Automatic Recognition of Fish Behavior with a Fusion of RGB and Optical Flow Data Based on Deep Learning

Simple Summary: Animal behaviors are critical for survival, which is expressed over a long period of time. The emergence of computer vision and deep learning technologies creates new possibilities for understanding the biological basis of these behaviors and accurately quantifying behaviors, which contributes to attaining high production efficiency and precise management in precision farming. Here, we demonstrate that a dual-stream 3D convolutional neural network with RGB and optical flow video clips as input can be used to classify behavior states of fish schools. The FlowNet2 based on deep learning, combined with a 3D convolutional neural network, was first applied to identify fish behavior. Additionally, the results indicate that the proposed non-invasive recognition method can quickly, accurately, and automatically identify fish behaviors across hundreds of hours of video. The rapid and precise recognition of fish behavior is critical in perceiving health and welfare by allowing farmers to make informed management decisions on recirculating aquaculture systems while reducing labor. The conventional recognition methods are to obtain movement information by implanting sensors on the skin or in the body of the fish, which can affect the normal behavior and welfare of the fish. We present a novel nondestructive method with spatiotemporal and motion information based on deep learning for real-time recognition of fish schools' behavior. In this work, a dual-stream 3D convolutional neural network (DSC3D) was proposed for the recognition of five behavior states of fish schools, including feeding, hypoxia, hypothermia, frightening and normal behavior. This DSC3D combines spatiotemporal features and motion features by using FlowNet2 and 3D convolutional neural networks and shows significant results suitable for industrial applications in automatic monitoring of fish behavior, with an average accuracy rate of 95.79%. The model evaluation results on the test dataset further demonstrated that our proposed method could be used as an effective tool for the intelligent perception of fish health status.