scholarly journals Impacts of Different Agro-Ecological and Management Practices on the Shrimp Productivity of Ghers in the Southwest Coastal Region of Bangladesh

2014 ◽  
Vol 18 (2) ◽  
pp. 149-155
Author(s):  
KA Huq ◽  
MM Haque ◽  
K Mazhabuddin ◽  
SU Ahmed
Keyword(s):  
Soil Quality ◽  
Water Exchange ◽  
Management Practices ◽  
Coastal Region ◽  
Stocking Density ◽  
Calcium Content ◽  
Quality Parameters ◽  
Phytoplankton Production ◽  
Positive Correlation ◽  
Positive Correlations

The study was undertaken to investigate the impacts of water and soil quality parameters, and management practices on shrimp productivity of ghers in three agro-ecological areas of Paikgacha, Shyamnagar and Rampal in the greater Khulna district of Bangladesh. Five ghers of existing culture systems from each of three locations were selected for this study. Findings revealed that water quality parameters including salinity, alkalinity and dissolved oxygen contributed significantly (p<0.05) and positively to shrimp productivity. Phytoplankton production also showed a positive correlation with shrimp productivity. Soil quality parameters including salinity, potassium and calcium content showed positive correlations with shrimp yield. In relation to management practices, stocking density, sources of PL form natural sources and supplementary feeding showed significant (p<0.05) and positive correlations with shrimp productivity. Water exchange also showed a positive correlation with shrimp yield.DOI: http://dx.doi.org/10.3329/pa.v18i2.18170 Progress. Agric. 18(2): 149 - 155, 2007

scholarly journals Influence of stocking density on water quality and growth performance of white leg shrimp (Litopenaeus vannamei) reared in fiberglass tanks, without water exchange

2019 ◽  
Vol 18 (06) ◽  
pp. 14-22
Author(s):  
Tu P. C. Nguyen
Keyword(s):  
Water Quality ◽  
Survival Rate ◽  
Growth Performance ◽  
Linear Relationship ◽  
Litopenaeus Vannamei ◽  
Water Exchange ◽  
Stocking Density ◽  
Quality Parameters ◽  
Final Weight ◽  
Ad Libitum

The present study evaluated the effects of stocking density on water quality parameters, growth performance and survival rate of white leg shrimp Litopenaeus vannamei, reared in fiberglass tanks, without water exchange. Three stocking densities (50, 100 and 200 shrimp/m2) were tested. Each treatment consisted of three replicates fiberglass tanks (500 L). The shrimp were fed ad libitum four times per day with a commercial pellet (40-42% protein). After an 8-week trial, concentrations of nutrients in the culture tanks showed an increasing linear relationship with increasing stocking density. The growth performance of shrimp in low stocking densities was significantly greater than that in high stocking densities. The results from this study demonstrate that with increasing the stocking density the production of shrimp increased but in a low final weight and survival compared to low stocking density.

scholarly journals Effect of aeration on growth and production of fish in intensive aquaculture system in earthen ponds

2017 ◽  
Vol 15 (1) ◽  
pp. 113-122 ◽  
Author(s):  
T Sultana ◽  
MM Haque ◽  
MA Salam ◽  
MM Alam
Keyword(s):  
Water Quality ◽  
Soil Quality ◽  
Pond Water ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Phytoplankton Production ◽  
Zooplankton Abundance ◽  
Aquaculture System ◽  
Earthen Ponds ◽  
Intensive Aquaculture

