Hungry little squirt moves into region

A tiny troublemaker has turned up in Pauatahanui Inlet, and the regional council is calling on boaties to aid in its containment.

An invasive foreign sea squirt, styela clava, has been found in the estuary. It has the potential to change parts of the marine environment, foul boats and be an impediment for marine farming, says Greater Wellington biosecurity manager Davor Bejakovich.

But vigilance by boaties could stop it from spreading further and becoming a region- wide nuisance.

‘‘By simply keeping the hulls of their moored boats clean and well antifouled, vessel owners can help prevent the spread of this pest to other areas,’’ he said.

Styela clava, also known as the clubbed tunicate, leathery sea squirt, or Pacific rough sea squirt, is thought to originate from the Northwest Pacific. It has a long, club-shaped body on a tough stalk and grows up to 16cm. Its surface is tough, leathery, rumpled, and nobbly. They can be brownish- white, yellowish- brown, or reddishbrown.

Styela clava is a ‘‘solitary’’ sea squirt, which means that each individual has its own stalk to attach itself to rocks, boats, wharves or any other structure in the sea. It can crowd out native marine plants and animals and filter feeds on large amounts of plankton that native species normally eat.

It was first found in New Zealand in 2005 in Auckland and has turned up at a number of ports since. The Ministry for Primary Industries led a programme to scope out its spread and attempt to remove it. It was found that it was not technically feasible to eradicate.

‘‘We can all do our bit to make sure it doesn’t spread to marine farms or high valued biodiversity areas like marine reserves, or around the country in general,’’ said Mr Bejakovich.

Contact Greater Wellington Regional Council Pest Animals 04 830 4414.