Little squirt may be big problem

The discovery of an invasive sea squirt on the hull of a fishing boat in Nelson has set off an investigation by Biosecurity New Zealand.

Investigators will try to find out whether the find represents an established population in Nelson that subsequently infested the vessel, or whether the specimen was picked up elsewhere.

The single adult specimen of the invasive sea squirt Styela clava was on the hull of a commercial fishing vessel, and senior marine adviser Brendan Gould said early information suggested it was most likely picked up in Nelson.

"This is because the vessel had been berthed in Nelson for almost nine months and had not been used over this period," Mr Gould said.

The boat had a significant amount of marine fouling species growing on the hull.

"This raises the possibility there may be a small population in Nelson," Mr Gould said.

The port had been surveyed for Styela in late 2005 but none was detected. He said if there was a population there, it did not appear to be widespread.

Styela is a big threat to the aquaculture industry. It smothers mussel lines and competes with other shellfish for food and space.

- NZPA