Production of Walleye,Stizostedion vitreum,in Earthen Ponds Fertilized with Organic and Inorganic Fertilizers and Stocked at Three Rates

Walleye, Stizostedion vitreum, fry were raised at densities of 20,30 and 40/m³ in ponds initially fertilized with alfalfa and yeast and supplementally fertilized with liquid inorganic fertilizers. Liquid fertilizers were added weekly to maintain N and P concentrations of 600 and 30 ug/L, respectively. Fish growth was not affected by stocking rate, but survival was significantly (P < 0.05) reduced in ponds stocked at the two higher rates. The fertilization procedure we used did not provide a sufficient forage base to support more that 20 walleye/m³.     

Significance of nitrogen fixation in fish ponds

The magnitude of nitrogen fixation in an inorganic fertilized and cereal fed system (fish pond) was measured by an in situ application of the acetylene reduction method. The effects of inorganic fertilization were intensively examined. In comparison with natural lakes, the fish ponds exhibited a relatively low fixation rate. The midday nitrogen fixation rate was usually less than 30 μg at N·m^?2·h^?1. The total income was equal to 5.7 kg N·ha^?1 or 0.575 g N·m^?2 for the growing season. Fish-induced bioperturbation and nitrogen fertilization, in the form of inorganic and organic fertilizers and foods, are considered to be the major regulatory factors in nitrogen fixation.     

Fertilizing fish ponds. I — Chemistry of the waters

Fertilization experiments were carried out in the Mex fish farm using superphosphate, ammonium nitrate and organic manure as fertilizers.The water was analysed monthly for inorganic phosphates, nitrates and silicates, in addition to chlorosity and pH.The ponds fertilized with chemical fertilizers exhibited a more rapid consumption of nutrients than the pond fertilized with organic manure.Phosphates and nitrates disappeared from the ponds after about two days of addition.     

Effect of varying closes of organic and inorganic fertilizers on plankton production and fish biomass in brackish water fish ponds

The effects of four different doses of organic (cowdung) and inorganic fertilizers (single super phosphate: SSP) in combination were studied on plankton production, species diversity and fish biomass in saline and freshwater fish ponds. Physico-chemical factors of pond waters were also monitored. Alkalinity and nutrients increased with increase in the dose of fertilizers. Dissolved oxygen (DO) also remained sufficiently high up to the third treatment; however, levels declined significantly in the ponds receiving the fourth treatment (20 000 kg ha^-1 year^-1 of cowdung and 3000 kg ha^-1 year^-1 of SSP). The highest plankton population, species diversity and higher fish biomass was also observed in ponds which received the third dose of fertilizers (10 000 kg ha^-1 year^-1 of cowdung and 1500 kg ha^-1 year^-1 of SSP). However, a decline in these parameters was observed in ponds which received the highest (fourth treatment) dose of fertilizers. Nutrients remained slightly lower in brackish-water fish ponds. When species diversity values were compared, it was observed that, although values werte higher in freshwater ponds, their abundance (no. 1¹) remained lower than in brackish-water fish ponds. Similarly, fish biomass also remained significantly higher in brackish-water ponds than in freshwater ponds. From these studies, it can be concluded that a combination of 10 000 kg of cowdung + 1500 kg ha^-1 year^-1 of SSP appears to be the optimum dose.     

Role of organic fertilizers in walleye (Sander vitreus) production in plastic‐lined culture ponds

This study used six 0.04 ha plastic‐lined ponds to compare the effects of a fertilization regime using a one‐time initial application of an organic fertilizer (alfalfa pellets) with the current regime of weekly applications of organic fertilizers on the abundance and distribution of aquatic invertebrates and walleye, Sander vitreus, fingerling production. Walleye, 3–4 days post hatch, were stocked on 1 May 2002 and harvested on 6–7 June 2002. Throughout the growing season, a ratio of 7:1 total nitrate‐nitrogen to total phosphorus was maintained in all ponds regardless of the treatment. Once fry were stocked, ponds in Treatment #1 were fertilized weekly with organic fertilizer (alfalfa pellets; 112 kg ha^?1 week^?1) for a total of 795 kg ha^?1 pond^?1. Ponds in Treatment #2 only received an initial application of alfalfa pellets (112 kg ha^?1). Ponds in Treatment #1 had significantly higher ammonia and nitrate levels as well as higher chironomid larvae but not zooplankton compared with the other treatment. At harvest, walleye in the Treatment #1 ponds were significantly longer and heavier; however, the survival and relative weight were not significantly different. These results suggest that weekly applications of organics are important for the benthic food base and growth of fingerling walleye reared in plastic‐lined ponds.     

