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Phylum Mollusca > Class Gastropoda > Family Nassariidae
Olive whelk
Nassarius olivaceus
Family Nassariidae
updated Aug 2020

Where seen? This large, handsome whelk is usually seen prowling alone on sandy and muddy areas near seagrasses and mangroves. Commonly seen especially on our Northern shores.

Features: 3-4 cm. Largest of the commonly encountered whelks on our shores. Shell conical, smooth with spiralling ridges. Colour brown to olive green sometimes with a pale spiral around the shell. Body pinkish with dark speckles and dark edge on the foot, very long siphon and short tentacles. Operculum thin, orange. It has been seen burrowing just beneath the sand, with its siphon sticking out.

Changi, Aug 05

Changi, Apr 05

Burrowing just beneath the sand
with siphon sticking out.
Changi, Aug 05
Hitching on a whelk: This whelk is sometimes seen with a large barnacle or two on the shell. Sometime also a tiny sea anemone.

Eating a bristleworm.
Changi, Feb 10

With a tiny sea anemone on the shell.
Kusu Island, Feb 08

Sometimes with large barnacles on the shell.
Changi, Jun 05

Olive whelks on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Punggol, Sep 18
Photo shared by Dayna Cheah on facebook.

Pasir Ris-Loyang, Oct 20
Photo shared by Richard Kuah on facebook.

Changi, Jul 20
Photo shared by Vincent Choo on facebook.

Pulau Ubin, Dec 09
Photo shared by Toh Chay Hoon on flickr.

Tuas, Dec 14
Photo shared by Marcus Ng on facebook.

East Coast Park, May 08
Photo shared by Loh Kok Sheng on his blog.

Berlayar Creek, Oct 15
Photo shared by Marcus Ng on facebook.

St John's Island, Mar 19
Photo shared by Frances Loke on facebook.

Links References
  • Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore (pdf), Lee Kong Chian Natural History Museum, National University of Singapore.
  • Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
  • Abbott, R. Tucker, 1991. Seashells of South East Asia. Graham Brash, Singapore. 145 pp.
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