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seagrass lagoon

Whelk
Nassarius sp.
Family Nassariidae

Whelks are common little snails in the seagrass lagoon.

Whelk Food: Whelks are active scavengers and often seen busily foraging in pools at the change of the tides. When not foraging, whelks hide in the sand.

These active snails are quite amusing to watch. The snail waves its siphon about to detect chemicals released by dead animals. The siphon is extended out of a little notch in the tip of the shell. The siphon of a whelk can be as long as its body! A choice morsel such as a dead crab is a magnet for these snails which hurry as fast as they can to the feast. They have been described as "extremely bold and agile". Their operculum is small, has a serrated edge and is made of a horny-like material.

Most whelks live in shallow waters, often in large groups. They are sometimes also called Nassa mud snails or Dog whelks.

Role in the habitat: Often, a tiny sea anemone hitches a ride on the shell of a whelk! The anemone probably benefits from the whelk's left overs, and avoids being permanently buried in the sediments. It is not certain if the whelk gets anything in return.

A pair of whelks
playing tag?

Olive whelk
Nassarius olivaceus

quick facts
About 2cm long, common in the seagrass lagoon

Classification:
Class Gastropoda
Phylum Mollusca

See also ...
Molluscs in general
Gastropods in general

Links
Nassariidae on The Gladys Archerd Shell Collection at Washington State University Tri-Cities Natural History Museum website: brief fact sheet on whelks with photos
Australian Shells by Patty Jensen on the Capricornica Publications Natural History Books website: an on-line identification source with brief fact sheet on whelks

Other references

Tan, Leo W. H. & Ng, Peter K. L., 1988, A Guide to Seashore Life. The Singapore Science Centre, Singapore. 160 pp. online version
Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
Ng, Peter K. L. & N. Sivasothi, 1999. A Guide to the Mangroves of Singapore II (Animal Diversity). Singapore Science Centre. 168 pp. online version
Woodward, Fred, 1993. Identifying Shells. The Apple Press, London. 80 pp.
Harasewych, M.G., 1991 edition. Shells: Jewels from the Sea. Courage Books, USA. 224 pp.

a companion website to the chek jawa guidebook website©ria tan 2003 www.wildsingapore.com

a companion website to the chek jawa guidebook
website©ria tan 2003 www.wildsingapore.com