An attempt to improve wildlife diversity at a wind farm in the North Sea has failed as 85% of oysters introduced there have died, reports the Volkskrant.

Eight months after two environmental groups introduced the creatures to try to improve the quality of underwater life at the Luchterduinen wind farm, most of the 600 oysters have perished.

The animals are thought to improve water quality and attract other wildlife, and the pilot study did however find that the 15% of remaining oysters had a positive effect.

A visit on Tuesday was supposed to introduce various stones to see which ones the creatures preferred, but the researchers have instead gone back to the drawing board, according to the Volkskrant.

A consortium, including scientists, Van Oord wind park company and the ASN bank hope to launch another trial within several months, planting the colonies further away from the seabed.