Planning on utilization of clean low-temperature seawater for fishery products in a fishing port

Abstract

In general, the deep seawater has some advantageous properties for utilization in the field of fisheries. Such properties are: (a) low-temperature and cleanness useful for keeping freshness and better quality of the fishery products while storing in a fishing vessel, washing, handling in a fishing port and distributing to the market and (b) nourishment effective for nursery of juvenile fish, breeding of the sea weed and for improving marine basic bio-production in case of discharging into the sea area. This paper presents our research and study on a utilization planning of clean low-temperature seawater from the deep sea for fishery production, aiming at supply of the safety and reliable fishery products, reduction of production cost and mitigation of environmental impact. As a result, our study proved that making best use of clean low-temperature deep seawater, production cost and power consumption for ice making can be reduced. In addition, an effective utilization planning was clarified to cope with supply scheme of clean low-temperature seawater to meet changes in landed quantity in a fishing port. Utilization of clean low-temperature deep seawater will be able to bring about more safety supply of the fishery products, reduction of the cost relating to producing clean low-temperature seawater now in use, and diminishing environmental impact. Moreover, this paper introduces the case study on the related planning in Rausu fishing port located in east side of Shiretoko Peninsula in northeastern part of Hokkaido. In the ambient sea area of Rausu fishing port, there exist the geographically sharp sea bottom and clean low-temperature deep seawater zone at water depth of -350 m, about 2.6 km offshore. Rausu fishing port is one of the leading fishing ports in Hokkaido, with annual fishery production of more than 10 billion yen. Major fishery are salmon set net fishery, gill net and long-line fishery and squid jigging fishery, etc.. In particular, landed quantity of salmon ranks at top level throughout Japan, and salmon is really a treasure fish in Rausu district.