Mikrocystos mackini 

Mikrocytosis is a disease of many oyster species. It's sometimes referred to as Denman Island disease.

Why mikrocytosis is a problem for New Zealand

This disease kills many of the oysters it infects, reducing oyster populations. If it came to New Zealand, mikrocytosis could harm our recreational and commercial oyster catches.

How could it get here?

An oyster with mikrocytosis could hitchhike to New Zealand on a boat's hull.

Even if you don't travel overseas, keeping your boat hull clean can stop pests and diseases spreading.

When is it a problem?

The disease develops over winter. Symptoms and oyster deaths usually start in the spring.

How to identify mikrocytosis

This disease looks like many other shellfish diseases, so if you find any diseased oysters:

  • take a photo
  • collect a sample
  • record the location and landmarks
  • call MPI on 0800 80 99 66
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