RIASSUNTO
ABSTRACT
Currently sea desert due to overabundance of sea urchins is occurring worldwide. Iso-yake means the desertlike state of the sea without seaweed. In Japan, such damage is severe, causing an adverse adversely affecting effect on coastal fisheries and the environment. In particular, along the Japanese coast, there are rich seaweed beds, and the abalone and other coastal fisheries are important industries. Therefore, there is also a major economic concern. Furthermore, in the Tohoku region, the Iso-yake tendency began after the 2011 East Japan earthquake and has become a problem. Therefore, a small remotely operated vehicle (ROV) has been developed to remove sea urchins. We study the ROV system and the status of sea urchin removal. The experimental area is Nojima island Shizugawa Bay, in Miyagi Prefecture (Tahara, 2019).
ROV SYSTEM FOR SEA URCHIN COLLECTION
The Vega is a medium-sized ROV manufactured by KOWA Corporation. The maximum depth is 150 m. The ROV is shown in Fig. 1 and Table 1. In this study, we add sub Thruster, robot Arm, and sensors.
The ROV is based on a ROV of less than 45kg and has a sea urchin collection system. Sea urchins are collected by vacuum into the nozzle attached to the tip of the ROV. It recognizes sea urchins via a recognition system with machine learning to assist operators in finding sea urchins. This ROV is used to collect sea urchins and to reverse sea desert. It is intended to be operated in shallow water about 20m of depth. It has four thrusters for forward, backward, ascending, and descending movements. In addition, a characteristic feature is two small thrusters for tilt control, which is important in sea urchin collection. This in consideration of tilt control will be described later. An important goal is to stop overfishing, other than sea urchins, in consideration of environmental issues. Therefore, it is necessary to selectively recognize and collect sea urchins. (James, 2012; James, 2016) Hence, it is important to educate the ROV operator using a sea urchin recognition system employing sea urchin image recognition.