Plea to stop slimy marine pest
As the weather warms up and the glistening Hauraki Gulf beckons, boaties are being asked to help slow the spread of the invasive sea squirt Eudistoma elongatum.
Auckland Council wants boaties to check their boat hulls and clean them, out of the water.
A native of Australia, it was first spotted in oyster farms in Houhora Harbour 12 years ago, and has now spread throughout the north.
Able to survive being out of the water between tides makes it a significant nuisance for mussel and oyster farmers.
Not poisonous or toxic, the squirt breeds in clusters of slimy white tubes that grow from five centimetres to more than a metre long and from 5 millimetres to two centimetres thick.
It accounts for half of marine waste on northern oyster farms during summer, Northland Regional Council Biosecurity Officer, Cameron Bunton said.
Sand, mud, wharf piles - the fast growing pest grows almost anywhere. It competes with natives for space, and filter feeds on the eggs and larvae of native marine life.
Warkworth marine biologist Dr Roger Grace spotted it at Sandspit seven years ago.
He raised concerns dredgings, from the Sandspit Marina build, dumped near Cuvier Island, could help spread the squirts in the gulf.
Found in Oakura Bay on Waiheke Island last year, it is now in the Mahurangi Harbour.
The tubes are incredibly difficult to control or pick off, as they grow back and spread from broken bits, Auckland Council Marine Biosecurity Advisor Samantha Happy advised.
It is a particular risk to moored boats in marinas that may not get cleaned or taken out regularly, she said.
Some Sandspit boats already have the squirts on them, Grace said.
Pontoons have also spread the pest in the north, Bunton said.
‘‘The pest will change our beautiful foreshores as we know it, forever, and is nearly impossible to control once it’s established,’’ Happy said.
If you see these pests outside of recorded sites note the location, take a photo/sample and report it to the Ministry for Primary Industries on 0800 80 99 66.
For advice, contact Auckland Council biosecurity on (09) 301 0101 or email@example.com.
Marine biologist Roger Grace found the invasive sea squirt Eudistoma elongatum at Sandspit in 2010.