Plastic-lined Ponds Research Articles

Technical and scale efficiency of intensive white-leg shrimp (Litopenaeus vannamei) farming in Vietnam: A data envelopment analysis

Intensive shrimp production is a potential pathway to increasing export quantity and meeting Vietnamese national export targets set for the 2020–2030 period. Vietnamese farmers need to efficiently manage their shrimp farming to compete in global markets. This study aims to investigate input- and output-specific technical and scale inefficiencies in Vietnamese shrimp farming practice and their determinants. The research used a survey among 200 shrimp farmers from Ca Mau, Kien Giang, and Soc Trang provinces in Vietnam, and applied a two-stage approach with a Russell-type (input–output) directional distance function for measuring input- and output-specific technical inefficiency, and a bootstrap truncated regression for exploring the determinants of inefficiencies. Results show that main drivers of technical inefficiencies in Vietnamese intensive white-leg shrimp farms are inappropriate management of energy (inefficiency of 32%), seed (inefficiency of 22%) and shrimp yield production (88%). Furthermore, male farmers experienced in shrimp farming, with proper training and applied plastic-lined ponds are generally better in managing pond areas, use of seed, feed, and labor. Technological innovations, better post larvae quality and their stocking management can help to improve shrimp farming performance.

Isolation and characterisation of sulphur oxidising bacterial isolates from two different pacific white shrimp, Penaeus vannamei culture systems

Sulphur reducing bacteria (SRB) and sulphur-oxidizing bacteria (SOB) are predominately involved in reduction and oxidation of sulphates and hydrogen sulphide, respectively, in pond and assist in maintaining healthy pond environment for shrimp culture. Hence, the present study aims to find out SOB two different Penaeus vannamei culture systems. Total 43 isolates from earthen ponds and 38 from plastic-lined ponds were obtained using thiosulphate agar and Starkey medium. The isolates were tested for their efficacy to reduce the pH of the growth media from 8.0 to ≤5.0 within 15 days of incubation. Data revealed the sulphate production was in the range of 2.5 to 195.36 mg/100 ml. The bacterial isolates from earthen pond showed significantly higher (P< 0.05) sulphate ion production compared to bacteria isolated from the plastic-lined pond. Among all these isolated bacteria, fifteen isolates possess autotrophic metabolism. SOBs were able to tolerate salt up to 13%. Morphological and biochemical characterization of isolated SOB revealed that as Bacillus species and Micrococcus sp. were present in the plastic-lined pond isolates whereas, Bacillus sp., Geobacillus sp., Amphibacillus sp., Anoxibacillus sp. and Alkalibacillus sp. were present in the earthen ponds. Thus, the earthen pond has more diverse SOB than in the plastic-lined pond.

Biofloc-based co-culture systems of Nile tilapia (Oreochromis niloticus) and redclaw crayfish (Cherax quadricarinatus) with different carbon–nitrogen ratios

This study aims to evaluate the production performance of biofloc-based co-culture systems of Nile tilapia and redclaw crayfish with varying carbon–nitrogen ratios (C/N). The experiment was conducted for 80 days in plastic-lined ponds with dimensions of 1 x 1 x 0.6 m. Two biofloc systems with two C/N ratios (10 and 15), using molasses as the carbon source and a control system without molasses were compared. Mixed-sex Nile tilapia with an initial average body weight of 7.00 ± 0.25 g were stocked at a density of 30 fish m−2. After 30 days of culture, redclaw crayfish with initial average body weight of 11.50 ± 0.55 g were added to the culture system at a density of 10 crayfish m−2. There were no significant differences in total animal biomass or total weight gain between treatments (P > 0.05). The total feed and overall feed conversion ratio (FCR) differed significantly (P < 0.05) between the biofloc systems and the control. Total ammonia nitrogen (TAN), nitrite nitrogen (NO2−N) and nitrate nitrogen (NO3−N) concentrations in biofloc systems with a C/N ratio of 15 were generally lower than those of other treatments. Dissolved oxygen concentrations decreased with the increase in the culture period in (4.13–4.40 mg L−1). Based on the results of this study, it can be concluded that an increase in the C/N ratio has positive effects on the feed utilization efficiency and water quality in biofloc-based tilapia–redclaw crayfish co-culture systems.

