Bioturbation Effects of Benthic Fish on the Phosphorus Dynamic in Overlying Water of Paddy Field

[Objective]The research aimed to investigate the bioturbation effects of benthic fish Misgurnus anguillicaudatus on phosphorus dynamic in overlying water of paddy field,as well as to explore the bioturbation mechanism.[Method]Based on simulation experiment,the phosphorus contents in overlying water were analyzed comparatively with and without Misgurnus anguillicaudatus by the using of ion chromatography and spectrophotometry.[Result]The concentrations of total phosphorus(TP),dissolved total phosphorus(DTP)and particular phosphorus(PP)in bioturbation group had no significant differences with those in control group in initial stage of experiment,and became significantly higher than control group in middle and late stages of experiment(P<0.05). The PP/TP ratios in bioturbation group were bigger than those in control group,the increase of TP concentration in bioturbation group was mainly due to the increase of PP. The ratios of dissolved inorganic phosphorus(DIP) to DTP (DIP/DTP) were significantly bigger than those in control group in middle and late stages of experiment(P<0.05).[Conclusion]The benthic fish had bioturbation effects on phosphorus in overlying water of paddy field,which increased the available phosphorus for rice growth.

Determination of the Contents of EPA and DHA and Lipid Constituents in Main Fresh Water Fishes in China

In this study the molecular formula and structure of lipid constituents of silver carp and bighead carp in middle reaches of Yangtze River were determined by gas chromatography-mass spectrometry. The position of double bounds was identified by the method of double bounds chemical localization. These carps are proved to contain eicosapantaenoic acid (EPA) and decosahexenoic acid (DHA). The contents of EPA and DHA, which were determined by gas chromatography, in silver carp and bighead carp were approximately the same as in tuna and salmon. The contents of EPA and DHA in 100 g wet sample were 0. 187 g, 0. 229 g and 0. 246 g, 0. 325 g respectively, but the cholesterol contents in silver carp and bighead carp were much lower than in tuna and salmon.

The Importance of Hunting and Hunting Areas for Big and Small Game （Food） for the Tourism Development in the Crna River Basin in the Republic of Macedonia

The Crna River is a river in the Republic of Macedonia, right tributary to Vardar. Its source is in the mountains of Western Macedonia, west of Krusevo. It flows through the village of Sopotnica, and southwards through the plains east of Bitola. The name means ＂black river＂ in Macedonian, which is translation for its former Thracian name. The purpose of this paper is to show the hunting and hunting areas for big and small Game （food）, the structure of the areas of certain hunting, fishing, fishing water objects, fish species, fishponds up to 20 years shown by municipalities and individual farms with ponds in the basin of Black River. It had used statistical data for the hunting grounds by areas, fishing ponds. Fish is very diverse in this river. Hunting in the Black River basin is of great importance for the economy of Republic of Macedonia. It is also a necessary factor for development of other economic activities.

Effect of Digested Sewage Sludge on the Ventilation and Coughing Rates of Two Fresh Water Fish

Addition of digested sewage sludge at concentrations of 2% and 10% (v/v) to the water increased coughing rate in big head and tilapia (P<0.05). Ventilation rate was significantly decreased (P<0.05) in big head and tilapia at sludge concentrations of 6% and 2% (v/v)respectively. Copper (Cu), cadmium (Cd) and zinc (Zn) are trace metals which are commonly found in sludge. Cu caused a significant increase (P<0.05) in coughing rate in both tilapia and big head at concentrations of 0.3 and 0.2 μg/ml respectively. Zn caused significant increase (P<0.05) in coughing rate only in big head at 2 μg/ml. Neither fish responded to Cd of up to 2μg/ml in the water. However, when the levels of these trace metals in the digested sludge were measured, they were below that which can cause significant changes in the respiratory movements. Therefore, the changes in ventilation and coughing rates after addition of sludge may be due to the presence of substances other than these metals. The results of this experiment provides a guideline to control the level of sludge that can be used in rearing these fresh water fish in ponds

