Mulberry Whelk Morula marginalba
The Mulberry Whelk is a very easily identified shell with its spiral rows of heavy, rounded nodules, which give this shell its very distinctive "mulberry" appearance.
The shell is whitish-grey with very dark purple to black coloured tubercles, adding to its "mulberry-like" appearance. The outer lip yellowish. Deep inside the shell is blue-white, with a white columella.
The Mulberry Whelk ranges from central Queensland to southern New South Wales.
It is abundant at most levels of of a rocky ocean shore, being especially so near limpets and surf-barnacles, upon which it preys.
It also is common in estuaries, where it preys on oysters. Here it is known as the Black Oyster Borer and is a hated pest of Oyster Farmers.
Adults shelter in crevices, while juveniles can be found under rock debris.
The Mulberry Whelk, or Black Oyster Borer preys constantly on other molluscs and barnacles.
It is able to bore a neat hole into their shell, and use its rasping tongue which is called a radula to cut up the animal and suck out the pieces. I measured one medium-sized Mulberry Whelk's radula at 8 cm long.
It is believed that the Mulberry Whelk is able to use a sulphuric acid from its salivary glands to dissolve and bore its way through the prey's limy shell. It is believed that this may only take two high tides.
Bennett, I. (1987) W.J. Dakin's classic study: Australian Seashores. p. 291, Angus & Robertson, Sydney.
Davey, K. (1998) A Photographic Guide to Seashore Life of Australia. p.114, New Holland, Sydney.
Edgar, G.J. (1997) Australian Marine Life: the plants and animals of temperate waters. p.259, Reed Books, Kew.
Quinn, G.P., Wescott, G.C. & Synnot, R.N. (1992) Life on the Rocky Shores of South-Eastern Australia: an illustrated field guide. p.50, Victorian National Parks Association, Melbourne.
Underwood, A.J. & Chapman, M.G. (1993) Seashores: a beachcomber's guide. p.42, New South Wales University Press, Sydney.
Wilson, B.R. & Gillett, K. (1979) A field guide to Australian Shells: Prosobranch Gastropods. p.156, A.H. & A.W. Reed, Sydney