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] It is commercially fished, and is commonly served in fish and chip shops in New Zealand under the name "lemonfish".

[4] 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.