A prominent Bluff oysterman says MPI should have put in security measures straight away when they found a parasite amongst oysters - not let everyone know a week later.

A parasite called bonamia has been found on two oyster farms in Stewart Island that is threatening to eradicate Bluff oysters altogether.

Willie Calder has been in the game for 43 years, and his family have been doing this since the mid 1800's, but he says it could be the end of his business if they aren't lucky.

Mr Calder said a no-movement rule needs to be enforced on fishing boats in the area because right now they are driving through beds and endangering the species, and MPI have done nothing.

"It's like Russian Roulette for us. Every day they go across there's the chance the particles get in the water and once it gets into our oysters it will spread like anything. That will be the end of us.

"It's just so irresponsible. It's incredible that MPI let that happen. Where is bio-security? Is it just left on land, or what? It's just hard to believe.

"There's no wild oyster fishery left anywhere in the world, so we're the last one left. If this parasite got into our oysters it'd probably just wipe us out."

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