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The Progressive Fish-Culturist
ISSN: 0033-0779 (Print) 1548-8640 (Online) Journal homepage: http://www.tandfonline.com/loi/uzpf20
Production of Crayfish in Rice Fields
Yew-Hu Chien & James W. Avault Jr.
To cite this article: Yew-Hu Chien & James W. Avault Jr. (1980) Production
of Crayfish in Rice Fields, The Progressive Fish-Culturist, 42:2, 67-71, DOI:
10.1577/1548-8659(1980)42[67:POCIRF]2.0.CO;2
To link to this article: http://dx.doi.org/10.1577/1548-8659(1980)42[67:POCIRF]2.0.CO;2
Published online: 09 Jan 2011.
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Date: 26 October 2017, At: 00:56
Production of Crayfish in Rice Fields
Yew-Hu Chien and James W. Avault, Jr.
Fisheries Section, School of Forestry and Wildlife Management
Louisiana State University, Baton Rouge, Louisiana 70803
ABSTRACT: A study was conductedto determinehow rice (Oryzasativa) and crayfish (Procambarus
clarkii) affect each other in the field and to determine optimal stocking rates of crayfish. High rice
productioncorrelated(P <0.01) with large numbers of adult crayfish present during the rice-growing
Downloaded by [UNSW Library] at 00:56 26 October 2017
season.Averagecrayfishproductionwassignificantly(P <0.05) higherin rice ponds(1,059kg/ha) than in
controlponds(800 kg/ha). Von Bertalanffy'sgrowthmodelrevealedthat the averagemaximum length
attained by crayfish in rice ponds(123.2 mm) was greater than in control ponds(106.9 mm).
Crayfish pond hectarage in Louisiana has expanded
from 5,000 ha in 1969 to nearly 20,000 ha in 1979; in
1979 Texas also had more than 1,000 ha of crayfish
ponds.The increase was due to a continuously growing
market demand for crayfish. Crayfish are now farmed in
impoundments that are wooded,in open ponds, and in
rice fields. Of these, rice fields offer the most readily
adaptable area for expansionof crayfish culture: levees,
pumps, and irrigation ditches are not initial costsfor
establishedrice fields. The annual hectarage planted to
rice in Louisiana and Texas has been stable, averaging
around 225,000 and 204,000 ha, respectively. Rice is
now planted in more than 1,000,000 ha in the United
States (Anon. 1976, 1977).
The general procedure for culturing crayfish in rice
pondsis to stock mature crayfish in late spring or early
summer, when few wild crayfish are in the field. Rice
fields are drained in late summer and allowed to dry for
about 2 weeks to support rice harvesting equipment.
Meanwhile crayfish burrowing has been completed.
Rice is usually harvested from mid-August to mid-September. When the field is refiooded,young crayfish are
flushed out of burrows and feed on decomposingrice
straw and associatedmicroorganisms.The crayfish harvest usually begins in January and continuesinto May.
Commercial crayfish farmers often plant millet or
other vegetation to increase food for crayfish. Crayfish
stocking takes place in early summer and is considered
necessaryonly in new ponds.Before pondsare refiooded,
they are drained for 2 to 3 weeks to control wild fish and
other predators.
No scientific research has been conductedon production of crayfish in rice ponds.This study was designedto
comparecrayfish productionin rice pondswith that in
control pondscontaining millet and natural vegetation,
and to comparerice and crayfish productionfrom ponds
receiving crayfish at different stocking rates.
VOL. 42, NO. 2, APRIL 1980
Material
and Methods
The present study was conductedat Ben Hur Farm,
Louisiana State University (LSU), Baton Rouge, during
1976 and 1977. We randomly assigned 18 earthen ponds,
each 0.05 ha and with an average depth of 0.8 m, to six
treatments in a 2 x 3 factorial arrangement; rice ponds
and control ponds contained crayfish at three different
stocking rates, with three replications each.The vegetation in control ponds was mainly millet (Echinocloa
frumentacea), and various amounts of smartweed (Persicaria sp.), alligatorweed (Alternanthera sp.), and other
natural vegetation, typical of that found in commercial
crayfish ponds.
