Due to the importance of water variables conditions and available food in the development and survival of fish larvae, the current research evaluates the effects of two different food treatments (ration + zooplankton and only zooplankton) and water quality in tanks with Brycon orbignyanus larvae. Total water transparency (45 cm) has been mainly associated with short residence time, continuous w...

In the course of the investigation into the bacteriology and epidemiology of cholera, which we are at present conducting in the Asansol Mining vSettlement, we found that during the hot dry months of the year (February to June)?which also constitute the epidemic season in that area? vibrios were extremely numerous in the smaller village ground tanks much used by the inhabitants for bathing; the ...

In order to study the water quality in fish tanks, a 166-day (January to July 1992) experiment was realized using the indigenous species "p acu" (Piaractus mesopotamicus). Two different protein levels were tested in the diet (16% and 34% crude protein) and three stocking densities (0.25, 0.50 and 0.77 fish/m2). From the results, it was observed that the interactions between stocking density and...

As implementation of the Ballast Water Convention draws nearer a major challenge is the development of protocols which accurately assess compliance with the D-2 Standard. Many factors affect the accuracy of assessment: e.g. large volume of ballast water, the shape, size and number of ballast tanks and the heterogeneous distribution of organisms within tanks. These factors hinder efforts to obta...

Topological concepts have been introduced into electronic, photonic, and phononic systems, but have not been studied in surface-water-wave systems. Here we study a one-dimensional periodic resonant surface-water-wave system and demonstrate its topological transition. By selecting three different water depths, we can construct different types of water waves - shallow, intermediate and deep water...

We measured the presence, viability and potential toxicity of cyanobacteria in ships’ ballast tanks during three domestic voyages through the North American Great Lakes. Using molecular methods, the toxin-producing forms of Microcystis and Anabaena were monitored in ballast water after ships’ ballast tanks were filled at their first port of call, and at subsequent ports as ships transited the G...

Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures <10°C. During July 2010 to March 2012, we surveyed monthly for Aedes larvae and pupae in 120 houses in 8 Hanoi districts. Aedes albopictus preferred discarded containers in summer and pupal density drastically decreased in winter. Aedes aegypti preferred concrete tanks and this preference increased in winter. E...

Four hundred and fifty eight water samples collected from domestic tanks and taps and community taps were analysed for bacterial contamination. Faecal pollution was more in domestic tanks and taps in Mehmoodabad, Korangi and least in water collected from community taps of Liaquatabad, Korangi and Mehmoodabad. Bacteria isolated were mostly E. coli, Enterobacter sp, Klebsiella sp. and A. faecalis...

We evaluated the consumption of duckweed (Lemna minor, Linnaeus) by juvenile Blue Tilapia (Oreochromis aureus, Steindachner) through 48 hour indoor tank feeding trials. Feeding trials consisted of 5 tanks (4 treatment, 1 control). Tanks were stocked with 25 g of fresh duckweed at the initiation of each feeding trial. Designated treatment tanks were also stocked with 1 tilapia per tank. At the e...

Experiments were conducted to study the performance of circular and square tank surface aerators on the oxygen transfer coefficient and to a limited extent on power requirements. All the tanks are geometrically similar except for their shapes. They consist of a rotor of diameter, D, fixed with six flat blades rotating with a speed, N, in pure waters of viscosity, υ, at room temperature. A simul...