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This research examined the impacts of acoustic stress in peled (Coregonus peled Gmelin, 1788), a species commonly cultivated in Russia. This study presents a comparative analysis of the macula sacculi and otoliths, as well as primary hematological and secondary telomere stress responses, in control and sound-exposed peled. The authors measured the effects of long-term (up to 18 days) exposure to a 300 Hz tone at mean sound pressure levels of 176-186 dB re 1 μPa (SPL pk-pk ); the frequency and intensity were selected to approximate loud acoustic environments associated with cleaning equipment in aquaculture settings. Acoustic exposure resulted in ultrastructure changes to otoliths, morphological damage to sensory hair cells of the macula sacculi, and a gradual decrease in the number of functionally active mitochondria in the red blood cells but no changes to telomeres. Changes were apparent following at least ten days of acoustic exposure. These data suggest that acoustic exposure found in some aquaculture settings could cause stress responses and auditory damage to peled and, potentially, other commercially important species. Reducing sound levels in fish rearing facilities could contribute to the formation of effective aquaculture practices that mitigate noise-induced stress in fishes.

A novel anaerobic, thermophilic, CO-utilizing bacterium, strain KarT, was isolated from a hot spring of Karymskoe Lake, Kamchatka Peninsula. The cells of the novel isolate were Gram-positive, spore-forming, short rods. The bacterium grew chemolithoautotrophically on CO, producing equimolar quantities of H2 and CO2 (according to the equation CO + H2O --> CO2 + H2), and in the absence of CO, under N2 in the gas phase, chemoorganoheterotrophically with yeast extract, sucrose or pyruvate. Growth was observed in the temperature range 50-70 degrees C, with an optimum at 60 degrees C, and in the pH range 6.2-8.0, with an optimum at pH 6.8. The micro-organism did not grow on solid media; it was able to grow only in semi-solid medium containing 0.5 % agar. The generation time under optimal conditions for chemolithoautotrophic growth was 1 h. The G+C content of the DNA was 46.5+/-1 mol%. Growth was completely inhibited by penicillin, novobiocin, streptomycin, kanamycin and neomycin. Analysis of the 16S rRNA gene sequence showed that the isolate should be assigned to the genus Carboxydocella. On the basis of the results of DNA-DNA hybridization and morphological and physiological analyses, strain KarT represents a novel species of the genus Carboxydocella, for which the name Carboxydocella sporoproducens sp. nov. is proposed. The type strain is KarT (=DSM 16521T = VKM B-2358T).