Spotted estuary smooth-hound

The spotted estuary smooth-hound or rig (Mustelus lenticulatus) is a houndshark of the family Triakidae, found on the continental shelves and in estuaries around New Zealand.^[2] It is closely related to the gummy shark (Mustelus antarcticus) of Australia.^[3] Males can grow up to a length of 125 cm (49 in), while females can reach a length of 151 cm (59 in).^[2] In 2025, rigs were found to be the first known sharks capable of sound production, namely, "clicks."^[4]

Spotted estuary smooth-hound
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Division:	Selachii
Order:	Carcharhiniformes
Family:	Triakidae
Genus:	Mustelus
Species:	M. lenticulatus
Binomial name
Mustelus lenticulatus Phillipps, 1932

• Sharks portal

It is commercially fished, and is commonly served in fish and chip shops in New Zealand under the name "lemonfish".^[5] In June 2018 the New Zealand Department of Conservation classified the spotted estuary smooth-hound as "not threatened" with the qualifier "conservation dependent" under the New Zealand Threat Classification System.^[6]