Change in temperature is often a major environmental factor in triggering waterborne disease outbreaks. Previous research has revealed temporal and spatial patterns of bacterial population in several aquatic ecosystems. To date, very little information is available on aquaculture environment. Here, we assessed environmental temperature effects on bacterial community composition in freshwater aquaculture system farming of Litopenaeus vannamei (FASFL). Water samples were collected over a one-year period, and aquatic bacteria were characterized by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and 16S rDNA pyrosequencing. Resulting DGGE fingerprints revealed a specific and dynamic bacterial population structure with considerable variation over the seasonal change, suggesting that environmental temperature was a key driver of bacterial population in the FASFL. Pyrosequencing data further demonstrated substantial difference in bacterial community composition between the water at higher (WHT) and at lower (WLT) temperatures in the FASFL. Actinobacteria, Proteobacteria and Bacteroidetes were the highest abundant phyla in the FASFL, however, a large number of unclassified bacteria contributed the most to the observed variation in phylogenetic diversity. The WHT harbored remarkably higher diversity and richness in bacterial composition at genus and species levels when compared to the WLT. Some potential pathogenenic species were identified in both WHT and WLT, providing data in support of aquatic animal health management in the aquaculture industry.

Evaluation of the condition of balance between fishes and available fish foods in impoundments of multispecies fish culture in Taiwan was made by analyzing the quantitative interrelations between the standing crop of fish‐food biota and the stocked fishes of ecologically different species in a 6‐hectare pond with organic fertilization and feeding, and 99 irrigation reservoirs with a total water surface area of 697 hectares. In a balanced condition, the growth rate of plankton, macrophytes, benthos and nekton (exclusive of stocked fishes) kept pace with the rate of consumption by the fishes, respectively, of planktophagic, macrophytophagic, benthophagic, and nektophagic species within the impoundment. Studies of the interaction between the fishes and the fish‐food biota in the two types of impoundments of multispecies fish culture with different management methods shed considerable light on fish food utilization and competition in pond ecosystems. On the principle of fish production, these studies provide a basis for improved management of impoundments.

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A novel ultraviolet (UV) atomization atomic fluorescence spectrometry (UV-AFS) system was developed for the quantitative analysis of trace cadmium ions (Cd) without preconcentration.

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