An experiment was conducted to assess the effect of aeration using blower on growth and production of tilapia (Oreochromis niloticus) in intensive aquaculture system in six (6) earthen ponds at BAU campus, Mymensingh from May to September, 2016. Treatment 1 (T1) with 3 aerated ponds and Treatment 2 (T2) with 3 non-aerated ponds were designed with similar stocking density (300/decimal) of tilapia. Oxygen supply was ensured by blower for 9 hours daily when oxygen depletion occurs in pond water. Fish growth, pond water and soil quality parameters were sampled and assessed. The DO content in the aerated ponds was higher (7.23 mg/l) from the beginning to the end of experiment compared to non-aerated ponds (2.33 mg/l). There were significant differences (p<0.05) of DO content between two treatments at first and last sampling stages. The higher length (15.64±1.56 cm) and weight gain (143.36±39.33 gm), higher SGR (% per day) for tilapia was (2.54±0.00) found in T1 compared to T2 (2.42±0.00) with significant differences (p<0.05) between two treatments. In addition, the higher production of tilapia was obtained in T1 (9581.87±0.00 kg/ha/100 days) compared to T2 (6490.80±0.00 kg/ha/100 days). The average phytoplankton production was relatively higher in T2 and conversely zooplankton abundance was higher in T1 without any significant differences (p>0.05) between the treatments for the abundances of various groups of phytoplankton and zooplankton. Different water quality parameters were found with the better range in aerated ponds. Various intrinsic relationships between DO and other water quality and weather parameters showed that DO content had negative relationships with rainfall, air pressure and humidity but the relationships were not statistically significant. Moreover, different soil quality parameters of pond sediments were found in ideal range for fish culture in both treatments. These results suggest that aeration can be a potential mechanism of aqua-farming to enhance the growth and production of tilapia and DO content in pond water synchronizing other water quality parameters in ponds.J. Bangladesh Agril. Univ. 15(1): 113-122, January 2017

scholarly journals The influence of water renewal rates on the reproductive and molting cycles of Penaeus paulensis in captivity

2003 ◽  
Vol 46 (2) ◽  
pp. 281-286 ◽  
Author(s):  
Sílvio Peixoto ◽  
Ronaldo Olivera Cavalli ◽  
Wilson Wasielesky Junior
Keyword(s):  
Water Exchange ◽  
Stocking Density ◽  
Quality Parameters ◽  
Molt Cycle ◽  
Nitrogenous Compounds ◽  
Eyestalk Ablation ◽  
Intermolt Period ◽  
In Captivity ◽  
Influence Of Water ◽  
Female Maturation

The present study analyzed the reproduction of wild-caught Penaeus paulensis in relation to its molt cycle. The experimental design consisted of two treatments (continuous water flow and batch renewal) with two replicates. The stocking density in experimental tanks (1.50 x 0.96m) was approximately 7 animals/m², resulting in 4 males (23.9 ± 2.3 g) and 6 females (52.0 ± 5.5 g) per tank. Shrimp had their uropods cut for individual marking and female maturation was induced through the unilateral eyestalk-ablation. The intermolt period of females and males (17.4 ± 3.2 and 17.8 ± 4.6 days, respectively), number of days between molting and the first spawn (6.9 ± 2.8 days) and number of spawns in the intermolt period (1.4 ± 0.5), presented no significant differences (P>0.05) between treatments. No influences on molt cycle or reproductive performance parameters could be related to differences in water quality parameters, especially nitrogenous compounds, suggesting a trend towards reduce water exchange in shrimp maturation. However, a relative decrease in the number of eggs per spawn was observed. This possibly was due to the smaller maturation tanks. The results of P. paulensis molt cycle could be useful for accompaniment and better planning of the reproduction in captivity.

scholarly journals An Assessment of the Soil Quality Index in a Mediterranean Agro Ecosystem

2019 ◽  
pp. 1042
Author(s):  
Vassilios Triantafyllidis ◽  
Achilleas Kontogeorgosa Chariklia Kosma ◽  
Angelos Patakas
Keyword(s):  
Soil Quality ◽  
Quality Index ◽  
Management Practices ◽  
Soil Health ◽  
Health Indicators ◽  
Decision Support Tool ◽  
Mediterranean Ecosystems ◽  
Quality Parameters ◽  
Soil Quality Index ◽  
Support Tool

Soil quality is a complex functional concept, which cannot be measured directly but only be inferred from both soil characteristics and cultivation practices. Among different approaches used, Soil Quality Index (SQI) is considered to be the most appropriate for quantitative assessment of soil quality. Since, there is no standard method for SQI estimation, the aim of this study is to identify soil quality parameters that could be used for the development of reliable SQI which could be effectively applied in Mediterranean ecosystems. Three different methods resulting in different SQIs were evaluated regarding their ability to monitor changes in agricultural soil properties over time. Overall, a set of soil’s parameters was used as soil health indicators (pH, CaCO3, EC, NO3-N, P, K, Mg, Cu, B, Zn, Fe, Mn, Silt, Clay, Sand and SOC) derived from 605 soil samples used to calculate the above SQIs. The most reliable SQI to distinguish the effect of the examined parameters was the weighted additive approach. These 16 soil indicators can be used as decision support tool for soil management practices, as well as indirect measures of soil function, serving to assess soil health for a sustainable Mediterranean agro-environment.

