ML20030D447
| ML20030D447 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/26/1981 |
| From: | Behrends L, Burch D, Maddox J TENNESSEE VALLEY AUTHORITY |
| To: | |
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| ML073410735 | List: |
| References | |
| NUDOCS 8109010403 | |
| Download: ML20030D447 (9) | |
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TILAPIA CULTURE IN HEATED EFFLUENTS:
POTENTI AL FOR COMMERCIALIZATION IN TEMPERATE CLIMATES L. L. Behrends, D. W. Burch, J. J. Maddox, R. G. Nelson, and E. L. Waddei.1, Jr.
Tennessee Valley Authority Muscle Shoals, Alabama, U.S.A.
ABSTRACT Because the Tennessee Valley is located in a temperate climate, a multi-seasonal approach has been developed for culturing the tropical fish tilapia.
During the winter (October-March), temperature of condenser cooling water (CCW) from open-cycle nuclear power plants ranges from
- to 32* C, and it is ideally suited for overwintering small fingerlings and selected brood stock iu raceways.
During warmer periods of the year when CCW is too warm for raceway culture, fingerlings are reared to market size in earthen cooling ponds or in farm ponda near the power plant site.
Hatchery methods have also been de reloped for mass production of tilapia and their hybrido.
The integrated atorcach of over-wintering, hatchery production, and grovout will be discussed relative to optimal use of heated effluents.
l.
INTRODUCTION The tilapia (Sarotherodon spg.), a diverse group of tropical fish native to Africa and the Middle East, are cultured extensively as food fish in tropical and subtropical countries.
Tilapic have several qualities which make them excellent candidates for culture.
They grow fast, have good market potential, are relatively resistant a low-oxygen and high-ammonia concentrn*. ions, reproduce readily, have few disease problems, and can be cultured both intensively in raceways and extensively in ponds.
The most unique and valuable asset of tilapia, however, is their ability to feed on planktca, the base of the food chain in pond culture systems.
Thus, instead of requiring a high-protein pelleted diet, tilapia may be cultured on a less costly yet readily available supply of plankton.
This is especially valuable since feeding conventional pellets may account for 40 to 60 percent of the operating costs of a fish-farmina enterprise.
Because of their culture assets, tilapia are considered prime candidates for culture in the United States and other temperate countries (Suffern, 1961) if economical methods can be developed for mass-producing and j
overwintering selected seedstocks.
l.1. Constraints to Culture in Temperate Climates Despite the excellent culture characteristics of tilapia, several technical factors prevent development of a wide-scale culture industry in temperate l
climates.
Because tilapia cannot survive in climates where water temperatures are often less than 10* to 12' C for prolonged periods, economical methods must be developed for overwintering seedstocks and broodfish during cooler periods of 8109010403 810826 PDR ADOCK 05000259 P
the year.
A second major problem involves mass production of suitable seedstoch NN (i.e., monosex stocks) for pond culture.
Because overwintered tilapia mature and breed at a small size, overpopulation and stunting occur in pond culture which renders the barvest unmarketable. Although methods are available for producing 100 percent male populations via hormone treatment (Shelton, et al.,
1978) or hybridization (Mires, 1977), the problem remains that practical and economical methods for mass-producing suitable seedstocks are still not avail-able.
Finally, although small isolated studies indicate that tilapia are highly L'rketable (Suffern, 1981), little work in processing or market development has been done.
1.2.
TVA's Development Work Since the late 1960's, the Tennessee Valley Authority (TVA) has been developing was'te heat utilization technologies (Burns, et al., 1980; Hubert, 1980). During the past four TVA has been developing the technical criteria required for intens!
y averwintering tilapia stocks.
Related studies have also been conducted on fertilization techniques and mass production of n.
suitable seedstocks for pond
. king.
This paper summarizes TVA's resetreh and development work related to the breeding, culture, and overwintering of tilapia.
Applied uses of waste heat and its role in development of tilapia culture in temperate climates will be emphasized.
2.
