Real-life story: boat owner discovers new caulerpa location
Before Auckland boat owner Ben Tothill set sail to the Bay of Islands this February, he made sure that he was armed with everything he needed to know about exotic caulerpa: He downloaded info to his device, familiarised himself with how it looked on the MPI website, and made sure to only anchor in safe locations.
The Bay of Islands is a popular cruising destination. This photo is taken from the Cape Brett walk, outside of the known caulerpa locations. Photo / Zoe Hawkins
This meant he was surprised - and worried - when he pulled up a substantial amount of seaweed that looked like it could be exotic caulerpa in Paradise Bay at Urupukapuka.
“Paradise Bay is a safe anchorage, and we anchored one night,” he recounts. “In the morning a good chunk of weed came up on the chain. It looked very like the images of caulerpa that had been on the MPI website, but as it came up it rolled off and fell in the water, so I couldn’t get a photo. I was concerned so filed a report online which was easy to do. I knew it wasn’t good.”
Within days, the report had been followed up by divers and confirmed to be exotic caulerpa; likely a range expansion of the nearby population in Omakiwi Cove.
Previous surveillance in the wider area had not revealed any exotic caulerpa, and authorities are now working with local groups to try to determine the extent of the seaweed’s spread and ensure the most effective response.
Ben says that his boat is equipped with an electric winch but that like most boat owners, he stands at the bow while the anchor is being lifted - which means he can quickly spot anything that shouldn’t be on his anchor and chain. “Most boaties are aware of what is on their anchor and chain, and they don’t generally pull up weed but my chain collected it from the ocean floor.”
More information:
For more information on exotic caulerpa in Northland click here.
Subscribe to the exotic caulerpa newsletter from Biosecurity New Zealand here.
Above images: how exotic caulerpa can look when pulled up on an anchor. Photos / Louise Clarke