A Fish Counting System with Video Camera for Hatchery-Produced Juvenile Fish

At fish farms and fish farming facilities, the number of fish is continuously monitored from hatching until shipment. Especially, whenever hatchery-produced juvenile fish are transferred from one indoor aquaculture tank to another, fish farmers who manage the juvenile fish must manually count thousands of the fish, which places a significant burden on them. This paper presents an automated system for counting hatchery-produced juvenile fish in fish farming facilities. This system aims to serve as a foundational technology for aquaculture production management, supporting sustainable production through data-driven aquaculture. In the proposed system, a slide is set up with a video camera positioned above to capture the surface of the slide. The flow of juvenile fish along with water on the slide is recorded, and the number of juvenile fish captured in the video is counted. In every frame of the video, the starting and the ending lines are prepared perpendicular to the direction of fish movement, and the fish regions are tracked between these lines. The count is increased by one when a fish region has crossed the starting line. Subsequently, each fish region is tracked across frames, where the count is increased if a fish region in which an occlusion occurs between multiple fish regions has been separated. Under a custom-built recording setup, experiments were conducted with 10 videos of approximately 200 black medaka being released down the slide, and 2 videos with thousands of hatchery-produced juvenile fish being released down the slide, recorded at an aquaculture facility. The results indicated that the proposed system counted the number of fish accurately in most cases, even in the presence of occlusions.