de la Bretonne, Larry W.

Romaire, Robert P.

English

Texas A&M University

Texas
Agricultural
Extension
Service
January, 1990
Southern
Regional
Aquaculture
Center
L-2446
SRAC Publication No. 240
Crawfish Culture
Site Selection, Pond Construction and Water Quality
Larry W. de la Bretonne, Jr. and Robert P. Romaire*
There are over 500 species of craw-
fishes worldwide in various sizes,
colors, life cycles and habitats.
Species of crawfish that are commer-
cially important in the Southeast
United States are the red swamp
crawfish, Procambarus clarkii, and
the white river crawfish, Procam-
barus acutus acutus.
The development of crawfish culture
was stimulated by the year-round
demand for crawfish and the
seasonality of crawfish catch from
natural production areas. The in-
dustry is relatively young - 20 years
- in comparison to other agricul-
tural industries.
Development of crawfish culture has
made a significant impact on craw-
fish availability. Ponds have made
crawfish available almost year-round
compared to a 3-month availability
from natural production areas. Craw-
fish production in Louisiana ranges
from 70 to 100 million pounds with
ponds producing an average of 60
percent of the catch.
Present pond area is as follows:
Louisiana, 125,000 acres; Texas,
• Louisiana Cooperative Extension Service and
Louisiana Agricultural Experiment Station,
respectively.
5,000; Florida, 2,500; South
Carolina, 1,000; Arkansas, 500; Mis-
sissippi, 250; and 100 acres or less in
Alabama, Georgia, Maryland and
North Carolina. Crawfish culture is
now the largest crustacean aquacul-
ture food industry in the United
States.
Culture methods used to grow craw-
fish are simple when compared to
other cultured aquatic animals.
Crawfish culture fits into farm
management plans by using marginal
agricultural lands, permanent farm
labor and farm equipment during off-
peak farming periods. The average
pond is 40 to 60 acres in size. No
hatcheries are used to produce
young crawfish for stocking ponds
nor are formulated rations used to
feed crawfish. Rather, young are
Procambarus clarkii
produced by brood stock contained
within the pond, and vegetation is
utilized as a forage for the crawfish.
Intensity of culture is low and risk
from diseases is low.
Disadvantages of crawfish culture
are the high volume of water (70 to
100 gallons per minute per surface
acre) required to maintain water
quality; high expense of harvesting;
the length and frequency of the har-
vesting season; and the need for
market expansion and product
development.
Research is presently being con-
ducted on better pond design,
oxygenation of pond water with pad-
dlewheel aerators, more efficient
traps and better harvesting methods,
better baits, determination of nutri-
tional requirements, feed develop-
ment and feeding, grading,
marketing and food processing.
Site location and
pond construction
Location and pond design are the
most important factors in a success-
ful pond. Crawfish ponds should be
located in flat, open areas and the
soils should be heavy clay. Some
sandy clay soils may hold water and
Texas Agricultural Extension Service. Zerle l. Carpenter, Director. The Texas A&M University System. College Station. Texas
are suitable for fish culture but are
unsuitable as a soil in crawfish
ponds. A heavy clay soil is necessary
to maintain the integrity of crawfish
burrows. Sandy soils are not recom-
mended for crawfish ponds.
Perimeter levees should have a core
trench filled with clay to prevent
water seepage. The minimum
perimeter levee base should be 9
feet wide to prevent leakage from
the burrowing activities of the craw-
fish. A levee system 3 feet high is
adequate to contain the 18 to 22
inches of water necessary to cultivate
Procambarns. The land should have
no more than a 6-inch slope between
perimeter levees; otherwise, the area
should be leveled or divided into two
or more ponds. Ponds with a steep
slope channelize water, have poorer
water quality, and reduce efficiency
of harvesting.
Interior baffle levees are built on the
same specifications as perimeter
levees and are spaced 150 to 300 feet
apart to facilitate water circulation
(Figure 1). A recirculation canal, ex-
ternal to the perimeter levee, and a
re-lift pump or paddlewheel aerator
is recommended to aid in water cir-
culation, and to minimize water
usage and pond water discharge.
