Shark of New Zealand with spots and specific behavioral patterns

The Spotted Estuary smoothhound or Rig (Mustelus lenticulatus) is a shark belonging to the family Triakidae, found on the continental shelves and in estuaries around New Zealand. There are five breeding stocks known. It is closely related to the Gummy shark (Mustelus antarcticus) of Australia. It is a species that schools and segregates by size and sex.


Family: Triakidae – Houndsharks

Genus: Mustelus 

Species: lenticulatus


Phylum– Chordata

Class– Chondrichthyles


Common NameGround Sharks

Family– Triakidae

Common NameHoundsharks




Average Size and Length: They are born between 20-32 cm/7.8 inches-1 foot. Mature males are between 78-89 cm/2.5-2.9 feet and mature females between 79-113 cm/2.6-3.7 feet. The maximum recorded for a male is 126 cm/ 4 feet, and for a female 151 cm/5 feet.

Teeth and Jaw: It has long upper labial furrows. The teeth are pavement like.

Head: It has fairly large, wideset eyes and widely spaced nostrils.

Demographic, Distribution, Habitat, Environment and Range: The Spotted Estuary smoothhound or Rig can be found in New Zealand. There are five breeding stocks. It can be found on the insular shelf in cold, temperate waters, close inshore to 722 feet, but deeper in the wintertime. It is the only shark from its genus within its range. They are considered demersal.

Diet: They primarily eat crustaceans, crabs in particular.

Aesthetic Identification: The Spotted Estuary smoothhound or Rig is a large shark that is grey-brown dorsally, and lighter ventrally. It is white spotted. The dorsal fin margins are unfrayed. It has relatively large pectoral and pelvic fins.

Biology and Reproduction: They are ovoviviparous, having 2-23 pups per litter. The litter size increases with the size of the female. The gestation period is 11 months. These sharks are fast growing, and are mature between 5-8 years, and they live to be at least 15 years of age.

Behavioral Traits, Sensing and Intelligence: The Spotted Estuary smoothhound or Rig is a schooling species. The move inshore for summer feeding and for their mating grounds. They are segregated by size and by sex. The immature schools are separate from the large, single-sex schools. Females migrate further than the male sharks.

Spotted Estuary Smoothhound or Rig Future and Conservation: They are currently of least concern. They are abundant and are commercially fished. Stocks have been rebuilt since fishing quotas were introduced. In June 2018 the New Zealand Department of Conservation classified the Spotted Estuary smoothhound as “Not Threatened” with the qualifier “Conservation Dependent” under the New Zealand Threat Classification System.

Spotted Estuary Smoothhound or Rig Recorded Attacks on Humans: Not a threat to humans.