Pest seaweed has besieged one of the region’s premier diving sites, prompting a series of underwater missions to remove the Asian invader.
A team of divers has spent the equivalent of a full working week trying to rip the menace from Pope’s Eye, according to Parks Victoria.
The weed was so “highly invasive” that it was also known as the Blackberry of the Sea, the department said.
The eight dive missions at Pope’s Eye had so far extracted about two tonnes of the spreading pest, which arrived in Victoria from waters off north-east Asia.
Video surveys identified the weed at Pope’s Eye last year after authorities first detected it in Port Phillip Bay 10 years prior.
Undaria reaches up to three metres long, with its fast rate of growth making it a threat of overgrowing and excluding native seaweeds.
“Undaria has a huge environmental impact on both the marine animals and plants,” said Parks Victoria marine pest project officer Jonathon Stevenson.
“The timing of its removal is very important. We have timed these dives to remove maturing plants before they reproduce, thus reducing its spread at this important site of marine conservation and recreational diving.
“Undaria is a significant problem across Port Phillip Bay. We’re making good progress in protecting Pope’s Eye, but it is an ongoing concern.”
Undaria was recently discovered south of Pope’s Eye at Point Lonsdale, indicating that the Port Phillip Bay outbreak now threatened to spread offshore. A separate outbreak was identified at Apollo Bay almost six years ago, forcing authorities to launch removal efforts.
Mr Stevenson urged boat owners to be aware they could potentially spread undaria to other locations when they moved their boats.
“Always wash vessels and equipment thoroughly in fresh water after use, and dry them before going to other parts of the coast. This will reduce the spread of this invasive pest beyond Port Phillip Bay and along our coastline,” Mr Stevenson said.
The horseshoe-shaped Pope’s Eye, a relic from the 1800s fortification of Port Phillip Heads, became
Victoria’s first fully protected Marine Reserve in 1979.
Parks Victoria credited the long-term protection of the reserve status with the size and numbers of fish and other marine life at the site.
Pope’s Eye was “one of Port Phillip Bay’s most popular dive and snorkel sites”, Parks Victoria said.