PRACTICAL CULTURE OF TILAPIA IN REATED EFFLUENTS Several potential benefits may be derived from the use of flowing warm water in raceway and pond culture of tilapia.
These 11clude a lengthened growing early sexual maturation and spawning, enhanced plankton production,
- season, dilution of harmful metabolites, attraction and harvest of tilapia from extensive cooling ponds, and most importantly, the overwintering of culture stocks.
2.1.
Overwintering Studies--Prctetype Facility (1978-79)
In 1978, a prototype overwintering facility was designed and built at Musc)e Shoals, Alaba ma.
The
lity, a series of several small raceways (170 i capacity) received a supply of warr water.dmulating power plant CCW temperatures.
Two raceway culture periods (30 and 32 days in duration) were monitored during the winter of 1978 to determine:
(1) growth characteristics of tilapia fingerlings tr.?er raceway conditions, (2) changes in water quality as a function of feed rate and water retentign time, und (3) he influence of flow rate and aeration on fish density (kg/m ) and fish-loading rate (kg/i/ min) (Behrends, et al., 1980).
Growth rates of fingerling tilapia were not reduced significantly until average dissolved oxygen concantrations were less than 3 ppm (38 percent satura-tion, water temperature = 27* C).
Based on pH, total ammonia nitrogen, and water temperature, the theoretical un-ionized ammonia concentration (toxic form of ammonia) ranged f rom 5 to 91 pg/t. When sufficient oxygen was available
(>3 ppm), these concentrations of ammonia did not adversely affect growtgof tilapia.
Fitjg1 fish densities in the raceways ranged from 27 to 40 kg/m (1.9 to 2.5 lb/ft
, while final fish-loading rates rsuged from 1.2 to 1.7 kg/i/ min (10 to 14 lb/ gal / min).
l l
l s
pm.
Based on the 1978 results, a 100,000-fingerling c.'pacity raceway facility C/
was built at the Browns Ferry Nuclear Plant (BFN) near Athens, Alabama.
2.2.
Overwintering Facility Design--BFN The demcastration facility at BFN consists of six fiberglass raceways (3. 7 m by 1.2 m by 1.2 m) Ic :ated inside a 14.6-m by 7.6-m double polyethylene greenhouse structure; a CCW delivery system capable of providing a maximum of 190 1/ min / raceway and a series of redundant backup systems for water flow, aeration, electrical service, and space heating (Waddell, unpublished paper). A deep well with a flow of 2301/ min (el5* C) is used for blending and as an auxiliary water source during multiple unit stutdowns.
Eighteen aquaria ~(100 i capacity) have also been installed to evaluate spawning characteristics of tilapia as a funccion of photoperiod and CCW temperatures.
The BFN primarily uses an open-mode cooling system with CCW temperatures averaging 14.4* C above ambient.
Effluent CCW temperatures range from 15* C in January to 46* C in August. As a safety feature, the CCW delivery system was retrofitted upstream of the radiological effluent injection site.
This measure eliminates the most significant source of radioactivity normally found in liquid effluents from nuclear power plants.
Also, condenser cooling water can be supplied to the delivery system from any of the three power production units.
This increases reliability of the warmwater source, although not to the extent that backup systems are not required.
2.3.
Overwintering Studies-- BEN (1979-81)
In mid-October 1979, 70,000 tilapia fingerlings, ranging in weight from 3.0 to 15.0 g, arrived from Auburr. University and were stocked into six raceways.
Two different species of tilapia, Sarotherodon aurea and S. nilotica were supplied as test species because of their favorable growth rates and relative cold t31erance (Lee, 1979). Growth, survival, and feed conversion values were satisftetory during the winter period.
By early February, the fish had increased their initial weight by 450 to 300 percent.
Unfortunately, on February 11, 1980 a multiple unit shutdown coup.ed with an unrelated computer and alarm failure resulted in intrusion of amoient river water and massive mortality ci tilapia stocks.
The fish were exposed ambient river water (5* C) for bout 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> before CCW temperatures rose to preshutdown levels.
