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Oyster Herpes in France Ravages Harvest
By Makiko Kitamura and Maki Shiraki - May 18, 2011 6:25 AM GMT+1000

A deadly virus is stalking France’s coastline, killing at least 60 percent of the young oysters there since 2008. Japan’s earthquake and tsunami may have wiped out the latest rescue plan.

The March 11 natural disasters destroyed the fishing industry in Miyagi prefecture, which produced 80 percent of Japan’s oyster seeds in 2009. That is forcing France to abandon plans to import and breed Miyagi’s Pacific oyster species, and find another solution for diners seeing fewer, and more costly, options.

The French eat about 108,000 metric tons of the mollusks, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Domestic production fell 38 percent last year, driving up wholesale prices 20 percent. Some brasseries in Paris sell the largest oysters for 6.5 euros ($9.17) apiece.

“This delays our exit from the crisis,” Maryline Maingam, a spokeswoman for France’s National Shellfish Committee, said in an interview. “There will still be oysters, but a lot less than before. For the next two years, we’ll have 40 percent to 50 percent production losses.”

France, whose oyster industry was worth about 400 million euros in 2010, imported young Miyagi oysters in October and February to test their resistance to the virus, a variant of Ostreid herpesvirus 1, or OsHV-1. That required special permission from the European Commission to circumvent 1991 restrictions on importing oysters for breeding.

$3.3 Billion Industry

Test results are expected this month, yet “the dramatic events in Japan in March 2011 have altered the chances of success of the Japanese track,” Veronique Lopes, a spokeswoman for the French Ministry of Agriculture, said in an e-mail.

The ministry is drawing up a new list of potential importers with “sufficient health guarantees,” she said.

Japanese oysters also are less attractive because of the possibility their beds were contaminated by radiation leaking from a damaged nuclear-power plant on the coast in neighboring Fukushima prefecture, Lopes said.

The virus is not just a blow to France, Europe’s biggest producer. The global industry, worth at least $3.3 billion in 2009, has been plagued by OsHV-1 in Ireland, England and Australia.

Oysters Scarce
In Ireland, Europe’s second-largest producer, about half of the bays where Pacific oysters are grown have been affected by the virus since 2008. Research has suggested “a very strong association” with imports of oyster seeds from France, said John Joyce, a spokesman for the Irish Marine Institute based in Galway.

The virus starts killing oysters when water temperatures top about 16 degrees Celsius (61 degrees Fahrenheit). It has reappeared along the French coast this year and mostly affects oysters under one year old, Tristan Renault, director of the genetics and pathology laboratory at the French Research Institute for Exploration of the Sea in La Tremblade, said in a phone interview.

Oysters need three years to mature, so the past winter was the first to show the effect on supply, Maingam said.

“We’re starting to feel it,” said Rodolphe Ziegler, a manager for seafood wholesaler Demarne Freres Ets. at Rungis, the world’s largest wholesale food market, outside Paris. “We’re starting to see a problem with deliveries of small sizes.”

Miyagi Destruction
Oyster production declined to 80,000 tons from 130,000 tons last year in France, Maingam said. Wholesale prices are 20 percent higher than a year ago, according to the National Institute of Statistics and Economic Studies in Paris.

The problem may worsen after 2012, when many of the French colonies wiped out by the virus would have been ready for the table. That’s also when the Japanese-imported oysters would have been growing.

Miyagi oystermen already have lost this year’s harvesting season, and they won’t be able to plant seeds for the breeding season typically beginning in July. Fishing and farming were suspended all along Miyagi’s coast because of efforts to locate the 9,000 people still missing after the natural disasters.

Oysterman Taro Abe in Onagawa village lost everything.

“Our wharf and processing facility were completely destroyed,” said Abe, who now spends his time searching for mementos and remnants of his home. “All I have left is debt.”

Resist Disease
The Miyagi oysters, whose scientific name is Crassostrea gigas, are more resistant to infectious diseases than other species and have a history of being sent abroad to jumpstart farming or revive crops devastated by illness. It is now the most widely farmed oyster species in the world, Renault said.

Miyagi oysters came to France’s rescue in the 1970s after the iridovirus killed most of the oyster population. The oysters also have been transplanted to more than 30 countries, including the U.S., China, South Korea, Spain and New Zealand.

“Crassostrea gigas has been cultivated all around the world, showing it is capable of adapting to different environments,” Renault said.

Oystermen prefer Miyagi’s seeds because the oysters also are free of a parasite found elsewhere in Japan, Renault said.

Now Japan may have to increase oyster imports to keep prices stable. To help Miyagi get back on its feet, iLink Systems Inc., an oyster distributor based in Sendai, in Miyagi prefecture, started the Save Sanriku Oysters project that is taking donations for new boats, farming equipment and facilities. Sanriku refers to the northeast coast that includes Miyagi.

Supplies ‘Tight’
“Particularly for farmers in their 60s carrying debts, there is talk of giving up,” said Hiroaki Saito, president of iLink.

Given the traumatic experience from the disasters, which left at least 400 fishermen dead or missing in Miyagi alone, money is not the only obstacle, said Katsutoshi Mori, president of the World Oyster Society.

“It’s a question of regaining spirit,” he said.

That leaves French wholesalers waiting and hoping for another rescue plan. The government is making 42 million euros a year available to support the farmers. Yet some smaller operations are shutting down because they aren’t producing enough healthy shellfish, Ziegler said.