Before and after the study, soil samples were obtained
from various locationsin each pond. Calcium content of
the soil was analyzed by the LSU Soil Testing
Laboratory.
Some rice farmers have claimed that the use of chemi-
cally treated rice seeds(for better germination and disease prevention) has causedcomplete disappearanceof
crayfish. The LSU Rice Experiment Station recommendsthat treated seedsnot be usedif crayfish cropsare
desired (LaCaze 1976). On 22 May 1976, untreated
Labelle rice seedswere planted in nine pondsat a rate of
153 kg/ha. When barnyardgrass (Echinochloa sp.) and
many other annual weedsgrew to 5 to 6 cm, a herbicide
(propanil) was sprayedon the pondsat a rate of 2.3 kg/ha
(Smith
and Seaman 1973). To avoid direct chemical
damage that propanil might causeto crayfish, the ponds
were not stockedwith crayfish until 2 weeks after the
propanil had been applied. Three different stocking
rates were used:108 pairs per pond(about 114 kg/ha), 54
pairs per pond (about 57 kg/ha), and 0 pairs per pond (no
crayfish), each with three replications. The water level
was gradually increased as the rice grew and was ultimately maintained at a depth of 5 cm. In early Sepo
67
Downloaded by [UNSW Library] at 00:56 26 October 2017
tember, 2 weeks before rice harvest, pondswere completely drained and allowedto dry out. Rice was harvested on 20 September 1976, and rice straw was left
standing in the field.
Millet seed was broadcast in nine ponds (control
ponds)at a rate of34 kg/ha on22 May 1976.No herbicide
was applied becausesuch spraying would have been
detrimental to Echinocloa sp. and to other broadleaf
weeds (Smith and Seaman 1973). Crayfish stocking in
the controlpondsand pondflooding,draining, and fertilizing were carried out as in the rice ponds.Both rice
and controlpondswere fertilized at a rate of 227 kg/ha of
8-24-24 (N-P-K) at preplanting, and 170 kg/ha of nitrogen fertilizer (urea) for top dressing.
Rice straw from rice pondswas sampledonceevery 1
to 4 weeks and analyzed in the LSU Geochemistry
Laboratory of the Coastal Studies Institute for total
organic nitrogen by using the Kjeldahl method
(Bremner 1965; Ho and Schneider 1974), and for total
carbonby using the Schollen-Bergermethod (Allison
onstrated in laboratory studies that at 21øC and under
aerobicconditions,it took only 8 weeks for the C:N ratio
of rice straw to drop to below 17. The slower decreaseof
the C:N ratio for rice straw in the present study can be
attributed partly to lower temperature and partly to
anaerobic decomposition (Acharya 1935a,b). LaCaze
(1970) stated that about 20% of the crayfish diet consists
of vegetablematerial. Vegetation, particularly as it decays, carries large numbers of attached microscopic
plants and animals that may serve as foodfor crayfish
before the rice straw becomes nutritious
below 17:1).
(C:N ratio
A significant inverse correlation was found between
the increment of calcium in the soil and crayfish yield
(Fig. 1); it would appear that crayfish removed calcium
from the environment. The importance of calcium in
crayfish productionwas reportedby de la Bretonne et al.
(1969).
1965; Ho and Schneider 1974).
To study growth we sampled crayfish every other
week from 22 January to 2 April 1977. After examination, all crayfishwere returnedto ponds.Three cylindrical, upright traps per pond (60/ha) were used to collect
crayfish.Total length (definedas the distancefrom the
tip ofthe rostrumto the tip ofthe telson,measuredto the
nearest 1.0 mm) and sex were recordedfor each crayfish
collected. The data were used to fit von Bertalanffy's
(1938)growthmodel,Lt= L• [1-e -k(t-to)]where
Lt -- length in millimeters at age t; e = 2.71828...;
L•--average
maximum total length; k = Brody's
growth coefficient(Brody 1927, 1945); t -- age (2 weeks,
in this case);and to -- theoretical adjustment parameter
(which expressesthe age when the length would have
been zero).
each population estimation.
