Oyster bed

There’s no need to worry – oyster herpes is not transferable to humans by eating “the food of love”.

This incurable, not to mention deadly, virus is a grave concern to the fishing communities in Europe. Oyster herpes is on the rise in Europe, and could go on spreading itself out even further, should the seas continue to get warmer, experts warn.

This past July farmed oysters were tested and the first known United Kingdom cases of herpes was detected in shellfish. This virus has already made its mark, killing somewhere between 20 and 100 percent of the breeding pacific oysters in some French beds from 2008 until 2010, according to, Ifemer, the French Research Institute for Exploitation of the Sea.

The reason that oyster herpes has been emerging more in Pacific oysters off of England still has scientists stumped, however many are speculating that Global Warming has something to do with it.

A new strain of Oyster herpes (Ostreid herpesvirus), remains dormant until the temperature of the water exceeds 16 degrees Celsius. UK waters reach this temperature in the height of summer, according to a member of the British government’s Fish Health Inspectorate, Kevin Denham.

Keeping that fact in mind, the director of Ifemer’s genetic and pathology lab, Tristan Renault, has commented that global warming “could be an explanation of the appearance of this particular type of virus.”

Though all of the herpes strains are DNA-based viruses, herpes, which infects everything from elephants to chickens to monkeys, comes in an astonishing number of species, each with their own distinct set of symptoms.

In humans, the best known forms of herpes are the Herpes simplex viruses, which spread through close contact and can produce symptoms such as oral and genital blisters.

Ostreid herpes viruses have been shown to affect not only oysters, but also scallops, clams and other scallops, explains Renault.

New Oyster Herpes

Shellfish who are infected with herpes are not new to the scientific world, however, in 2008 – the first year where there was a marked increase in the mortality rates detected in France – Ifremer stumbled upon a new strain of the virus.

Much like the other strains of the oyster herpes virus which infect mollusks, this new strain singles out younger oysters during the breeding season when the bodies of the mollusks’ are focusing all their energy on producing sperm and eggs, leaving them without enough energy to maintain their immune system Renault explains.

However, this new strain of oyster herpes is “more virulent than strains we have identified before,” Renault continued, adding that the virus is extremely efficient when it comes to killing its hosts, and can eradicate 80 percent of the oysters in a bed inside a week.

The most starting thing about this new strain of oyster herpes, is that the only visible sign there is something amiss, is the mortality rate, because oyster herpes does not have any visible symptoms, and can only be diagnosed through a lab test.

The first-ever comprehensive global report on the state of shellfish has been released by The Nature Conservancy at the International Marine Conservation Congress in Washington, DC.

This one of its kind report is a collaborative work carried out by scientists from five different continents employed by academic and research institutions as well as by conservation organizations.

The report, which focuses primarily on the distribution and condition of native oyster reefs, show that 85 percent of oyster reefs have been completely destroyed worldwide and that this type of environment is the most severely impacted of all marine habitats.

In a majority of individual bays around the globe, the loss exceeds 90 percent and in some areas the loss of oyster reef habitat is over 99 percent. The situation is especially dire in Europe, North America and Australia where oyster reefs are functionally extinct in many areas.

“We’re seeing an unprecedented and alarming

decline in the condition of oyster reefs, a critically

important habitat in the world’s bays and estuaries,”

says Mike Beck, senior marine scientist at The Nature

Conservancy and lead author of the report.

Many of us see oysters as a culinary delight only, but oyster reefs provide us humans with a long row of valuable favours that we rarely think about. Did you for instance known that oyster reefs function as buffers that protect shorelines and prevent coastal marshes from disappearing, which in turn guard people from the consequences of hurricanes and other severe storm surges? Being filter feeders, oysters also help keep the water quality up in the ocean and they also provide food and habitat for many different types of birds, fish and shellfish.

Even though the situation is dismal, there is still time to save the remaining populations and aid the recuperation of damaged oyster reefs. In the United States, millions of young Olympia oysters have been reintroduced to the mudflats surrounding Netarts Bay in Oregon, in an effort to re-create a self-sustaining population of this native species. The project is a joint effort by government and university scientists, conservation groups, industry representatives, and local volunteers.

“With support from the local community and other partners, we’re demonstrating that shellfish restoration really works”, says Dick Vander Schaaf, Oregon director of coast and marine conservation for the Conservancy. “Expanding the effort to other bays and estuaries will help to ensure that the ecological benefits of oyster reefs are there for future generations.”

If wish to learn more about the global oyster reef situation, you can find the report here.