Soil quality of Bhilwara District (Rajasthan) in relation to pisciculture

The present paper deals with the physico-chemical data of 13 rainfed and drainable dry bundhs of Bhilwara District (India). All the dry bundhs studied showed a slightly alkaline pH ranging from 7.5 to 8.5. Electrical conductivity ranged from 2 to 8 millimhos/cm. Organic carbon in sediment fluctuated from 0.30 to 0.75%. Nitrogen, phosphate and potassium levels were fairly good, at 30 to 50 and 24 to 36 mg/100 g of soil respectively. Based on these data it was inferred that these dry bundhs were highly productive and suitable for freshwater fish culture.

Physical soil characteristics of waterlogged and saline lands of five districts of Haryana, India

Physical characteristics of waterlogged and saline soils of five districts, namely Rohtak, Faridabad, Gurgaon, Sonipat and Jhajjar, of Haryana were studied to evaluate the aquaculture potential. The soil samples from 76 sites were procured and analysed for pH, electrical conductivity, soil particles and water retention capacity, since the knowledge of these parameters is essential for the preliminary evaluation of a site for aqua-farming. Six soil types were identified and clay-loam was observed to be the maximum at 45 (59.21%) sites, followed by silty-clay loam at 14 (18.42%), sandy-clay loam at six (7.89%), silty-loam at four (5.26%), sandy-loam at four (5.26%) and loam at three (3.94%) sites. The pH of soil indicated moderate to high alkaline conditions ranging between 8.01and 9.00 at 53 (69.73%) sites, 9.01 and 10.00 at 17 (22.36%) sites, and low between 7.01 and 8.00 at six (7.89%) sites. The electrical conductivity was found to range between <1 and 10 mmho cmˉ¹ with the value of <1.0 mmho cmˉ¹ at 36 (47.36%) sites. The water retention capacity was observed mostly to be moderate. The paper describes the interrelationship between these parameters with reference to the suitability for aqua-farming.

Year-round and rotational freshwater prawn, Macrobrachium rosenbergii and paddy farming: soil quality, production and economics

A study was carried out at five upazillas (Dumuria, Fakirhat, Pirojpur sadar, Gopalgonj sadar and Kalia) of five southern districts of Khulna, Bagerhat, Pirojpur, Gopalgonj and Narail to understand the comparative production performance and any effect on soil quality in case of year-round golda (Macrobrachium rosenbergii), alternate prawn-paddy and year-round paddy farming. A direct interview of 55 farmers was taken, using pretested questionnaire, and soil samples were taken from selected farms before and after each crop. Among the five upazillas, farmers in Gopalgonj sadar and Kalia are not practicing year-round golda. Rotational golda-paddy farming has been recorded to result in maximum profit, with the highest of Tk. 310,912/ha/year in 2003 at Dumuria. Only paddy farming is less profitable than other two cropping patterns, irrespective of study sites. The nutrient status of soil in rotational golda and paddy farming has been found improved, compared to that of only golda or paddy farming.

Water quality and nutrient dynamics - Lake Victoria, Kenya

Limnological studies in Lake Victoria (Kenyan portion) have been sporadic. Water quality and nutrient dynamics studies are being undertaken in fifteen sampling sites that have been divided into four ecological zones namely: Nyanza Gulf, Rusinga Channel, open waters inshore and open waters. The ongoing study will show how the physical and chemical paramenters affect fish distribution and abundance.

