Protecting our Happy Place
For many of us, the sea is our happy place. A day out with family or mates, getting some kai, or whatever gets us out in a boat – among waves and fresh air. That’s our marine paradise.
But this is threatened by invasive marine pests, like exotic caulerpa or Mediterranean fanworm, that cause harm when they get established somewhere new.
Two Types of Risk
Over the years, there’s been a lot of talk about hull fouling. If you have a moored boat, that’s still something you need to manage to keep your boat moving well and avoid moving around fouling species like the clubbed tunicate and Mediterranean fanworm.
But the arrival of exotic caulerpa in northern waters is showing there’s another type of threat. This second type of risk is from invasive seaweeds that can spread as fragments. These get snagged on your anchor, anchor chain or any gear that goes down near the seabed, such as fishing or dive gear.
So now boaties with moored boats or trailered boats are being asked: every time before you move during a trip, please check your anchor, anchor chain and gear and flick off seaweeds.
Or, when you’re in or near an exotic caulerpa controlled area – in the Bay of Islands, Hauraki Gulf or off Coromandel, bag any seaweed you find and bin it for disposal back on land. If you can’t do this safely, put the seaweed back in the water in the area it came from.
At the bottom of the South Island, there are special rules in place because of Bonamia, the oyster parasite, or Undaria in Fiordland. So, if you are heading that way, just check the rules before you leave home.
Regular Maintenance
Avoiding biosecurity harm is just another reason to keep up the maintenance of your boat, along with prolonging its life and keeping it functioning well.
For trailer boats, you’re asked to drain the bilge each time you leave the water and then hose the boat down with freshwater when you get home as part of your routine after a trip.
Owners of moored boats are asked to regularly clean the hull and keep it anti-fouled. Take a hint from the experienced boat-owners who make this look really easy, because they’ve worked out the services they need and book them well in time.
Know the Rules
There are a few types of biosecurity rules to keep an eye on – for your own region and for any region you may visit, so you “know before you go”.
Several regions have rules about the level of allowable fouling on a boat. The reality is that the longer you leave it and the more there is on the hull, the harder and more expensive it will be to get off. So it’s a good idea to keep it light, anyway.
Some regions also have rules about in-water cleaning, which makes sense because it matters what happens to the species and materials that come off your boat’s hull.
Regional Marine Biosecurity Rules
Helpful Maps
Maps can really help you with understanding what a problem like the exotic caulerpa means for your trip planning.
Here are three kinds of maps to help boaties:
- Biosecurity New Zealand has worked with the New Zealand Hydrographic Authority to get the Caulerpa restricted areas in northern regions marked up on charts. These should be appearing on commercial navigation products like Navionics.
Map of Exotic Caulerpa affected areas at Great Barrier Island / MPI - Biosecurity New Zealand’s geospatial team has developed a new interactive map, The Biosecurity Map for Boaties, that shows all the restricted areas around New Zealand’s coast and also in rivers and lakes, with key information about what the restrictions are.
- Also, the Auckland Council is running a Community Viewer that shows you both the restricted areas and locations you might want to avoid to stay clear of Caulerpa.
We all need to do our bit to stop these invasive pests from spreading and causing more harm. Let’s keep our favourite boating places pest-free, so we can continue boating in our boating paradise.
For more information: biosecurity.govt.nz/boaties