“If the mortality continues, this year will be tight, and next year, also,” he said.

To contact the reporters on this story: Makiko Kitamura in Tokyo at mkitamura1@bloomberg.net; Rudy Ruitenberg in Paris at rruitenberg@bloomberg.net; Maki Shiraki in Tokyo at mshiraki1@bloomberg.net

The French ate an average of about 108,000 metric tons of the mollusks in recent years, from Nice in the south to Calais in the north, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Photographer: Bill Daley/Chicago Tribune/MCT via Getty Images

Workers walk in front of stranded fishing vessels following the March 11 earthquake and tsunami in Kesennuma, Miyagi prefecture, Japan. Photographer: Kimimasa Mayama/Bloomberg

A deadly virus is stalking Frances coastline, killing at least 60 percent of the young oysters there since 2008. Japans earthquake and tsunami may have wiped out the latest rescue plan.
The March 11 natural disasters destroyed the fishing industry in Miyagi prefecture, which produced 80 percent of Japans oyster seeds in 2009. That is forcing France to abandon plans to import and breed Miyagis Pacific oyster species, and find another solution for diners seeing fewer, and more costly, options.
The French eat about 108,000 metric tons of the mollusks, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Domestic production fell 38 percent last year, driving up wholesale prices 20 percent. Some brasseries in Paris sell the largest oysters for 6.5 euros ($9.17) apiece.
This delays our exit from the crisis, Maryline Maingam, a spokeswoman for Frances National Shellfish Committee, said in an interview. There will still be oysters, but a lot less than before. For the next two years, well have 40 percent to 50 percent production losses.
France, whose oyster industry was worth about 400 million euros in 2010, imported young Miyagi oysters in October and February to test their resistance to the virus, a variant of Ostreid herpesvirus 1, or OsHV-1. That required special permission from the European Commission to circumvent 1991 restrictions on importing oysters for breeding.
Test results are expected this month, yet the dramatic events in Japan in March 2011 have altered the chances of success of the Japanese track, Veronique Lopes, a spokeswoman for the French Ministry of Agriculture, said in an e-mail.
The ministry is drawing up a new list of potential importers with sufficient health guarantees, she said.
Japanese oysters also are less attractive because of the possibility their beds were contaminated by radiation leaking from a damaged nuclear-power plant on the coast in neighboring Fukushima prefecture, Lopes said.
The virus is not just a blow to France, Europes biggest producer. The global industry, worth at least $3.3 billion in 2009, has been plagued by OsHV-1 in Ireland, England and Australia.
Oysters Scarce
In Ireland, Europes second-largest producer, about half of the bays where Pacific oysters are grown have been affected by the virus since 2008. Research has suggested a very strong association with imports of oyster seeds from France, said John Joyce, a spokesman for the Irish Marine Institute based in Galway.
The virus starts killing oysters when water temperatures top about 16 degrees Celsius (61 degrees Fahrenheit). It has reappeared along the French coast this year and mostly affects oysters under one year old, Tristan Renault, director of the genetics and pathology laboratory at the French Research Institute for Exploration of the Sea in La Tremblade, said in a phone interview.
Oysters need three years to mature, so the past winter was the first to show the effect on supply, Maingam said.
Were starting to feel it, said Rodolphe Ziegler, a manager for seafood wholesaler Demarne Freres Ets. at Rungis, the worlds largest wholesale food market, outside Paris. Were starting to see a problem with deliveries of small sizes.
Miyagi Destruction
Oyster production declined to 80,000 tons from 130,000 tons last year in France, Maingam said. Wholesale prices are 20 percent higher than a year ago, according to the National Institute of Statistics and Economic Studies in Paris.
The problem may worsen after 2012, when many of the French colonies wiped out by the virus would have been ready for the table. Thats also when the Japanese-imported oysters would have been growing.
Miyagi oystermen already have lost this years harvesting season, and they wont be able to plant seeds for the breeding season typically beginning in July. Fishing and farming were suspended all along Miyagis coast because of efforts to locate the 9,000 people still missing after the natural disasters.
Oysterman Taro Abe in Onagawa village lost everything.
Our wharf and processing facility were completely destroyed, said Abe, who now spends his time searching for mementos and remnants of his home. All I have left is debt.
Resist Disease
The Miyagi oysters, whose scientific name is Crassostrea gigas, are more resistant to infectious diseases than other species and have a history of being sent abroad to jumpstart farming or revive crops devastated by illness. It is now the most widely farmed oyster species in the world, Renault said.
Miyagi oysters came to Frances rescue in the 1970s after the iridovirus killed most of the oyster population. The oysters also have been transplanted to more than 30 countries, including the U.S., China, South Korea, Spain and New Zealand.
Crassostrea gigas has been cultivated all around the world, showing it is capable of adapting to different environments, Renault said.
Oystermen prefer Miyagis seeds because the oysters also are free of a parasite found elsewhere in Japan, Renault said.
Now Japan may have to increase oyster imports to keep prices stable. To help Miyagi get back on its feet, iLink Systems Inc., an oyster distributor based in Sendai, in Miyagi prefecture, started the Save Sanriku Oysters project that is taking donations for new boats, farming equipment and facilities. Sanriku refers to the northeast coast that includes Miyagi.
Particularly for farmers in their 60s carrying debts, there is talk of giving up, said Hiroaki Saito, president of iLink.
Given the traumatic experience from the disasters, which left at least 400 fishermen dead or missing in Miyagi alone, money is not the only obstacle, said Katsutoshi Mori, president of the World Oyster Society.
Its a question of regaining spirit, he said.
That leaves French wholesalers waiting and hoping for another rescue plan. The government is making 42 million euros a year available to support the farmers. Yet some smaller operations are shutting down because they arent producing enough healthy shellfish, Ziegler said.
If the mortality continues, this year will be tight, and next year, also, he said.
To contact the editor responsible for this story: Kae Inoue at kinoue@bloomberg.net

