持続的増養殖生産を目ざしたサケの健康管理とHACCPシステムをベースとした安全・安心な秋サケ製品の提供

Sustainable propagation of salmonid fish under the ocean ecosystem is essential for salmon industry. Salmonid fish including chum salmon (Oncorhynchus keta), pink salmon (O. gorbuscha) and masu salmon (O. masou) are important species for hatchery reared and released fish in Japan. Diseases, especially viral and bacterial diseases are serious problems and one of the limitations of successful propagation and/or aquaculture of salmonid fish. Methods currently used to control the diseases in hatcheries are 1) hygiene and facility sanitation, 2) disinfection of water supply and waste water, 3) health monitoring of matured fish and hatched fry. Under these circumstances, hatched fish are healthy and specific pathogen free, but there is still a possibility of infection with some pathogens in environmental waters after they are moved to river or pond. For prospective study, development of effective vaccines and immunological tools for judgment of vaccination effect is necessary. To create safe and worry free salmon products, we have established a system using a risk analysis based on hazard analysis (HA) and set up the critical control point (CCP) from fishing through processing to distribution. Model program for improvement the quality control of fisheries products from fishing to market was created using chum salmon as a model fish species in 1999 with Hokkaido government, Japan. One town, located in east part of Hokkaido, was selected to become the model district in addition to its position as leading producer of chum salmon. This town received high marks for its efforts to promote the advanced measures to preserve freshness, as well as its approach to enhance the quality control of the marine products, such as the positive sanitation and hygiene measures adopted by local processors. This town implemented a local HACCP manual. Through this HACCP effort, the industry in the town district was integrated. Today, Japanese government considers that a safe and worry-free food product of the highest quality, by practicing the HACCP program and Good Practice program is necessary for fisheries industry and consumer. This Local Town District HACCP System has been accepted in many fishermen's cooperatives, and created this HACCP system in many towns and areas in Hokkaido and Tohoku. This risk analysis using HA and set up the CCP are combined with traceability system and accepted among consumers in Japan.水産増養殖の最終目標は食料資源の生産供給であり，安全で安心して食べることのできる魚介類の提供が求められている。サケ資源を食料源として持続的に有効活用するためには，健康種苗を育成・放流し，資源管理のもと，成長した個体を捕獲して安心して食べられるよう，漁獲から加工，流通・消費者に至る過程を管理する必要がある。魚を家畜同様，ヒトが管理すると病気の発生は避けられず，適切な防疫対策の実施が必須である。サケ・マス類の病原体は，成熟時に卵巣腔液や精漿に出現し，卵子や精子が汚染される。古くはこの汚染発眼卵が病原体伝播に大きくかかわり，孵化稚魚の発病による産業被害を引き起こした。現在は採卵親魚の健康調査を実施し，病原体の疫学調査に資すると共に，受精直後および発眼期に卵表面の消毒を行い，病原体フリーの用水で孵化・飼育を行って健康種苗を確保して放流している。漁獲後は，食品としての安全性を確保すると共に消費者に安心を提供することが重要である。安全性は科学的に確認でき，客観的に評価できるが，安心は安全性と異なり心的な問題である。食品として信頼して食べるためには，健康障害を起こす可能性のある要因を科学的に整理し，その成果を安全性確保に生かす必要がある。現在はリスク分析手法を用いて，生産現場から食卓までの危害分析（HA）を行い，重要な管理点（CCP）を設定して，リスクを制御する方法が広く採用されている。加工場のHA-CCPのみならず，リスク管理を導入したフードチェーン・アプローチによって安全性が確保され，トレーサビリティーの導入により消費者に生産者の顔が見えるようになり，食品産業に従事する人々も責任を自覚するようになってきた。水産食品には，刺身や寿司に代表されるように，加工工程で熱を加えないものも多く，これらの安全性を確保するには，加工場での衛生管理はもちろん，原料段階での衛生管理・品質管理が重要である。加工原料としての漁獲物を衛生細菌による汚染から守ることは，より安全な食品を消費者へ提供するために必要な処置と考える。漁獲から消費者までの水産物の流れは，漁場→漁港→産地卸売市場→加工場→消費地卸売市場→小売店→消費者となっている。加工場から消費者への行程は衛生管理が普及しているが，漁獲から加工場に至るまでの漁港を含めた食品衛生に関する配慮がいま求められている。衛生管理型漁港の整備，漁港の衛生レベルの設定，水産物の衛生品質管理に優れた産地市場を認定し，認定市場を参考に産地市場の衛生品質管理の向上を目指す取り組み，さらに養殖魚のJASの導入が進んでいる。資源管理に関してもMSC（Marine Stewardship Council）に対抗し日本版マリンエコラベル（MEL-Japan）が設立されている。今回，北海道の代表的な水産物であるサケを例に，漁獲から加工・流通・消費に至る各過程での衛生管理，特に，今まで見過ごされてきた漁獲から加工場に入るまでの衛生管理の必要性とトレーサビリティーについて考え，地域ぐるみの衛生管理を紹介したい。Lecture