Ponds designed to recirculate water
are important in areas where water
is scarce or where expensive subsur-
face water must be pumped from
great depths.
Drains should be matched with the
pond size, pumping capacity and
projected rainfall. A three-tier 1/2-
inch mesh aeration screen should be
used to oxygenate water pumped
into the pond. Crawfish ponds
should be isolated from crops that
require frequent use of pesticides
and fertilizers.
Consult your local Soil Conservation
Service technician for assistance in
planning your crawfish pond, map-
ping out land elevations, and deter-
mining the volume of dirt that must
be moved during construction.
Types of crawfish ponds
Crawfish ponds are generally
categorized as wooded, semi-
wooded and open ponds. Open
ponds are further subdivided into
permanent, ricefield and marsh
ponds.
Wooded ponds - The earliest type
of pond used for crawfish cultivation
in Louisiana was the wooded pond.
These ponds are built in forested
areas on heavy clay soils near
drainage canals filled with precipita-
tion from surface runoff. Wooded
ponds produce 200 to 800 pounds of
crawfish per acre. Production is
limited by the inability to manage
water effectively. These ponds have
internal borrow ditches that channel
water directly to the drains, imped-
ing water circulation throughout the
baffle levees
! t ! t
external
levee
6" drain
pipe circulation
... pump
supply
pump
return channel
Figure 1. Recirculation design for crawfish pond.
pond. Wooded ponds have poor
stands of vegetative forage because
of shading, but leaf litter provides a
significant amount of forage for the
crawfish. Water flow and crawfish
harvest are difficult because the
trees hinder movement of water and
obstruct harvesting boats. Tree-free
lanes are cut to provide trapping
areas in wooded ponds.
Semi-wooded ponds - After several
years of alternate flooding and
drying, wooded ponds have high
hardwood mortality, thus reducing
tree density and generally improving
crawfish habitat. A vegetative forage
base of terrestrial grasses and
aquatic plants is developed which re-
quires better water circulation and
more intense water management.
Properly managed semi-wooded
ponds produce 15 to 30 percent
more crawfish than wooded ponds,
but poorly managed semi-wooded
ponds produce fewer crawfish than
wooded ponds because water quality
is often poorer.
Open ponds - Open ponds (those
containing few or no trees) are
recommended for crawfish aquacul-
ture. Open ponds account for 65 to
70 percent of the production area in
Louisiana and are the main type of
pond found in other states.
• Permanent ponds. Permanent
crawfish ponds are those con-
structed solely for the purpose
of cultivating crawfish. Crawfish
can be harvested in permanent
ponds 1 to 2 months longer be-
cause there is no conflict with
planting, draining and harvest-
ing schedules of other crops.
Crawfish yields are 1,000 to
3,000 pounds per acre with an
average of 1,500 to 1,800 pounds
per acre.
• Ricefield ponds. Ricefield craw-
fish ponds are productive, open
ponds because they are located
on fertile soil and often have baf-
fle levees, a good water supply
and recirculation capability.
Crawfish yield is generally 1,000
to 2,500 pounds per acre with an
average production of 1,200
pounds per acre. Generally total
production is decreased because
of the shortened harvest period.
These ponds are drained early
to replant rice in the spring.
Crawfish are commonly double-
cropped with rice in Louisiana
and Texas.
• Marsh ponds. Marsh ponds are
constructed in coastal areas and
have low crawfish yield (50 to
500 pounds per acre). High con-
centration of organic matter in
soils reduces water quality and
decreases crawfish production.
Marsh ponds are generally not
recommended for crawfish
production.
Water supply
Water quantity and water quality are
the most common limiting factors in
crawfish aquaculture. A pumping
capacity of 70 to 100 gallons per
minute per surface acre is needed to
exchange (turn over) water in a 4- to
5-day period. This exchange rate is
necessary to maintain satisfactory
water quality in the fall when water
is flooded onto vegetation in the
pond during warm weather. Craw-
fish producers can reduce water
demand by flooding the pond to an
8- to 10-inch level rather than the
full 18- to 22-inch level at the initial
flood in fall, and thereafter recir-
culating! flushing the pond with
fresh, oxygenated water as needed to
maintain satisfactory water quality.
