Research status and prospects of automatic feeding boats for shrimp and crab ponds

A large-scale aquaculture of shrimp and crab ponds can be found with a high demand for automatic feeding in China. Automated feeding is crucial to the output and quality of cultivated species, due to cost savings and minimum pollution of aquaculture water bodies. It is also one of the most critical steps to enhance the efficiency of shrimp and crab pond aquaculture in mechanization and automation. Given the limited swimming ability of shrimp and crabs, it is essential to evenly distribute feed throughout the pond, according to their feeding behaviors. Previous research has been increasingly focused on the automatic feeding boats of shrimp and crab ponds, particularly on precise positioning, uniform feeding, automatic navigation, and operation. In this study, a research survey was implemented on the feeding boats for the shrimp and crab ponds in the world. Subsequently, the current research status of automatic feeding boats was outlined for the shrimp and crab ponds. Three key aspects were: the propulsion system of feeding boats, the bait delivery mechanism, and precise feeding control technology. Firstly, the current propulsion systems of feeding boats were primarily paddle wheels and propellers, each of which shared their own strengths and weaknesses suitable for different scenarios. Structural optimizations were conducted to improve the speed, efficiency, and maneuverability. Additionally, the blowers and integrated screw systems were explored for feeding boats, in response to the aquaculture environment with dense aquatic plants. However, two mechanisms were still in the exploratory phase. Secondly, the feeding and scattering mechanisms were designed to achieve the transportation and scattering of feed under various aquaculture conditions. 1) The feeding mechanism mainly included a screw, rotary valve, and vibrating feeding. The lower feed breakage rates and higher transportation speeds were achieved for the high efficiency and accuracy. 2) The scattering mechanism was primarily used as centrifugal scattering discs, particularly for a wide scattering range. Some optimizations were also implemented to achieve higher uniformity in the scattering and lower feed breakage rates using various simulation software. According to the feeding characteristics of shrimp, direct feeding was applied in shrimp ponds. Thirdly, the precise feeding control technology focused mainly on three aspects: 1) According to different breeding needs, path planning involved planning edge-following and coverage paths using a combination of sensors, satellite navigation systems, and path planning. 2) Automatic recognition was used for shrimp and crabs using machine vision and acoustic technology. The feeding boat was formulated feeding strategies, according to their distribution within the aquaculture pond. 3) Precise control was carried out to predict and accurately adjust the amount of feed using deep learning. Furthermore, the limitations of current research were examined to predict future trends: 1) To enhance adaptability and operational reliability in complex environments, 2) To investigate the interaction mechanism among feed particles, feeding boats, and breeding organisms, 3) To improve precision performance using artificial intelligence technologies, and 4) To realize the standardization and systematization. From the perspective of practical application, an emphasis was put on the standardizations of equipment layout, pipeline distribution, and waterweed planting. The findings can offer valuable insights for further research, development, and promotion of automatic feeding boats for shrimp and crab ponds in China.