Science Centres: Aquatic Biodiversity and Biosecurity

Improved hull maintenance (vector control) was more effective than attempted eradication or yacht quarantine in reducing the rate of spread of a hypothetical marine pest.

A new NIWA model shows that improved hull maintenance is the most effective way of preventing the spread of marine pests by yachts.

Many non-native marine species establish initially within human transport hubs, such as shipping ports and marinas, and are then spread to other locations by boats leaving the infested hub. This ‘stepping-stone’ pattern of invasion resembles the spread of human disease.

NIWA scientists adapted human disease models to simulate the spread of a hypothetical non-native fouling species around New Zealand on yachts. They incorporated field data on the transmission of marine organisms, size and occupancy rates of New Zealand’s 36 yachting marinas, and the travel and maintenance histories of about 1200 yachts.

The model simulated about 146 000 yacht movements between 36 marinas over ten years.

The scientists used their model to estimate the effectiveness of four management strategies in preventing the spread of the invader. Initial results suggest that improved hull maintenance (applying antifouling paint more frequently), was the most effective, reducing infection risk by an average of 42 percent at each marina.

The model is being developed as an interactive tool for research and management. This research was supported by Yachting New Zealand and funded by the Foundation for Research, Science & Technology.