From 3 April to 1 June 1977 crayfish were harvested
29 times. All crayfish captured were sievedthrough a
1.9-cm wire mesh trap to retain crayfish of harvestable
size (75 mm or longer).
and Discussion
The initial ratio of organiccarbonto nitrogen (C:N) of
the rice straw was 107:1 before flooding. At an average
water temperature of 10øCunder partly anaerobic(water-logged)conditions,it took 16 w.eeksfor the C:N ratio
to dropbelow 17. Russel-Hunter(1971) stated that detritus must attain a C:N ratio of 17:1 or lower before it is
suitable for animal nutrition; a higher ratio would result in protein deficiency. Goyert et al. (1975) dem68
(•
CA--859.3175-0.9458
PD
2-
--
•o
--I
-2'
•
-3'
-
Four populationestimatesofcrayfishwere madeafter
the secondsampling period by using Peterson'ssingle
censusmethod(Ricker 1975). Crayfish were marked by
clipping the edge of the uropods,the telson, or both. A
different mark was usedfor each adjacent pond and for
Results
•Z
-66
-•
•
•
1'0
1'1
1'2
1'3
(100 k9/ha)
CRAYFISH
PRODUCTION
Fœg.]. Relation oœtheincremento[soil c•lci•m (•A) to cr•fis•
pro•ction (PD) [rom B•n •r F•rm, &S•, ]9?6-??.
Rice production (Table 1) averaged 3,382 kg/ha
(range, 2,519 to 4,702 kg/ha). The average rice (Labelle)
productionin Louisiana was 4,424 kg/ha in 1975 (Anon.
1976). The low average production in this study was
mainly attributed to the late planting of rice and the
infertile bottom soil of new ponds.Average rice production was higher in pondswith higher stocking rates of
crayfish; however, these differences were not statistically significant. Although the ponds used were newly
constructed,native crayfish existed therein; therefore,
no comparison of rice production between ponds with
and without crayfish could be made. However, a high
positive correlation (P •0.01) was found between rice
THE PROGRESSIVE
FISH-CULTURIST
Table 1. Rice production at harvest with three stocking
ratesof crayfish and the number of adulta crayfish found
tn each ricepond from six samplingsfrom 22 January to
2 April 1977.
Table 2. Production of harvestablecrayfish (75 mm or
longer) from 3 April to I June 1977 from six treatments:
riceponds(R) and controlpondsa(C) containingcrayfish
stockedat three different rates, Ben Hur Farm, LSU.
Average rice
production
Stocking
Pond
number
R-2
R-5
R-7
R-3
R-6
Downloaded by [UNSW Library] at 00:56 26 October 2017
R-11
R-1
R-9
R-12
(kg/ha)
rates of
No. of
crayfish
(kg/ha)
adult
crayfish
0
0
0
57
57
57
114
114
114
3
7
7
7
8
8
12
20
21
Per
Per
pond
stocking Overall
density average
3061
7
3258• 294g--
rates
Pond of crayfish
number
(kg/ha)
Average
yield(kg/ha)
Production
per pond
(kg/ha)
Per
stocking
density
Overall
average
Rice ponds
R-2 0
1274
1214
R-5
0
R-7
0
947--•_
1043
916._]
2519--]
2575--•
3714•3242
--3382
R-3
57
R-6
57
R-11
57
976
1058
1078
1044__]
3438_J
4151--]
3020• 3958_
R-1
114
R-9
114
838
R-12
114
1012•
1306
1052
--
4702•
Adult crayfish can be distinguished from young-of-the-year crayfish
by their larger size,darker bodycolor,harder shell, and longer claws.
production and the number of adult crayfish found in
each rice pond during sampling (Table 1). In short,
higher rice productioncorrelatedwith a greater number
of adult crayfishpresentin pondsduring the rice-growing season.Accordingto Coche(1967), there is a 5 to 15%
increase in rice production in pondsused for both rice
and fish culture. It is unknown why larger numbers of
adult crayfishwere correlatedwith higher rice production. The correlation may be due to the addition of organic fertilization from crayfishexcretaor to the tilling
of rice seedlingsby crayfish activity. It is also possible
that better rice growth providesbetter crayfishprotection from predation and results in greater survival.
