Invasion History

First Non-native North American Tidal Record:
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Bullia rhodostoma is a sand-dwelling whelk, native to the coast of South Africa, from Cape Town (Atlantic Ocean) to the border of Mozambique (Indian Ocean) (Branch et al. 2007; Academy of Natural Sciences of Philadelphia 2006-2013). One dead specimen was collected in San Francisco Bay in 1966 (Carlton 1979). We know of no further records from this area or of any introductions to other locations.

North American Invasion History:

Invasion History on the West Coast:

A specimen of Bullia rhodostoma was found in dredged mud from a lagoon in Alameda, California in 1966. It was 37 mm in size, with its body and operculum intact. There are no further records from California or elsewhere. This species has direct development from egg capsules (Branch et al. 2007), so ballast water transport is unlikely. Aquarium transport is possible, but the vector of introduction is unknown.


Bullia rhodostoma is a sand-dwelling whelk, with an elongate, elliptical-conical shell. It is dextrally coiled, with a long pointed spire, and typically 7-8 whorls. The operculum has smooth margins. The shell is cream-colored, with a narrow, oval, orange aperture. The living animal has a large flat foot. The shell reaches 55 mm in length (Branch et al. 2007).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Subclass:   Prosobranchia
Order:   Neogastropoda
Family:   Nassariidae
Genus:   Bullia
Species:   rhodostoma


Potentially Misidentified Species

Bullia digitalis
Native to South Africa

Bullia pura
Native to South Africa



Bullia rhodostoma, the Smooth Plough Shell, lives in the intertidal zone of sandy, wave-swept beaches. Sexes are separate and eggs are laid in oblong capsules, which are buried in the sand. Development is direct (McGwynne and Van der Horst 1985; Branch et al. 2007). These snails characteristically use their large feet to ‘surf’ up and down beaches, and crawl on the sand, using a 'rowing' motion. They feed on stranded carrion (Branch et al. 2007).




Birds, fishes, crabs

Trophic Status:




General HabitatUnstructured BottomNone
Tidal RangeLow IntertidalNone
Tidal RangeMid IntertidalNone

Tolerances and Life History Parameters

Broad Temperature RangeNoneWarm-temperate
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Only one specimen of Bullia rhodostoma is known from outside its native range and no impacts have been reported.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
WA-V None 0 Native Estab
NEP-V Northern California to Mid Channel Islands 1966 Def Failed
P090 San Francisco Bay 1966 Def Failed
WA-IV None 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Academy of Natural Sciences of Philadelphia 2006-2014b OBIS Indo-Pacific Molluscan Database. <missing URL>

Branch, G. M.; Griffiths, C. L.; Branch M. L.; Beckley, L. E. (2007) <missing title>, Strulk Publishers, Cape Town, South Africa. Pp. <missing location>

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

McGwynne, L. E.; Van der Horst, G. (1985) Patterns of reproduction in three sandy-beach whelks, Journal of Molluscan Studies 51: 190-197