Rig sharks



Recent research by NIWA confirms the long-held belief that Porirua Harbour is an important nursery for rig, the species that forms the backbone of the fish and chip industry in New Zealand. Rig, known to science as Mustelus lenticulatus and to the fish trade as lemon fish, is a common member of the shark family, found in relatively shallow inshore waters. With a maximum length of 1.5 metres, it is dwarfed by the 3 to 4-metre mako and bronze whaler and by the 7-metre great white shark. It is of no danger to swimmers.


Rig breed successfully only in harbours and sheltered inlets of the North Isalnd. Porirua Harbour is one of these. While not as important as Kaipara and Raglan harbours, Porirua is now known to be of high value as a nursery for first and second year fish.


Rig are caught in commercial quantities all around New Zealand. Although they are landed throughout the year, the largest catches are made between October and March.


Rig grow rapidly, reaching maturity at between five and eight years, and live to at least 15. It is the females that migrate into the shallow harbours, where they give birth to an average of 11 live young each year. Males are seldom found in these areas.




Genetic studies tell us that all rig belong to one common stock and that females do not return to their own place of birth to deliver their young.


Thus rig found in the South Island must have migrated there from the north during their early years.


We are proud that the Inlet is helping to sustain the mainland's fish trade.




Last Updated: 14/12/2015 12:00am