An assessment of water quality in integrated poultry-cum-fish reservoir, NIFFR New-Bussa in reference to maximizing the water resources potentials of Nigeria for sustainable aquaculture under the sub-theme "Fish production and the environment"

In this reservoir, the parameters being assessed are very important in the aspect of fish culture. These parameters are: physical parameters which includes temperature (O), Transparency (M).Chemical parameters include: Dissolve oxygen (mg/l) pH concentration and the Biological Parameters which include phytoplankton and zooplankton. The phytoplankton and zooplankton identification and estimation were carried out in the NIFFR Limnology Laboratory, (Green House), New Bussa. Each identified zooplankton and phytoplankton species was placed according to its major group e.g. zooplankton was grouped into three families, Roifera, Cladocera and Copepods. During this study period it was observed that copepods have the highest total number of zooplankton both beside the poultry and monk (station 'A'&'B'). Water temperature of station 'A' (beside the poultry house) ranges from 27 C-29, 5 c also same station 'B' (near the monk). Dissolve oxygen station 'A' range from 6.30mg/l-7.40mg/l while that of station 'B' ranges from 6.20mg/7.50mg/l, turbidity reading of station A'ranges from 0.19m-0.3m while station 'B' ranges from 0.22m-0.37m. The last parameter, which is pH concentration, in both stations 8.2 was observed this is an indication that the pH was constant. According to some literature review all the water parameter figures obtained were good for fish culture

Temporal and spatial variations in the quality of water in El Gergal Reservior, Seville, Spain

It is often difficult to define ‘water quality’ with any degree of precision. One approach is that suggested by Battarbee (1997) and is based on the extent to which individual lakes have changed compared with their natural ‘baseline’ status. Defining the base-line status of artificial lakes and reservoirs however, is, very difficult. In ecological terms, the definition of quality must include some consideration of their functional characteristics and the extent to which these characteristics are self-sustaining. The challenge of managing lakes in a sustainable way is particularly acute in semi-arid, Mediterranean countries. Here the quality of the water is strongly influenced by the unpredictability of the rainfall as well as year-to-year variations in the seasonal averages. Wise management requires profound knowledge of how these systems function. Thus a holistic approach must be adopted and the factors influencing the seasonal dynamics of the lakes quantified over a range of spatial and temporal scales. In this article, the authors describe some of the ways in which both long-term and short-term changes in the weather have influenced the seasonal and spatial dynamics of phytoplankton in El Gergal, a water supply reservoir situated in the south of Spain. The quality of the water stored in this reservoir is typically very good but surface blooms of algae commonly appear during warm, calm periods when the water level is low. El Gergal reservoir is managed by the Empresa Municipal de Abastecimiento y Saneamiento (EMASESA) and supplies water for domestic, commercial and industrial use to an area which includes the city of Seville and twelve of its surrounding towns (ca. 1.3 million inhabitants). El Gergal is the last of two reservoirs in a chain of four situated in the Rivera de Huelva basin, a tributary of the Guadalquivir river. It was commissioned by EMASESA in 1979 and since then the company has monitored its main limnological parameters on, at least, a monthly basis and used this information to improve the management of the reservoir. As a consequence of these intensive studies the physical, chemical and biological information acquired during this period makes the El Gergal database one of the most complete in Spain. In this article the authors focus on three ‘weather-related’ effects that have had a significant impact on the composition and distribution of phytoplankton in El Gergal: (i) the changes associated with severe droughts; (ii) the spatial variations produced by short-term changes in the weather; (iii) the impact of water transfers on the seasonal dynamics of the dinoflagellate Ceratium.

Final Evaluation Memorandum: Strategies for Resolving Low Dissolved Oxygen and Methylmercury Events in Northern Suisun Marsh

