The planktonic diatoms, Asterionella formosu Kutz. and Synedru acus Hass., were cultivated in 96-well flat-bottom plastic plates with 100 pL of medium per well. At regular time intervals, cells were counted using an inverted microscope. Typically, the number of cells per well increased over 10 days from 50-200 to >1000. The first growth inhibition experiments were successfully run at room temperature using natural illumination. However, for better control of the growth conditions, a special micro-incubator was manufactured. This device hosted two incubation plates and was equipped with Peltier elements for cooling below room temperature, and a small luminescent lamp. For automatic counting, two digital micro-photographs of each well were taken, first at a 0.2 msec exposure and the second at a 5 msec exposure. The images were treated by means of custom software based on ImagePro to identify and count the diatom cells. Cultivation of diatoms on the micro-scale proved to be a convenient technique. Using this technique, we were able to study the effects of mercaptoethanol, Cu2+ on A. formosa and Cu2+, Hg2+, Cd2* and phenanthroline upon the growth of S. ucus.

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 (SPLpk–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.

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