Stopping the spread of marine pests in the Marlborough Sounds

Invasive marine pests are a threat to the biodiversity and coastal environment of the Marlborough Sounds. Invasive marine species can fall into two categories: fouling species (such as the clubbed tunicate Styela clava and Mediterranean fanworm) and exotic diseases (such as Bonamia ostrae) that can infect fish or shellfish.

Managing marine pests are far more complex than terrestrial pest species given the nature of the marine environment, and at the marinas we do our part by ensuring all visiting or new vessels adhere to the 6 or 1 rule. This requires all visiting boats to have been antifouled in the last six months, or lifted and washed in the last month. If you are visiting from a high-risk location, we may make extra checks. Please take photos of your boat before it goes back in the water, and keep receipts from your haul-out or maintenance contractors as evidence.

While as far as we know the Marlborough Sounds is free of the main marine pests like Mediterranean fanworm, we can never be 100% sure. We ask all of our customers to please take precautions when on the move this summer. Make sure your boat is well antifouled to manufacturer’s specifications, and check the hard-to-reach spots like keelbulbs, props and water intakes carefully.

For new and returning customers, arrival in our regional waters, your vessel must have no more than light fouling (unless exempt). Light fouling means 1–5% of visible hull surface covered by macrofouling or filamentous algae. Usually, the remaining area is covered in slime. Read the local rules in more detail here

Photos: Juvenille fanworm and fanworm growing on boat hulls. If you see Mediterranean fanworm in the Marlborough Sounds, please report it urgently to Marlborough District Council using this link.   Photo credit / G Read, Lyttleton and Hamish Lass / Bay of Plenty Regional Council

And while the Northern regions are combating an invasive seaweed called exotic caulerpa, we are fortunate it hasn’t made its way down here so far. Please take a moment to familiarise yourself with what exotic caulerpa looks like, and in the unlikely event you see some, report it to MPI urgently.  Good practice in the meantime is to check your anchor, chain, dive gear and fishing gear every time, before you change locations. If you find something that might be caulerpa, don’t put it back in the sea – dispose of it onshore in the rubbish bin.

For more information:

Marlborough District Council

Top of the South Marine Biosecurity Partnership – the boaties guide to marine biosecurity

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