An aeration screen is used to
oxygenate water as it is pumped into
the pond. A properly managed open
crawfish pond will generally require
nine water exchanges per production
season to maintain acceptable water
quality. Water quantity is a major
constraint to crawfish culture.
Both subsurface and surface water
are acceptable for crawfish cultiva-
tion. Subsurface water from wells .
provides predator - and disease-
free water but wells have limited dis-
charge capacity and a greater
expense in pumping. Subsurface
water often contains soluble iron
and hydrogen sulfide that must be
reduced before water enters the
pond. Water recirculation systems
are usually recommended for ponds
that must rely on subsurface water.
Surface water is desirable for large
ponds because it is less expensive to
pump, but it may not be reliable in
quantity and quality. Crawfish ponds
are initially flooded in September
and October, usually two of the drier
months in the year. Surface water
contains predacious fishes which are
removed through the aeration
screen. Smaller fish passing through
the l/2-inch mesh aeration screen
need not be removed, because they
do not pose a predation problem to
young crawfish, and these fishes are
killed when the pond is drained in
the summer.
Mechanical paddlewheel aerators,
0.25-0.33 horsepower per surface
acre, can be used to aerate and circu-
late crawfish pond water with more
cost effectiveness than water replace-
ment by pumping. Pond location and
local energy costs dictate the type of
pump and power source used for
crawfish ponds.
Water quality
Over 99 percent of production
problems in crawfish ponds can be
directly attributed to improper water
management. A good water quality
management program requires that
crawfish ponds be properly designed
and constructed, and that they have
a dependable supply of surface or
subsurface fresh water. Inadequate
concentration of dissolved oxygen
(DO) is the most serious water
management problem in crawfish
aquaculture. Low concentration of
DO results in high crawfish mor-
tality; moreover, crawfISh do not
feed or grow well and can become
predisposed to diseases in ponds
with chronically low concentrations
of DO.
Most serious water quality problems
occur 2 to 6 weeks after flooding
ponds in September/October, and
from April to June because warm
water in these months increases the
biological oxygen demand (BOD) of
inundated vegetation, thus decreas-
ing DO. Dissolved oxygen should be
maintained above 3 parts per million
for optimal crawfish production.
Significant mortality occurs when
DO is less than 1 part per million.
. Dissolved oxygen should be
measured daily. Oxygen deficiency is
corrected by replacing pond water
with fresh, oxygenated water, or by
recirculating the water with pumps
or mechanical aerators.
Other water quality variables impor-
tant in crawfish production are the
pH; total hardness and total
alkalinity; ammonia, nitrite, iron and
hydrogen sulfide content. The water
pH should range from 6.5 to 7.5 at
dawn, and both total hardness and
total alkalinity should range between
50 to 250 parts per million as
CaC03, but 100 parts per million are
optimal. If the pH, hardness and
alkalinity are low, agricultural lime-
stone should be incorporated into
the pond bottom.
Un-ionized ammonia (NH3-N) and
nitrite (N02-N) are toxic to crawfish
at concentrations exceeding 2 and 4
parts per million, respectively. But
concentrations this high are not like-
ly to occur in crawfish ponds be-
cause the crawfish production inten-
sity is low, and ammonia is rapidly as-
similated by aquatic macrophytes.
Iron and hydrogen sulfide are toxic
to crawfish at concentrations often
found in subsurface well water; how-
ever, the two compounds are
oxidized to non-harmful concentra-
tions when well water is oxygenated
prior to entering the pond.
This publication was supported in part by a Grant from the United States Department of Agriculture, Number 87-CRSR-2-3218, sponsored jointly by
the Cooperative State Research Service and the Extension Service.
Educationalprograms conducted by the Texas Agricultural Extension SeNice serve people ofall ages regardless ofsocioeconomic level, race, color,
sex, religion, handicap or national origin.
Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June
30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas Agricultural Extension Service, The
Texas A&M University System.
2M-12-90, Reprint FISH


Crawfish Culture: Site Selection, Pond Construction and Water Quality.

Texas A&amp;M Repository

TexasAgriculturalExtensionServiceJanuary, 1990SouthernRegionalAquacultureCenterL-2446SRAC Publication No. 240Crawfish CultureSite Selection, Pond Construction and Water QualityLarry W. de la Bretonne, Jr. and Robert P. Romaire*There are over 500 species of craw-fishes worldwide in various sizes,colors, life cycles and habitats.Species of crawfish that are commer-cially important in the SoutheastUnited States are the red swampcrawfish, Procambarus clarkii, andthe white river crawfish, Procam-barus acutus acutus.The development of crawfish culturewas stimulated by the year-rounddemand for crawfish and theseasonality of crawfish catch fromnatural production areas. The in-dustry is relatively young - 20 years- in comparison to other agricul-tural industries.Development of crawfish culture hasmade a significant impact on craw-fish availability. Ponds have madecrawfish available almost year-roundcompared to a 3-month availabilityfrom natural production areas. Craw-fish production in Louisiana rangesfrom 70 to 100 million pounds withponds producing an average of 60percent of the catch.Present pond area is as follows:Louisiana, 125,000 acres; Texas,• Louisiana Cooperative Extension Service andLouisiana Agricultural Experiment Station,respectively.5,000; Florida, 2,500; SouthCarolina, 1,000; Arkansas, 500; Mis-sissippi, 250; and 100 acres or less inAlabama, Georgia, Maryland andNorth Carolina. Crawfish culture isnow the largest crustacean aquacul-ture food industry in the UnitedStates.Culture methods used to grow craw-fish are simple when compared toother cultured aquatic animals.Crawfish culture fits into farmmanagement plans by using marginalagricultural lands, permanent farmlabor and farm equipment during off-peak farming periods. The averagepond is 40 to 60 acres in size. Nohatcheries are used to produceyoung crawfish for stocking pondsnor are formulated rations used tofeed crawfish. Rather, young areProcambarus clarkiiproduced by brood stock containedwithin the pond, and vegetation isutilized as a forage for the crawfish.Intensity of culture is low and riskfrom diseases is low.Disadvantages of crawfish cultureare the high volume of water (70 to100 gallons per minute per surfaceacre) required to maintain waterquality; high expense of harvesting;the length and frequency of the har-vesting season; and the need formarket expansion and productdevelopment.Research is presently being con-ducted on better pond design,oxygenation of pond water with pad-dlewheel aerators, more efficienttraps and better harvesting methods,better baits, determination of nutri-tional requirements, feed develop-ment and feeding, grading,marketing and food processing.Site location andpond constructionLocation and pond design are themost important factors in a success-ful pond. Crawfish ponds should belocated in flat, open areas and thesoils should be heavy clay. Somesandy clay soils may hold water andTexas Agricultural Extension Service. Zerle l. Carpenter, Director. The Texas A&M University System. College Station. Texasare suitable for fish culture but areunsuitable as a soil in crawfishponds. A heavy clay soil is necessaryto maintain the integrity of crawfishburrows. Sandy soils are not recom-mended for crawfish ponds.Perimeter levees should have a coretrench filled with clay to preventwater seepage. The minimumperimeter levee base should be 9feet wide to prevent leakage fromthe burrowing activities of the craw-fish. A levee system 3 feet high isadequate to contain the 18 to 22inches of water necessary to cultivateProcambarns. The land should haveno more than a 6-inch slope betweenperimeter levees; otherwise, the areashould be leveled or divided into twoor more ponds. Ponds with a steepslope channelize water, have poorerwater quality, and reduce efficiencyof harvesting.Interior baffle levees are built on thesame specifications as perimeterlevees and are spaced 150 to 300 feetapart to facilitate water circulation(Figure 1). A recirculation canal, ex-ternal to the perimeter levee, and are-lift pump or paddlewheel aeratoris recommended to aid in water cir-culation, and to minimize waterusage and pond water