Complete mortality of the less cold tolerant S. nilotica occurred, while S,.
aurea, the most cold tolerant of the tilapia species, experienced 95 percent mortality. More tilapia finger-lings were acquired from Florida and reared in the racewnys during the remainder of the overwintering period.
In mid-April, most of these finbarlings were taken to Auburn University for pond and cage production tests.
During the~1980-81 overwintering period, emphasis was placed on overwintering a diversity of brood-stock and fingerlings for expanded breeding and pond culture studies respectively.
"our stocks of brcod-sized tilapia (3,. aurea, S. nilotica, S. hornorum, and S.
mossambica) and two all-male hybrid strains and (S,. _nilotica'g / S. hornorum d) were succ(essfully overwintered.S. mossambica Q x S,. horuorum d ),
By early April, the hybrid S. mossambica g x S[. hornorum d had increased its initial weight (2.5 g) by 570 percent.
Few operational problems were encountered during the 1980-81 overwintering period, due primarily to the adding of several auto-matic backup systems (Waddell, unpublished paper).
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2.4.
Tilapia Breedir<, and Hybridization Studies Production of all-male tilapia fingerlings by hybridization is advantageous for several reasons.
Unwanted reproduction in culture ponds can be avoided if all-male fingerlings are stocked. Also several crosses exhibit hybrid vigor for cold tolerance and growth (Lee, 1979), both significant factors for culture in temperate climates. During 1980, 36 small nylon nets (1.2 e by 1.2 m by 2.7 m, 0.15-cm mesh) were suspended in an earthen pond and evaluatec as portable breed-ing ' units for producing hybrid tilapia fry (behrends and Smitherman, 1981).
Adult fish (brooders) were stocked into the nets in June, and fry (and eggs) were collected every two weeks for a 6-week period.
Three dif ferent crosses which theoretically produce 100 percent male offspring were evaluated.
Of these, only the female j[. mossambica x malc j[. hornorum cross produced signifi-cant numbers of fry.
At a stocking rate of 24 brooders (20 feuales and 4 males),
10,860 fry and fertilized eggs were produced during a 6-week period.
Subsequent net-breeding trials wera conducted to quc m.
'y the relative eaue of producing S. aurea, S. nilotica, S,. hornorum, and S,. mossambica, and all their hybrids (Behrends and Smitherman, unpublished data).
Breeding studies were continued during the winter of 1980-81 to ascertain the feasibility of inducing tilapia broodstock to spawn early via photoperiod and tempereture manipulation.
Generally, tilapia will not spawn in north Alabama ritil late May.
However, by late February all four apecies were exhibit-ing breeding behavior and spawning occurred in all species by mid-March.
Invari-ably, early spawning occurred only after CCW temperatures were above 24" C anc photoperiods were greater than 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />.
However, our data strongly suggests that temperature was a much stronger stimulus to spawning than photoperiod, as long as the photoperiod was greater than 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />.
This is a favorable impli-cation for hatchery work at closed-eycle plants where CCW temperatures are much warmer during winter months.
The early spring spawning approach to fingerling production may have advan-tages over the tradit'onal overwintering approach.
Instead of overwintering summer-produced fingerlings, : elected groups of broodfish could be overwintered and induced to spawn An early March.
Theoretically, for each kg of female l
broodstock overwintered, 3,000 fry could be produced in the initial spawn, thus increasing the capacity of the overwintering system. More breeding and nursery i
areas wuold be required for this operation.
Early spring spawning would require l
that young-of-the-year tilapia reach marketable weight during their first culture season. This procedure remains to be tested.
2.5.
Pond Grovout of Tilcpia Fond production of tilapia can be accomplished with pelleted feeds, organic fertilizers, or a combination of bs h.
TVA has developed aa integrated warmwater aquaculture system for reclaiming valuabic plant nutrients from animal wast _s which accumulate during livestock feeding in confinement (Behrends, et al.,
1980, in press; Behrends, 1980; and Maddox, et al., 1979).
During the past five years, experiment; were conducted to develop criteria for such a system (figure 1).
