Pattern classification and recognition of movement behavior of medaka (Oryzias latipes) using decision tree

Behavioral sequences of the medaka (Oryzias latipes) were continuously investigated through an automatic image recognition system in increasing temperature from 25 degrees C to 35 degrees C. The observation of behavior through the movement tracking program showed many patterns of the medaka. After much observation, behavioral patterns could be divided into basically 4 patterns: active-smooth, active-shaking, inactive-smooth, and inactive-shaking. The "smooth" and "shaking" patterns were shown as normal movement behavior, while the "smooth" pattern was more frequently observed in increasing temperature (35 degrees C) than the "shaking" pattern. Each pattern was classified using a devised decision tree after the feature choice. It provides a natural way to incorporate prior knowledge from human experts in fish behavior and contains the information in a logical expression tree. The main focus of this study was to determine whether the decision tree could be useful in interpreting and classifying behavior patterns of the medaka.