discharge.Ponds designed to recirculate waterare important in areas where wateris scarce or where expensive subsur-face water must be pumped fromgreat depths.Drains should be matched with thepond size, pumping capacity andprojected rainfall. A three-tier 1/2-inch mesh aeration screen should beused to oxygenate water pumpedinto the pond. Crawfish pondsshould be isolated from crops thatrequire frequent use of pesticidesand fertilizers.Consult your local Soil ConservationService technician for assistance inplanning your crawfish pond, map-ping out land elevations, and deter-mining the volume of dirt that mustbe moved during construction.Types of crawfish pondsCrawfish ponds are generallycategorized as wooded, semi-wooded and open ponds. Openponds are further subdivided intopermanent, ricefield and marshponds.Wooded ponds - The earliest typeof pond used for crawfish cultivationin Louisiana was the wooded pond.These ponds are built in forestedareas on heavy clay soils neardrainage canals filled with precipita-tion from surface runoff. Woodedponds produce 200 to 800 pounds ofcrawfish per acre. Production islimited by the inability to managewater effectively. These ponds haveinternal borrow ditches that channelwater directly to the drains, imped-ing water circulation throughout thebaffle levees! t ! texternallevee6" drainpipe circulation... pumpsupplypumpreturn channelFigure 1. Recirculation design for crawfish pond.pond. Wooded ponds have poorstands of vegetative forage becauseof shading, but leaf litter provides asignificant amount of forage for thecrawfish. Water flow and crawfishharvest are difficult because thetrees hinder movement of water andobstruct harvesting boats. Tree-freelanes are cut to provide trappingareas in wooded ponds.Semi-wooded ponds - After severalyears of alternate flooding anddrying, wooded ponds have highhardwood mortality, thus reducingtree density and generally improvingcrawfish habitat. A vegetative foragebase of terrestrial grasses andaquatic plants is developed which re-quires better water circulation andmore intense water management.Properly managed semi-woodedponds produce 15 to 30 percentmore crawfish than wooded ponds,but poorly managed semi-woodedponds produce fewer crawfish thanwooded ponds because water qualityis often poorer.Open ponds - Open ponds (thosecontaining few or no trees) arerecommended for crawfish aquacul-ture. Open ponds account for 65 to70 percent of the production area inLouisiana and are the main type ofpond found in other states.• Permanent ponds. Permanentcrawfish ponds are those con-structed solely for the purposeof cultivating crawfish. Crawfishcan be harvested in permanentponds 1 to 2 months longer be-cause there is no conflict withplanting, draining and harvest-ing schedules of other crops.Crawfish yields are 1,000 to3,000 pounds per acre with anaverage of 1,500 to 1,800 poundsper acre.• Ricefield ponds. Ricefield craw-fish ponds are productive, openponds because they are locatedon fertile soil and often have baf-fle levees, a good water supplyand recirculation capability.Crawfish yield is generally 1,000to 2,500 pounds per acre with anaverage production of 1,200pounds per acre. Generally totalproduction is decreased becauseof the shortened harvest period.These ponds are drained earlyto replant rice in the spring.Crawfish are commonly double-cropped with rice in Louisianaand Texas.• Marsh ponds. Marsh ponds areconstructed in coastal areas andhave low crawfish yield (50 to500 pounds per acre). High con-centration of organic matter insoils reduces water quality anddecreases crawfish production.Marsh ponds are generally notrecommended for crawfishproduction.Water supplyWater quantity and water quality arethe most common limiting factors incrawfish aquaculture. A pumpingcapacity of 70 to 100 gallons perminute per surface acre is needed toexchange (turn over) water in a 4- to5-day period. This exchange rate isnecessary to maintain satisfactorywater quality in the fall when wateris flooded onto vegetation in thepond during warm weather. Craw-fish producers can reduce waterdemand by flooding the pond to an8- to 10-inch level rather than thefull 18- to 22-inch level at the initialflood in fall, and thereafter recir-culating! flushing the pond withfresh, oxygenated water as needed tomaintain satisfactory water quality.An aeration screen is used tooxygenate water as it is pumped intothe pond. A properly managed opencrawfish pond