The French ate an average of about 108,000 metric tons of the mollusks in recent years, from Nice in the south to Calais in the north, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Photographer: Bill Daley/Chicago Tribune/MCT via Getty Images

Workers walk in front of stranded fishing vessels following the March 11 earthquake and tsunami in Kesennuma, Miyagi prefecture, Japan. Photographer: Kimimasa Mayama/Bloomberg

A deadly virus is stalking Frances coastline, killing at least 60 percent of the young oysters there since 2008. Japans earthquake and tsunami may have wiped out the latest rescue plan.
The March 11 natural disasters destroyed the fishing industry in Miyagi prefecture, which produced 80 percent of Japans oyster seeds in 2009. That is forcing France to abandon plans to import and breed Miyagis Pacific oyster species, and find another solution for diners seeing fewer, and more costly, options.
The French eat about 108,000 metric tons of the mollusks, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Domestic production fell 38 percent last year, driving up wholesale prices 20 percent. Some brasseries in Paris sell the largest oysters for 6.5 euros ($9.17) apiece.
This delays our exit from the crisis, Maryline Maingam, a spokeswoman for Frances National Shellfish Committee, said in an interview. There will still be oysters, but a lot less than before. For the next two years, well have 40 percent to 50 percent production losses.
France, whose oyster industry was worth about 400 million euros in 2010, imported young Miyagi oysters in October and February to test their resistance to the virus, a variant of Ostreid herpesvirus 1, or OsHV-1. That required special permission from the European Commission to circumvent 1991 restrictions on importing oysters for breeding.
Test results are expected this month, yet the dramatic events in Japan in March 2011 have altered the chances of success of the Japanese track, Veronique Lopes, a spokeswoman for the French Ministry of Agriculture, said in an e-mail.
The ministry is drawing up a new list of potential importers with sufficient health guarantees, she said.
Japanese oysters also are less attractive because of the possibility their beds were contaminated by radiation leaking from a damaged nuclear-power plant on the coast in neighboring Fukushima prefecture, Lopes said.
The virus is not just a blow to France, Europes biggest producer. The global industry, worth at least $3.3 billion in 2009, has been plagued by OsHV-1 in Ireland, England and Australia.
Oysters Scarce
In Ireland, Europes second-largest producer, about half of the bays where Pacific oysters are grown have been affected by the virus since 2008. Research has suggested a very strong association with imports of oyster seeds from France, said John Joyce, a spokesman for the Irish Marine Institute based in Galway.
The virus starts killing oysters when water temperatures top about 16 degrees Celsius (61 degrees Fahrenheit). It has reappeared along the French coast this year and mostly affects oysters under one year old, Tristan Renault, director of the genetics and pathology laboratory at the French Research Institute for Exploration of the Sea in La Tremblade, said in a phone interview.
Oysters need three years to mature, so the past winter was the first to show the effect on supply, Maingam said.
Were starting to feel it, said Rodolphe Ziegler, a manager for seafood wholesaler Demarne Freres Ets. at Rungis, the worlds largest wholesale food market, outside Paris. Were starting to see a problem with deliveries of small sizes.
Miyagi Destruction
Oyster production declined to 80,000 tons from 130,000 tons last year in France, Maingam said. Wholesale prices are 20 percent higher than a year ago, according to the National Institute of Statistics and Economic Studies in Paris.
The problem may worsen after 2012, when many of the French colonies wiped out by the virus would have been ready for the table. Thats also when the Japanese-imported oysters would have been growing.
Miyagi oystermen already have lost this years harvesting season, and they wont be able to plant seeds for the breeding season typically beginning in July. Fishing and farming were suspended all along Miyagis coast because of efforts to locate the 9,000 people still missing after the natural disasters.
Oysterman Taro Abe in Onagawa village lost everything.
Our wharf and processing facility were completely destroyed, said Abe, who now spends his time searching for mementos and remnants of his home. All I have left is debt.
Resist Disease
The Miyagi oysters, whose scientific name is Crassostrea gigas, are more resistant to infectious diseases than other species and have a history of being sent abroad to jumpstart farming or revive crops devastated by illness. It is now the most widely farmed oyster species in the world, Renault said.
Miyagi oysters came to Frances rescue in the 1970s after the iridovirus killed most of the oyster population. The oysters also have been transplanted to more than 30 countries, including the U.S., China, South Korea, Spain and New Zealand.
Crassostrea gigas has been cultivated all around the world, showing it is capable of adapting to different environments, Renault said.
Oystermen prefer Miyagis seeds because the oysters also are free of a parasite found elsewhere in Japan, Renault said.
Now Japan may have to increase oyster imports to keep prices stable. To help Miyagi get back on its feet, iLink Systems Inc., an oyster distributor based in Sendai, in Miyagi prefecture, started the Save Sanriku Oysters project that is taking donations for new boats, farming equipment and facilities. Sanriku refers to the northeast coast that includes Miyagi.
Particularly for farmers in their 60s carrying debts, there is talk of giving up, said Hiroaki Saito, president of iLink.
Given the traumatic experience from the disasters, which left at least 400 fishermen dead or missing in Miyagi alone, money is not the only obstacle, said Katsutoshi Mori, president of the World Oyster Society.
Its a question of regaining spirit, he said.
That leaves French wholesalers waiting and hoping for another rescue plan. The government is making 42 million euros a year available to support the farmers. Yet some smaller operations are shutting down because they arent producing enough healthy shellfish, Ziegler said.
If the mortality continues, this year will be tight, and next year, also, he said.
To contact the editor responsible for this story: Kae Inoue at kinoue@bloomberg.net