scholarly journals Growth and Economic Performances of Macrobrachium rosenbergii (De Man, 1879) Culture in South-West Coastal Region of Bangladesh

2016 ◽  
Vol 9 (1) ◽  
pp. 53-57
Author(s):  
MA Samad ◽  
AK Paul ◽  
MR Haque ◽  
H Ferdaushy
Keyword(s):  
Macrobrachium Rosenbergii ◽  
Coastal Region ◽  
Stocking Density ◽  
Quality Parameters ◽  
Mustard Oil ◽  
Net Benefit ◽  
Mean Values ◽  
Maize Bran ◽  
Mustard Oil Cake ◽  
De Man

The growth performance of Macrobrachium rosenbergii (Deman,1879) under different stocking densities was conducted under three treatments each with three replications namely T1: 10m-2 T2: 12m-2; T3: 14m-2 for a period of six months from April to September, 2012 in 9 experimental ponds in Terokhada Upazilla under Khulna district. Supplementary feeds (mustard oil cake (20%), wheat bran (20%), rice bran (20%), fish meal (25%) and maize bran(15%) were used for all stocked individual. Water quality parameters and growth performances were monitored monthly. The mean values of water temperature, transparency, dissolve O2, pH and salinity were varied from 28.88 ± 0.161±oC(T2) to 31.32 ± 0.97±oC (T1), 29.73 ± 0.34cm(T1) to 32.70 ± 0.28cm(T2), 5.33 ± 0.184mg-1(T3) to 6.17 ± 0.13 mg-1 (T1), 6.52 ± 0.205(T2)to 6.79 ± 0.18(T1) and 13.75 ± 0.16(T2) to 15.22 ± 0.20(T1). The weight gain of Macrobrachium rosenbergii were 59.79± 0.15 g(T1), 50.86±0.14g(T2),48.78±0.12g(T3).The survival rate (%) of M. rosenbergii were 75.02±0.577 (T1), 66.66±0.88 (T2), 61.01±0.577(T3) respectively. Yields (Kg ha-1 6 month-1) Macrobrachium rosenbergii were 2302.04kg (T1), 1768.52 kg (T2), 1393.808 kg (T3) respectively. Total cost 656000 ± 17480 Tk ha-1 (T1), 596120 ± 4520 Tk ha-1 (T2) and 549100 ± 9440 Tk ha-1 (T3) respectively and total return of different treatments T1, T2 and T3 were 1492400 ± 12800 Tk ha-1, 1078200 ± 11930 Tk ha-1 and 806480 ± 9190 Tk ha-1 respectively. Net benefit were 801900 ± 7340 Tk ha-1, 49400± 5930 Tk/ha and 288600 ± 13240 Tk ha-1 in T1, T2, T3 treatments respectively. From these findings, it could be concluded that highest yield was achieved from T1 and lowest in T3 which was significantly (P<0.05) different among the treatments where stocking density were less than other treatments.J. Environ. Sci. & Natural Resources, 9(1): 53-57 2016

Conditions for Positive and Negative Correlations Between Fitness and Heterozygosity in Equilibrium Populations

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1333-1340 ◽  
Author(s):  
Hong-Wen Deng ◽  
Yun-Xin Fu
Keyword(s):  
Single Population ◽  
Positive Correlation ◽  
Genetic Explanation ◽  
Genetic Causes ◽  
The Past ◽  
Fitness Traits ◽  
Genetic Systems ◽  
Positive Correlations ◽  
Non Equilibrium