will generally requirenine water exchanges per productionseason to maintain acceptable waterquality. Water quantity is a majorconstraint to crawfish culture.Both subsurface and surface waterare acceptable for crawfish cultiva-tion. Subsurface water from wells .provides predator - and disease-free water but wells have limited dis-charge capacity and a greaterexpense in pumping. Subsurfacewater often contains soluble ironand hydrogen sulfide that must bereduced before water enters thepond. Water recirculation systemsare usually recommended for pondsthat must rely on subsurface water.Surface water is desirable for largeponds because it is less expensive topump, but it may not be reliable inquantity and quality. Crawfish pondsare initially flooded in Septemberand October, usually two of the driermonths in the year. Surface watercontains predacious fishes which areremoved through the aerationscreen. Smaller fish passing throughthe l/2-inch mesh aeration screenneed not be removed, because theydo not pose a predation problem toyoung crawfish, and these fishes arekilled when the pond is drained inthe summer.Mechanical paddlewheel aerators,0.25-0.33 horsepower per surfaceacre, can be used to aerate and circu-late crawfish pond water with morecost effectiveness than water replace-ment by pumping. Pond location andlocal energy costs dictate the type ofpump and power source used forcrawfish ponds.Water qualityOver 99 percent of productionproblems in crawfish ponds can bedirectly attributed to improper watermanagement. A good water qualitymanagement program requires thatcrawfish ponds be properly designedand constructed, and that they havea dependable supply of surface orsubsurface fresh water. Inadequateconcentration of dissolved oxygen(DO) is the most serious watermanagement problem in crawfishaquaculture. Low concentration ofDO results in high crawfish mor-tality; moreover, crawfISh do notfeed or grow well and can becomepredisposed to diseases in pondswith chronically low concentrationsof DO.Most serious water quality problemsoccur 2 to 6 weeks after floodingponds in September/October, andfrom April to June because warmwater in these months increases thebiological oxygen demand (BOD) ofinundated vegetation, thus decreas-ing DO. Dissolved oxygen should bemaintained above 3 parts per millionfor optimal crawfish production.Significant mortality occurs whenDO is less than 1 part per million.. Dissolved oxygen should bemeasured daily. Oxygen deficiency iscorrected by replacing pond waterwith fresh, oxygenated water, or byrecirculating the water with pumpsor mechanical aerators.Other water quality variables impor-tant in crawfish production are thepH; total hardness and totalalkalinity; ammonia, nitrite, iron andhydrogen sulfide content. The waterpH should range from 6.5 to 7.5 atdawn, and both total hardness andtotal alkalinity should range between50 to 250 parts per million asCaC03, but 100 parts per million areoptimal. If the pH, hardness andalkalinity are low, agricultural lime-stone should be incorporated intothe pond bottom.Un-ionized ammonia (NH3-N) andnitrite (N02-N) are toxic to crawfishat concentrations exceeding 2 and 4parts per million, respectively. Butconcentrations this high are not like-ly to occur in crawfish ponds be-cause the crawfish production inten-sity is low, and ammonia is rapidly as-similated by aquatic macrophytes.Iron and hydrogen sulfide are toxicto crawfish at concentrations oftenfound in subsurface well water; how-ever, the two compounds areoxidized to non-harmful concentra-tions when well water is oxygenatedprior to entering the pond.This publication was supported in part by a Grant from the United States Department of Agriculture, Number 87-CRSR-2-3218, sponsored jointly bythe Cooperative State Research Service and the Extension Service.Educationalprograms conducted by the Texas Agricultural Extension SeNice serve people ofall ages regardless ofsocioeconomic level, race, color,sex, religion, handicap or national origin.Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas Agricultural Extension Service, TheTexas A&M University System.2M-12-90, Reprint FISH

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Crawfish Culture: Site Selection, Pond Construction and Water Quality.

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Crawfish Culture: Site Selection, Pond Construction and Water Quality.

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