Control Strategy for Viral Diseases of Salmonids and Flounder

Salmonid fish and flounders are economically important fish cultured in northern Japan. Viral diseases remain one of the limitations to the successful propagation in aquaculture. The incidence of disease, especially viral disease, has been increasing. Methods currently used to control viral disease in hatcheries are: (a) hygiene and sanitation, (b) disinfection of water supplies and wastewater, (c) selection of pathogen- free broodstock, (d) health monitoring of hatched fry, (e) control of normal intestinal flora, (f) vaccination, and (g) temperature control

Viral Infections of Cultured Fishes in Japan

Infectious pancreatic necrosis virus and infectious hematopoietic necrosis virus were isolated in the 1970's. These two viral diseases are still serious problems among the cultured salmonids in Japan. Since then, various viral infections of fish have been reported, more than 20 fish viruses have been isolated and more than five viruses have been observed by electron microscopy. Six viral diseases are major problems and cause economic losses among cultured fishes in Japan. These are IPN and IHN of salmonids, viral pancreatic-hepatic necrosis of yellowtails, rhabdovirus infection of Japanese flounder and black rock fish, "Kuchishiro-sho" of tiger puffer and epidermal necrosis of Japanese flounder. Besides these, there are several viral infections: herpesvirus infections of salmonids, especially epithelial tumor (induced by OMV or YTV); epithelial tumor of carp (Herpesvirus cyprini); and lymphocystis disease of several marine fishes. Eel virus from the European eel, eel virus of America and eel virus of Europe X were also isolated from cultured eel. Recently however, many other viruses were isolated from diseased and healthy fishes, including icosahedral cytoplasmic deoxyribovirus, papovavirus, herpesvirus, picornavirus and reovirus from cultured eel. Chum salmon virus was isolated from masu salmon. Reovirus and Coronavirus cyprini were isolated from common carp and birnavirus was isolated from Japanese flounder and red sea bream. In the blood of salmonids, the causative agent of viral erythrocytic necrosis was observed and in moribund fry of ishidai and epithelial necrosis of black sea bream and red sea bream, picornavirus and paramyxovirus were observed by E.M.The Second Asian Fisheries Forum. 17-22 April 1989. Tokyo, Japan

Viral Infections of Cultured Fish in Japan

Since infectious pancreatic necrosis virus and infectious hematopoietic necrosis virus were first isolated in the 1970s, more than 20 fish viruses have been isolated and at least 5 viruses have been observed by electron microscopy. Viral diseases are major problems and cause economic losses among cultured fishes in Japan and other countries. This paper reports our current understanding of the extent of viral infection in the cultured fishes of Japan.Nineteenth U.S.-Japan Meeting on Aquaculture. 29-30 October and 2 November 1990. Ise, Japan