The averagecrayfishyield of 1,058 kg/ha in rice ponds
and 800 kg/ha in control ponds (Table 2) was significantly (P < 0.05) different. There were no significant
differencesin averageyields between different stocking
rates for rice ponds or for control ponds. LaCaze (1970)
stated that if the spraying of propanil is not homogeneous and exceedsthe rate of 1.1 kg/ha in any part of a
field, damage to crayfish might result. In the present
study, propanil was used once to kill weeds at a recommended rate of 2.3 kg/ha (Smith and Seaman 1973) and
seemingly did not adversly affect crayfish production.
The von Bertalanffy's growth equationsfor length of
crayfishwereLt = 123.2 [1.e -0.153(t+5.820)]
in rice
pondsand Lt = 106.9 [1-e -0.184(t+5.687)]
in control
ponds,respectively. Crayfish in rice pondshad a higher
L• value and a higher growth rate (smaller value of k)
than those in control ponds. Crayfish in rice ponds
VOL. 42, NO. 2, APRIL 1980
Stocking
Control ponds
C-10
0
842
C-13
0
678
C-15
0
916•
C-14
57
758
C-17
57
858
C-18
57
666--]
C-4
114
1064-•
C-8
114
690 •-
C-16
114
812
761
800
827
--
726__]
Control pondscontained40-60% of millet and various natural vegetation.
reachedcommercialharvestable size of 75 mm or longer
by early March (24 weeks after flooding),about 2 weeks
earlier than crayfishin controlponds.The growth rate of
crayfish in rice pondswas better due to a more abundant
food supply and an average lower population density
(Fig. 2). Since the millet was not as denseas rice, and the
other vegetation was also sparse,the available foodand
cover for crayfish in control pondswas less than in rice
ponds. By early April, crayfish in control ponds were
significantly smaller than those in rice ponds.After the
middle of May, a larger number of stunted crayfish was
observed;this was a result of poor growth causedby food
deficiency (Avault et al. 1974). No significant differences were found for k among stocking rates.
No significant differences in population estimates
were observed among the six treatments for various
sampling dates (Figs. 2,3). As expected,consistentdecreases in crayfish populations (Romaire 1976) due to
natural mortality (i.e., predation, disease,and old age)
were not observed for the four population estimates
69
17
16
RICE PONDS
15
.•Z
ß-1 .-112
(..3
11
(8-week period). Natural mortality during this 8-week
period may have been small and masked by recruitment
of crayfish. LaCaze (1976) stated that normally crayfish
are reasonably active above 10øCand inactive below this
temperature. During the sampling period the weather
gradually turned warmer, facilitating recruitment. Th•s
was evidenced by the average population estimate increaseafter the beginning of March (Fig. 3) and reflected
by the increasing catch per unit of trapping effort. Since
even the highest stocking rate (114 kg/ha) did not adversely affect growth rate (k), an even higher stocking
rate seems possible to increase the population of
young-of-the-year crayfish and thus, production. A
stocking rate greater than 114 kg/ha may be desirable
for new rice-crayfish farming, especiallywhen there are
few wild (native) crayfish in the field.
Downloaded by [UNSW Library] at 00:56 26 October 2017
Acknowledgments
CONTROL
8
•
•
2-19FEB. 2 FEB.-5
MAR.
PONDS
5-1•MAR 19MAR.-2
APR.
This study was supported by the Louisiana Agricultural Experiment Station and by the Louisiana Sea
Grant Program maintained by NOAA, U.S. Department
of Commerce.