The French ate an average of about 108,000 metric tons of the mollusks in recent years, from Nice in the south to Calais in the north, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Photographer: Bill Daley/Chicago Tribune/MCT via Getty Images

Workers walk in front of stranded fishing vessels following the March 11 earthquake and tsunami in Kesennuma, Miyagi prefecture, Japan. Photographer: Kimimasa Mayama/Bloomberg

A deadly virus is stalking Frances coastline, killing at least 60 percent of the young oysters there since 2008. Japans earthquake and tsunami may have wiped out the latest rescue plan.
The March 11 natural disasters destroyed the fishing industry in Miyagi prefecture, which produced 80 percent of Japans oyster seeds in 2009. That is forcing France to abandon plans to import and breed Miyagis Pacific oyster species, and find another solution for diners seeing fewer, and more costly, options.
The French eat about 108,000 metric tons of the mollusks, typically on the half-shell atop a bed of ice and garnished with a squeeze of lemon or splash of vinegar. Domestic production fell 38 percent last year, driving up wholesale prices 20 percent. Some brasseries in Paris sell the largest oysters for 6.5 euros ($9.17) apiece.
This delays our exit from the crisis, Maryline Maingam, a spokeswoman for Frances National Shellfish Committee, said in an interview. There will still be oysters, but a lot less than before. For the next two years, well have 40 percent to 50 percent production losses.
France, whose oyster industry was worth about 400 million euros in 2010, imported young Miyagi oysters in October and February to test their resistance to the virus, a variant of Ostreid herpesvirus 1, or OsHV-1. That required special permission from the European Commission to circumvent 1991 restrictions on importing oysters for breeding.
Test results are expected this month, yet the dramatic events in Japan in March 2011 have altered the chances of success of the Japanese track, Veronique Lopes, a spokeswoman for the French Ministry of Agriculture, said in an e-mail.
The ministry is drawing up a new list of potential importers with sufficient health guarantees, she said.
Japanese oysters also are less attractive because of the possibility their beds were contaminated by radiation leaking from a damaged nuclear-power plant on the coast in neighboring Fukushima prefecture, Lopes said.
The virus is not just a blow to France, Europes biggest producer. The global industry, worth at least $3.3 billion in 2009, has been plagued by OsHV-1 in Ireland, England and Australia.
Oysters Scarce
In Ireland, Europes second-largest producer, about half of the bays where Pacific oysters are grown have been affected by the virus since 2008. Research has suggested a very strong association with imports of oyster seeds from France, said John Joyce, a spokesman for the Irish Marine Institute based in Galway.
The virus starts killing oysters when water temperatures top about 16 degrees Celsius (61 degrees Fahrenheit). It has reappeared along the French coast this year and mostly affects oysters under one year old, Tristan Renault, director of the genetics and pathology laboratory at the French Research Institute for Exploration of the Sea in La Tremblade, said in a phone interview.
Oysters need three years to mature, so the past winter was the first to show the effect on supply, Maingam said.
Were starting to feel it, said Rodolphe Ziegler, a manager for seafood wholesaler Demarne Freres Ets. at Rungis, the worlds largest wholesale food market, outside Paris. Were starting to see a problem with deliveries of small sizes.
Miyagi Destruction
Oyster production declined to 80,000 tons from 130,000 tons last year in France, Maingam said. Wholesale prices are 20 percent higher than a year ago, according to the National Institute of Statistics and Economic Studies in Paris.
The problem may worsen after 2012, when many of the French colonies wiped out by the virus would have been ready for the table. Thats also when the Japanese-imported oysters would have been growing.
Miyagi oystermen already have lost this years harvesting season, and they wont be able to plant seeds for the breeding season typically beginning in July. Fishing and farming were suspended all along Miyagis coast because of efforts to locate the 9,000 people still missing after the natural disasters.
Oysterman Taro Abe in Onagawa village lost everything.
Our wharf and processing facility were completely destroyed, said Abe, who now spends his time searching for mementos and remnants of his home. All I have left is debt.
Resist Disease
The Miyagi oysters, whose scientific name is Crassostrea gigas, are more resistant to infectious diseases than other species and have a history of being sent abroad to jumpstart farming or revive crops devastated by illness. It is now the most widely farmed oyster species in the world, Renault said.
Miyagi oysters came to Frances rescue in the 1970s after the iridovirus killed most of the oyster population. The oysters also have been transplanted to more than 30 countries, including the U.S., China, South Korea, Spain and New Zealand.
Crassostrea gigas has been cultivated all around the world, showing it is capable of adapting to different environments, Renault said.
Oystermen prefer Miyagis seeds because the oysters also are free of a parasite found elsewhere in Japan, Renault said.
Now Japan may have to increase oyster imports to keep prices stable. To help Miyagi get back on its feet, iLink Systems Inc., an oyster distributor based in Sendai, in Miyagi prefecture, started the Save Sanriku Oysters project that is taking donations for new boats, farming equipment and facilities. Sanriku refers to the northeast coast that includes Miyagi.
Particularly for farmers in their 60s carrying debts, there is talk of giving up, said Hiroaki Saito, president of iLink.
Given the traumatic experience from the disasters, which left at least 400 fishermen dead or missing in Miyagi alone, money is not the only obstacle, said Katsutoshi Mori, president of the World Oyster Society.
Its a question of regaining spirit, he said.
That leaves French wholesalers waiting and hoping for another rescue plan. The government is making 42 million euros a year available to support the farmers. Yet some smaller operations are shutting down because they arent producing enough healthy shellfish, Ziegler said.
If the mortality continues, this year will be tight, and next year, also, he said.
To contact the editor responsible for this story: Kae Inoue at kinoue@bloomberg.net

