Design and Development of a Low-Cost Floater for Sustainable Fishing

While it is widely recognized that fish are an ecologically and commercially important group, our current knowledge of fish occurrence, composition (diversity), abundance and behavior (e.g., migration) is limited to anecdotal sightings and reports, often from laypersons. In situ marine monitoring bridges this gap and allows us to track and monitor marine life. One such system is the SOUND system: a swarm of low-cost Lagrangian floats that can noninvasively support aquaculture and fisheries, especially in remote areas and developing countries. The swarm of floats works together in a group and uses underwater acoustic communication. It provides long-term data on the fish population, which can shed light on the interdependencies of spatially segmented ecosystems, the top-down regulation of bio-geophysical processes and the sensitivity of the environment to anthropogenic stress factors. SOUND Floater consists of a piston-based buoy control system, an active sonar system with on-board analysis and a satellite communication module. It is capable of probing the water to a depth of 50 m while maintaining position with an accuracy of $< $10 cm, detecting schools of fish from a distance of 500 m and operating for five consecutive days. In this technical communication article we present the detailed design of the SOUND prototype, including its mechanical, electrical, and algorithmic parts. We report on results from laboratory pool and from two sea trials.