Nitrogen and Phosphorus Removal from Lake Kinneret Inputs

The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Population size was enhanced and the diary was developed intensively resulting in the enhancement of domestic and husbandry sewage production that increased as well. The natural intact Hula Valley-Lake Kinneret ecosystem was heavily anthropogenically interrupted: The Hula was drained and Kinneret became a national source for domestic water supply. Some aspects of the environmental and water quality protection policy of the system are presented. The causation and operational management implications for the reduction of Nitrogen and Phosphorus migration from the Hula Valley are discussed. Drastic (81%) restriction of aquaculture accompanied by sewage totally removed achieved a reasonable improvement in pollution control which was also supported by the Hula Project. The implications of anthropogenic intervention in the process of environmental management design are presented.

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.

Microbial Assessment and Antibiotic Susceptibility Profile of Bacterial Fish Isolates in an Aquaculture Production Site in Mefou Afamba Division of Cameroon

The practice of integrated fish farming and the use of local fish meal and manure for fish feeding in Cameroon constitute potential sources of resistant pathogenic bacteria in the fish pond environment.Therefore,a periodical and constant monitoring of the microbiological quality of fish pond is imperative.This study was to assess the microbial contamination of Mfou aquaculture production site and evaluate the antibiotic resistance profile of bacterial fish isolates.Samples of pond water(n=36),sediment(n=36),fishmeal(n=12)and African catfish(Clarias gariepinus),kanga(Heterotis niloticus)and Nile Tilapia(Oreochromis niloticus)(n=36,each)were collected to determine TVAC(Total Viable Aerobic Bacterial Count),FC(Fungal Count),SAC(Staphylococcus aureus count),TCC(Total Coliform Count)and FCC(Feacal Coliform Count).The fish skin isolates of S.aureus,Enterobacter sakazakii,Citrobacter freundii,Serratia fonticola,Klebsiella oxytoca,Proteus spp.,Aeromonas hydrophila,Kluyvera spp.,Moraxella spp.,Pasteurella multocida and Pseudomonas fluorescens were tested against penicillin G(10μg),chloramphenicol(30μg),sulfamethoxazole/trimethoprim(25μg),erythromycin(15μg),tetracycline(30μg),using the disk diffusion method.Results reveal a heavy contamination of fish farms with microbial load above the recommended limits.Our study indicates that fish ponds are sources of zoonotic pathogens underlining their epidemiological and clinical relevance.All bacterial isolates were multiresistant with a multiple antibiotic resistance index above 0.2.These data raise concern about the microbial contamination of aquaculture and associated public health risks in Cameroon.

Treatise by Olbrycht Strumieński (1573)--The First Polish Book on Hydraulic Engineering

The treatise by Olbrycht Strumieński is chronologically the first book in Poland, and the second in Europe, describinglevelling instruments. A few years after Strumieński’s death, the text was published by Stanisław Stroynowski. Until the 19th century,only three Polish-language treatises addressed the problems of levelling. Strumieński described the technique of building andmanaging fish ponds in Moravia, Bohemia and Poland. The presented surveying instruments and measuring methods are sufficientfor the design and construction of a pond that can survive for over 300 years. Strumieński also presented the principles of freshwateraquaculture. Poland, along with Bohemia, Moravia and Hungary, was an exporter of freshwater fish to Western Europe from the 16thto the mid-18th century.

The Development of a Renewable-Energy-Driven Reverse Osmosis System for Water Desalination and Aquaculture Production

Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis （RO） system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of （1） a wind-driven pumping subsystem, （2） a pressure-driven RO membrane desalination subsystem, and （3） a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids （TDS） of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.

Modeling of comprehensive power load of fishery energy internet considering fishery meteorology

Accurate calculation for comprehensive power load of fishery energy internet plays a significant role in reasonable using of energy and reducing environmental pollution.However,as fishery power load is of greatly unique meteorology sensitivity,it continues to be a difficult problem.Therefore,the research of fishery meteorology is an important part of the rational development of fishery resources,the protection of production safety,and the pursuit of high and stable yield.This paper makes a deep study on the power load of the fishery energy internet under the influence of fishery meteorology and takes onshore fish pond as the research object.First of all,the power load is divided into three parts:oxygen enrichment power load,feeding power load,and water replenishment and drainage power load.The impact mechanism of fishery meteorology(including temperature,surface wind speed,precipitation,relative humidity,etc.)on it is described,and then the overall power load is obtained through modeling and integration.Finally,taking the Yuguang Complementary Project in Zhouquan Town,Tongxiang,Zhejiang Province,China as an example,using the meteorological data of its typical spring day and using the MATLAB tool to solve,the hourly comparison of the three types of power loads,the comprehensive power load demand,the full-day electricity charge forecast and the total annual power consumption are calculated.The annual power consumption per hectare and per kilogram of output calculated by simulation are basically consistent with the order of magnitude of the survey data,which proves the validity of the model proposed.The model established in this paper is an original work,and the exploration of fishery energy internet can draw lessons from it.

