96 — Knobbed whelk, Austrofusus glans

Austrofusus glans, Waikanae Beeach, 1982.

Austrofusus ?glans. Main Beach, Mt. Maunganui,
2016.

A gradation of Austrofusus cf. chathamensis,
Ocean Beach, Mt. Maunganui.

Austrofusus cf. chathamensis,
Ocean Beach, Mt. Maunganui.

The knobbed whelk, Austrofusus glans (Röding, 1798) is a smallish (~50mm) whelk, endemic to New Zealand and found from the intertidal down to considerable depths (~200–300m). It is very common and the only whelk to be commercially harvested.

They were introduced into New Zealand's quota management system (QMS) in 2006, but as they are a low-value species, they are mostly taken as bycatch in bottom-trawls for other species. A. glans are reported to be scavengers, although data are scant regarding ecological interactions with other species.

The genus Austrofusus has a rich fossil history in New Zealand dating back about 11 million years. But now there are only two extant species: A. glans from mainland New Zealand and A. chathamensis Finlay, 1928, from the Chatham Islands.

Personally, I'm not convinced that A. chathamensis exists, as I have examples from Mt. Maunganui which intergrade between the two forms. I suspect that this is yet another issue to be resolved using molecular techniques. Who knows, I could be completely wrong.











More info:

More pictures: http://www.mollusca.co.nz/speciesdetail.php?speciesid=1068&species=Austrofusus%20glans#prettyPhoto

Fossil history: https://www.gns.cri.nz/static/Mollusca/taxa/BM539.html