Biological Resources for Development of Aquaculture in Thi Nai Lagoon,Vietnam

The diversity of aquatic resources in Thi Nai Lagoon decreased due to the lack of harmonious use and integrated long-term planning on the use of living resources.There remained a lack of mechanisms and regulations for coordination of activities in the lagoon by Binh Dinh Provincial People’s Committee(PPC).The aim of the study was to investgate the aquatic species and water quality in Thi Nai Lagoon,Vietnam.Data were collected at 23 different points on Thi Nai Lagoon,with three replicates at each point.There were 106 species of fish presented on the lagoon and in different sizes,including 17 mollusc species and 15 crustaceans species.In the dry season,there were 167 phytoplankton species in five divisions,10 classes in 39 orders in 59 families including 77 genus.Zooplankton had eight chordata in 10 classes of 18 orders including 44 families,64 genus and 102 species.Arthropoda had the largest number of species,78 species,accounting for 76.5%of total species.In the rainy season,only 48 species of Arthropoda,Cnidaria,Annelida,Chaetognatha and Rotifer were affected and some were not encountered in the wet season,such as mollusca and chordata.While water quality variables were still good for aquaculture,within permitted limits of TCVN standard and criteria,there were still problems caused by production discharges and living activities of inhabitants around the lagoon,such as sedimentary matters.

Morphological and Genetic Differentiation of Fish of the Subgenus Chrysichthys chrysichthys from Ivorian Rivers

Fish of the Chrysichthys genus are subject to intense exploitation, which is threatening the available stock. The implementation of a sustainable resource management plan requires a good knowledge of the biodiversity of this genus. The aim of this study was to determine the morphological and genetic characteristics of the fish of the subgenus Chrysichthys chrysichthys in order to identify descriptors for differentiating the species of this subgenus present in C?te d’Ivoire. The biometric analysis involved forty-one morphological measurements taken from each of the 255 specimens sampled in five hydro systems. The genetic analysis of the D-loop mitochondrial DNA sequence was carried out in 34 specimens. The amplicons obtained by PCR were subjected to sequencing. Individual analysis of morphometric characters divided the subgenus into two different species: C. maurus and C. auratus. The high classification rate (>90%) of the Discriminant Factor Analysis confirmed the existence of these two species. Wilk’s Lambda test revealed thirteen discriminating descriptors. Phylogenetic analysis confirmed the existence of both species. Within the C. maurus species, fish from the river Bia are genetically different from those from other rivers. On the other hand, this population is fairly close to that of the C. auratus species, which is also divided into two different clades. Finally, molecular analysis corrected the taxonomic status of the fish.

Influence of Constructed Wetland and Soil Filter Systems in the Dynamics of Phytoplankton Functional Groups of Two Subtropical Fish Farm Wastewaters

Environmental pressure, land utilization, and economic feasibility have resulted in the development of alternatives to treatment fish farm wastewater. We examined the influence of two water treatment systems—a constructed wetland (CW) and a soil filter system (SF)—on the constitution of the phytoplankton community analyzed through the functional grouping of species and nutrients removal of aquaculture farm. The CW provided high removal efficiency: 82.9% for ammonia, 87.0% for nitrate, 96.9% for nitrite, 85.5% for total phosphorus, 88.5% for SRP and 71.6% for BOD. Removal efficiency of SF was lower than CW, removing 82.1% of ammonia, 7.2% of total phosphorus, 45.9% of SRP and 39.4% of nitrite, but was satisfactory. The functional group F, made up of Chlorophyceae Dictyosphaerium pulchellum and Kirchneriella lunaris, was the most representative in both systems, followed by functional group P and constituted by Zygnemaphyceae Melosira sp. The number of functional groups decreased in the outlet of the two treatment systems, where S1, H1 and W1, characteristic of eutrophic environment, were retained. Data show that CW and the SF system are potentially applicable to the fish farm wastewater treatment and ensure an improvement in water quality.

Treatment of Bullfrog Farming Wastewater in a Constructed Wetland

The aim of this study was to install and assess the efficiency of a constructed wetland for wastewater treatment from bullfrog farming (Lithobates catesbeianus) at fattening growth phase. Water detention time was not controlled since wastewater input flow varied according to the biomass of animals maintained in stalls. The study was divided into two phases, with higher and lower bullfrog biomass respectively for phase I and II. A higher removal of nitrite, biochemical oxygen demand, and thermotolerant coliforms was observed at phase I whereas a higher removal of turbidity, nitrate, total phosphorus, total suspended solids, total dissolved solids, and chlorophyll a occurred at phase II. Wastewater treatments using constructed wetland systems with high organic load require a higher water detention time for a better load removal. The treatment effect was positive since this wastewater flowed directly into fishponds or streams, which might promote eutrophication. Thus, wastewater treatment is essential to minimize the impact caused by frog farming on receiving water bodies, promoting the sustainability of this activity in Brazil.

