Date: 30/09/2020

AUT PACIFIC OYSTER SURVEY - Manukau Harbour takes only 5 mins!

Over the last 50 years much of the coast of the Manukau has become infested with the invasive Pacific oyster (Crassostrea gigas), which was introduced from Asia and became established in the early 1970s. In New Zealand the Pacific oyster has been considered by biosecurity, primary industry, and conservation departments and ministries to be an invasive species. It is a fast growing pest that has quickly replaced the native New Zealand rock oyster. It has no place in the wild, especially on our beaches and intertidal rock platforms, where it forms dense clumps that accumulate mud, changing the character of the rock platforms and beaches.

This marine pest has large, rounded, radial folds which are often extremely rough and sharp, especially when they break up on our beaches, making once very popular swimming beaches unsuitable for swimming due to the risk of cutting feet on the razor sharp oyster shells. They also pose a danger to those engaging in water recreational activities, especially to boats; making channels unusable as they form large clumps along the intertidal shorelines and bars of the Manukau, and even cutting into our dogs paws!

TOES and MHRS have worked with AUT over a number of years in developing a portable oyster crushing machine to grind the oyster shells into a fine sand ensuring that swimmers and other users, including our pets are not cut by these sharp shells.

Similar land based machines have been developed for the Nelson scallop industry where the scallop shells are ground into a fine sand for use in the horticultural industry.

Such a pilot program could be developed into a much larger program for use on the Manukau Harbour to turn the troublesome oyster shells into a fine sand to be used as a sand substitute to refurbish beaches around the Manukau Harbour.

It would be great if you are able to complete the AUT Pacific Oyster Survey to start a long overdue program to return the Harbour to a quality environment. Click the link to fill in the online survey. Thanks

Please feel free to pass the link for the survey on to friends and family who use the Manukau Harbour for recreation.