Hotel owner praised for spotting guest’s invasive clam collecting behaviour

Horizon Regional Council has praised the keen eye of a central North Island hotelier who spotted invasive clams left behind by guests.
photo: LDR / Supply

A hotel owner in a village near two national parks has been praised for his quick action after discovering a biosecurity threat left behind by some of his guests.

Andrew Dewing was checking the rooms of departing guests at a hotel in the central North Island village of Ōwhango when he discovered a collection of freshwater golden clams (Corbicula fluminea).

The village is close to Whanganui and Tongariro National Parks and is the starting point for excursions along the Whanganui River.

The highly invasive clam was discovered in the Waikato region in May last year and is currently being managed by Biosecurity New Zealand.

Prolific breeders can reach extremely high densities, producing up to 400 fry per day.

This means they clog water-based infrastructure, such as power plants, irrigation systems and water treatment plants, and compete with native species for food and space.

DeWine said he was immediately suspicious when he spotted the clams. He contacted Horizon Regional Council freshwater advocate Dave Cade, also known as Didymo Dave.

“I had seen Didymo Dave’s Facebook posts and had interacted with him a little bit. One of his posts was about golden clams, and I was like, ‘Oops, we can’t have golden clams here.'”

Devin took the photo. The clams were reported to Biosecurity New ZealandThe study found they were collected from a known site in Lake Karapiro.

The clams were destroyed and Biosecurity New Zealand staff provided information about the clams to the clam collectors.

Horizons Regional Council said DeWine acted quickly.

Horizons pest and plant protection team leader Michael Beech said the regional council was working with tribal authority Ngā Tāngata Tiaki o Whanganui and the community to raise awareness of how to protect the Whanganui River catchment from golden clams and other freshwater pests.

“Biosecurity is a team sport and everyone has a role to play in protecting our precious freshwater spaces,” Beach said.

“We appreciate Andrew’s keen eye and thank him for taking the right action and reporting this immediately. We want our waterways, and others, to be safe from this invasive species.”

Nicki Atkinson, freshwater ecosystems and threats manager at the Department of Conservation, said golden clams could cause serious damage to local freshwater fauna and ecosystems.

“It is vital that we do everything we can to stop the spread of the virus.”

Horizons said anyone who saw the freshwater clams should take photos and report them to Biosecurity New Zealand, and leave the clams where they were found.

“Don’t touch it.”

– LDR is a local news organisation co-funded by RNZ and NZ On Air