Results of yield trials indicate that for optimum product?on of market-sized fish, plankton culture ponds should be fertilized daily during March through October with up to 60 kg/ha/ day of fresh swine manure (dry-matter basis). Warm CCW should be directed into the ponds at a rate sufficient to flush them every
- 10. days.
Shorter retention perieds (5 days or less) result in less plankton i
production and hence, less fish production.
Longer retention periods (la days or more), although allowing greater plankton production, also result in less
POWER PL ANT CCWDENSER EFFLUENT Iv, ARM WATER)
~ WIN TE R TILAPIA *0/ERWINTERING"~
OPERATION FACILIT Y SUMMER OPERAT @
PRIMARY WASTE TREATMENT NECT SECONDARY WASTE TREAT.
R
/ CULTURE OF FILTER-MENT / SAND FILTRATION CED
' gSUMMER ONLY)
{ FEEDING FISHI tCULTtGE OF AQUATc FtANG I;
DISCHAROC OF COOL CONFINED SWl*%
_ SWINE TER FACIUTY WASTE
- ($TORAGI CLEAN WATER FIGURC t 810LOttCAL RECYCLING OF LIVE 310cd WASTE NUTRIENTS AND CNERGY, fish production due to the buildup of toxic metabolites, such as amnonia.
stocking rate of 10,000 to 15,000/ha, production in excess of 6,000 kg/ha is At a possible during a 6-month growing season (Behrends, et al., in press).
Fertility rates and stocking densities have also been developed for static water systems (i.e., no flowing water), and other nanure sources and Smitherman, 1978, and Stickney and Hesby, 1977).(Moav, et al., 1977; Collis Culture ponds caa also be used in intensely fed production systems if large volumes of warm wate. are available to supply oxygen and dilute culture-related metabolites.
In Taiwan, tilapia standing crops of near 110,000 kg/ha have been achieved in flowing water ponds with aeration and a natritionally balanced diet (Lovell, 1980).
ha e application at power plant site., Intensive pond production syatems, although feed where land may not be available for devel-of large extensive production systems.
rent 3.
OPTIMIZING U:3E OF HEATEIs EFFLUENTS IN TILAPIA CULTURE One of the most commonly voiced concerns in power plant aquaculture relates to the problem of wide seasonal variation in effluent temperatures.
This is especially critical at as ruch as 25* to 30' C.open-cycle power plants where CCW temperatures may vary Culturally, systems to accommodate these large fluctuations in temperature.this problem can be m adoption of a multiseasonal approach to culturing tilapia which optimizes theTVA has proposed use of warm flowing water on an annual basis.
48 47 46 44 43 EARLY
$PA ING 40
/
38
- OVERW;NTERING OF BROODSTOCK b
e OVERW!NTERING -
g, 37 AND FINGERL>NGS
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g 36
/
p 35 4 34 33 W
n.
32 2 31 N
p 30
- \\
- GROW-OUT IN FAR4 S
] 26 m 2s A 24 W
1 23 GROW-OUT IN POW 7R PL ANT
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22 COOLING PONDS 21 j
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20 t
69
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18 17
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JAN FEB MAR APR MM JUN JUL AUG SEP OC7 NOV DEC FIGURE 2 BROWNS FERRY CONDENSER EFFLUENT TEMPERATURES AND RELATED TIL APIA CULTURE ACTIVITIES Figure 2 illustrates the proposed culture accivities as they relate to the CCW temperature of BFN.
The upper and lower lines represent the mean maximum and mean mini um temperatures rest.
Ively.
During winter and sprine, emphasis will be on hatchery operations and producing stocker-sized fingerlings, while final growout will be performed in ponds during late spring, st mer, and fall.
Final growout can be performed at the power plant site in appropriately sized cooling ponde or in conventional farm ponds near the power plant site.
The farm pond approach has considerab appeal since it has the po* 'ttal for expanding the land base for tilapia culture to thcusands of acres.
CONCLUSION Although more development work will be required before tilapia culture becomes an aquaculture industry in temperate climates, recent developments in hatchery and overwintering systems will certainly expedite the extension process.
