E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Ceratostoma inornatum (Rècluz, 1851)
Asian Drill; Japanese Oyster Borer; Japanese Oyster Drill; Japanese Rocksnail
Family: Muricidae
Photo of species

© Aaron Baldwin  Email the photographer   (Photo ID #2340)

E-Fauna BC Static Map
Distribution of Ceratostoma inornatum in British Columbia
Details about map content are available here.


The Japanese Oyster Drill is an introduced species in British Columbia that originates in Asia: Japan, and Korea (Global Invasive Species Database 2011). It arrived here with Japanese Oyster seed and was reported as abundant in Ladysmith Harbour and Boundary Bay by 1958 by Carl and Guiget (1958). It is an invasive species that destroys populations of oysters, particularly that of Crassostrea gigas (Global Invasive Species Database 2011).

"Ceratostoma inornatum tends to feed on young oysters such as Crassostrea gigas (Ray, 2005). C. inornatus uses its radular which acts as the drill, and "it secretes digestive enzymes into the hole, through which the snail sucks up the partially liquefied flesh." It eats about 3 oysters per week (Global Invasive Species Database 2011).

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Ocenebra inornata (Recluz, 1851)
Ocenebra japonica (Dunker, 1869)
Ocinebrellus inornatus (Récluz, 1851)
Pteropurpura inornata (Récluz, 1851)

Additional Range and Status Information Links

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-02-22 8:55:23 PM]
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