Science Centres: Aquatic Biodiversity and Biosecurity

NIWA’s Dr Nick Gust (standing) and Lindsay Hawke search Lyttelton Port for Styela clava. (Photo: Chris Woods, NIWA)

A biosecurity survey team from NIWA and the Cawthron Institute has found large increases in populations of the invasive sea squirt Styela clava in Lyttelton Harbour in the past year.

Surveys conducted in November and December found that numbers of S. clava had increased considerably in Lyttelton Port and Magazine Bay Marina since they were first surveyed in November 2005. Specimens of all sizes were recorded, indicating wellestablished, reproductive populations.

Biosecurity New Zealand commissioned NIWA to conduct surveys of the two Lyttelton sites and Tutukaka Marina (Northland) to get a detailed picture of the distribution and relative abundance of S. clava prior to developing management trials. As in 2005, only very low numbers of S. clava were found at Tutukaka.