AbstractThe past decades have witnessed extensive efforts to correlate fitness traits with genomic heterozygosity. While positive correlations are revealed in most of the organisms studied, results of no/negative correlations are not uncommon. There has been little effort to reveal the genetic causes of these negative correlations. The positive correlations are regarded either as evidence for functional overdominance in large, randomly mating populations at equilibrium, or the results of populations at disequilibrium under dominance. More often, the positive correlations are viewed as a phenomenon of heterosis, so that it cannot possibly occur under within-locus additive allelic effects. Here we give exact genetic conditions that give rise to positive and negative correlations in populations at Hardy-Weinberg and linkage equilibria, thus offering a genetic explanation for the observed negative correlations. Our results demonstrate that the above interpretations concerning the positive correlations are not complete or even necessary. Such a positive correlation can result under dominance and potentially under additivity, even in populations where associated overdominance due to linked alleles at different loci is not significant. Additionally, negative correlations and heterosis can co-occur in a single population. Although our emphasis is on equilibrium populations and for biallelic genetic systems, the basic conclusions are generalized to non-equilibrium populations and for multi-allelic situations.

scholarly journals Comparison of Forecasting Models for Real-Time Monitoring of Water Quality Parameters Based on Hybrid Deep Learning Neural Networks

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1547
Author(s):  
Jian Sha ◽  
Xue Li ◽  
Man Zhang ◽  
Zhong-Liang Wang
Keyword(s):  
Neural Network ◽  
Water Quality ◽  
Deep Learning ◽  
Real Time ◽  
Best Management Practices ◽  
Input Data ◽  
Management Practices ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Real Time Monitoring

Accurate real-time water quality prediction is of great significance for local environmental managers to deal with upcoming events and emergencies to develop best management practices. In this study, the performances in real-time water quality forecasting based on different deep learning (DL) models with different input data pre-processing methods were compared. There were three popular DL models concerned, including the convolutional neural network (CNN), long short-term memory neural network (LSTM), and hybrid CNN–LSTM. Two types of input data were applied, including the original one-dimensional time series and the two-dimensional grey image based on the complete ensemble empirical mode decomposition algorithm with adaptive noise (CEEMDAN) decomposition. Each type of input data was used in each DL model to forecast the real-time monitoring water quality parameters of dissolved oxygen (DO) and total nitrogen (TN). The results showed that (1) the performances of CNN–LSTM were superior to the standalone model CNN and LSTM; (2) the models used CEEMDAN-based input data performed much better than the models used the original input data, while the improvements for non-periodic parameter TN were much greater than that for periodic parameter DO; and (3) the model accuracies gradually decreased with the increase of prediction steps, while the original input data decayed faster than the CEEMDAN-based input data and the non-periodic parameter TN decayed faster than the periodic parameter DO. Overall, the input data preprocessed by the CEEMDAN method could effectively improve the forecasting performances of deep learning models, and this improvement was especially significant for non-periodic parameters of TN.

scholarly journals Effects of Management and Hillside Position on Soil Organic Carbon Stratification in Mediterranean Centenary Olive Grove

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Jesús Aguilera-Huertas ◽  
Beatriz Lozano-García ◽  
Manuel González-Rosado ◽  
Luis Parras-Alcántara
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Quality ◽  
Management Practices ◽  
Soil Management ◽  
Olive Grove ◽  
No Tillage ◽  
Short Term ◽  
Degradation Degree

The short- and medium—long-term effects of management and hillside position on soil organic carbon (SOC) changes were studied in a centenary Mediterranean rainfed olive grove. One way to measure these changes is to analyze the soil quality, as it assesses soil degradation degree and attempts to identify management practices for sustainable soil use. In this context, the SOC stratification index (SR-COS) is one of the best indicators of soil quality to assess the degradation degree from SOC content without analyzing other soil properties. The SR-SOC was calculated in soil profiles (horizon-by-horizon) to identify the best soil management practices for sustainable use. The following time periods and soil management combinations were tested: (i) in the medium‒long-term (17 years) from conventional tillage (CT) to no-tillage (NT), (ii) in the short-term (2 years) from CT to no-tillage with cover crops (NT-CC), and (iii) the effect in the short-term (from CT to NT-CC) of different topographic positions along a hillside. The results indicate that the SR-SOC increased with depth for all management practices. The SR-SOC ranged from 1.21 to 1.73 in CT0, from 1.48 to 3.01 in CT1, from 1.15 to 2.48 in CT2, from 1.22 to 2.39 in NT-CC and from 0.98 to 4.16 in NT; therefore, the soil quality from the SR-SOC index was not directly linked to the increase or loss of SOC along the soil profile. This demonstrates the time-variability of SR-SOC and that NT improves soil quality in the long-term.

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