Qualification of spontaneous undirected locomotor behavior of fish for sublethal toxicity testing. Part I. Variability of measurement parameters under general test conditions

An automated, personal computer-based video-processing, object-recognition, and object-tracing system was used to record and analyze undirected sponta neous locomotor behavior of small groups of undisturbed semiadult zebra fis h (Brachydanio rerio) in laboratory tanks. The primary data provided by the monitoring system were the individually assigned, time-stamped coordinates of the fish in two-dimensional projection. Secondary parameters (position, velocity of movement in the horizontal and the vertical direction, and tem poral intraindividual and interindividual association) were calculated. The computed parameters offered a multidimensional description of spontaneous undirected swimming behavior of the fish and proved to be largely independe nt of water temperature, length, weight, and sex ratio of the zebra fish wi thin the standardized range, but varied significantly with the feeding regi me, time of day, number of fish per tank, and batch. Statistical characteri stics of the behavioral parameters confirmed them as being appropriate for parametric statistical analyses.