Marteilia maurini, M. refringens, M. sydneyi

Marteiliosis is a disease of shellfish. Mostly it infects rock oysters, but it can also infect mussels.

Why is marteiliosis a problem for New Zealand?

This disease can kill nearly all oysters it infects. If it got here, it could devastate our oyster populations.

How could it get here?

This disease infects bivalves. Bivalves are shellfish with 2 shells, like oysters. A shellfish infected with marteiliosis could hitchhike to New Zealand on a boat hull.

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

Where will I find it?

Marteiliosis can infect a range of bivalve species but is most likely to infect oysters.

How to identify marteiliosis

This disease looks like many other shellfish diseases.

Creamy coloured healthy oyster. Sick oyster with yellow, watery body.

Left: Healthy oyster. Right: Sick oyster with yellow, watery body. Image: R Adlard/DAWR

Healthy mussel with firmer body. Sick mussel with watery body.
Left: Healthy mussel. Right: Sick mussel with watery body. Image: Anders Alfjorden/SVA

If you find any diseased oysters

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

Find out more

Note: This information is a summary of this disease's potential impacts on New Zealand.

Last reviewed: