Oyster drill

Ceratostoma inornatum and Urosalpinx cinerea


Photo credit: ©Marco Faasse
  • Found on the lower shore and sublittoral to a depth of about 12 m, feeding especially on oysters.

  • Ceratostoma inornatum (Asian oyster drill) has a narrow and elongated physiology. It is around 2.5cm (1 inch). The radula is the band of teeth that acts as a "drill" to penetrate the shells of oysters.
  • Urosalpinx cinerea (American oyster drill) has a grey or yellowy straight shell, up to 2.5cm (1 inch) long. There may be some brown banding present. It uses its radula and chemicals from a boring organ to break into oysters.

Origin and Distribution:
  • The Asian oyster drill is native to Japan and the Republic of Korea. It is now known from France and has also spread to North America.
  • The American oyster drill is native to the east coast of the USA. It is now present on the south coast of England.

  • Urosalpinx cinerea and Ceratostoma inornatum predate on native and commercial oyster beds. They feed by boring through oyster shells.
  • These species can cause a 25% reduction in oyster farm production.

How might it get here?
  • Contamination of aquaculture seed stock and equipment.

Is it found in Ireland or Northern Ireland?
  • It is not present in Ireland or Northern Ireland.

Prevent Spread:
  • Promotion of native species and biodiversity.
  • Ensure compliance with the ICES Code of Practice on the Introductions and Transfers of Marine Organisms 2005.
  • Inspect – remove – dispose – Report.
  • Audit your activities.
  • Ensure biofouling control on aquaculture equipment.
  • Prevent fouling of vessels and mooring lines.
  • Always remove fouling prior to long distance journeys.
  • Remove unused equipment and stock.
  • Report all sightings.

You can help by reporting any sightings:
Invasive Species Ireland

Invasive Species Ireland