Effect of temperature on early life history in weatherfish, Misgurnus fossilis (L. 1758)

Effect of incubation temperature (range: 9–36 °C; interval: 3 °C) on artificially propagated weatherfish (Misgurnus fossilis) early ontogeny (during interval from egg fertilization to the finish of hatching) was investigated. Both, the amplitude of the incubation period (evaluated in four crucial moments), the total hatching period duration was inversely proportional to the incubation temperature and ranged from 17.5 days at 9 °C to 1.8 days at 24 °C (expressed at H50) or from 137 hours at 9 °C to 9 hours at 24 °C, respectively. There were no influence of rising temperature on the total length of newly hatched larvae (TL = 4.23–4.67 mm), in contrast to negative correlation with developmental stage (9–18 °C: stage 37; 21–24 °C: stage 36), i.e. the length might determine the age at hatching, rather than the age at hatching determines the hatching length. The thermal tolerance range in term of survival lies between 9 and 24 °C (the thermal optimum 15–24 °C, i.e. weatherfish is a warm-mesothermic species). Temperatures above 24 °C (in our study 27–36 °C) are considered the lethal temperatures already during embryonic period. It is highly recommended to distinguish an impact of suboptimal temperatures 9–12 °C on development during explored interval only, in contrast to possible other effect of these lower temperatures in context of the whole early ontogeny

Clove oil as an anaesthetic for different freshwater fish species

Abstract HAMACKOVA, J., J. KOURIL, P. KOZAK and Z. STUPKA, 2006. Clove oil as an anaesthetic for different freshwater fish species. Bulg. J. Agric. Sci., Results of experiments with clove oil utilization as an anaesthetic for fish realized in the University of South Bohemia Research Institute of Fish Culture and Hydrobiology at Vodтany are described. A series of observations was performed to evaluate the anaesthetic effects of clove oil on a broad spectrum of fish species. In selected fish species, the effect of fish size, temperature of aquatic environment, anaesthetics concentration and exposure time upon the anaesthetic effects were studied. Within the realized experiments, concentration of 0.03 -0.05 ml.l -1 can be generally recommended for fish. The only exception are salmonids and sturgeons which need lower (0.02 -0.03 ml.l -1 ) and higher (0.07 ml.l -1 ) concentrations, respectively. Exposure period between 2 and 4 min. is sufficient for full anaesthesia and is strongly dependent on water temperature

Effect of temperature on early life history in weatherfish,

Effect of incubation temperature (range: 9–36 °C; interval: 3 °C) on artificially propagated weatherfish (Misgurnus fossilis) early ontogeny (during interval from egg fertilization to the finish of hatching) was investigated. Both, the amplitude of the incubation period (evaluated in four crucial moments), the total hatching period duration was inversely proportional to the incubation temperature and ranged from 17.5 days at 9 °C to 1.8 days at 24 °C (expressed at H50) or from 137 hours at 9 °C to 9 hours at 24 °C, respectively. There were no influence of rising temperature on the total length of newly hatched larvae (TL = 4.23–4.67 mm), in contrast to negative correlation with developmental stage (9–18 °C: stage 37; 21–24 °C: stage 36), i.e. the length might determine the age at hatching, rather than the age at hatching determines the hatching length. The thermal tolerance range in term of survival lies between 9 and 24 °C (the thermal optimum 15–24 °C, i.e. weatherfish is a warm-mesothermic species). Temperatures above 24 °C (in our study 27–36 °C) are considered the lethal temperatures already during embryonic period. It is highly recommended to distinguish an impact of suboptimal temperatures 9–12 °C on development during explored interval only, in contrast to possible other effect of these lower temperatures in context of the whole early ontogeny

Corrosion modeling of simple glasses from the systems SiO2-Na2O-CaO and SiO2-Na2O-MgO

Static corrosion tests were conducted on two model glasses with the following composition (in mol%): 75 SiO2, 15 Na2O, 10 CaO and 75 SiO2, 15 Na2O, 10 MgO. The tests were performed in deionized water at 80 °C. Glass grains were combined with a monolithic sample in one reacdon vessel to achieve sufficient elemental release and to provide a monolithic sample for analysis. Vapor hydration tests (VHT) were performed on monolithic samples at 200 °C. Solution composition was analyzed with atomic absorption spectrometry (AAS), depth profiles of all elements in the surface layers of monolithic samples were analyzed with secondary neutral mass spectrometry (SNMS), and both monolithic and crushed samples were analyzed with scanning electron microscopy with energy dispersive spectrometry (SEM/EDS). Solution compositions and saturation indexes of secondary minerals were modeled with the geochemical code PHREEQC version 2.41 using LLNL database. The results showed that the sodium diffusion profiles in the surface layers of the glasses were established during the first few hours of the test. Both glasses showed that the dissolution rate depends on the chemical affinity for dissolution between the surface gel layer and the corrosion solution. Α glass alteration model based on transition state theory taking into account solution chemistry and precipitation of secondary alteration products is presented