Tình hình sử dụng thảo dược trong nuôi tôm vùng Đồng bằng sông Cửu Long

Herbal plants are used to improve health, prevent and treat aquatic animal diseases, especially in marine shrimp farms in the Mekong Delta. However, detailed information on the use of herbal plants in shrimp farming in the Mekong delta is limited. This kind of information is important in the assessment of the characteristics, needs and potential use of herbal plants for the marine shrimp industry. The current study reports on a survey conducted in 2018 into the current use of herbal plants in shrimp farming. Ninety shrimp farmers in Ca Mau and Soc Trang provinces participated in the survey. Results showed: (i) herbal plants were used in both intensive shrimp farming in earthen ponds and super-intensive shrimp farming in plastic-lined ponds. The percentages of farmers using herbal plants in Ca Mau and Soc Trang were 58% and 51%, respectively; (ii) 18 herbal plant species were used in the shrimp farming process. (iii) the enhancement of shrimp immune system was the reason for application of herbal plants by most of shrimp farmers, followed by antibacterial activity of herbal plants; (iv) in Ca Mau, the group of farmers using herbs reported differences in the size of the harvested shrimp, costs and profits compared to those in the herb-nonuse group. It can be concluded that the use of herbal plants in marine shrimp farming in the Mekong Delta has demonstrated positive effects and has the potential to become widespread in a near future.

Fish farming water quality monitored by optical analysis: The potential application of UV–Vis absorption and fluorescence spectroscopy

In the present study, the fish farming water quality was determined by conventional limnological analysis during a Nile tilapia production cycle in four plastic-lined ponds. The water quality was obtained by measuring the dissolved oxygen, pH, water temperature, electrical conductivity, total dissolved solids and water transparency. In addition, optical measurements based on fluorescence and UV–Vis absorption spectroscopies were also carried out, aiming to determine the potential application of these techniques to fish farming water quality monitoring. The presence of proteins and chlorophyll (Chl) were optically monitored throughout the fish production cycle. The results demonstrated that emission of protein-like fluorescence, mainly attributed to the tryptophan in the 300–400 nm range, when excited between 220 and 290 nm, presented higher fluorescence intensity when compared to Chl emission. The optical results also revealed an unexpected emission band in two different ponds. This emission may be associated to the fluorescence of the phycoerythrin (PE), an auxiliary pigment to the chlorophyll, which are commonly found in cyanobacteria. This result was also confirmed by UV–Vis absorption data and by the analysis of stomach content of the fishes during the production cycle. In summary, our study has demonstrated that fluorescence spectroscopy and UV–Vis absorption techniques have a great potential to a fast qualitative analysis of water quality in fish farming.

Commercial Diets in Phase I Palmetto Bass, Morone saxatilis × Morone chrysops , Production in Plastic-lined Ponds: Fertilizer or Feed?

The role of offering a commercial pelleted diet has been characterized as both an expensive organic fertilizer and as a selected food item for larval hybrid striped bass (palmetto), Morone saxatilis × Morone chrysops, culture operations. In this study, we examined the effects of providing a commercial diet on fish production and zooplankton dynamics during phase I culture in plastic-lined ponds. We also sought to estimate relative dietary contribution of a commercial fish feed relative to natural pond biota using stable isotope tissue analysis. Palmetto bass were stocked into six 0.04-ha plastic-lined ponds at a rate of 125,000/ha. During the 31-d culture period, ponds were fertilized with alfalfa pellets at a rate of 112 kg/ha/wk. At 14 d post-stock (dps), Silver Cup Trout Fry diet was offered at a rate of 13.6 kg/ha/d and fertilization was discontinued in three ponds. Although mean final fish length was significantly greater within the fed treatment, no other production parameters were found to be different (P < 0.1). Following feed application, copepod concentrations within the fed ponds were greater in magnitude by 24 dps. Through stable isotope tissue analysis, we found a significant enrichment in both 13C and 15ν of fish, zooplankton, and Chironomidae larvae within the fed ponds (P < 0.10). Using a three-source mixing model, the mean (±SE) percent composition of feed in the fish's isotopic signature increased from 5% ±2 to 20% ±6 within 16 d. Although fish production was not greatly affected through the addition of a commercial fish feed, enriched 13C and 15ν of fish tissue indicate that palmetto bass fingerlings increasingly utilized the prepared diets over time. However, based on the isotopic values of fish and potential food sources, it can be estimated that natural pond biota likely accounted for up to 80% of nutrient assimilation in the hybrid striped bass.

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.

Chironomid abundance and consumption by juvenile channel catfish in plastic-lined and earthen culture ponds

In 2004, research was conducted to compare chironomid larvae populations and their use by channel catfish (Ictalurus punctatus) fingerlings in two different culture systems. Over a 4-month culture period, chironomid larvae densities in plastic-lined ponds were significantly less than those in earthen ponds. The consumption of chironomid larvae by channel catfish fingerlings was related to chironomid abundance in earthen ponds. The significance of these findings is the possible relationship among pond type, initial consumption of commercial diets and subsequent survival rates of fingerling channel catfish.