Percid Pond Production Techniques

Tremendous variation in survival and growth of percid fry stocked in ponds was addressed through manipulation of amounts and kinds of fertilizers added and stocking densities of fish. Ponds were filled with water from nearby eutrophic lakes less than one week prior to stocking. Survival in these ponds averaged 64%. whereas ponds filled one month before stocking averaged only 14%. Optimal inorganic fertilization was identified as weekly restoration to 600µg N/L (NH4 +NO₃) and 30µg P/L as PO₄ ^-3. Organic fertilization gave variable results and water qualities. In one experiment, low organic fertilization alone (28 kg alfalfa meal/ha/week) provided survival and growth comparable to optimal fertilization with inorganic nutrients. Although similar in results, inorganic fertilization was more cost effective than the alfalfa meal. Low fish predation from low stocking or survival allowed Daphnia to overgraze algae. This resulted in a crash in both algae and zooplankton in the ponds. Doubling the initial stocking density increased harvests from 150.000 to 300,000 fish/ha and increased yield from 45 to 100 kg/ha.     

Comparisons of Two By-Products and a Prepared Diet as Organic Fertilizers on Growth and Survival of Larval Paddlefish,Polyodon spathula,in Earthen Ponds

Two agro-industrial by-products, rice bran (RB) and distillers dried solubles (DS), and a prepared diet (PD) were evaluated as organic fertilizers for the production of juvenile paddlefish in nine 0.02-ha earthen ponds over a 40-day culture period. Paddlefish yield from ponds fertilized with RB (209 kg/ha) was significantly greater (P≤0.05) than that from ponds fertilized with DS (129 kg/ha), but it was not significantly greater than yields from ponds fertilized with PD (258 kg/ha). Fish survival from ponds fertilized with PD (79%) was significantly higher than from ponds fertilized with RB (55%) or DS (50%). There was no significant difference in survival between ponds fertilized with RB and DS. Secchi disk visibilities in ponds fertilized with RB were significantly lower than in ponds fertilized with DS and PD. Relatively low Secchi disk visibilities in RB-fertilized ponds were because of a brown stain or coloration which reduced sunlight penetrationa and growth of filamentous algai, not observed in Ds- or PD-fertilized ponds. Larvae congregated in areas where PD was being applied, whcih suggested direct feeding on PD. Paddlefish did not respond when RB and DS were applied to ponds. Cost per juvenile paddlefish raised in ponds fertilized with RB was $0.004, cheaper than $0.011 for fish raised in ponds fertilized with PD or DS. Rice bran is the recommended agro-industrial by-product to raise juvenile paddlefish greater than 120 mm total length based on improved fish yields, pond water quality, and lower cost per fish. The prepared diet may be used not only as an organic fertilizer, but also as a supplemental feed.     

Production and Collection of Copepod Nauplii from Brackish Water Ponds

Copepod nauplii are a nutritious food item for first-feeding marine fish larvae. Unfortunately, mass culture techniques for producing copepod nauplii are not well established. Copepod nauplii can be collected from wild zooplankton populations or specially prepared ponds and transferred to larval fish tanks for feeding. This study evaluated the use of two trapping methods for harvesting zooplankton, particularly copepod nauplii, from fertilized ponds and the impact on the zooplankton population. Nine, 0.11 ha brackish-water (～2-7 ppt salinity) ponds were filled and fertilized with organic and inorganic fertilizers. The change in zooplankton abundance, mainly rotifers, nauplii and adult copepods, was monitored in the ponds for 22 d following initial pond filling. Beginning on day 8, three ponds were trapped with a large plankton net (Trap I), three with a pump and bag trap method (Trap II), and three ponds were not trapped. The ponds were trapped with the corresponding method for 1 h per day, for 15 d. The two trapping methods were similar in their efficiency to harvest nauplii, averaging 8,383,400 ± 2,508,378/h and 6,695,822 ± 433,533/h for Traps I and II, respectively. The zooplankton harvested by Trap I was not correlated to the densities in the ponds. However, the number of rotifers and nauplii harvested by Trap II was correlated to the rotifer and nauplii densities in the ponds. Both trapping methods were similar in terms of labor requirements and ease of use. Both methods were effective in collecting zooplankton without negatively impacting pond abundance.     