Yesterday (11 / 5), in Ben Tre province, the Ministry of Agriculture and Rural Development organized conference "Assessment of disease of shrimp, oysters and implementing recovery management and supervision of production ". Deputy Nguyen Thi Xuan Thu presided over the meeting.

In 2011, shrimp diseases continue to occur with high levels of damage in all farming systems, both in modern farming. Might say, dead shrimp not only because white spot disease, but also in the expression on the liver and pancreas. Currently, even in large farms, with many years experience in the profession has yet to find remedies. Particularly about the oysters, mainly in Ben Tre (2.560ha), Tien Giang (2.150ha) and Vietnam (509ha) with very high mortality rate up to 70-90% in some areas in Thanh district Phu (Ben Tre). The beach areas of agriculture, almost 100% dead oysters.

The conference has over 12 presentations by scientists, including: Presentation of the General Department of Fisheries, Department of Animal Health, Institute of Aquaculture II, III ... and the report of the Department of Agriculture and Rural Development Ben Tre, Ca Mau, Bac Lieu, Kien Giang, Soc Trang, Tra Vinh, Ninh Thuan ...

Survey samples at various times, in many areas, presentations of Aquaculture Research Institute II in favor of some pathogens, such as in oysters, which are intensity Perkinsus sp infection is high. Besides the presence of Perkinsus sp also coincides with the presence of feathers and other species of bacteria opportunities (V. alginolyticus, V. parahaemolyticus, V. vulnificus) but not the primary causative agent. Template histological appearance is similar to Rickettsia infection. Samples in Tien Giang and Can Gio showed infection rates clam Perkinsus sp. very high.

In shrimp, the epidemic is taking place on both tiger shrimp and white shrimp in the stage of 20-30 days old. Mortality in the survey not due to white spot disease, the gold or Taura syndrome. In addition to signs of liver atrophy on shrimp disease, also appear in other cases such as the liver duct, pale, swollen or in combination with signs of white spot disease. Sample analysis results showed the presence of signs of infection, gangrene. In addition, the presence in combination with other agents such as WSSV, IHHNV, MBV, YHCV and parasites. Signs of necrosis and infection with high frequency on shrimp samples can be considered a major cause of dead shrimp in the survey.

Although the consensus report on the survey a few numbers and statistics but without the high consistency and certainty in the discussion on the cause of death of shrimp, clams. A proper solution just yet, when determining the true causes of disease. So the delegates, especially the provincial delegates, farms should agree on the proposed investment, the survey added. Agencies needed for this study.

Deputy Nguyen Thi Xuan Thu said: "The situation is more diseases earlier this year, we can say is very serious. Can not say the reason is that these farms are not breeding, not understanding the process and methods adopted. But to say that there are other factors. The difficulty is that the survey group has not definitely determined, obviously, the causative agent. For the Ministry, the Ministry will direct the Department of Animal Health and the team will have more research, but the immediate application of integrated measures to prevent the disease is still needed. "

While awaiting further research, Aquaculture Research Institute II proposed integrated solution for the prevention and treatment of shrimp, oysters that many delegates at the conference agreed a review. Integrated solution are: For shrimp, the application of biosecurity is needed. Pay attention to seasonal stocking. Because white spot disease related to low temperature, while liver disease related to pancreas temperature and high salinity. Should focus on environmental improvement over the pond thoroughly.

In addition to substrate processing and kill crustaceans to prevent white spot disease focus on treatment of water (can use formol) to kill the protozoa, because this group is a group of protozoa as hosts for the group of intracellular bacteria. An examination of selected good seed before stocking in order to avoid infection from the beginning is very important. Stocking density was also much discussion participants recommended: with tiger prawns from fish/m2 15-20, 40-50 fish/m2 white shrimp.