TVA will continue its development work in tilapia culture with an emphasis on extending it from the power plant site to the farm.
i
ACKNOWLEDGEMENTS l
TVA expresses its gratitude to Auburn Univercity's Department of Fisheries and Allied Aquacultures for its cooperation in preriding fingerlings and exper-tise.
We also acknowledge John P. Kingsley, Philij W. Barron, and H. Steven j
Coonrod 11 for their technical help.
REFERENCES 1.
Behrends, L.
L., Recycling Livestock Wastes via Fish Culture, Aquaculture Magazinc, (7) pp. 38-39, 1980.
2.
Behrends, L. L. and R. O. Smitherman, Mass Production of Hybrid Tilapia Fry in Suspended Nylon Mesh Nets, Research Workshop, Summary of Papers, Catfish Farmers of America, p. 62, 1981.
3.
Behrends, L.
L., J. B. Kingsley, J. J. Maddox, R. S. Pile, J. C.
- Roethell, and E. L. Waddell, Jr..
Intensive Production of Tilapia Fingerlings in Thermal Effluents, Research Workshop, Summary of Papers, Catfish Farmers of America, p. 42, 1980.
4.
Behrends, L.
L., J. J. Maddox, C. E. Madewell, and R. S. Pile, Comparison of Two Methods of Using Liquid Swine Manure as an Organic Fertilizer in the Production of Filter-Feeding Fish, Aquaculture (20) pp. 147-153, 1980.
5.
Behrends, L.
L., J. B. Kingsley, J. J. Maddox, and E. L. Waddell, Jr., Use of Thermal Effluents and Organic Manures to Enhance Pond Production of Freshwater Fish: An Integrated Approach--Part 1 In press.
6.
Burns, E.
R., L. L. Behrends, J. J. Maddox, C. E. Madewell, D. A. Mays, and R. S. Pile, Agricultural Uses of Power Plant Waste Heat, in L. B. Goss (ed.), Factors Affecting Power Plant Waste Hcat Utilization.
chap. 1. Pergamon Press, New York, 1980.
7.
Collis, W. J. and R. O. Smitherman, Produ nion of Hybrid Tilapia with Cattle Manure and a Commercial Diet, in R. O.
of the Symposium on the Culture of Exotic Species,Smitherman (ed.), Proceedings Fish Culture Section, American Fish Society, 1978.
8.
Hubert, W.
A., Aquacultural Uses of Power Plant Waste Heat, in L. B. Goss (ed.), Factors Affecting Power Plant Waste Heat Utilization, chap.
1, Pergamon Press, New York, 1980.
9.
Lee, J.
C., Rept 'uction and Hybridization of Three Cichlid Fishes, Sarotherodon aurea, S. hornorum, and S._nilotica in Aquaria and in Plastic Pools, Ph.D. thesis, Auburn University, Auburn, Alabama, 1979.
10.
Lovell, R.
T., Feeding Tilapia, A_quoculture Magazine
'7) pp. 42-43, 1980.
11.
Maddox, J.
J., L. L. Behrends, R. S. Pile, and J. C. Roetheli, Waste Treatment for Confined Swine by Aquaculture, American Society of Agricultural Engineers, Paper No.
70-4077, 1979.
12.
Moav, R.
C., G. W. Wohlfarth, and G. L. Schroeder, Intensive Polyculture of Fish in Freshwater Ponds, I. Substitution of Expensive Feeds by Liquid Cow Manure, Aquaculture,10(1) pp. 75-43, 1977.
M 13.
Stickney, R. R., ano J. H. liesby, Water Quality - Tilapia aurea Interactions in Ponds Receiving Swine and Poultry Wastes, Proceedings, 8th Annual Meeting World Mariculture Society, pp. 55-73, 1977.
14.
Waddell, E. L., Jr., Tilapia Culture in IIcated Ef fluents:
Facility Design, Operation, and Evaluation, Unpublished Paper.
15.
Suffern, J.
S., The Potential of Tilapia in Un' Led States Aquaculture, Aquaculture Magazine, (6) pp. 14-18, 1980, 1