selec-

tive for large paddlefish will not capture

most sport fish as long as the reservoir is

not stocked with striped bass or tiger

muskie. Some of the money generated

from the harvest would sustain the pro-

gram for re -stocking. Overall, the esti-

mated economic impact from 2000 acres

with 75 percent of the fish recovered is

estimated to be around $7 million.

There are some disadvantages to using

large reservoirs for paddlefish produc-

tion. Most large reservoirs are considered public water and

would have to be approved for production through govern-

ment bureaucracy. Some reservoirs in the fall or during

heavy rains have rapid draw downs to lower the water level

that could permit the fish to escape. Poaching could be a pos-

sibility and would require better security around the reser-

voir. Total harvest is not possible, which would leave some of

the large fish in the reservoir to be removed later.

Currently, there are no states that practice paddlefish reservoir

ranching as a business in public waters. However, the Ken-

tucky legislature mandated that its citizens be surveyed for

their opinion on reservoir ranching of paddlefish in selected

public reservoirs. The majority of the results (about 70 per-

cent) gave positive acceptance by the public to permit this type

of production with paddlefish. Recently, the Kentucky De-

partment of Commerce started to evaluate the potential of a

pilot project. For more information, email smims@kysu.edu

Summary

Raising paddlefish in ponds with channel catfish or in reser-

voir ranching is both sustainable and economically promising

in temperate climates. The fish grows fast by filter

feeding on zooplankton and is valuable for its bone-

less meat and black roe processed as caviar. Cur-

rently, there are only a few hatcheries that produce

stocker paddlefish, and supply of the fingerlings is

limited, which inversely effects the price ( ≥$3).

Chefs at high -end restaurants indicated that the

meat was versatile, with many ways of preparation,

and that the caviar was a suitable substitute for the

more pricy sturgeon caviar.

However, inconsistent supply of

these products has slowed its mar-

ket development. To develop this

industry and increase supply, ex-

isting bodies of water are needed

to produce paddlefish. Catfish

farmers and land owners should

consider stocking paddlefish into

their ponds and private reservoirs.

Federal and state governments

need to consider changing regula-

tions to permit the stocking and

harvesting of paddlefish in se-

lected public reservoirs.

SARE Research

Synopsis

The SARE project Enhancing

Farmers’ Income through Polycul-

ture of Paddlefish with Catfish in the Southern Region was

conducted from 1999 -2002. Paddlefish were stocked in com-

mercial catfish ponds (five acres or larger) at 50 and 75 fish/

acre located in Kentucky, Alabama and Oklahoma. These

states represent low catfish production in the United States

and often lower profit margins with monoculture of catfish.

Survivals ranged from 70 to 85 percent in both densities for

all three locations. Mortalities were attributed to stocking

stress in transport and/or bird predation, not to low dissolved

oxygen or poor water quality. The growth model for this re-

gional project gave significantly greater average weight gains

of fish in KY (6.pounds) and AL (5.5 pounds) than fish in OK

(4.9 pounds). The addition of paddlefish to a catfish pond

demonstrated an increase in production of over 300 pounds/

acre, which could contribute to farm income. Estimated prof-

its could range from $100 to $200/acre when farmers pur-

chase fingerlings at $3 each and sell fish at $1/pound at the

pond bank. Overall, the polyculture system gave similar re-

sults in paddlefish growth and survival despite wide geo-

Survey of caviar taste test (top). High -end

restaurant with paddlefish caviar and meat

(bottom).

S u s t a i n a b l e S t r a t e g i e s f o r P a d d l e f i s h S A R E 6

graphical distances among the states tested, demonstrating

the versatility of this fish to adapt to varying climatic and

water quality conditions.

Fresh fillets were test marketed and chef surveyed at high -

end restaurants in Louisville and Lexington, KY. Market sur-

vey responses were scored on a scale of 5, with 1 equaling

strongly disliked or undesirable and 5 equaling strongly liked

or desirable. The taste, texture, color and overall product av-

eraged 3.8, 4.1, 4.3 and 4.1, respectively. The chefs indicated

that the product was very versatile because they were able to

cook it many different ways such as baked, broiled, smoked,

fried, etc., mainly due to its firm texture. Further, the chefs

said that the product was unique, providing their customers

with a new experience that was highly desirable and well re-

ceived by high -end clientele. Chefs preferred fillets fresh, not

frozen. Chefs were willing to purchase the fresh fillets at

prices between $7.99 and $8.99 a pound.

Paddlefish Industry Contacts

Aquaculture of Kentucky, Inc.

Owner: Dr. Bob Goetz

1424 Hammond Road

Farmington, KY

270 -227 -5888
bobzenda@vettequest.com

Big Fish Farms

Owner: Renee Koerner

Manager: Keith Koerner

303 Prospect St

Bellevue, KY 41073

513 -290 -6446
www.bigfishfarms.com
paddlefish@fuse.net
renee@bigfishfarms.com
ronincaviar@bigfishfarms.com

Osage Catfisheries, Inc.

Owner: Mr. Jim Kahrs

1170 Nichols Road

Osage Beach, MO 65065

573 -348 -2305
fishery@usmo.com

References

1. Harvey, D.J. 2004. Aquaculture Outlook. Electronic Outlook report from the Economic Research Service LDP -AQS -20,

October 8, 2004, United States Department of Agriculture, Washington, D.C., 26 pp.

2. Harvey, D. 1991. Aquaculture: situation and outlook report. USDA Economic Research Service AQUA -7. September

1991. 43pp.

3. Milstein, A. 1997. Do management procedures affect the ecology of warm water polyculture ponds? World Aquaculture 28

(3):12 -19.

4. Carlson, D.M. and P.S. Bonislawsky. 1981. The paddlefish ( Polyodon spathula ) fisheries of the midwestern United States.

Fisheries 6(2):17 -22, 26 -27.

5. Mims, S.D. 2001. Aquaculture of paddlefish, Polyodon spathula, in the United States. Aquatic Living Resources 14:391 -

398.

6. Tucker, C. S. and E. H. Robinson. 1990. Channel Catfish Farming Handbook. VanNostrand Reinhold (AVI Book), New

York, New York. 454 pp.

7. Onders, R.J., S.D. Mims, C. Wang and W.D. Pearson. 2001. Reservoir ranching of paddlefish. North American Journal of

Aquaculture 63: 179 -190.

SARE Publication #07AGI2005

This fact sheet is based on a SARE -funded project.

For more information, please visit www.sare.org >

Project Reports > Search the database

for project # LS99 -104