Cawthron’s focus in this project is on biosecurity risks to New Zealand from vessel traffic, and the development of management strategies for biofouling.  Our initial work on vessel sea chests has been completed, and the next phase involves an evaluation of in situ heat treatment methods.  A new programme will assess the en route survivorship of hull fouling organisms on merchant vessels along trans-Tasman (Australia to New Zealand) and trans-equatorial pathways.  Our research on biofouling management focuses on the efficacy of in-water vessel defouling using rotating brush hull cleaning methods.  We are also investigating the relative risk of in-water cleaning of fouled vessels vs ‘doing nothing’, part of which involves experimental investigations into the survival of defouled material under different environmental conditions.

Funding: FRST and MAF Biosecurity New Zealand
Project Manager: Grant Hopkins

Cawthron is developing molecular tools for detection of marine pests, as well as tools for enumeration of ballast organism for compliance. These tools, when developed, will improve surveillance and assist inspection authorities in ensuring that ships meet compliance regulations (IMO Convention and New Zealand Import Health Standard) in ballast management.

Funding: FRST and MAF Biosecurity New Zealand
Project Manager: Doug Mountfort

This theme explores the opportunities for managing marine pests after they have become established, recognising that natural dispersal barriers provide ongoing opportunities for control, for example through the management of anthropogenic vectors. Initially we are developing anthropogenic transport and natural dispersal models to simulate the spread of pest species at a regional scale. Using examples of high risk organisms with contrasting dispersal strategies, the application of these models will be used to illustrate the efficacy of managing internal borders in a case study region. Knowledge gained on the role of artificial structures in marine bioinvasion will add another dimension, by identifying how such structures can provide habitats that facilitate the spread of pest species beyond natural barriers.

Funding: FRST
Project Manager: Barrie Forrest

The development of coastal areas has resulted in the creation of extensive areas of artificial habitat in the form of wharf pilings, marina pontoons, moorings, aquaculture structures and so on.  The role of such structures as points of incursion for pest organisms, as reservoirs for their spread to natural habitats, or as ‘stepping stones’ for spread across natural dispersal barriers, is not well understood.  Our initial research to address such questions uses the sea squirt Didemnum vexillum as a model organism.  In 2007/2008 we are investigating the role of larval supply and habitat suitability in the spread and establishment of Didemnum.  Of particular interest is the relative importance of larval inoculation pressure vs benthic processes (e.g., predation) in Didemnum’s invasion success in natural habitats.

Funding: FRST
Project Manager: Barrie Forrest

We have developed a number of response tools for incursions of fouling pests based on smothering or encapsulation techniques using dredge spoil, geotextile fabric, and polyethylene wrappings.  The recent focus of the wrapping work has been on the encapsulation of artificial structures, which results in mortality of target organisms because of anoxia within the encapsulated water.  These techniques have also been adapted for use on vessels, and trialled on a range of vessel types and sizes.  Given the inherent difficulties of marine pest management in natural habitats, we have also recently undertaken a collaborative project to evaluate the efficacy of in situ heat treatment using a surface-generated supply of steam.  As part of present work, we are undertaking a review and synthesis of these and other response tools, to identify the pros and cons of the various techniques and further research needs.

Funding: FRST and MAF Biosecurity New Zealand
Project Manager: Barrie Forrest

A benefit-cost model for assessing marine biosecurity risks and establishing priorities for management has recently been developed.  Future work will explore how marine biosecurity priorities can be determined alongside other environmental risks.  Various approaches for this purpose have been evaluated and a Relative Risk Model technique identified as a potentially useful tool for integrating biosecurity risk.  Initial application of this method via a regional case study has revealed that the biosecurity elements need to be further developed, which will occur over 2007/2008.  This work will contribute to the ongoing development of Biosecurity Risk Management Plans for particular sectors (e.g., aquaculture) and for regional management authorities.

Funding: FRST, Regional Councils and Port Companies
Project Manager: Chris Batstone