Аннотация:
The instrumental methods that allow to determine authentically the environmental characteristics in real time "in situ" are considered. Their classification is developed basing on physics measurements and on interpretation of hydrobiological data as well. The main attention is given to meters using rapid optical measurement principles to conduct both rapid estimation of fish food base and the character of its formation. The main criterion for choosing meters is their methodological compatibility with CTD-complexes. Modern serial models for optical measuring instruments and recommendations for their use are presented from the standpoint of significance for fisheries.