Oncorhynchus Masou Virus (OMV) Epidemiology and its Control Strategy

Distribution of salmonid herpesvirus was known in USA and Japan. Herpesviruses isolated in USA were classified to serotype 1 (SaHV-1) and in Japan were serotype 2 (SaHV-2). The reference strain of SaHV-1 is Herpesvirus salmonis and SaHV-2 is Oncorhynchus masou virus (OMV) strain OO-7812. OMV disease (OMVD) causes oncogenic and skin ulcer conditions. The main susceptible fish species are kokanee salmon (Oncorhynchus nerka), masu salmon (O. masou), coho salmon (O. kisutch) and rainbow trout (O. mykiss). Economic losses caused by this virus were recognized among kokanee salmon, coho salmon and rainbow trout. At the beginning of the 1980s, OMV was distributed widely in the northern part of Japan. Since 1988, OMV was isolated from coho salmon and since 1991 this virus was found in rainbow trout. Recently, re-appearing OMVD has become a major problem in pond culture of rainbow trout in the central part of Japan. OMV is sensitive to ultraviolet irradiation and iodophore treatment. Although detection of OMV in carrier fish is difficult using polymerase chain reaction (PCR) and OMV replicates and appears in ovarian fluid at mature stage, it can be controlled by disinfection. OMVD was successfully controlled by disinfection of all facilities and eggs with iodophore just after fertilization and again at early-eyed stage

Viral Infections of Cultured Fishes in Japan

Since infectious pancreatic necrosis virus and infectious hematopoietic necrosis virus were first isolated in the 1970s, more than 20 fish viruses have been isolated and more than 7 viruses have been observed by electron microscopy, in Japan. Viral diseases are major problems and cause economic losses among cultured fishes in Japan and other countries.International Symposium on Infectious Viruses in Fish. 9-11 October 1992. Seoul, Korea

Study on the Intestinal Microflora of Salmonids

A study on the actual condition and changes of normal bacterial flora in the intestines of salmonids was carried out to determine the actual status of bacterial flora in the digestive tract, particularly in the intestines, in the course of their life cycle, i.e. migration from fresh water to the sea and back to the original river. From the results of this study, it would be concluded as follows. The intestinal microflora of healthy salmonids are mainly composed of the genus Aeromonas and the family Enterobacteriaceae of a so called terrestrial type, if they are living in fresh water. Contrarily, the flora are mainly composed of the genus Vibrio of marine or halophilic type when they are living in sea water. If fish move to the sea or upstream a river in their life cycle, the flora in their intestines would undergo changes in order to adequaely adapt the fish themselves for their living environments

A Coagglutination Test with Antibody-Sensitized Staphylococci for Rapid and Simple Diagnosis of Bacterial and Viral Diseases of Fish

The application of a coagglutination test for the diagnosis of diseases in fish was studied using staphylococci specifically sensitized with antibodies against the bacteria causing bacterial kidney disease (BKD), furunculosis, vibriosis and goldfish ulcer disease, and also against the virus causing infectious pancreatic necrosis (IPN). This method proved to be a simple, rapid and reliable diagnostic test suitable for use in the laboratory or field and requires no special apparatus. Procedures for this method are summarized as follows: 1. The kidney or affected tissue samples from the diseased fish are homogenized in four to nine times their volume of PBS or HANKS' BSS. If the antigen is heat stable, it is also heated in a boiling water bath for 30min. 2. The supernatant material is collected after centrifugation at 4000rpm for 20min. This may be omitted if a centrifuge is unavailable. 3. One drop of the supernatant material and one drop of antibody-sensitized staphylococci suspension are mixed on a glass slide and incubated in a wet chamber at room temperature. The slide is examined after 30, 60 and 90min. 4. If coagglutination is observed, the infected fish should be examined using another method to confirm the diagnostic results

Role of Viruses in the induction of skin tumours and tumour-like proliferations of fish

Skin tumours of fish are easily recognizable lesions, some of which have been known for centuries. Causes of fish tumour formation are varied and are often proposed to be multifactorial. In more than half of all cases examined by electron microscopy and virological methods, virus or virus-like particles were found in tumour tissues. So far, oncogenicity has been clearly demonstrated only for herpesviruses isolated from benign tumours. Classification of fish skin tumours, tumour-associated and tumour-inducing viruses, and the possible reasons for seasonal variation in skin tumour prevalence, are reviewed. It is postulated that fundamental principles determine the role of viruses in the induction of skin tumours of fish within a framework of different biological and environmental parameters