The good news is that there are no new nasties stuck to Opua's little harbour's bottom.

The bad news is that marine pest species found in the port in the past are still there.

A search carried out by Niwa on behalf of the Ministry for Primary Industries did not turn up any new invasive marine pests in the water, seabed or structures.

The survey was carried out in May as part of a surveillance programme for non-native marine organisms that could threaten New Zealand's marine environment. It focuses on detecting new incursions of marine pests. The secondary goal is to monitor the spread of marine pests already established here.


Opua is one of 11 of the highest risk-ports in New Zealand that are checked twice a year, once in winter and once in summer.

Pest species found in the port in the past and that are now widespread include the clubbed tunicate (Styela clava) and the Australian droplet tunicate (Eudistoma elongatum).

These pests probably arrived on the dirty hulls of vessels.

With the weather warming and more boaties moving around, the risk is greater for pests to be carried in that way to other areas in Northland.

The same risk applies to vessels arriving from other regions. Boaties are being asked by Northland Regional Council, other bio-security departments and marina and port managers to ensure - and in some cases prove with documentation - that they maintain their vessels' hull cleanliness.