4 Oct 2023

Pest gold clam invasion prevention ‘fast-moving’, council official says

5:51 pm on 4 October 2023
Lake Ōkataina has been closed to boats. Photo / Laura Smith

Lake Ōkataina has been closed to boats. Photo: LDR / Laura Smith

Officials are searching Rotorua's Lake Ōkataina amid fears of invasive freshwater gold clams.

The lake is closed for October while security guards are at the lake and a public road was blocked.

It comes after Biosecurity New Zealand closed the lake to boating and fishing throughout October to install protections against the invasive freshwater pests.

Councillors discussed how to protect the region's lakes and why a public road had been blocked, during an infrastructure and environment committee meeting on Wednesday.

Last week, the Ministry for Primary Industries issued a month-long controlled area notice at Lake Ōkataina after locals and iwi Ngāti Tarāwhai raised concerns. Fishing, jet skiing and boating are banned during the closure.

Gold clams have become well-established in the Waikato River. They have multiplied to occupy a 99-kilometre stretch, but had not been found outside of this area.

The Gold clam (Corbicula fluminea) is also known as the Asian clam.

The Gold clam (Corbicula fluminea) is also known as the Asian clam. Photo: Supplied/ NIWA

During Wednesday's meeting, Rotorua Lakes councillor Conan O'Brien asked Bay of Plenty Regional Council councillor Kevin Winters about investment into the issue, including for boat cleaning.

Winters said the Ministry for Primary Industries (MPI) would provide funding.

He understood Te Arawa Lakes Trust would provide staff, paid for by MPI.

"At this stage we don't have any money in the budget for clams because they are not in our regional pest management strategy yet, because they are not here."

Everyone had a role to play in biosecurity at the lakes, he said.

MPI has been searching the lake and sifting sediments and testing DNA, including at Ōkataina, Sport, recreation and environment manager Rob Pitkethley said.

Rotorua Lakes Council sport, recreation and environment manager Rob Pitkethley. Photo / Laura Smith

Rob Pitkethley. Photo: LDR / Laura Smith

Boats going into Ōkataina would be stopped and checked, and information gathered on where they came from.

The established populations were suspected to have been in the Waikato for a "couple of years", although only discovered in May, he said.

Discussions were underway on what it meant for other Te Arawa lakes, he said.

"There is a very strong message going to MPI about State Highway 5 [and] SH30. There are not a lot of ways in from the Waikato. What are the other control methods that MPI need to be thinking about, wider than the entrance to Ōkataina?"

He described it as a "fast-moving situation" in terms of asking MPI questions on the issue.

Security was employed to block boat access to the lake last week.

O'Brien said he believed this occurred on 27 September, before official restrictions came into effect on 1 October.

Councillor Conan O'Brien has asked about the invasive gold clam. Photo / Laura Smith

Conan O'Brien. Photo: LDR / Laura Smith

He said he understood it was a "time is of the essence" situation, but asked what the process was now.

He was concerned about someone setting up a perimeter on land the council was responsible for, blocking public access, without an enforceable action.

Pitkethley said the council had been aware that MPI was considering restrictions and in light of that "imminent" decision on the lake's closure.

"Technically, yes, there was a blockage across a public road."

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

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