The purpose of the project is to improve our understanding about best management practices that can be utilized on diked managed wetlands in Suisun Marsh for reducing the occurrence of low dissolved oxygen (DO) and high methylmercury (MeHg) events associated primarily with fall flood-up practices. Low DO events are of concern because they can lead to undue stress and even mortality of sensitive aquatic organisms. Elevated MeHg levels are of concern because MeHg is a neurotoxin that bio-magnifies up the food chain and can cause deleterious effects to higher trophic level consumers such as piscivorous fish, birds, and mammals (including humans). This study involved two years (2007-2008) of intensive field data collection at two managed wetland sites in northwest Suisun Marsh and their surrounding tidal sloughs, an area with prior documented low DO events. In addition, the study collected limited soils and water quality field data and mapped vegetation for three managed wetland sites in the central interior of Suisun Marsh, for the purpose of examining whether wetlands at other locations exhibit characteristics that could indicate potential for similar concerns. In Year 1 of the study, the objective was to identify the baseline conditions in the managed wetlands and determine which physical management conditions could be modified for Year 2 to reduce low DO and MeHg production issues most effectively. The objective of Year 2 was to evaluate the effectiveness of these modified management actions at reducing production of low DO and elevated MeHg conditions within the managed wetlands and to continue improving understanding of the underlying biogeochemical processes at play. This Final Evaluation Memorandum examined a total of 19 BMPs, 14 involving modified water management operations and the remaining five involving modified soil and vegetation management practices. Some of these BMPs were previously employed and others have not yet been tested. For each BMP this report assesses its efficacy in improving water quality conditions and potential conflicts with wetland management. It makes recommendations for further study (either feasibility assessments or field testing) and whether to consider for future use. Certain previously used BMPs were found to be important contributors to poor water quality conditions and their continued use is not recommended. Some BMPs that could improve water quality conditions appear difficult to implement in regards to compatibility with wetland management; these BMPs require further elaboration and feasibility assessment to determine whether they should be field tested. In practice for any given wetland, there is likely a combination of BMPs that would together have the greatest potential to address the low DO and high MeHg water quality concerns. Consequently, this report makes no sweeping recommendations applicable to large groups of wetlands but instead promotes a careful consideration of factors at each wetland or small groups of wetlands and from that assessment to apply the most effective suite of BMPs. This report also identifies a number of recommended future actions and studies. These recommendations are geared toward improving the process understanding of factors that promote low DO and high MeHg conditions, the extent of these problems in Suisun Marsh, the regulatory basis for the DO standards for a large estuarine marsh, the economics of BMPs, and alternative approaches to BMPs on diked managed wetlands that may address the water quality issues. The most important of these recommendations is that future BMP implementation should be carried out within the context of rigorous scientific evaluation so as to gain the maximum improvement in how to manage these water quality issues in the diked managed wetlands of Suisun Marsh.

Investigation into the factors associated with poor water quality in intensively cultured prawn ponds

Water quality problems are reported to be the factor limiting prawn production in the local prawn farm. This investigation was carried out to monitor water quality and its relationship to physical, chemical and biological conditions in the ponds in order to establish what factors should be monitored in order to predict problems. Pond collapse was found to be associated with high concentrations of ammonium, high pH and blue-green algae dominated phytoplankton populations. There was no easy means of predicting the imminent collapse of ponds as the phenomenon was never associated with the extreme of any of the conditions monitored. Rather it seemed to be related to the stability of the pond's algal population, which was largely unaccounted for. Recommendations toward improving water quality are proposed.

Evaluation of chemical tests for the quality of prawns

The object of this study was to determine the value of physical, bacteriological and chemical tests used to find out and compare the indices of quality of prawns stored at 0°C and at 18°C. pH value, nature of drip, the total bacterial count, presence or absence of tryptophan, trimethylamine content, glycogen, lactic acid, vitamins such as thiamin, riboflavin and niacin were estimated periodically to evaluate the quality of prawns stored at 0°C, whereas in addition to organoleptic changes, pH, bacterial count, nature of growth in peptone water, soluble protein in salt solution and loss of moisture, glycogen, lactic acid, and changes in vitamin B contents were noted periodically for prawns stored at -l8°C. Riboflavin and niacin were not affected appreciably but the retention of thiamin in prawns was very low.

Postmortem changes in hilsa fish. Pt. 2. Studies on physical and bacteriological changes in iced and frozen stored hilsa fish (Tenualosa ilisha Ham.)

