The Pacific Oyster (Crassostrea gigas) in the Isefjord, Denmark

Jing Wang, Kenn Chrisoffersen, Sine Buck & Ying Tao

Studenteropgave: Semesterprojekt


The Pacific Oyster (Crassostrea gigas) is one of the alien species that were introduced and cultured in Europe. Researches show that C. gigas has reached a high density in the Limfjord as oyster reefs in recent years. Since 1986, several attempts for cultivations of C. gigas had been done in the Isefjord, and stopped in 1998. Till now, there is no previously specific study on C. gigas done in that area. In order to investigate the density of pacific oysters in the Isefjord, and to estimate whether C. gigas has become an invasive species or not, three locations in the Inner Broad of the Isefjord were chosen as study sites: Sømine station, Ejby Harbor, and Munkholm Bridge. The oysters that have been collected from these locations are considered from one metapopulation, and the overall density is calculated as 0.03±0.03 ind. m-2. Besides, relationships between density, dry and wet (meat) weight, shell length, age class, as well as growth rate were analyzed and compared with some other studies in the world. It is believed that C. gigas has no pronounced threat as an invasive species to the ecosystem in the Isefjord yet. However, if temperatures in summer are continually optimal for reproduction of pacific oysters, there is possibility that C. gigas will expand much further, even accumulate as oyster reefs.

UddannelserMiljøbiologi, (Bachelor/kandidatuddannelse) Bachelor el. kandidat
Udgivelsesdato1 jun. 2007
VejledereBenni Winding Hansen


  • Pacific oyster
  • Isefjord
  • Crassostrea gigas
  • invasive species