1977
Fig. 2. Average population estimates of young-of-the-year
crayfish from rice ponds and control ponds, Ben Hur Farm,
LSU, 2 February to2 April 1977. Controlpondscontainedmillet
and other natural vegetation.
17-
15-
14-
U.l•
•u.,i
i_n-
-•Z
'-1.-112_
13.1O•
u.i
o
11-
10-
8
Acharya, C. 1935a. Studies on the anaerobicdecompositionof
plant materials. I. Anaerobic decompositionof rice straw.
Biochem. J. 29:528-541.
1935b. Studies on the anaerobic decompositionof
plant materials. II. Somefactorsinfluencingthe anaerobic
decompositionof the rice straw. Biochem.J. 29:953-960.
Allison, L. 1965. Organic carbon. Pages 1374-1377 in C.A.
Black, ed. Methods of soil analysis. Agronomy 9. Am. Soc.
16-
•
References
i
2-19FEB. 19FEB.'5
MAR.
1977
Agron., Madison, Wis.
Anonymous. 1976. Production: 1975. Jan. Rice J., pp. 11-13;
The rice miller's rice acreage in the United States-1976.
Nov.-Dec. Rice J., pp. 12-13.
1977.Tighter supplies,better prices.July-Aug. Rice
J., pp. 10-11, 27.
Avault, J.W., Jr., L. de la Bretonne, Jr., and J.V. Huner. 1974.
Two major problemsin culturing crayfish in ponds:oxygen
depletion and overcrowding.Pages 139-144 in Freshwater
crayfish, Vol. 2: Papers from SecondInt. Symp. Freshwater
Crayfish, Baton Rouge, La.
Bremner, J.M. 1965. Organic forms of nitrogen. Pages 12381255 in C.A. Black, ed. Methods of soil analysis.Agronomy 9.
Am. Soc. Agron., Madison, Wis.
Brody, S. 1927. Growth rates. University of Missouri, Agric.
Exp. Stn. Bull. 97.70 pp.
1945. Bioenergeticsand growth,with specialreferenceto the efficiencycomplexin domesticanimals.Reinhold
Publ. Corp., New York. 1025 pp.
Coche, A. 1967. Fish culture in rice fields-a world wide syn5-1•MAR.19MAR-12APRthesis. Hydrobiologia 30( 1):1-44.
de la Bretonne, L., J.W. Avault, Jr., and R.O. Smitherman.
1969. Effects of soil and water
Fig. 3. Average population estimates of young-of-the-year
crayfish from three stocking rates: 0(I), 57(II), and 114(111)
kg/ha, Ben Hur Farm, LSU, 2 February to 2 April 1977.
70
hardness
on survival
and
growthof red swampcrawfish,Procambarusclarkii, in plastic pools. Proc. Annu. Conf. Southeast. Assoc. Game Fish
Comm.
23:626-633.
THE
PROGRESSIVE
FISH-CULTURIST
Downloaded by [UNSW Library] at 00:56 26 October 2017
Goyert, J.C., J.W. Avault, Jr., J.W. Rutledge, and T.P. Hernendez. 1975. Agricultural by-productsas supplementalfeed for
crawfish. La. Agric. 19(2):10-11.
Ho, C.L., and S. Schneider. 1974. Water and sediment chemistry. Vol. III, Appendix VI, Sec.I, Louisiana offshoreoil port:
Environmental baseline study. 71 pp.
LaCaze, C. 1970. Crawfish farming. In Crawfish farming. Research symposium,sponsoredby the Louisiana State University Cooperative Extension Service and the Louisiana
Crawfish Farmers Assoc., Baton Rouge. 74 pp.
1976. Crawfish farming. La. Wildl. Fish. Comm.
Fish. Bull. 7.27 pp.
Ricker, W.E. 1975. Computation and interpretation of biological statistics of fish populations.Bull. Fish. Res. Board Can.
191. 382 pp.