Studies were conducted to evaluate the quality of hilsa fish during icing and freezing storage at -20°C by determining organoleptic and bacteriological aspects. The fishes stored in ice were organoleptically in acceptable condition 2 for 20 days. The bacterial load in muscles of 4 days ice stored fish was 2.5x10² CFU/g which gradually increased up to 1.8x10⁵ CFU/g after 20 days when the fishes were organoleptically in acceptable condition. The keeping qualities of different days of ice stored fishes were also evaluated during their subsequent frozen storage at -20°C. Both 4 and 7 days of ice stored fishes were organoleptically in acceptable condition up to 48 weeks but the highest degree of freshness was found for fish stored in ice for 4 days before freezing at -20°C. The result indicates that the longer is the duration of ice storage before freezing, the shorter is the shelf life of the fish. The initial bacterial load prior to freezing of the 4 and 7 days of ice stored samples were 2.5x10³ CFU/g and 3.8x10⁴ CFU/g, respectively which reduced to 2.21x10² CFU/g and 2.38x10² CFU/g, respectively at the end of the 24 weeks of frozen storage. However, after 40 weeks the bacterial load in the frozen stored sample fell below the detection level.

Quality aspects of some exportable dried fishery products of Bangladesh

A study was conducted to evaluate the quality aspects of eight exportable dried fishery products of Bangladesh. The products were evaluated by examining organoleptic properties, water reconstitution behavior, microbiological and biochemical aspects. The water reconstitution rate was faster in ribbon fish and Bombay duck, and slower in other fishes and air bladder and shark fin products. Organoleptic and physical characteristics in respect of color, odor, texture, insect infestation and broken pieces of the products revealed that all of the products were either in excellent or acceptable condition. Total viable bacterial load ranged from 0.95 x 104 CFU/g to 1.8 x 104 CFU/g in dried products. Coliform bacteria was absent in all the dried fishery products. The results of moisture, crude protein, lipid and ash content of the products ranged from 16.20 to 23.51%, 58.37 to 82.86%, 0.17 to 14.44% and 0.58 to 9.23%, respectively. Non-protein nitrogen (NPN) contents were in the range of 0.104 to 2.372% and the pepsin digestibility values were of 88.41 to 94.23%. The results of the study suggested that the exportable dried products were of good quality and hygienically safe.

Water quality management on the enhancement of shrimp (Penaeus monodon Fab.) production in the traditional and improved-traditional ghers of Bangladesh

On-farm research on enhancement of P. monodon production through water quality management was carried out in five ghers of Paikgacha, Khulna. Based on the prevailing condition of the ghers, lime in the form of CaCO(sub 3), urea and TSP were used as the major inputs to minimize the soil-water acidity and to ensure the availability of natural food particles in the water bodies. Exchange of water at required level also practiced for the qualitative improvement of culture water. Ghers of varying sizes showed that water quality management and fertilization have a positive impact on production performance of P. monodon (61.59% increment) that yielded an average production of 385.43 kg/ha/crop against the present traditional rate of 238.50 kg/ha/year.

A baseline fish survey and water quality assessment of Butiaba-Wanseko area on Lake Albert

This report gives the baseline information specifically on water quality (physical/chemical, nutrient and phytoplankton biomass status) of the open part of the lake, a river flowing into the lake and a lagoon, within Butiaba-Wanseko area. Oil and gas exploration in the Albertine Graben are on-going activities by Tullow Oil Plc, and Heritage Oil and Gas (Heritage). Part of the activities involve 2-D TZ seismic surveys in exploration area Block 2 (Butiaba-Wanseko area) in Buliisa District. A study of the transition zone (basically along the shoreline was undertaken by National Fisheries Resources Research Institute (NaFIRRI) on behalf of Environmental Assessment Consult Ltd (EACL) during September 2007. A major objective of the study was to carry out a baseline survey of the fisheries and water quality of the lake shore between Wanseko and Butiaba prior to the proposed 2-D Seisimic investigation.

