Science Centres: Aquatic Biodiversity and Biosecurity

As this newsletter goes to press, NIWA divers are searching Auckland’s Waitemata Harbour, and Waikawa Marina near Picton, for the invasive sea squirt known as the club tunicate (Styela clava).

Biosecurity New Zealand commissioned these rapid surveys after the club tunicate was found in the Viaduct Harbour, and provisionally identified on the hull of a yacht which sailed from there to Waikawa Marina. A survey of Lyttelton Harbour is also planned.

The club tunicate can grow up to 160 millimetres long and reach densities of up to 500–1500 individuals per square metre. It competes for space and food with other marine species and is causing problems in northern hemisphere marine farms.