DDT and Its Metabolites in Fresh Water Fish Samples

Twenty two fresh water fish samples namely Puntius sarana （Shawrputi）, Cyprinus carpio （Karp）, Oreochromis niloticos （Telapia）, Channa punctatus （Taki）, Wallogonia attu （Boal）, Eutropiichthys vacha （Bacha）, Macrognathus aculiatus （Baim）, Ailia coila （Kajoli）, Mystus cavasisus（Gulsa）, Ompok pabda （Pabdha）, Corica soborna （Kachki）, Mystus vittatus （Tengra）, Glossogobius giuris （Baila）, Macrobrachium malcolmsli （Chingri）, Amblypharyngodon microlepis （Mola）, Anabas testudineus （Koi）, Macrognathus aculiatus （Baim）, Channa striatus （Shole）, Heteropnueste fossilis （Shing）, Puntius sophore （Small Puti） and Pseudambassis ranga （Telapia） were collected from two rivers and one cultured fish pond. The samples were extracted by QuEChERS method, cleaned up with conc. H2SO4 treatment and cleaned extracts were analyzed by GC-ECD. Small size cultured rui fish sample which did show detectable amount of DDT and its metabohtes was used for the recovery experiments. Percent recovery was found to be in the range of 70%-113%. Amount of total DDTs were found to be 54.34, 48.81, 62.09, 54.72,78.81, 60.07, 47.0, 42.7, 26.31, 10.36, 25.32, 12.96, 20.10, 12.78, 17.65, and 4.71, 8.58, 11.3 and 19.01 ng/g in gulsa, pabhda, baila, bacha, baim, small purl, tengra, chanda, kachki, boal, taki, chingri, mola, shole, shing, koi, swarpurl, karp and telapia fish samples, respectively. However, the residual amounts of DDTs in all the fish samples were below maximum residue limit （MRL of DDTs in fish 5.0 mg/kg） according to Codex Alimentarius Commission. The ratios of 4,4＇-DDT/DDTs were in the range of 0.03-0.44 which indicated that exposure to DDT is not due to recent use.

Effect of Fertilizer Diammonium Phosphate on Liver,Kidney and Muscle 5-Nucleotidase Activity of Fresh Water Teleost Fish Clarias batrachus

The toxic effect of fertilizer Diammonium phosphate resulted in alterations of 5'-Nucleotidase activity of tissues liver, kidney and muscles offish C. batrachus at varying intervals and exposures. Alterations in 5'-Nuclcotidase activity of body organs gave an idea of the toxicity caused by the fertilizer. Thus the enzyme 5'-Nucleotidase can be used to monitor the pollution in aquatic ecosystem.

Water-trapping and drag-reduction effects of fish Ctenopharyngodon idellus scales and their simulations

In the last decades, surface drag reduction has been re-emphasized because of its practical values in engineering applications,including vehicles, aircrafts, ships, and fuel pipelines. The bionic study of drag reduction has been attracting scholars' attentions. Here, it was determined that the delicate microstructures on the scales of the fish Ctenopharyngodon idellus exhibit remarkable drag-reduction effect. In addition, the underlying drag-reduction mechanism was carefully investigated. First,exceptional morphologies and structures of the scales were observed and measured using a scanning electron microscope and3-dimensional(3D) microscope. Then, based on the acquired data, optimized 3D models were created. Next, the mechanism of the water-trapping effect of these structures was analyzed through numerical simulations and theoretical calculations. It was determined that there are many microcrescent units with certain distributions on its surface. In fact, these crescents are effective in generating the "water-trapping" effect and forming a fluid-lubrication film, thus reducing the skin friction drag effectively.Contrasting to a smooth surface, the dynamics finite-element analysis indicated that the maximum drag-reduction rate of a bionic surface is 3.014% at 0.66 m/s flow rate. This study can be used as a reference for an in-depth analysis on the bionic drag reduction of boats, underwater vehicles, and so forth.

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.