Managing marine pest threats at Port Vila, Vanuatu

NIWA biosecurity scientist Dr Graeme Inglis has recently been in Vanuatu, where he joined a team whose task ultimately is to upgrade Star Wharf, Port Vila’s cargo wharf.

Graeme’s role was twofold:

(i) to provide basic training in marine pest surveys to staff from the Vanuatu Department of Fisheries and Environment
(ii) to undertake an initial assessment of marine pest risks associated with demolishing the wharf.


“The existing wharf is in a dilapidated condition,” says Graeme, “but it is a vital piece if infrastructure for the economy of Vanuatu. The upgrade will allow for separate port facilities for cargo services and the increasing number of cruise ships coming to Port Vila.”

Graeme led a preliminary underwater survey of the wharf structure. This aimed to establish the presence or absence of a suite of known, high-profile ‘target’ marine pests from tropical waters. The survey team also collected a set of biological samples from the wharf piles that will act as a reference in future surveys.

 

What the divers found: fouling and marine life under Star Wharf. (Photos: Graeme Inglis)

Target non-native species found


The survey team found and provisionally identified five species on the target list of potentially invasive non-natives. These were a barnacle (Amphibalanus (Balanus) amphitrite), and four bryozoans (Amathia distans, Bugula neretina, Watersipora subtirquata, and Zoobotryon verticillatum). These records await formal identification by speciaist taxonomists.

All five species are now relatively widespread in tropical waters. They cause nuisance fouling on ships, piers, buoys, and other man-made structures in marine environments. When they occur in large densities they can increase drag on vessel hulls, increasing operating and maintenance costs. They also can foul aquaculture facilities, increasing costs and stock mortality.

Because of the high levels of fouling on wharf structures, Graeme recommended that, when removed, any piles or other fouled structures should go to landfill rather than be dumped at sea. This will mitigate the risk of distributing them further in Vanuatu’s marine environment.

Graeme also strongly recommended that effective monitoring and early detection systems for invasive pests should be introduced around Port Vila’s new port facilities. This includes assessing the risk pathways and species of concern to Vanuatu, and increasing local staff’s marine pest monitoring and management capability.


Contact: Graeme Inglis


NIWA was contracted to Soros Associates Pty and EcoStrategic Consultants in this project. 

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