A Stereo Photographic Method for Measuring the Spatial Position of Fish

Abstract

In studies of fish behavior or the ecology of schooling fish and in estimating fish biomass, information on fish position and size are required. A method was designed for determining the position of fish in three dimensions using stereo photographs taken with an under water stereo camera system. From the obtained fish positions, the distance between fish and the camera, the size, aspect and bearing angles of fish in the field of view of the camera were calculated. The absolute errors in measurement using the present method are 0.75% for length and 0.77% for distance. The method can be successfully applied to fish with any aspect within the field of view of the stereo camera system. The results suggest that in situ information on fish can be studied in detail using this technique. © 1985, The Japanese Society of Fisheries Science. All rights reserved.