HARMLESS: Hannah Urbschat, an animal keeper at Vivace Caviar in Loxstedt, Germany, carries a female sturgeon into a laboratory to be milked of its roe.
By Janet Binder
Animal keeper Hannah Urbschat is doing something that is part of a small revolution in harvesting caviar, reputedly the world’s most luxurious food.
While two of her colleagues hold a female sturgeon, Hannah uses her two thumbs to press downwards along the sides of the fish. From a tiny opening, a mass of unfertilized black eggs — caviar — spills into a waiting bowl.
A few minutes later, the sturgeon has been put back into the water and swims away gracefully, and unharmed.
The setting is Loxstedt in north-western Germany, and it is unique anywhere in the world for the fact that the roe is harvested from sturgeon without killing them first.
Marine biologist Angela Koehler of the Alfred Wegener Institute for Polar and Marine Research (AWI) is credited with developing the method and the AWI has taken out a worldwide patent on it. Now, the method has gone from the theoretical into actual practice.
There have been repeated attempts in the past to keep the sturgeon alive by milking the roe when it is ready to release, just before the mating stage, Koehler notes.
The problem was that mature eggs of a living sturgeon are not stable. They clump together on contact with water and burst when salt is added. Only immature eggs have the firmness necessary for further processing. To get at these, the fish has to be cut open.
“Slaughtering (the fish) is brutal, and in economic terms is madness,” Koehler says. Even when being raised under the best aquaculture conditions, it takes five to eight years before a female sturgeon produces her caviar for the first time.
The marine biologist actually had not been involved in the caviar business until 2005, the year when she watched sturgeon being slaughtered in Iran.
“Things started turning over in my head then,” she said. Koehler set about her research and conducted experiments over several years.
She found the solution for harvesting fish eggs by seeing how things are done by the living fish in nature.
When the eggs are fertilised during mating, the caviar is splashed with a liquid containing calcium.
This activates an enzyme in each egg that stabilizes its outer sheath.
“The solution was actually right there in plain sight,” Koehler now says.
Together with a chemist and a biophysicist and with support from the AWI, she founded a company called Vivace Caviar. The firm invested 6 million euros (8 million dollars) in its 7,500-square-metre hall and production facility near Bremerhaven on the North Sea coast.
Now, around 7,000 sturgeon are swimming around in numerous basins. These fish in the future are expected to produce around 7 tons of caviar per year.
Queries have come not only from Germany, but also from the United States, Asia, the Gulf region, Scandinavia and Switzerland.
One new customer is Der Alte Gasthof, a restaurant on the North Sea vacation island of Sylt.
It long ago took caviar off the menu because of the ethical issues, but now, restaurant owner Christa Kaplan says, “We have gladly put it back on offer after hearing about the Vivace caviar and testing it.
“It has a wonderful taste, there are no preservatives in it, and on top of that, you have a clear conscience while eating it.”
Since they are harvested at the ripe stage, the eggs need no chemical treatment, barring a bit of salt to maintain their smooth outer surface. By contrast, the immature eggs sold by the sturgeon slaughterers are covered with blood corpuscles and follicle cells.
“These are a paradise for bacteria and funghi,” marine biologist Koehler warns.
“To prevent such eggs from quickly spoiling, they are conserved in a toxic agent, borax.” Too much borax is injurious to human health.
Each year, some 150 tons of “black gold” are harvested in aquaculture sites in Iran, Russia, China and Europe.
Wild sturgeon have long since been placed under protection and may not be slaughtered. Consumers pay between 1,500 and 3,000 euros per kilogram for the delicacy. Exceptional types of caviar, such as from the Beluga sturgeon, can cost up to 5,000 euros, Koehler says.
About an hour after she had massaged the female sturgeon for the first time, keeper Hanna Urbschat is massaging the fish again.
“The first time around, you don’t get everything out,” she says. Depending on the age and weight of the animal, between 700 and 1,400 grams can be harvested. “The process is harmless for the sturgeon,” she adds. -DPA
