Digital diary system for fishery and applications of fishery management

Abstract

To assist coastal fisheries, we have been working to utilize IT. This paper reports on sea cucumber resource management using a digital diary system that we have developed. At Rumoi, which is located in western Hokkaido, fishing for sea cucumber is carried out in the summer each year by dredge net fishing. Although fishing for sea cucumber has been conducted for over 30 years, since 2003 the price of sea cucumber has risen sharply due to growing demand in China, and there are concerns over sea cucumber depletion due to the rapid increase in catch sizes. During the fishing seasons from 2007 to 2009, we estimated resource amounts by using the swept area method by fitting data loggers that record GPS position information to 3 vessels from among the total of 16 sea cucumber dredge net fishing vessels in Rumoi and matched the vessel trajectories with fishing diaries written in notepads by the fishers. The results showed that sea cucumber resources were decreasing year by year. We then developed a real-time fishery resource management system with the aim of allowing the fishers themselves to perform autonomous resource management by using estimates of the resource amount. The system consists of a digital diary system and a vessel monitoring system. Both of these system components are connected to the Internet via mobile phone lines, with fishing operation information and catch information from the digital diary system and position information from the vessel monitoring system collected on a server in real time. In 2012, the fishery resource management system was installed on all 16 vessels, with real-time resource estimates carried out on a weekly basis. The fishers worked toward autonomous resource management where they decided the resource amount to leave behind, and used the difference from the estimated resource amount as the permissible catch limit for that year. Furthermore, the sharing of position information using the vessel monitoring system enabled efficient utilization of the fishing grounds and coordination of fishing operations. The fishers closed the fishing season early based on variations in the catch per unit effort that was updated in real time as an indicator. These results show that the sea cucumber resource amount was maintained and demonstrate the usefulness of the developed real-time fishery resource management system.