New Zealand Boaters Fight Off Voracious Fanworms That Hitchhike On Hulls, Threaten Seaport Aquatic Life
Marine specialists in Auckland, New Zealand are fighting the spread of the rapidly-multiplying Mediterranean fanworm with a new weapon — a prototype chlorine decontamination bath used to soak the hulls of boats to cut down the spread of the hitchhiking aquatic pest.
"They're similar to earth worms. If you chop them into three pieces, they've found that they actually end up re-growing both a head end and a tail end, so they're pretty good at restoring themselves," said Irene Middleton, aquatic biosecurity officer for the Northland Regional Council, in an April 19 ONE News broadcast outlining the new de-contamination efforts.
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The Mediterranean fanworm, Sabella spallanzanii, is a marine animal typically found in estuaries or sheltered sites at depths of one to 30 meters, or about three to 90 feet, according to the biosecurity website of the New Zealand Ministry for Primary Industries. The fanworm consists of a tube always anchored to a hard surface, topped with a single spiral fan called a radiole. The fan is white, banded with brown and orange, with an orange central stem. The tube is tough and flexible,often muddy in appearance and may have other organisms growing on the surface. The Mediterranean fanworm can grow to a length of 40 centimeters, or slightly more than one foot. The fanworms can form dense groups that compete with native species for food and space.
"Recent studies have indicated some impact on the establishment of new generations of some species and on nutrient flow," according to the Ministry for Primary Industries."While they have not yet been recorded to have had significant impacts on fisheries or aquaculture, there is potential that dense beds could become a nuisance to recreational and commercial fishers through the clogging of dredges and fouling of other fishing gear."
The fanworm grows faster in New Zealand than anywhere in the world, ONE News reported.
"It loves New Zealand. So in the northern warm waters of New Zealand, the fanworm grows like new forest, it just sprouts like nothing else," said Don McKenzie, biosecurity team leader for the Northland Regional Council. "The fanworm bullies its way in and pushes the others out."
Most Auckland marinas are contaminated, but the port of Lyttelton has brought the pest under control, according to the TV report. Small numbers of fanworms were found and treated in Whangarei, Tauranga, Wellington, and Nelson, where most cases were identified on the hulls of recreational boats.
The same species of marine pest is also in Australia, where it is called the European fanworm.
In Australia, the European fanworm was first discovered in Western Australia in 1965, according to the New South Wales Department of Primary Industries. The marine species has since been recorded in Victoria, South Australia, Tasmania, and New South Wales. In New South Wales, it was first discovered in Snug Cove, in Twofold Bay, in November 1996. Since then, monitoring by New South Wales Department of Primary Industries has documented fluctuations in the size of the population over many years, with the number of fanworms in 2013 being similar to that in 2005.
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