Influence of Physico-Chemical Factors, Zooplankton Species Biodiversity and Seasonal Abundance in Anzali International Wetland, Iran

Anzali International wetland is located in the south coast of the Caspian Sea. Physicochemical analysis and zooplankton survey of the wetland were carried out on monthly basis for the period of one year from January 2012 to December 2013 at 9 different stations of Anzali wetland and its related channel to the Caspian Sea. Water temperature of the wetland followed more or less similar trend as that of air temperature. pH determined alkaline nature of the wetland ranging between 7.05 to 9.47, dissolved oxygen was recorded in the range of 3.36 mg/l to 10.51 mg/l while other parameters recorded were water temperature (10 to 23 C), Nitrate (0.48 to 4.36 mg/l), Total Phosphates (0.15 to 0.67 mg/l), Salinity (220 to 692 mg/l), Electrical Conductivity (235 to 1369 μs/cm), TDS (246 to 1971 mg/l), BOD (2 to 36 mg/l) and COD (4 to 74 mg/l). During study period, total 60 species of zooplankton were identified in four main groups such as Protozoa (22 sp.), Rotifera (29 sp.), Copepoda (5 sp.) and Cladocera (4 sp.). The highest numbers of zooplankton were recorded in summer months and lowest in winter which is the second rainy season of this area. The water body is receiving domestic discharge, agricultural run-off and industrial wastes leading to large amount of nutrient inputs to the ecosystem which indicates the eutrophic statue of the wetland. The aim of present study was to investigate the interrelationship between physicochemical factors and zooplankton population in context of their seasonal abundance.

Improved survival in channel catfish fed mannanoligosaccharides in an extruded diet

The high temperature and pressure achieved during cooking extrusion has been shown to affect nutrient availability. To determine the effects of extrusion temperature on the efficacy of mannanoligosaccharide (Bio-Mos?) in channel catfish, 4 experimental diets were fed for 9 wks and then challenged with Edwardsiella ictaluri bacterium. Catfish (9.9 ± 0.4 g) were randomly assigned to the following treatments: Low-None (low temperature process without additive);High-None (high temperature process without additive);Low-Bio (low temperature process with 4 g/kg diet Bio-Mos?);High-Bio (high temperature process with 4 g/kg diet Bio-Mos?). Although specific growth rate and food conversion ratio were similar among treatments (P > 0.10), survival after E. ictaluri challenge was highest (P ?-laden feed resulted in survival numbers similar to diets without Bio-Mos?. Extruding catfish diets supplemented with Bio-Mos? at lower temperatures may provide another strategy to control enteric septicemia of catfish.

Study of Zooplankton Species Structure and Dominance in Anzali International Wetland

Anzali International wetland is one of the most important places for various organisms such as fishes. Zooplankton are the first consumers in the ecosystem, and they are perfect food for the larvae of fishes. The present study conducted monthly during January 2012 to December 2013 in 9 different stations with zooplankton population and chemical characteristics analysis such as water temperature ranged from 10°C - 22°C, pH determined alkaline nature of the wetland ranged from 7.05 to 9.47, dissolved oxygen was recorded in the range of 3.36 mg/l to 10.51 mg/l, nitrate was ranged between 0.48 - 4.36 mg/l, total phosphates was between 0.15 - 0.67 mg/l, salinity was recorded between 220 - 692 mg/l, TDS was determined between 246 - 1971 mg/l, BOD and COD was also recorded 2 - 36 mg/l and 4 - 74 mg/l respectively. Total 61 zooplankton species were found belonging to 4 groups: Protozoa (22 sp.), Rotatoria (29 sp.), Copepoda (5 sp.) and Cladocera (4 sp.). Rotatoria were found dominating other groups of zooplankton. Kruskal Wallis test showed that there was significant difference between density of zooplankton in different stations, months and seasons (P ≤ 0.05) and significant differences were found between densities of different zooplankton phylum (P ≤ 0.05). The water body is continuously receiving domestic discharge leading to large amount of nutrient inputs and high amount of phosphate and nitrate in the water body indicates that water is eutrophic in nature.

Culture of Eriocheir sinensis Larvae in Ponds in Greenhouse

A total of 15 pools were selected from a greenhouse, and they were randomly and evenly divided into three groups.In each group, one stocking density of Eriocheir sinensis was arranged. The results showed that after 45-d culture, the crab number per kilogram reached about 300 with survival rate of about 20%; the initial stocking density had significantly effect on the body size of E. sinensis on sell, instead on the survival rate of E. sinensis larvae. Therefore, it is feasible to conduct the culture of E. sinensis larvae in a pool in greenhouse.

