A method for the analysis of schooling behavior applicable to field and laboratory studies is presented. Three indices were developed to measure the behavior of a school, from motion pictures. Two of the indices are measures of the distance among individuals in a school, and the other is a measure of the differences in orientation among the individuals. A value for each index was calculated for each motion-picture frame analyzed. A coordinate reader and digitizer used to analyze films permitted the operator to record automatically on IBM cards the X and Y coordinates for the positions of the head and tail of each fish in a frame. A computer program was written to calculate the three indices from the coordinates, to convert the measurements to actual distance, and to make statistical comparisons.Laboratory experiment on the influence of food deprivation on schooling behavior of juvenile jack mackerel, Trachurus symmetricus (Ayres) indicated: schools became compact immediately after feeding; the intervals among fish expanded during a deprivation period; and differences in orientation were related to the size of the individuals.
Effects of motion picture frame rate on material and texture appearance