Angling of hybrid sunfish from a hatchery pond with potential implications for community fisheries

Hatcheries are frequently called upon to produce catchable-sized fish for stocking community fishing ponds.Desirable attributes of fish selected for stocking into community ponds are that they are easy to produce in a hatchery system to sizes anglers are interested in catching and they provide anglers with high catch rates once stocked.Hybrid sunfish[male Bluegill(Lepomis macrochirus)×female Green Sunfish(L.cyanellus)]have attributes that potentially make them attractive for use in community fishing ponds.We assessed initial angler catch rates of 100 stocked hybrid sunfish in a 0.12-ha hatchery pond and after being subjected to angling(four,1-hr catch-and-release fishing events with five anglers).We also investigated whether catch rates would change following a supplemental stocking of an additional 100 hybrid sunfish(four,1-hr catch-and-release fishing events with five anglers).The anal fin of each fish in the second stocking was hole punched to differentiate them from those of the first stocking and fish caught by anglers were hole punched in the caudal fin each time they were caught before being released back into the pond.Angler catch rates were highest during initial fishing events that followed stocking(9.2 fish/angler hr and 18.0 fish/angler hr)and substantially declined in subsequent events(≤3.4 fish/angler hr).Catches of the newly stocked fish and previously stocked fish contributed to the high catch following the supplemental stocking.Most(80%)of the fish were caught in the first 30 min of each event and 45%were caught during the first 10 min.Anglers were able to catch 88%of the fish from the first stocking and 67%from the second stocking at least once.No mortality occurred during the study as all fish were recovered when the pond was drained.Our results suggest that hybrid sunfish will potentially provide high initial catch rates following stocking into community ponds,but managers should expect reduced catch rates following initial fishing even without harvest.Additional stocking will be needed to provide periodic increases in angler catch rates even without harvest.

Determination of five endosulfan pesticides in the fish pond water by dispersive liquid–liquid microextraction combined with GC–MS

A simple and rapid dispersive liquid-liquid microextraction(DLLME)technique coupled with gas chromatography-ion trap mass spectrometry(GC-MS)was developed for the extraction and analysis of five endosulfan pesticides from the fish pond water.In this work,different parameters affecting the extraction process such as the type and volume of extraction solvent,type and volume of disperser solvent,and extraction time were studied and optimized.Under optimized conditions,the enrichment factor ranged from 189 to 269 and the relative recovery ranged from 88.5%to 94.9%.The linear range was 2.0-80.0 mg/L;the limits of detection and quantitation were in the range 0.04-1.06 mg/L and 0.12-3.53 mg/L,respectively.The relative standard deviations were in the range 0.94%-2.08%(n D 5).The obtained results show that DLLME combined with GC-MS is a fast and simple method for the determination of endosulfan pesticides in fish pond water.

Evaluation of limnological dynamics in Nile tilapia farming tank

For fish farming,water is the limiting factor for good productivity.Limnological characteristics determine the health and the productivity of the fish and can indicate possible problems arising in the ecosystem.The present study aimed to verify the nictemeral and vertical dynamics of limnological characteristics in a tilapia farming tank coated with geomembrane and with low water renewal.Collections were carried out in a 24 hour on period of 18 days with an interval of three hours between the water collections.In order to determine the vertical dynamics,water samples were taken at three depths(5,35,and 70 cm)in the central region of the tank.It was found that the parameters analyzed showed changes in the period.Dissolved oxygen and pH changed sharply in the 24-hour period(p$<0.05$),with values of 3.86 mg L$^{-1}$at 6:00 AM and 18.39 mg L$^{-1}$at 3:00 PM;and 8.0 at 06:00 AM and 9.65 mg L$^{-1}$at 6:00 PM,respectively.With respect to the three layers of the tank,the difference between the values of dissolved oxygen in the epilimnion and the metalimnion(above 14 mg L$^{-1}$)is clear,while in the hypolimnion the concentration of this oxygen was 7.57 mg L$^{-1}$(p$<0.05$).Nitrite and phosphorus had similar behavior,with more pronounced values in hypolimnion.There is a strong correlation between temperature and depth of the tank($r=-0.85,~p=5.86\times 10^{-9}$),depth and dissolved oxygen($r=-0.77,p=9.97\times 10^{-6}$),temperature and ammonia($r=-0.82,~p=6.33\times 10^{-8}$),depth and ammonia($r=0.79,~p=4.79\times 10^{-7}$),and nitrite and dissolved oxygen($r=-0.72,~p=2.15\times 10^{-4}$).The principal component analysis showed that there was a separation between the strata epilimnion,metalimnion,and hypolimnion.The response surface analysis showed the interaction between depth,temperature and the variables dissolved oxygen,ammonia,and phosphorus.The result of this study helps to illustrate the dynamics of a tilapia tank covered with geomembrane and low water renewal over a period of 24 hours at different layers of the water body.