Agricultural Innovations

Polyculture and Reservoir Ranching: Sustainable 

Aquaculture Strategies for Paddlefish (Polyodon 

spathula) Production

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. 

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

Fact Sheet Practical applications for

sustainable agriculture

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 organisms including fish, mollusks, crustaceans and aquatic 

plants under individual or corporate ownership. Aquaculture 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 majority 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, modernization of traditional production systems, and the development of innovative production methods should be practiced to increase efficient use of water resources and lower 

production costs (2).

Traditional aquacultural species in pond culture are expensive 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. photosynthesis), enhance water quality, and increase fish productivity of existing waters (3). The purpose of this fact sheet is 

to describe two production systems, polyculture and reservoir ranching, that show promise of becoming popular

(Introduction continued on page 2)
Su s tai nab le S t r a tegie s f o r Paddle fi 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. Paddlefish reproduction can be induced with hormones to propagate; and fingerlings can be raised intensively up to stocker 

size of more than 12 inches in the same season. Mature female fish (about 20 to 70 pounds) can produce about 15 percent of their body weight in roe (3 to 10 pounds). However, 

there are some disadvantages to paddlefish and their production. They have poor tolerance for low dissolved oxygen (<2 

ppm), and show handling stress when water temperatures are 

higher than 70o F. Artificial propagation and fingerling production are complex procedures and fingerlings are vulnerable to bird predation (5). 

Paddlefish have long been an alternative to sturgeon as a 

source of meat and caviar. Formerly abundant in the Mississippi 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. Continued loss and alteration of natural spawning habitat, organochlorine (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 paddlefish 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 demand 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 private and public reservoirs throughout the United States built 

for flood control management and/or hydroelectric production. 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 caviar 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 species such as paddlefish could take advantage of the zooplankton 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 because 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. 
Su s tai nab le S t r a tegie s f o r Paddle fi 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 certain 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 assessed before stocking. For example, in 

Kentucky, we had an average fish survival 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 producing 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 attachment 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 released 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 female paddlefish for roe. Catfish ponds present a higher level 

of risk for caviar production than reservoir ranching due to possible mortality 

from frequent handling of the paddlefish 

during catfish harvest or low dissolved 

oxygen (<2 ppm). However, some producers 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 selectively remove only the paddlefish. Gill 

nets of four-inch mesh or larger will usually 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 Polyculturing 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/acre1$500-1000/acre2

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. 
Su s tai nab le S t r a tegie s f o r Paddle fi s h S A R E 4

reported better water quality such as lower ammonia and nitrite 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 diversification.

There are some disadvantages to using paddlefish in polyculture 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 (< 2 ppm). They are vulnerable 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 permitted to grow to maturity of seven to nine years and harvested for their meat and roe. Paddlefish are usually over 10 

pounds after two years, and females will usually reach maturity 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 

50oF. When the water temperature is over 50oF, 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 walleye. They should not be stocked in reservoirs stocked with 

striped bass or tiger muskie, large predator fish that could 

consume them or 

could get entangled in gill nets at 

harvest. This system is very economical for paddlefish caviar production, 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 harvest/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 Revenue2 Returns above Variable Cost3

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.
Su s tai nab le S t r a tegie s f o r Paddle fi 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 paddlefish for 

stocking a 

local reservoir. Moreover, aquaculture infrastructure 

such as the 

hatchery 

and processing plant could increase employment in 

rural areas. At harvest, large mesh gill 

nets (6 inches in bar mesh) that are selective 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 program for re-stocking. Overall, the estimated 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 production. Most large reservoirs are considered public water and 

would have to be approved for production through government 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 possibility and would require better security around the reservoir. 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 Kentucky 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 percent) gave positive acceptance by the public to permit this type 

of production with paddlefish. Recently, the Kentucky Department 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 reservoir ranching is both sustainable and economically promising 

in temperate climates. The fish grows fast by filter 

feeding on zooplankton and is valuable for its boneless meat and black roe processed as caviar. Currently, 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 market development. To develop this 

industry and increase supply, existing 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 regulations to permit the stocking and 

harvesting of paddlefish in selected public reservoirs.

SARE Research 

Synopsis

The SARE project Enhancing 

Farmers’ Income through Polyculture of Paddlefish with Catfish in the Southern Region was 

conducted from 1999-2002. Paddlefish were stocked in commercial 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 regional 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 profits could range from $100 to $200/acre when farmers purchase fingerlings at $3 each and sell fish at $1/pound at the 

pond bank. Overall, the polyculture system gave similar results in paddlefish growth and survival despite wide geoSurvey of caviar taste test (top). High-end 

restaurant with paddlefish caviar and meat 

(bottom).
Su s tai nab le S t r a tegie s f o r Paddle fi 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 highend restaurants in Louisville and Lexington, KY. Market survey 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 averaged 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 received 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