Effects of Three Fertilization Treatments on Water Quality, Zooplankton, and Striped Bass Fingerling Production in Plastic-Lined Ponds

Abstract Three pond fertilization treatments were compared in plastic-lined ponds to determine their effects on water quality, zooplankton, and production of fingerling striped bass Morone saxatilis. Treatment 1 used only alfalfa meal (100–200 kg/ha); treatment 2 used alfalfa meal (100–150 kg/ha) followed by ammonium nitrate and phosphoric acid after 24 h to maintain 210-μg N/L and 30-μg P/L target levels; and treatment 3 used alfalfa meal (100–150 kg/ha) followed by ammonium nitrate and phosphoric acid after 24 h to maintain 300-μg N/L and 20-μg P/L target levels. Treatment 1 promoted the most desirable water quality, including moderate pH and was most conducive to survival and production of fingerling striped bass. Mean pH values were 8.3 for treatment 1, 8.5 for treatment 2, and 8.6 for treatment 3; differences among treatments were significant (P ≤ 0.05). Mean adult crustacean densities were lowest in treatment 1 ponds and highest in treatment 3 ponds; however, mean total zooplankton densities were similar among treatments. Mean adult crustacean density correlated negatively with survival (r 2 = 0.74; P = 0.003) and positively with growth of fingerling striped bass (r 2 = 0.90; P = 0.0001), indicating that fish grazing pressure was fish density-dependent and that adult crustaceans were important food items for striped bass. Mean striped bass survival at harvest was 86.7% for treatment 1, 53.1% for treatment 2, and 36.4% for treatment 3; however, production of striped bass fingerlings (range, 160.7–173.5 kg/ha) was similar among treatments. Growth of striped bass was negatively correlated with survival (r 2 = 0.86; P = 0.0003), suggesting that growth was density-dependent and food was probably limiting in ponds with high survival rates. Survival was negatively correlated with pH (r 2 = 0.77, P = 0.002), suggesting that alkalinity could be a source of fish mortality.

Effects of Cottonseed and Alfalfa Meals as Fertilizers on Production of Palmetto Bass (Morone saxatilis×M. chrysops) Fingerlings in Plastic-Lined Ponds

Effects of cottonseed meal versus alfalfa meal fertilization on water quality, zooplankton density, and production of phase I palmetto bass, Morone saxatilis × M. chrysops, were compared in plastic-lined ponds. Cottonseed meal promoted better (P < 0.05) water quality, timing of high zooplankton density development, and growth and yield of palmetto bass. Cost of cottonseed meal toward fish production was $0.75/kg of fish, while that of alfalfa meal was $1.74/kg of fish.

A Method for Rearing Large Numbers of Pond Midge Larvae, with Estimates of Productivity and Standing Crop

A method for rearing large numbers of larval midges in plastic-lined ponds, with fertilization only, is presented. Estimates of standing crop and productivity of these midges are presented, along with comparative data on standing crop and productivity for other animals from the literature. To test the efficacy of harvesting floating plants for reversing eutrophy in lakes (Yount, 1964), we built a series of small ponds and fertilized them heavily. This fertilization made the ponds highly eutrophic. Within a few days, egg masses of midges were common and larval chironomids occurred in immense numbers on the pond bottoms. We suspended artificial larval substrates in these ponds, which enabled us to estimate not only the standing crop of larval midges but also their productivity. A number of articles report success with rearing pond midges, for example Branch (1923), Sadler (1935) (cf. Needham 1937), Buschkiel (1932; fide Huet, 1960: 85), Beerman (1952), Konstantinov (1961), Biever (1965) and others. These studies are aimed at raising midges for fish food or for special studies on midges, such as that of giant chromosomes, and require a sometimes complex feeding program as well as expensive concrete-lined ponds or laboratory control. In most cases these papers give no quantitative data. The method here described is inexpensive and requires no feeding beyond fertilization of the ponds, thus obviating complexity and reducing the cost and trouble of building the ponds. Data on both standing crop and productivity of the midges obtained by this method will be discussed. METHODS An area of about 10 m2 was dug to a depth of approximately 0.6 m and lined with two layers of 4 mil black polyethylene plastic. Black was chosen so that light would not destroy the plastic quickly as it does transparent polyethylene, and two layers were used to help prevent pinhole leaks from being a problem. The pond basin was