Filming yacht hulls from around the world – the Biosecurity HullCam
Science Centres: Aquatic Biodiversity and Biosecurity
Working with the HullCam in an Auckland marina.
The HullCam is easy to operate in the field, and has been used to sample yachts ranging from 10 to 25 m in length.
A look at a boat hull through the HullCam’s ‘eye’.
The past 50 years have seen major advances in the development of toxic antifouling paints to prevent the growth of marine species on ship and boat hulls. Despite these efforts, hull fouling continues to be one of the main ways in which exotic marine species are introduced into New Zealand and other countries.
Between 400 and 500 ocean-going yachts visit New Zealand each year – and even more during the America’s Cup. These yachts can pose a biosecurity risk if they carry problem species on their hulls, especially because they travel more slowly than merchant vessels, and spend more time in destination ports. However, in contrast to merchant vessels, these yachts have not received much attention.
NIWA, through the National Centre for Aquatic Biodiversity & Biosecurity, is currently researching the development of better predictive tools to identify and manage the marine biosecurity risks posed by ocean-going yachts visiting New Zealand.
NIWA and the Ministry of Agriculture and Forestry have been working together to collect information on the recent travel and maintenance history of yachts entering New Zealand from overseas, and the amount and diversity of fouling organisms found on them. We can estimate the fouling on boat hulls by using ‘HullCam’, a specially designed piece of sampling equipment with a remote underwater video lens attached to a frame. The frame has wheels mounted to it that allow it to roll along or across a yacht hull while being steered from the surface by a telescopic arm. The remote lens, aided by twin underwater lights, transmits a moving image to a digital video camera at the surface. Still images can then be captured off the footage to determine the composition and abundance of fouling assemblages.
So far we have used the HullCam to sample fouling assemblages on nearly 100 yachts. Scuba divers and the HullCam were used to sample some of the boats, and both methods recorded similar estimates of fouling cover and composition. However, the HullCam is more efficient; two people, or even one, can use the HullCam to sample hulls (at least three staff are required for diving), and it takes half the time of divers to sample a single yacht. Divers can also make only a limited number of repetitive ascents in a single day.
Robust and predictive models require many samples for calibration. With the HullCam we can easily get information on the degree of fouling on international yacht hulls. We intend to sample another 100 international yachts during the coming boating season, and develop a predictive model from the data.