For oysters, the occurrence of Perkinsus related to temperature and high salinity. Therefore, attention should be paid to the farming season to harvest the right times. The treatment of seed before stocking is necessary. Clam processor like fresh water bath by affecting spore form of Perkinsus. Should also pay attention to the sanitation yard clam: to gather clams die, you can use lime or localized disease measures have cut the time off or to limit the presence of pathogens that persist in the yard oysters. Clam density should also be noted san said. The environmental monitoring and warning of epidemics, combined tightly managed breeding areas should be done regularly for all the shrimp, and clam farming.

Deputy Minister of Agriculture and Rural Development Nguyen Thi Xuan Thu:

- Mekong Delta area of ​​aquaculture is important, but in recent years the disease situation alarming. Objective may be due to climate change and new pathogens have appeared in some farming areas. Subjective profit in 2010 because of the high aquaculture farmers do not schedule many seasons, stocking planning, safety and hygiene. Quarantine issues local seed is not a strict quarantine; waste management may be better handled violated the rearing environment, water and land.

- Confirm the pathogen is unclear, although orientation. Attach importance to disease problems in fish may be high, although damage in the farming sector is not small compared with outbreaks of animal: bird flu, blue ear pig. The publication of translations in the fisheries sector has not taken place, but very embarrassing documents to the local implementation is not complete.

- First of all, there should be monitoring specific measures such as repeat disease surveillance process, especially processes that control seed. Should check the risk of some diseases that are spread by re-checks farms, made barricades to prevent the spread of wide-ranging. Should have planned specific areas of shrimp, and manage the implementation of the provisions of the seed base.

**A relatively new virus is causing havoc in the international oyster industry. Charlotte Johnston, TheFishSite editor speaks with David Jarrad from the Shellfish Association of Great Britain about the fatal oyster herpes virus.**

Officially identified in France no more than 24 months ago, the Ostreid herpesvirus-1 (OsHV-1) is one that has spread fast.

The disease only affects the Pacific oyster, native oysters remain uninfected, says Mr Jarrad. To date the disease has been associated with large scale mortalities. It is likely the disease has been present for a lot longer, says Mr Jarrad, but has been unknown to the industry.

In Europe, the virus is mostly affecting younger stock, although some adult stocks have been affected, he says.

Adult mortality varies between 10 - 30 per cent, however juvenile mortality is a lot higher, between 60 - 100 per cent.

The cause of the virus is still unknown, although it has been suggested that there are a number of causative agents. One of these is varying climates and temperatures. A French scientist, Tristan Renault, from the genetics and pathology lab at the IFREMER (French Research Institute for Exploitation of the Sea), has suggested in recent publications that one of the contributing factors to the appearance of the disease could be global warming and a subsequent significant rise in the ocean’s temperature.

Only very occassionally have mortalities occurred when the temperature has been less than 15-16 degrees Celsius.

However Mr Jarrad says that there is a lot of uncertainty about the disease, and until more research is completed, nothing can be set in stone.

Large scale mortalities began in France four to five years ago, with the disease then spreading to Southern Ireland. In early 2010, oyster farms in South England were infected, with smaller mortalities in the Netherlands. Later on in the year, farms in New Zealand became aware of the disease and in January 2011, Australia confirmed an outbreak of the virus.

Prevention

Mr Jarrad says that the most efficient method to prevent the spread of the disease is too minimise the movement of stock. However this is not always successful. In Whitstable, South England, a closed farming system was in place, however oysters were still found to be infected with the virus.

The government and seafood bodies have advised producers not to bring any oysters for re-watering into the UK from affected areas.

In Whitstable, it has been discovered that some stocks are still infected with the virus, but no further mortalities have occurred. It is still unknown whether stock can hold the virus dormant and then rid themselves of it.

To date, all mortalities have been connected back to presence of the virus in oyster stocks.

In 2010 the EU introduced the regulation 175/2010, which require all member states to test areas of large scale mortality for presence of the pathogen. If the virus is present, containment zones are established and movement in and out of that zone prohibited.

Mr Jarrad says that this regulation was due to expire on 31 December 2010, however due to situation continuing to be of great concern to the industry, it has been extended until 30th April 2011.

Research is ongoing, allowing member states more time to look into the disease and its effects on oyster populations.

He says that the Shellfish Association of Great Britain would like to see more regulation, to prevent the spread of the virus. Whilst the UK is keen to adopt certain measures, other countries aren't as interested, he suggested.

Effects on the industry

The virus has started to cause a shortage of oysters across Europe. With France being the number one producer of oysters in Europe, French growers have been forced to approach UK seed hatcheries. This has meant that a lot of UK production has gone to France, which Mr Jarrad says leaves the UK in a precarious situation.

If the virus continues to spread and wipe out stocks, the sourcing of future stocks is an issue that the industry will have to address. In the meantime, prices of oysters have been on the rise.

In New Zealand, it is suspected that the disease has killed off half the juvenile crops in the North Island. The financial loss caused by what the NZ Ministry of Agriculture identifies as Ostreid herpesvirus-1 (OsHV-1) has so far been estimated at NZ$ 30 million.

The Ostreid herpesvirus-1 presents no threat to humans.

This scientific opinion published on 11 January 2011 replaces the previous version published on 17 November 2010.

Following a request from European Commisssion, the Panel on Animal Health and Welfare was asked to deliver a scientific opinion on the increased mortality events in Pacific Oysters (Crassostrea gigas).

