The exotic caulerpa threat to Auckland coastlines
Exotic caulerpa is the name for two species of fast-spreading seaweeds that can grow rapidly, smothering our sea-beds. It can also affect fishing, boating, and cultural activities, making it a serious concern for everyone who enjoys the ocean. We need to stop it spreading to new locations.
Why exotic caulerpa is a problem
Exotic caulerpa is spreading fast, covering over 1,500 hectares of the upper North Island seabed (as of August 2024). In some areas, it forms thick carpets, while in others, it’s more spread out. This fast-growing seaweed takes over space, pushing out native species and upsetting the balance of local marine ecosystems. It can also affect fishing, boating, and cultural activities, making it a serious concern for everyone who enjoys the ocean.
Main photo credit: NIWA
Know where you can go
We know that this pest gets spread over long distances on vessels and equipment. It’s been found around the Hauraki Gulf in popular anchorage locations. You may need to avoid seafloor disturbance or clean anchors and equipment before you move.
For the latest updates and affected areas, visit Biosecurity New Zealand.
How to identify exotic caulerpa
There are a number of common seaweeds that appear similar to exotic caulerpa which is a green seaweed with leaves up to 10cm long and long runners with roots. Unlike similar species, it has distinctive ‘oar shaped’ leaves.
Learn more on the Biosecurity NZ website.
Help stop the spread
Ensure your boat and gear are free of seaweed before moving to a new location. Follow the legal rules in areas affected by caulerpa. Report any sightings of exotic caulerpa - take a photo, record the location, and report it to MPI on 0800 80 99 66.
Read more on OurAuckland.
Help protect our marine environment.
Boaties, fishers, and beachgoers can all play a part in slowing the spread of caulerpa.
Here’s how you can help:
- Anchor and fish with care – Avoid anchoring or disturbing the seafloor in infested areas. Anchors and chains can break caulerpa into pieces, spreading it further.
- Check and clean your gear – Before moving to a new spot, remove any seaweed from anchors, fishing gear, dive equipment, and other gear.
- Bag it, bin it, or put it back – If you find caulerpa, bag and bin it properly. If that’s not possible, return it to where it came from—never move it elsewhere.
- Report new sightings – If you see unusual seaweed in a new area, take a photo, note the location, and call MPI on 0800 80 99 66.
- Follow local rules – Controlled Area Notices (CANs) are in place to protect marine life. Avoid affected areas whenever possible.
By working together, we can help stop caulerpa from spreading in the Hauraki Gulf, Bay of Islands, Coromandel, and beyond.
Photo credit: NIWA
Read more
Boaties' guide to the exotic caulerpa rules in Auckland
Exotic caulerpa can travel quickly over long distances on vessels and equipment, and that’s why it’s been found around the Bay of Islands, Hauraki Gulf and parts of the Coromandel in popular anchorage locations.
Caulerpa threat: boaties urged to help stop the spread this summer
Boaties heading out on the water this summer are being urged to take extra care to prevent the spread of exotic caulerpa.
Successful ‘lighting strike’ on invasive Caulerpa seaweed
A bright light is proving effective for killing Caulerpa seaweed, which is a rapidly spreading invasive seaweed in northeastern New Zealand.
Understanding exotic caulerpa around Aotea
Recent exotic caulerpa surveillance around Aotea gives insight into the extent of the pest seaweed.
Two new sites of exotic caulerpa confirmed in the Hauraki Gulf
As announced by MPI, exotic caulerpa has recently been confirmed at two new locations – the Mokohinau Islands and Rakino Island.
Suction dredge to combat exotic caulerpa on Aotea Great Barrier and Kawau islands
As part of MPI’s accelerated caulerpa response programme, Auckland Council is enhancing its biosecurity response in the Hauraki Gulf.
Caulerpa update shows active response
A new report shows the work being done to respond to invasive marine pest, exotic Caulerpa.
Hope in battle against exotic caulerpa following Govt’s $5 m injection
The government has announced a $5 million injection of funding to go towards the fight against exotic caulerpa.