Effects of lining and drying on the chemical composition of sediments and influence of organic carbon on carp growth in aquaculture ponds

Chemical characteristics and P‐fractionation of sediments from the Deroua fish culture farm (Beni Mellal, Morocco) were analysed in 1998 and 1999. The high concentrations of organic N and organic C in the sediments reflect the high productivity of phytoplankton in the lined ponds. Despite the fact that these ponds were not frequently fertilized, inorganic P was more important in the sediments. The P released from CaCO₃≈P was the principal source of P for phytoplankton. The mineralization rate of organic C during the drying period was about 87 µg g^?1 day^?1 in the sediments. The mineralization rate of organic N seems to be less, compared with organic C. The experimental results indicate that the C:N ratio and texture of sediments could explain the immobilization of organic N. All forms of P remained almost unchanged after the drying period except for Fe(OOH)≈P. The ferric (oxy) hydroxides protect NaOH_ext‐P from the bacterial lyses and stabilize therefore their concentration. The inorganic P represented about 88% of Total P in the sediments and may influence the mineralization rate of organic P. The growth of silver carp were reduced in presence of high concentrations of organic C in sediments (> 30 mg/g). Compounds toxic to fish such as Fe²⁺, Mn²⁺, H₂S and CH₄ were then released in the water column.     

Effect of using different types of organic animal manure on plankton abundance, and on growth and survival of Tilapia rendalli (Boulenger) in ponds

An experiment was conducted to evaluate the effect of using different types of organic manure on the plankton abundance, and growth and survival of Tilapia rendalli juveniles in ponds. Fish weighing 18.15±0.44 g were stocked into 12, 20 m² ponds at 2 fish m^?2 (40 fish pond^?1). There were three replicate ponds per treatment (chicken manure, cattle manure, pig manure, and no‐manure as a control). After 84 days the T. rendalli in the chicken manure treatment were significantly larger and had higher net annual yields than those in the cattle manure, pig manure and no‐manure treatments. The survival rates were not significantly different across the treatments. Significantly higher amounts of chlorophyll a and higher numbers of zooplankton were found in ponds fertilized with the chicken manure treatment. The overall results obtained in this study suggest that the use of chicken manure produces better results than cattle and pig manure treatments on unfertilized ponds.     

Effect of organic fertilizer on heterotrophs and autotrophs: implications for water quality management

Alfalfa meal as a source of organic fertilizer was used in a series of pond, enclosure and laboratory experiments to determine its effect on bacteria, algae and water quality. Bacteria and flagellate algae were increased, whereas nonflagellate algae were not significantly affected by organic loadings. Bacterial and algal turnover rates we re 1.9-2.7 times daily and 0.18-0.22 times daily at 20-25^oC, respectively. Oxygen consumption rates were enhanced by increasing organic input or temperature. Dissolved oxygen in ponds with organic fertilizer was significantly lower than that in ponds without organic input. Because of low N and P content and high oxygen consumption, organic fertilizer alone is unlikely to provide adequate nutrients for algae and sufficient oxygen for fish. To stimulate the growth of food organisms for fish in aquaculture ponds, a combined use of inorganic and organic fertilizer is recommended, but the amount of organic fertilizer should be determined with care to avoid water quality deterioration. The amount of 10mg alfalfa 1^?1 wk^?1 is considered the upper safety limit for organic fertilization. The nitrogen and phosphorus ratio should be kept weekly at 20:1 by weight to promote the development of food organisms in ponds.     

