Parasite in oysters

A parasite is an organism which feeds on the oyster and finally kills it. The parasite, Bonamia ostreae, has been found in farmed oysters in Big Glory Bay, Stewart Island. There are 3 oyster farms in this area with millions of oysters. They will all be removed in the hope that the parasite will not spread to the wild Bluff oysters.

Farmed oysters in the Marlborough Sounds will also be removed. There are 10 marine farms there which grow mussels as well as flat oysters. The Ministry for Primary Industries, MPI, says that all must be removed because of the risk of the parasite travelling through sea currents to Stewart Island. Movement of boats and equipment will be restricted. This area had the parasite in 2015 and it has come back again.

Any shell fish which are big enough can be sold because they are still safe to eat but most are too small. The owners will look for compensation from the government.

This parasite has wiped out oyster farms in France and Ireland.

A related parasite, Bonamia exitiosa, wiped out 1.5 billion wild Bluff oysters in 2001 and 2002. For oyster lovers, Bluff oysters are the best.


• marine (adj) – related to the sea
• Primary Industries – products we grow e.g. meat, fruit, fish (secondary industries are manufactured)
• sea currents – movement of the water, usually in the same direction
• compensation (n) – money to help cover the loss
• wiped out (phrasal verb) –completely destroyed, all gone


  1. I often use your listenings for my students and they are so useful. I love them so keep up your great work-
    Kind Regards
    Helen Lord

  2. Thank you Helen for that feedback.

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