Pacific Oysters now invade the Oslofjord.

Pasific oysters were first discovered outside coastal towns Kragerø, Lyngør and Tønsberg a couple of years ago,  and are now also found in the Oslo Fjord. The species has become more common in European seawater  over the past 10 to 20 years, but has now spread north with the ocean currents along the west coast of Sweden to the Oslofjord.

One possible source may be the production of oysters in the Danish Limfjord, claims Anders Jelmert, a research scientist at the Norwegian Institute of Marine Reseach. Another contribution may be the increased water temperature in the sea. The larvae of the Pacific oyster is spread  by ocean currents and displace flat oyster, a species that is natural for Norwegian waters.

Although oysters are considered good food, scientists are not particularly happy to see it along the Norwegian coast.

Pacific oyster does not exist naturally in Norwegian waters, and the introduction of the species in Norwegian waters not desirable. Moreover, the Pacific oyster is called an ''Engeneering species'', as  it converts the environment to their advantage and can form large surfaces with razor sharp edges.

The pacific Oyster has a deeper shell shape and is more wavy on the shell surface than the "Norwegian" flat oyster. It can grow as large as 30 cm. Although oysters are considered a delicacy, there is no effective method for harvesting them in the wild. Therefore, there is no effective containment of the species, says Jelmert.

So, - wherever you encounter the Pacific Oyster along the coast this summer, pick it, open it raw, gratinate in the oven with garlic, butter and parsley, - and enjoy it with a glass of Campagne, - of course!