Effects of Using Rice Bran and Cottonseed Meal as Organic Fertilizers on Water Quality,Plankton, and Growth and Yield of Striped Bass,Morone saxatilis,Fingerlings in Ponds

Several significant differences in water quality, primary production, production of plankton, or yield of striped bass, "Morone saxatilis," fingerlings were found between ponds fertilized with either rice bran and inorganic fertilizer or those ferilized with cottonseed meal and inorganic fertilizer. Ponds fertilized with rice bran had the lowest ammonia concentrations and Secchi disc readings and the highest concentrations of cladocerans and crustracean zooplankton. At harvest, after 82 days of culture, striped bass fingerlings from ponds fertilized with rice bran were significantly larger than were those from ponds fertilized with cottonseed meal. Numbers of fingerlins produced per hectare did not differ by treatment but ferilizer cost were US$94.78/ha less for ponds fertilized with rice bran.     

Use of duckweed (Lemna sp.) grown in sugarmill effluent for milkfish, Chanos chanos Forskal, production

Abstract. Oxidation treatment of sugarmill waste using duckweed ( Lemna sp.) as part of the system, to reduce effluent nutrient concentrations and biological oxygen demand (BOD), was evaluated during a 6 month milling season in Negros Oriental, Philippines. Mean ammonia concentration in effluent water was reduced from 0·87 to 0·31 mg/l NH₃-N and orthophosphate from 0·93 to 0·51 mg/l P₂O₅, while mean BOD was reduced from 611 to 143mg/t BOD₅, after treatment. Seasonal mass fish kills in the adjoining bay no longer occurred during the 3 years following introduction of this treatment. The mean duckweed production (dry weight) was 8–8g/m²/day. Duckweed was harvested from a 1·9ha area of the system and transferred to an adjacent milkfish, Chanos chanos Forskal, farm. Its fertilization effect, in terms of lablab production ( lablab is the biological complex of bluegreen algae, diatoms, bacteria and various animals which forms a mat at the bottom or floats in patches), was evaluated in the milkfish ponds. This was compared with ponds fertilized with either inorganic fertilizers or cow manure, in the traditional way. Lablab growth was significantly increased using duckweed, with ash-free dry weight production averaging 32g/m²/day following fertilization with duckweed compared with 4g/m²/day using inorganic fertilizers. Milkfish net production averaged 320 kg/ha/90-day crop in inorganically fertilized ponds. 545kg/ha/90-day crop for cow manure and 820kg/ha/90-day crop in duckweed-fertilized ponds. The system is described and the benefits of this integrated waste treatment-fish production facility are discussed.     

Simulation of food and oxygen limitations on the growth of Nile tilapia, Oreochromis niloticus L., in fishponds

A model for dynamic simulation of the growth of the Nile tilapia, Oreochromis niloticus (L.), in relation to food amount and composition, temperature, and dissolved oxygen concentration was applied to tilapia ponds. To model food competition between stocked fish and fingerling recruits, a pond food module was added. Data for model calibration were from uniform experiments with all-male O niloticus ponds fertilized with inorganic fertilizers and chicken manure in Honduras, Rwanda and Thailand. Calibration consisted of iterative determination of two model parameters: (1) CONLEV, the consumption rate without food or oxygen limitations; and (2) TPFS, the total daily food supply by the pond. Calibration results showed that, in most ponds, final fish weight could be simulated with acceptable values for CONLEV and TPFS. Both CONLEV and TPFS were related to natural productivity indicators (net primary production and chlorophyll a concentration). For each pond, an estimate of the degree of food and/or oxygen limitation could be given. Validation of the model with independent data from Indonesia and Panama was unsuccessful. The relationships used to estimate values of CONLEV and TPFS from primary productivity measurements were not satisfactory. A more detailed approach to modeling food competition and oxygen limitation under these conditions is necessary. The model provides a conceptual framework for the analysis of fish growth in ponds, tying together effects of food quantity and composition, temperature, and dissolved oxygen concentration.     

Effect of fertilization frequency on pond productivity and fish biomass in still water ponds stocked with Cirrhinus mrigala (Ham.)

