FIELD: measurement technology. SUBSTANCE: method determining density of concentration of fish includes survey with use of laser underwater TV system with range gating, visual or computer counting of number of fishes observed in frame. Counting registers not only fishes illuminated by laser pulse but as well those present at this moment in space between TV camera and illuminated zone and observed in the form of silhouettes. Density of concentration of fishes is computed by division of number of observed fishes by value of volume of spherical sector whose radius equals product of light velocity in water by half-time of delay of gate of opening of detector of laser underwater TV system relative to pulse of laser radiator. In this case angles correspond to angle of view of detector of laser underwater TV system. EFFECT: raised authenticity of results of counting of fishes most distant but still visible, present on boundary of underwater. 4 dwg
