Tech expected to streamline weed eradication in waters

Gaye Searancke
Gaye Searancke
Developing technology could be a game-changer for eradicating invasive species from New Zealand waters, and one environmental advocate can see its use in a multimillion-dollar Fiordland project.

Land Information New Zealand chief executive Gaye Searancke told the Environmental Defence Society conference in Christchurch this week new equipment, even dams, were having an impact on the land.

She also highlighted the rapid changes in the land.

Among those was the drastic decrease of size in the Southern Alps glaciers; a recent glacier inventory suggested ice coverage had reduced by 31% since 1978.

She also highlighted how the Clyde Dam in Central Otago had changed its surrounding environment since construction started in the 1980s.

"You can see how dramatically the dam has impacted on the river valley," she said.

Recent imagery showed the increase in greenery on the steep hillsides as more grapevines were planted.

Other changes included how alien weed species had made their way into lakes.

Having highlighted the difference in Rotorua’s lakes’ health, Ms Searancke said she was thankful the species causing trouble there had been eradicated from South Island waters.

Technology could be harnessed for finding relatively quickly what weeds were where.

Niwa recently announced an addition to its technology toolbox.

The portable invasive species detection device would be strapped to survey boats to identify invasive weeds using sonar.

Capable of feeding back footage and using artificial intelligence to recognise weeds, it drops GPS pins for divers to find the exact spot.

"This will be way more efficient than surveillance diving, which is a painstaking task."

Similarly to Lake Rotoiti, where invasive weed was taking over and stopping native species thriving, Fiordland’s unique coastal environment was under threat from Undaria pinnatifida.

This year, with $2million through the government Jobs for Nature programme, a project is aimed to contain the invasive seaweed in Breaksea Sound, and completely eliminate it from Chalky Inlet.

Fiordland Marine Guardians chairwoman Dr Rebecca McLeod said the development of technology could be a game-changer for marine pest surveillance in the Fiordland area.

"Trying to detect marine pests over such vast areas using current techniques such as dive inspections is expensive, time-consuming, and doesn’t cover nearly enough area."

It was vital technology was developed.

"We are ramping up a huge effort in Breaksea Sound to deal with a large amount of the invasive kelp Undaria.

"This involves teams of scuba divers trained in detecting and removing the kelp.

"Many tonnes of the kelp will be removed in a bid to contain this outbreak.

"This approach will effectively hold the line whilst we wait for a tool to be developed to treat natural underwater habitats for invasive species like this."

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