Four different fertilization frequencies, namely twice per week, once per week, twice a month and once a month, were used in ponds to assess their effects on nutrient release, pond productivity and fish biomass. All ponds received the same total fertilizer inputs during the experimental period of 60 days (cow dung 208.3 kg ha^?1 week^?1, TSP 9.8 kg ha^?1 week^?1, urea 6.0 kg ha^?1 week^?1). Studies have revealed that the highest values of fish biomass, specific growth rate (SGR), net primary productivity (NPP), plankton population and nutrients were observed in the ponds that were fertilized twice a month. A strong and significant correlation of fertilization frequency was observed with dissolved oxygen, biochemical oxygen demand (BOD), alkalinity, nutrient release, NPP, plankton density (no. L^?1), fish biomass and SGR. The linear relationship between NPP and fish biomass/SGR for all the ponds was strong (r²= 0.88). Sediment chemistry revealed that O‐PO₄, NO₃‐N, organic carbon and electrical conductivity (EC) increased significantly (P<0.05) with a decrease in the frequency of fertilization, while alkalinity and calcium were high in ponds that were fertilized twice a month.     

Experimental evaluation of inorganic fertilization in larval giant grouper (Epinephelus lanceolatus Bloch) production

A major constraint in successful larviculture of groupers has been the small gape of the larvae and hence the requirement for small prey at first feeding. In this study, we examined how maintaining a phosphate concentration of 100 μg P L^?1 and an inorganic nitrogen (N) level of 700 μg N L^?1 via weekly fertilization with inorganic fertilizers affected phytoplankton, zooplankton and giant grouper larval survival in relation to a control group that was provided with rotifers immediately after larvae hatched. Unicellular algae, zooplankton within the size ranges of 10–50 μm and 50–100 μm and survival of giant grouper larvae were all significantly higher in the fertilized treatment compared with the control. Stomach analysis revealed that ciliates and flagellates were actively consumed by larval fish in the fertilized group, whereas few rotifers were consumed in the control. We conclude that the inorganic fertilization method provides high densities of suitable‐sized prey for larval groupers at the onset of exogenous feeding before they are able to consume larger, commercially available rotifers and copepods.     

Evaluation of Nile tilapia pond management strategies in Egypt

Five pond management strategies for Nile tilapia Oreochromis niloticus L. production were evaluated in 0.1‐ha earthen ponds in Egypt during a 145‐day production cycle. Pond management strategies developed by the Pond Dynamics/Aquaculture Collaborative Research Support Programme (PD/A CRSP) were compared with a traditional and a modified Egyptian pond management strategy. Young‐of‐year Nile (mixed‐sex or sex‐reversed) tilapia were stocked into ponds at 20 000 fish ha^?1. Sex‐reversed tilapia were stocked into chemical fertilization, organic fertilization plus formulated feed and feed only treatment ponds, whereas mixed‐sex tilapia were stocked into organic fertilization plus formulated feed and chemical plus organic fertilization plus formulated feed treatment ponds. Nile tilapia yields ranged from 1274 to 2929 kg ha^?1. Nile tilapia yields in organic fertilization plus formulated feed treatments were significantly greater than the yield from chemical fertilization ponds. PD/A CRSP pond management strategies did not produce significantly greater Nile tilapia yields than the traditional Egyptian system, but a larger percentage of harvested tilapia in the organic fertilization plus feed treatments were classified in the first and second class size categories compared with the traditional Egyptian system. Organic fertilization plus formulated feed pond management strategies had the highest net returns, average rate of return on capital and the highest margin between average price and break‐even prices to cover total variable costs or total costs.     

Effect of Using Low-Protein Diets in Semi-Intensive Pond Cage Culture of Tilapia,Tilapia rendalli (Boulenger)