Changes in Some Parameters of Salting Brazilian Freshwater Fish Effect of Aqueous Extract of Basil

Salting is a traditional process to preserve food,while news species have been salted showing good results.However,salt accelerates lipid oxidation,influencing shelf-life of salted products.Using of antioxidants increases salted and/or desalted products shelf-life.Among the antioxidants employed in food industry spices have shown satisfactory results.In this work aqueous basil extract(Ocimunbasilicum)in pintachara salt was used.Pintachara is a hybrid of pintado and cachara(genus Pseudoplatystoma)whose flesh is much appreciated,being desirable to develop new product of this fish.The aqueous basil extract was used in a brine salt,and process was carried out with a control treatment.Samples were obtained during salting in 1,14,24,36,48 hours.In each sample period it analyzed moisture,water activity,salt content e TBARS.The aqueous basil extract interfered in salting processes and showed antioxidant action in this process.Practical applications:Brazilian consumers appreciate salted fish,as influence of Portuguese culture.There are some typical regional products,such as the pantaneiro cod,which consists on catfish from Pantanal that is salted as cod.The development of hybrids from native fishes in aquaculture leads to higher lipid content in the hybrids and the addition of natural antioxidants during salting process increases the product shelf-life and keeps the sensorial properties.

Consequences of Direct Transfer to Fresh Water on the Blood Variables of Sarotherodon melanotheron(Rüppell,1852)

Alterations in blood variables of Sarotherodon melanotheron transmitted immediately from brackish water(salinity 13.71‰)to fresh water(salinity 0.12‰)were examined to evaluate the consequence of abrupt alterations in the environment on fish blood parameters.The results acquired revealed that significant reduction(p<0.05)in mean values of Haemoglobin(Hb)from 7.37±1.22 to 4.30±0.82dl-1;Packed Cell Volume(PCV)23.48±3.22 to 15.08±2.97%;Red Blood Cell(RBC)5.99±0.72 to 3.31±0.77 Cells x106;Mean Corpuscular Haemoglobin Concentration(MCHC)31.68±3.66 to 28.48±2.03 pg;and Platelets(PLT)195.44±16.77 to 138.99±9.05103 uL-1.However,notable elevation was recorded in the values of Erythrocyte Sedimentation Rate(ESR)from 4.89±0.16 to 10.58±1.48 mm/hr;White Blood Cell(WBC)27.03±2.96 to 33.09±3.72 x 109 L-1;Mean Corpuscular Volume(MCV)39.33±3.07 to 45.88±7.03 fL Neutrophils(NEUT)41.71±3.08 to 48.30±7.99%;Lymphocytes(LYMP)54.60±3.99 to 46.36±9.87%and Monocytes(MON)3.80±1.04 to 5.97±1.99%.These variations in the blood parameters were more perceptible in adult than juvenile fish.Results from this study consequently imply that direct transfer of fish to a region of lower salinity may have damaging effect on the physiology of S.melanotheron as observed in this study.

Influence of Management on the Water Quality and Sediment in Tropical Fish Farm

A seven-month research evaluated the management effect on the water quality and sediment of seven fish ponds. Water and sediment were collected at nine sample sites: seven in the fish ponds;one in inlet water and another in the fish farm’s effluent. The soil samples were analyzed for macro- and micro-nutrients and the water samples were analyzed for physical and chemical parameters. Management and local climate conditions affected nutrient seasonality in the sediment and featured high concentrations of Al, Ca, Cu, K, Mg, C, Na, Zn and OM at the effluent with low pH, ranging between 4.4 and 6.5. Sudden decrease of DO (less than 3 mg/L) during the rainy season, with a 180 mmrainfall, and a TSS increase (approximately 10 mg/L) were reported. Use of organic manure in fish pond V6 caused higher rates of ammonia (over 1 mg/L). Due to the sediment’s acid pH (less than 4.8) and Al at 0.92 mg/L at the effluent, great care was required in the fish farm. Maintenance and procedures management in the fish farm under analysis should be given more attention since high levels of Al, Fe and acid pH and low levels of potassium and phosphorus in the sediment may produce unfavorable conditions in the water column, and may ultimately have an impact on fish.

