Tipa variability and enhancement in Tai Tokerau

 The problem

The Tai Tokerau tipa (scallop) fishery SCA1 is highly valued by commercial, recreational and customary fishers. However, the growth and recruitment of scallops is variable resulting, in a somewhat unpredictable fishery.

More information on the Scallop Northland scallop fishery (SCA1) 

This unpredictability is clearly visible in SCA1 - also referred to as the Northland scallop commercial fishery - where the last 15 years have seen major variation in both the overall catch, and the location within the fishery where this catch has been taken.

Successful enhancement measures (as in the Coromandel scallop fishery) could potentially convert the Tai Tokerau scallop industry into a larger more consistent fishery for the benefit of both commercial and customary fishers.

The solution

NIWA, in association with the Northland Scallop Enhancement Company, is looking into the variability of scallop spat recruitment at selected sites in Tai Tokerau.  The aim is to develop enhancement measures, potentially based on mātauranga Māori, to improve the survival of juvenile scallops within Tai Tokerau.

There are three key elements to this research:

• investigate and consolidate mātauranga Māori pertaining to scallop management and enhancement in Tai Tokerau
• investigate spatial and temporal distribution of scallop seed settlement
• develop scallop spat enhancement methods and demonstrate effectiveness on a pilot scale.

The result

Previous studies have shown that scallop spat distribution varies both spatially and temporally (within and between years). Although scallops are known to spawn more than once per year, the Christmas spawning event is considered to be the most important and reliable, and is the event targeted in this project.

Larval scallop settlement collectors have been deployed at four key locations in Tai Tokerau:

• Rangaunu Bay
• Doubtless Bay
• Whangaroa environs
• Bream Bay.

Broad-scale scallop settlement will be monitored over two to three years, enabling an identification of where spat are present consistently from year to year, as well as helping to identify factors that influence spat variability in Tai Tokerau.

A draft report investigating the traditional Māori utilisation and management of tipa in Tai Tokerau has been completed by Mr Mike Stevens of Taiaho Limited (Kaikohe) and distributed to Māori stakeholders for review. This report collated relevant information from three key sources, including:

• archaeological data and analyses
• ethnographic and historical reports
• interviews/discussions with Māori from Tai tokerau and elsewhere.