HACCP based management system for improving quality of freshwater giant prawn, Macrobrachium rosenbergii

The study was conducted on the present status of HACCP based quality management system of golda, Macrobrachium rosenbergii farms in Fulpur region of Mymensingh. Information was collected on general condition of farms, culture systems and post-harvest quality management. In almost all farms, there is no or inadequate infrastructure facilities such as, road access, electric supply, telecommunications, ice, feed storage facility, vehicle for golda transportation, washing and toilet facilities. The problems associated with sanitation and hygiene was: widespread use of cow dung, poultry manure and construction of open toilet within the vicinity of prawn culture pond. Different grades of commercially available and locally prepared feeds were used for golda culture in the pond. Golda post-larvae (PL) of 40-50 days old were stocked with carp species. The price of golda PL ranged from Tk. 1.00 to Tk. 1.25/piece. The pond size varied from 50 decimal (0.2 ha) to 2.5 acre (1.0 ha) with an average depth of 2-2.5 m. The culture period of golda varied from April-May to November-December and survival rate ranged between 75 and 80%. Production of golda varied from 250-500 kg/acre (625-1,250 kg/ha). Harvested golda were transported to city market within 4 h. Two size grading were generally followed during pricing, e.g. Tk. 500 to 550/kg for >100 g size and Tk. 300/kg for <100 g size. The cost-benefit ratio was found to remain around 1:1.25 depending on availability of PL. Water quality parameters such as, water temperature, pH, dissolved oxygen, total alkalinity and chlorophyll a in five golda farms in Fulpur region were monitored. Water temperature ranged from 29°C to 33°C, dissolved oxygen from 2.28 to 4.13 mg/l, pH between 6.65 and 7.94, alkalinity from 44 to 70 mg/l and chlorophyll a concentration from 61.88 to 102.34 µg/l in the five investigated ponds. The Aerobic Plate Count (APC) of the water sample was within the range of 2.0x10^6 - 2.96x10^7 CFU/ml and of soil samples within the range of 6.9x10^6 - 7.73x10^6 CFU/g. Streptococcus sp., Bacillus sp., Escherichia coli, Staphylococcus sp., Pseudomonas sp. and Salmonella sp. were isolated from pond water and sediment. Different feed samples used for golda was analyzed for proximate composition. Moisture content ranged around 14.14-21.22%, crude protein 20.55-44.1%, lipid 4.67-12.54% and ash 9.7-27.69%. The TVB-N values and peroxide values of feeds used as starter, grower and fish meal were found within the acceptable ranges and samples were free from pathogenic organisms. A training was organized for the golda farmers on HACCP, water quality and post-harvest quality management of prawn.

Study on regional differences in soil-water characteristics and their relevance to aquaculture productivity and fish disease

A total of 45 ponds used for fish polyculture were investigated in three zones of Bangladesh to identify the differences among the zones in respect to aqua-ecology, culture practices, fish productivity and health management. Four hundred and fifty fish from three zones were clinically examined by naked eye and histopathology. Out of total number of fish examined, 45 fish from Dhaka zones were examined for parasites and bacteria in addition to histopathology. Faded and haemorrhagic gill, skin, fin, scale loss and lesions were observed during fish examination. Aeromonas spp. Pseudomonas spp. and Streptococcus spp. were isolated respectively from 56%, 46% and 39% affected fish. Among the five water quality parameters analyzed, the highest average hardness and alkalinity respectively were recorded in Rajshahi (156 ppm and 142 ppm) followed by Dhaka (146 ppm and 132 ppm) and Chittagong (81 ppm and 90 ppm). The highest average pH was recorded in Mymensingh (7.52) followed by Rajshahi (7.13) and Chittagong (7.05). Water holding capacity of soil in Rajshahi zone was poor compared to other zones and farmers were found to be reluctant to fish farming.