Effects of Different Combinations of Two Spices:Clove and Nutmeg Seed Extracts on Antioxidants Levels in African Catfish(Clarias gariepinus)

The effect of different combinations of botanical spices such as clove and nutmeg in different proportion on the antioxidants activities which include lipid peroxidation(LPO),superoxide dismutase(SOD),catalase(CAT),glutathione-S-transferase(GST)and glutathione peroxide(GPX)in juveniles and adults sizes of Clarias gariepinus was investigated using different combinations of clove(C),and nutmeg(C.N 0:0-Control 0%of Clove and Nutmeg;C.N 1:3-25%Clove and 75%Nutmeg;C.N 3:1-75%Clove and 25%Nutmeg;C.N 2:2-50%Clove and 50%Nutmeg;C.4-100%Clove;N4-100%)in triplicates.The results from the study indicated that the anaesthetic caused a substantial(p<0.05)modifications in the five antioxidants under examination.The highest deviations in the studied antioxidants were observed in the fish exposed to C4 combination of the anaesthetics and the lowest in the control.The results from this work therefore suggest that the anaesthetics can alter antioxidants levels in the fish which was more noticeable in the fish exposed to C.N 3:1-75%Clove and 25%Nutmeg;C.N 2:2-50%Clove and 50%Nutmeg;C.4-100%Clove;N4-100%.Hence fish farmers and scientists are advised to take caution when combining these plant extracts for use in aquaculture.

Identification of Bacterial Fish Pathogens in Brazil by Direct Colony PCR and 16S rRNA Gene Sequencing

Intensive fish farming systems in Brazil have increased the disease incidence, mainly of bacterial origin, due to higher stocking density, high organic matter levels and poor quality of the aquatic environment that causes high mortality rates during outbreaks. The identification of pathogenic species using a fast and reliable method of diagnosis is essential for successful epidemiological studies and disease control. The present study evaluated the use of direct colony PCR in combination with 16S rRNA gene sequencing to diagnose fish bacterial diseases, with the goal of reducing the costs and time necessary for bacterial identification. The method was successful for all 178 isolates tested and produced bands with the same intensity as the standard PCR performed using pure DNA. In conclusion, the genetics methods allowed detecting the most common and important pathogens in Aquaculture, including 12 species of occurrence in Brazilian fish farms. The results of the present study constitute an advance in the available diagnostic methods for bacterial pathogens in fish farms.

Effluent of a Polyculture System(Tilapias and Shrimps):Assessment by Mass Balance of Nitrogen and Phosphorus

From the estimation of the mass balance model, which can also be classified as “black box” model, it is possible to infer the impact of management on the system considered. This study aimed to evaluate water pollution generated by wastewater from a polyculture system of tilapia and shrimp and discuss the management employee and their relation to the quality of the effluent released. It used a pond measuring 1500 m2, average depth 1.6 meters, where 12 cages of 1 m3 populated with tilapia juveniles were installed 33 days after the shrimps’ population. The tilapia juveniles were distributed in densities from 200 to 400 fish per cubic meter, reaching the density of 2.4 fish per square meter within the total pond area. Shrimp post-larvae were released outside the cages within the pond area in a density of 3.3 organisms per square meter. Total density considering fish and shrimps was of 5.7 organisms per square meter in the pond area. Water samples were taken weekly in affluent and effluent of the pond (January-August/2009). The mass balance model was calculated from the difference between the estimated load for the output and input of the pond. The average flow rate was 4.46 L/s. The average loads nitrogen was 0.072 Kg/day (affluent) and 0.179 Kg/day (effluent) and phosphorus 0.0136 Kg/day (affluent) and 0.031 Kg/day (effluent). The mass balance resulted in mean values of 0.11 ± 0.06 Kg/day for total nitrogen and 0.017 ± 0.010 Kg/day for total phosphorus indicating that the system exported nutrients. The use of Best Management Practices (BMP) likes better feed and water management as a way to minimize nutrient export.

Enhancement of Penaeus vannamei shrimp growth using nanobubble in indoor raceway pond

The effects of nanobubble on the growth environment,such as dissolved oxygen(DO)and total virus-bacteria,and growth performance,such as growth,feed conversion ratio(FCR),survival rate(SR),total harvest,and productivity,were investigated in Penaeus vannamei shrimp ponds.The present study was carried out in 50 m2 indoor raceway ponds for 81 days with stocking density being set to 680 shrimp m3 in two types of treatment:nanobubble and diffuser aerator.A paddlewheel was used to distribute the oxygen saturation levels throughout the ponds.The presence of nanoparticles was detected using a dynamic light scattering method and was reported to be 82.38 nm in size and26 mV for zeta potential value.DO was significantly higher under nanobubble treatment.Total virus-bacteria and FCR decreased,whereas SR,growth(weight and length),total harvest,and productivity increased with increasing DO.The SR was reported to reach 95%.The average weight and length of P.vannamei were 15.1±1.8 g and 13.1±1.1 cm,respectively.The total harvest and productivity have doubled to 436 kg and 8.7 kg/m3.The results revealed that nanobubble has managed to maintain DO at the optimal range and affected the shrimp growth significantly(P<0.05).