Waikato Regional Council will again be engaging a dive team to survey coastal marine areas around the Coromandel Peninsula to determine the presence and extent of marine pest species.

This biosecurity surveillance work, which will particularly target Mediterranean fanworm (Sabella spallanzanii) and clubbed tunicate, will be undertaken in 2021/2022 and 2022/2023.

Marine pests are species that are not native to New Zealand, but which may be introduced by human activities and harm the natural environment and resources. Marine pests

• pose a major threat to the ecological, cultural, economic and recreational values of the marine environment
• can out-compete, smother, predate on or otherwise adversely affect native species and habitats
• are extremely difficult and costly to eradicate or contain, once established – prevention is far more effective
• are mostly introduced to coastal marine areas by ‘hitchhiking’ on incoming vessels and can be spread via domestic vessel movements, or ‘pathways’.

Marine pests are mainly spread by heavily fouled vessel hulls so the dive team will target pathways of boats and check vessels, marine structures (marinas, wharves, jetties and moorings), popular anchoring spots and mussel and oyster farms. If infested vessels are found, owners may be requested to remove and antifoul them.

Previous surveys have shown the eastern side of the Coromandel to be free of marine pests, however, the west coast of the peninsula is not so good.

The natural spread of Mediterranean fanworm is continuing up the coast from the Coromandel Harbour. At the time of the last survey, in 2018/19, the fanworm was found as far north as Colville, up from Papa Aroha in the previous two years.

The council regularly checks for marine pests to see how much of a problem they are. Please help prevent their spread: make sure your hull has been checked, cleaned and antifouled before heading away.

Don’t know what a marine pest is? Check out marinepests.nz for some of the pests we look out for.

Caulerpa – Great Barrier Island 2021 biosecurity response

Plan to visit Aotea Great Barrier Island this summer?

Biosecurity New Zealand has placed a controlled area notice (CAN) on Blind Bay, Tryphena Harbour and Whangaparapara Harbour to minimise the spread of Caulerpa brachypus, a seaweed native to the Indo-Pacific region and which was discovered for the first time in New Zealand in August 2021. Ngāti Rehua Ngāti Wai ki Aotea has imposed a rāhui on the same areas, and both the CAN and rāhui are in place until 30 June 2022.

The controls make it illegal to take any marine life (fish, shellfish, crays, seaweed) from the three affected harbours. If you anchor in those areas, you must have a permit from Biosecurity New Zealand to move on.

Caulerpa can be spread by fragments being carried by coastal currents. Caulerpa can break into little pieces by wave action or when anchors and fishing gear are moved into or through weed beds. Pieces can get tangled in or stuck on equipment (for example, nets, dive and fishing gear, and cray pots). Caulerpa can survive out of water for up to a week or more if it's in a moist location (like in an anchor locker or a bunched-up fishing net).

To find out more about Biosecurity New Zealand’s Caulerpa response and what the CAN and rāhui mean for recreational water users, click here.

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