Romaire, R.P. 1976. Population dynamics of red swamp crawfish, Procambarusclarkii (Girard), in pondsreceiving fertilization, and two agricultural foragesas supplemental feed.
M.S. thesis, Louisiana State University. 92 pp.
Russel-Hunter, W.D. 1971. Aquatic productivity: an introduction to some basic aspectsof biological oceanographyand
]imno]ogy.Macmillian Company, New York. 360 pp.
Smith, R.J., Jr., and D.E. Seaman. 1973. Weeds and their control. Rice in the United States: varieties and production.
Agric. Handb. 289. U.S. Dep. Agric. 154 pp.
von Berta]anffy, L. 1938. A quantitative theory of organic
growth. Hum. Biol. 10(2):181-213.
Accepted 7 December 1979
Effect of Chloride Ion Concentration and pH
on the Transport of Nitrite
Across the Gill Epithelia of Coho Salmon
It has been hypothesizedthat nitrite, an intermediate
product of nitrification, may accumulate in the
bloodstream of fish by passing through the gill
epithelium primarily in the form of nitrous acid
(Wedemeyer and Yasutake 1978). Furthermore, Perrone and Meade (1977) conjecturedthat the chloride ion
may protect against nitrite toxicity by direct competition with nitrite (nitrous acid) for transport acrossthe
gill membrane.
In a series of experiments, cohosalmon (Oncorhynchus kisutch) were exposedto a fixed level of nitrite
while the pH and chlorideion (C1-)concentrationof the
environment were altered. The concentrationof plasma
nitrite
was measured after 24 h to further
elucidate the
mode of entry of nitrite and the site of chloride ion
protection.
We selecteda nitrite concentration of 10 mg/L as the
level mostlikely to producestressin the fish but little or
no mortality. Four environmentswere chosenfor testing: pH 6.5, C1-15 and 50 mg/L, and pH 8.0, C1-15 and
50 mg/L.
Coho salmon averaging 25.2 __3.0 cm and 175.1
__8.9 g were placedin a flow-throughbioassaysystem
similar to that of Perrone and Meade (1977). Chloride
ion concentration was altered by adding sodium
chloride,and pH was manipulatedby using a Tris buffer. Water quality was monitoredby usingthe methods
outlined in Perrone and Meade (1977). Six fish were
tested in each environment
and each of the four envi-
ronmentswas replicated.At the end of a 24-h exposure,
VOL. 42, NO. 2, APRIL 1980
fish were removed and anesthetized in a 500-mg/L solution of MS-222, and a blood sample of 0.5 - 1.0 cms was
taken from the dorsal aorta (Scheffman 1959). The blood
sample was then analyzed for ferrihemoglobin by
methods outlined by Dubowski (1960), with a buffer of
pH 7.4. Up to five hematocrits per sample were then
taken to measure plasma nitrite.
Plasma nitrite was analyzed by using a modification
of the procedure for measurement of nitrite in water
supplies (American Public Health Association et al.,
1971). Centrifuged hematocrit tubes were broken at the
plasma-erythrocyte interface, and a Hamilton syringe
was usedto aspirate a sample of plasma. Sampleswere
diluted 1:50, plasma to distilled water, and brought to a
total
volume
of 2.0 mL. If nitrite
concentrations
were
extremely high or low, we altered the dilution. A 2.0-mL
sample was selectedbecauseit is the smallest volume
conducive to accurate measurement in a spectrophotometer, and determinations could be made by
using only limited quantities of plasma.
We added 40 •L of sulfanilamide reagent (5 g sulfanilamide, 50 mL concentrated HC1, diluted to 500 mL
with distilled water) to the diluted sampleand allowedit
to react for 10 min; 40 •L of EDTA reagent (500 mg
dihydrochloride EDTA in 500 mL distilled water) were
then added and allowed
to react for 10 min. The absorb-
ance of the samplewas then measuredon a Bauschand
Lomb Spectronic70 spectrophotometeragainst a blank
at 543 nm. A new blank was required for each sample
becauseof the variability in plasma hue from different
71
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