A Whangārei fisherman and diver who regularly visits the Bay of Islands says all Northlanders who live, work or play around its moana should be contributing to make sure the new invasive seaweed caulerpa doesn’t spread.

Jason Kena (Ngāti Whātua) regularly heads from Whangārei to the Bay of Islands for fishing or diving.

He said it is up to everybody to do their bit as kaitiaki of the moana, which is essential to the people of Te Tai Tokerau and their way of life.

“We value our ocean, we value our kaimoana. We are the kaitiaki of our ocean. Everybody needs to get on board,” Kena said.

Kena and his mates went rock fishing at Rawhiti over King’s Birthday weekend. They were greeted at the end of Rawhiti Rd by kuia Whaea Crystal, one of the mana whenua ambassadors raising awareness of caulerpa via handing out Government Biosecurity New Zealand/Northland Regional Council pamphlets about the pest. The fishermen were asked to notify hapū if they saw caulerpa.

The men’s visit came not long before the start of the Government and mana whenua Bay of Islands moana fishing, diving and anchoring ban and rāhui started on Monday (June 12). They were fishing outside the future CAN zone.

“It was great to see kuia and kaumātua handing out pamphlets. They’re doing their bit for their ropu,” Kena said.

He said caulerpa was an issue for the east coast of the North, but people from the west coast of Te Tai Tokerau also had to contribute to looking after the east.

“Plenty of people go from the west coast to the east coast to fish, it’s what they do,” Kena said.

The Government and mana whenua ban across more than 1000 hectares was gobsmacking, Kena said.

“What’s scary about this stuff is how fast it spreads. We don’t want to be in a situation in 10 years where we have no kai, no fish, no seafood,” Kena said.

A fragment of caulerpa the size of a freckle can grow to cover an area the size of a rugby field in the right conditions.

He and his mates did not see caulerpa where they were fishing.

Meanwhile, Spearfishing New Zealand spokesman Graeme Heapy from Ōpua said caulerpa in the Bay of Islands was of concern.

“I am very concerned about any invader that looks like it might destroy the environment coming into our area,” Heapy said.

Heapy organised the New Zealand Spearfishing Nationals in the North over King’s Birthday weekend.

He said there were almost 65 divers from around New Zealand who took part in the three-day event. Boats departed Waitangi daily for spearfishing around the Cavalli Islands and Cape Brett.

Participants had been asked to keep an eye out for caulerpa, but none had been found by the divers.

NRC biodiversity and biosecurity working party chair Geoff Crawford is a New Zealand representative spearfisherman, who had been due to participate in the tournament but was unable to. Crawford instead contributed to the tournament’s caulerpa awareness.

Heapy said caulerpa was a topic of conversation among the spearfishing and fishing community, but most people knew little about the invasive weed, having never seen it in real life.

Meanwhile, another just-ended fishing competition, the 100 anglers participating in the four-day Bay of Islands Swordfish Club annual light tackle tournament that finished on Wednesday, also had a caulerpa awareness briefing, Heapy said.

The 32 boats used by the anglers departed from Russell wharf daily to fish, also around the Cavalli Islands and Cape Brett.

Heapy, a fisherman, spearfisherman and diver who took part in the competition, said the boats taking part did not anchor, but drift fished using live baits.

Participants in both competitions did not use the eastern Bay of Islands Omākiwi and CAN zone for their events, so caulerpa was not much of a concern to them in that sense, he said.

Ōpua Cruising Club commodore Ian Templeman was not overly concerned about caulerpa in the Bay of Islands.

“We’re aware of its arrival and we’ll watch the situation,” Templeman said.

He said the club had not received educational material about caulerpa from the Ministry for Primary Industries or others.

“I’m sure if it’s something we should be really worried about we would have been bombarded with material,” Templeman said.

He said caulerpa would not significantly affect Ōpua Cruising Club members, who were more into racing.

“The people who will be affected are the Bay of Islands people who like pottering to anchorages.”

He said there had been previous situations with biosecurity problems that were meant to have closed down the world. Fanworm had arrived about eight years ago but had not turned out to be the problem it had been promoted as. Covid-19 had arrived “but we were all still alive”.

“I suspect we will survive caulerpa.”

■ Local Democracy Reporting is Public Interest Journalism funded through NZ On Air