ABSTRACT

An experiment was carried out to determine the effect of using low-protein diets on production of Tilapia rendalli in semi-intensive pond cage culture. This was carried out at Bunda College of Agriculture's fish farm, University of Malawi, where two 200-m² earthen ponds of 1-m depth were used for two months from February 2003 to early April 2003. Each pond had 6 cages of 1 m³ in size stocked with 15 fish, each 4.8 ± 1.2 g average weight and 6.7 ± 0.6 cm average length. Chicken manure was used as the organic manure applied at 500 kg/ha/wk and also acted as a control. All treatments were replicated three times. It was observed that fish growth was higher in the soybean meal-based diet, with final weight of 34.4 g, followed by sunflower cake, with final weight of 23.3 g. The lowest was 14.4 g in the chicken manure only, and cottonseed-based diet had final weight of 19.5 g. These results also agree with the specific growth rate (SGR) that ranged from 2.1%/day in the cages only fertilized with chicken manure to 3.6%/day in the soybean-based dietary treatment. The lowest feed conversion ratio of 1.2 was also observed in the soybean-based dietary treatment. This suggests that the use of lower protein diets that contain soybean would produce better results and may increase yield when combined with fertilization, as evidenced by high fish survival rates of more than 93% in all treatments.     

Effects of Organic and Chemical Fertilizers and Biological Control of Problem Organisms on Production of Fingerling Striped Bass,Morone saxatilis

Sixteen 0.04-ha ponds were fertilized with similar amounts of nitrogen (N) and available phosphorus (P) provided by either alfalfa meal, urea and phosphoric acid, or a combination where half of the P was provided by phosphoric acid and half by alfalfa meal. Half of the ponds fertilized with the combition of nutrients were stocked with adult male common carp, Cyprim carpio, at an average biomass of 168 kg/ha to provide biological control of rooted aquatic plants and clam shrimp, Cyzicus morsie. All ponds were stocked with 25,000 larval striped bass, Morone saxatilis, at an age of D4 (Dl is the day of hatch). Median harvest density and survival were about 100,000ha and 16%. Number harvested was directly related to numbers sampled with a light and dip net at D5 and D8. Low survival was probably related to high afternoon water temperatures (25-26°C) and relatively low morning dissolved oxygen (4.6-6.5 mg/L) when larvae were D5. Stocking larvae at an age prior to swim bladder inflation resulted in an inflation success of 99%. Dynamics of average net photosynthesis, chlorophylla concentrations, and densities of crustacean zooplankton, as well as mean number, biomass, and length of fingerlings harvested were similar in all treatments, regardless of whether the source of P was organic, inorganic, or the combination. Growth rate of larvae from DS to D8 was considered satisfactory (≥0.4 mm/day) with average densities of crustacean zooplankton of 10-20/L. The average growth rate of larvae from D8 to D40 was negatively related to number harvested. A weekly fertilization rate of available P from 28-38 µg/L resulted in satisfactory average growth rate (0.83 mm/day) of decreasing numbers of larvae at increasing ages: D8-D19-150.000ha. D19-D25-125.000/ha, and D25-D40-73,000/ha The presence of adult common carp provided several benefits: effective control of Chara and filamentous algae; a lower average percentage of fingerlings stranded in vegetation when ponds were drained (0.4% vs 10.1%); lower pH; effective control of clam shrimp.     

Effects of Pond Volume Manipulation on Production of Fingerling Largemouth Bass,Micropterus salmoides

Hatchery ponds were manipulated by timing of filling to increase the efficiency of production of fingerling largemouth bass, Micropterus salmoides. The effects on pond productivity of fertilizing with chicken manure versus plant meals (consisting of equal parts by weight of cottonseed meal, alfalfa meal, and wheat shorts) were also examined. When ponds were filled in stages, more favorable water temperatures for largemouth bass were achieved, and desirable dissolved oxygen concentrations were maintained. Chlorophyll a levels and plankton community respiration rates were higher in ponds that were fertilized with the plant meals than in ponds fertilized with chicken manure (25% dry matter). Secchi disk visibility was relatively greater in chicken manure ponds than in ponds fertilized with the plant meals; however all differences were not significant. Zooplankton densities were comparable among treatments. Filling ponds in stages had no significant effects on chlorophyll a, plankton community respiration rate, Secchi disk visibility, or zooplankton abundance and population dynamics. Daily production of largemouth bass was greater in ponds filled in stages and fertilized with plant meals than in other treatment ponds. Yield was highest in stage-filled ponds fertilized with plant meals and lowest in full ponds fertilized with chicken manure. Filling ponds in stages reduced the fertilizer cost per kilogram of largemouth bass by 50% in ponds fertilized with plant meals and by 65% in manure-fertilized ponds.