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.

Collective behavior in animal groups: Theoretical models and empirical studies

“…Even if, as I will discuss, the statistical analysis suffered of some methodological problems, this was the first attempt to establish a quantitative basis for 3D observational data. Many more recent studies also focused on fish ( Van Long et al, 1985;Parrish and Turchin, 1997;Viscido et al, 2004;Tien et al, 2004), since experiments can be performed in laboratory tanks, under variable conditions. Moreover, fishes are often studied in shallow water, where they form pseudo-2D schools, making the experimental analysis much easier.…”