Diseases of Cultured Kuruma Shrimp in Japan : a Review

Abstract

After the establishment of a large scale production method for penaeid shrimp larvae in the middle of 1960s, the culture production of kuruma shrimp Penaeus japonicus rapidly increased and attained the peak of 3, 020 metric tons in 1988 in Japan. Development of formulated diet and introduction of a double-harvest system were the main factors for the expansion. In addition to aquaculture, 300 million juveniles of P. japonicus have been produced at public sea farming centers and stocked in coastal waters to enhance the natural resources every year since the late 1970s. The number of shrimp pathogens reported in Japan is smaller than that reported from overseas, mainly because almost one shrimp species, P. japonicus has been farmed in Japan. Baculoviral mid-gut gland necrosis (BMN), penaeid acute viremia (PAV) (= white spot disease : WSD) and vibriosis (Vibrio penaeicida infection) have been known as major infectious diseases of cultured shrimp in Japan. BMN was a serious problem in larval production at hatcheries from the early 1970s to the mid 1980s, but the disease has not occurred since 1993, due to the dissemination of the practical countermeasure, egg washing. Vibriosis was prevalent especially from the late 1980s to the early 1990s when the culture system became intensive, and the losses by this disease were estimated to be 20-30% of annual shrimp production. PAV, which was introduced into Japan with live stock of young P. japonicus from China in 1993, has been not only giving serious economic losses to the shrimp aquaculture industry, but also causing various troubles in sea farming operation for shrimp. In this paper eight infectious and three non-infectious diseases of P. japonicus reported in Japan are reviewed.