Tasmanian local Keith said he’ll never give up the fight.
(Keith Thomas-Wurth)

Most Australians may not realise the damage these invasive species inflict on fragile underwater ecosystems, but for conservationists in the nation’s south, the fight to protect them is relentless.

The Northern Pacific seastar remains a big problem throughout Tasmania, largely in the River Derwent, where they outcompete native species and suffocate marine environments.

It’s believed they first arrived here in the 1980s as stowaways on ships, but have since absolutely exploded in numbers.

Estimates suggest there are now as many as 30 million in the state.

They’re a devastating problem because they’re both prolific breeders and hearty underwater warriors that prey on vulnerable native wildlife and have few predators of their own.

An incredible 160 kilograms were removed from the water in the latest clean-up effort.
(Keith Thomas-Wurth)

But local man Keith Thomas-Wurth is leading the charge to remove as many of the pests as possible.

Alongside volunteers, he told Yahoo News Australia that they’ve hauled out a collective 12,000kg of them in just five years.

While experts acknowledge that complete eradication is unlikely, removal efforts remain crucial to protect endangered species and ease pressure on local wildlife populations.

Keith is determined to save the spotted handfish, which is particularly threatened.

At Nutgrove Beach at the end of April, Keith and his team removed a total of 5,497 seastars, collectively weighing an incredible 160 kilograms.

Keith said the results of the seastar clean-up are confronting in more ways than one.

The numbers are high — a sign the invasive population is thriving — but they also reflect the scale of the response, with thousands removed in an ongoing effort to protect fragile marine ecosystems.

“The Seastar clean-up results may be among the most difficult things to come to terms with,” he said.

“When the numbers are big, it’s bad, but at the same time, it’s good.

“Big numbers mean the population is growing — that’s bad. But big numbers removed are good.”

He branded the latest results “outstanding in every way”.

“We had six land helpers sign on, 22 snorkellers and 5 scuba divers,” Keith said.

“There is no way anyone can convince me that Tasmanians are not an amazing bunch of people.”

Over the last five years, some 12,000kg of invasive seastars have been pulled from Tasmanian waters.
(Keith Thomas-Wurth)

What makes the Northern Pacific seastar so destructive?

The Northern Pacific seastar is highly destructive because of its voracious appetite and rapid reproduction.

It feeds on a wide range of marine life, including mussels, clams, and other shellfish, often stripping entire areas of these key species.

Its ability to tolerate a broad range of temperatures and salinities allows it to thrive in diverse coastal environments, giving it a competitive edge over native species.

Its regenerative abilities make it even more resilient. A single arm can grow into a whole new seastar, allowing populations to rebound quickly even after attempts at control.

This combination of aggressive feeding, fast reproduction, and resilience means the Northern Pacific seastar can dramatically alter marine ecosystems, displacing native species and destabilising the balance of local habitats.