The mandate terms of reference specifically requested to assess the relative importance of possible causes, including infectious agents with special focus on Ostreid Herpesvirus-1(OsHV-1) µvar), as well as environmental factors. It was also requested to assess which other mollusc species could be involved and finally the risk of infection posed by the transference of adult Pacific oysters when they are sourced from an area affected by the increased mortality event.

The following approach was taken: 1) a description of the production systems and husbandry methods for Pacific oyster production in Europe 2) a review of abnormal mortality events prior to 2008 in Pacific oyster 3) a description of the surveillance methods in place for investigation of abnormal mortality in European member states 4) a collection and analysis of the available information on mortality events during the period of 2008-2010 5) a description of infectious agents, host and environmental factors that have been associated with increased mortality. The question regarding the possible involvement of other mollusc species in “increased mortality” was addressed by presenting evidence of susceptibility (EFSA 2008) to OsHV-1 for certain mollusc species.

The Animal Health and Welfare (AHAW) panel concluded that OsHV-1 (reference strain and µvar) has been predominantly demonstrated in Pacific oysters spat and juveniles from events of increased mortality. The available evidence suggests that OSHV-1 infection is a necessary cause but may not be sufficient by itself as other factors appear to be important. OsHV-1 µvar has not been sufficiently characterised to be defined as a new genotype but may be considered as a different strain. OsHV-1 µvar seems to be the dominant viral strain in the 2008-2010 increased mortality events but it is not clear if this is a result of increased virulence or other epidemiological factors. The sensitivity and specificity of current diagnostic methods for OsHV-1 is not known. The role of other pathogenic agents such as Vibrio spp. has not yet been resolved.

Climatic and seasonal factors alone are not likely to be a sufficient cause for the increased Pacific oyster mortality reported in France, United Kingdom and Republic of Ireland in 2008-2009 although these events are seasonal in their occurrence. An increase or a sudden change in the temperature of the water around oysters has been shown to be an important risk factor predisposing for the disease. Up to now no outbreaks have been reported when the water temperature is below 16ºC. Husbandry practices such as introduction of non certified possibly infected spat, movements and mixing of populations and age groups are probably important risk factors.

Events of increased mortality have been only observed in Pacific oyster. In addition to C. gigas, there is evidence of susceptibility to OsHV-1 in Ostrea edulis, Pecten maximus and Ruditapes philippinarum. There was no investigation on susceptibility to OsHV-1 µvar made on other mollusc species other than C. gigas.

OsHV-1 (reference strain and µvar) was detected by PCR in Pacific oyster older than 18 months associated with increased mortality. Therefore it is concluded that oysters older than 18 months can be a source of virus and it is not safe to transfer oysters older than 18 months from affected areas to areas not affected by increased mortality events.

The AHAW panel recommended that a clear case definition for “increased mortality” in Pacific oyster needs to be developed. An acceptable baseline mortality and “increased mortality” in Pacific oyster needs to be defined where unit of concern (population, lease area, batches and/or production units), season, age/size, observation period should be taken into account as well as a description of an appropriate method for mortality estimation.

A description of the Pacific oyster aquaculture industry in Europe namely regarding number of farms, production figures, and traceability on movements/transfers both on hatchery and grow out sites should be achieved in accordance to the requirements by Council Directive 2006/88/EC.

The panel recommended that to best promote and preserve high health status and in particular to prevent and/or control increased mortality, measures are urgently needed to improve the general level of biosecurity in the oyster aquaculture industry in Europe. Furthermore to minimize the risk of subsequent transfer of infectious agents from hatcheries and wild- caught spat, there is a need to establish the health status of oyster spat at source. An assessment of the health status should include results of regular batch laboratory testing (at least in regards to OsHV-1, ref strain and µvar, Vibrio species, and histopathological examination) and epidemiological assessment.

Improved diagnostic methods should be developed to check for the presence of OsHV-1 µvar and other strains.The methods for detection of OsHV-1 (including different strains) need to be validated and harmonized. Relevant genomic information of the OsHV-1 µvar virus should be obtained for a better characterization of the strain in order to i) perform phylogenetic studies, ii) improve diagnosis iii) investigate potential for increased infectivity and virulence. The phylogenetic relationship of OsHV-1 strains should be investigated. Clear criteria for viral strain differentiation taking in account genotype and epidemiological criteria are necessary.

To better understand existing and emerging health problems, a robust health surveillance system for Pacific oyster production in Europe is needed. Well designed epidemiological research studies, including comparison studies, in order to determine the potential importance of infectious agents and other environmental factors on increased mortality in pacific oyster are necessary.

Ostreid herpesvirus-1 µ variant , Australia
Information received on 07/01/2011 from Dr Andy Carroll, Chief Veterinary Officer , Department of Agriculture, Fisheries and Forestry, Australian Government , Canberra, Australia
Summary
Report typeImmediate notification
Start date24/11/2010
Date of first confirmation of the event22/12/2010
Report date07/01/2011
Date submitted to OIE07/01/2011
Reason for notificationEmerging disease
Morbidity98 %
Mortality98 %
Zoonotic impactNo
Causal agentOsHV-1 µ var DNA sequence detected in affected oysters. Causation not proven.

