The impact of short-term fluctuations of temperature on the production indices of aquatic animals: Oreochromis niloticus (L.) and Pistia stratiotes (L.)

Short-term small periodic fluctuations of temperature within the range of ecological valence are favorable for Nile tilapia Oreochromis niloticus L. and water lettuce Pistia stratiotes L. At alternate thermal regimes, the specific growth rate is higher, production and energetic indices are better, the efficiency of food utilization for growth is higher, and the expense of oxygen on gaining the mass unit of a fish body is lower when compared to the optimal for constant thermal regimes of growth. During temperature fluctuations, the mineralization rate of dissolved and suspended organic matter increases.