New outbreaks
Summary of outbreaksTotal outbreaks: 1
Location(s)NEW SOUTH WALES (Woolooware Bay)

Total animals affectedSpeciesSusceptibleCasesDeathsDestroyedSlaughtered
Pacific oyster (Crassostrea gigas)**

Outbreak statisticsSpeciesApparent morbidity rateApparent mortality rateApparent case fatality rateProportion susceptible animals lost*
Pacific oyster (Crassostrea gigas)********

* Removed from the susceptible population through death, destruction and/or slaughter
** Not calculated because of missing information

Epidemiology
Source of the outbreak(s) or origin of infectionUnknown or inconclusive

Epidemiological commentsThe New South Wales Department of Industry and Investment is investigating a syndrome of mortality in Pacific oysters (Crassostrea gigas), detected on oyster leases in Woolooware Bay, Botany Bay, New South Wales.
Unhealthy oysters were observed after a plume of discoloured water was seen in the area following rainfall. Initial testing did not indicate presence of an infectious agent. A second submission (about one week after the first) indicated acute ulcerative changes indicative of an infectious agent.
The New South Wales Department of Industry and Investment identified the presence of ostreid herpesvirus-1 µ variant (OsHV-1 µ var) by PCR testing, subsequently this was confirmed by the Australian Animal Health Laboratory using conventional PCR. Virus particles could not be detected by transmission electron microscopy conducted on tissues from PCR positive samples.
The die off has also been observed in wild Pacific oysters in the nearby area. Mortalities have not been observed in other mollusc species, including adjacent Sydney rock oysters (Saccostrea glomerata). Oyster leases in other locations within Botany Bay have not been affected, and are under surveillance. Mortality in Pacific oysters has been 100% for spat (2.2mm), 95% for market sized stock.
The New South Wales Food Authority advises there is no evidence to suggest any food safety issues with infected oysters.
The estuary is formally closed to all shellfish and associated equipment movements excepting movement of product to market. No Pacific oysters are available for market.
Surveillance outside and within containment and/or buffer zone including testing of source stock is being planned.
There is no treatment for affected animals.

Control measures
Measures appliedQuarantine
Movement control inside the country
Tracing back
No vaccination
No treatment of affected animals

Ostreid herpesvirus-1 , New Zealand

Information received on 07/12/2010 from Mr Barry O'Neil, Assistant Director General (Biosecurity), Biosecurity New Zealand, Ministry of Agriculture and Forestry, New Zealand, Wellington, New Zealand, New Zealand

Summary
Report type Immediate notification
Start date 17/11/2010
Date of first confirmation of the event 06/12/2010
Report date 07/12/2010
Date submitted to OIE 07/12/2010
Reason for notification Emerging disease
Morbidity 80 %
Mortality 80 %
Zoonotic impact No
Causal agent Ostreid herpesvirus-1 (OsHV-1)

New outbreaks
Summary of outbreaks Total outbreaks: 12
Location(s)

* WAIKATO (Coromandel)
* NORTHLAND (Kerikeri; Whangarei; Parengarenga; Hokianga; Orongo Bay; Rangaunu; Whangaroa (Inner); Kaipara (Northern); Waiheke; Waikare (Inner))
* AUCKLAND (Mahurangi (Northern))

Total animals affected
Species Susceptible Cases Deaths Destroyed Slaughtered
Pacific oysters (Crassostrea gigas) ** 0 0
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Pacific oysters (Crassostrea gigas) ** ** ** **

* Removed from the susceptible population through death, destruction and/or slaughter
** Not calculated because of missing information

Epidemiology
Source of the outbreak(s) or origin of infection

* Unknown or inconclusive

Epidemiological comments Ministry of Agriculture and Forestry Biosecurity New Zealand (MAFBNZ) is investigating a syndrome of increased mortality in Pacific oysters (Crassostrea gigas) reported to be more severe in younger oysters and, potentially, at elevated water temperatures.
Normal mortality on farms is between 5 and 10 percent – there is varying die-back, but losses of between 50 to 80 percent of all sp

OYSTER HERPESVIRUS - NEW ZEALAND
********************************
A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Thu 2 Dec 2010
Source: World Fishing & Aquaculture [edited]

Puzzled scientists are battling to identify why millions of Pacific
oysters are dying in New Zealand waters. Up to half of the juvenile
Pacific oyster stocks in the North Island are thought to have died,
and up to 10 percent of the adults, according to Oyster Industry
Association chairman Callum McCallum.

Aquaculture New Zealand said up to 80 percent of juvenile oysters on
some farms have died.

The European Food Safety Authority (EFSA) has called on animal health
experts for a scientific opinion on widespread die-offs of Pacific
oysters (_Crassostrea gigas_).

Acting on a request from the European Commission, EFSA has
specifically asked whether the juvenile stocks may have been killed
off by a combination of a herpes-like virus -- ostreid herpesvirus-1
(OsHV-1) -- and environmental factors.

In the UK, the movement of oysters from parts of the Kent coast has
been banned after the herpes decimated juvenile Pacific oyster stocks.
The OsHV-1 virus has wiped out stocks in France in recent years and
the UK has declared a containment area on the Thames and north Kent
coasts.

A spokeswoman for the Centre for Environment, Fisheries and
Aquaculture Science (CEFAS) said OsHV-1 is an emerging disease that
has been associated with high levels of mortality in Pacific oysters
in France, Jersey, and some bays in the Republic of Ireland.