Scientist gets the dirt on marine pests

A visiting scientist hopes to uncover some of the secrets of marine pests that could threaten New Zealand's valuable aquaculture industry.

French Canadian marine biologist Anais Lacoursiere-Roussel is spending three months in New Zealand investigating how recreational boating affects the spread of invasive marine species such as sea squirts Didemnum vexillum and Ciona intestinalis.

Her work is part of a collaboration between McGill University in Montreal, where she is working towards a doctorate, and Fisheries and Oceans Canada. It is part of a wider study, called the Canadian Aquatic Invasive Species Network, that has brought scientific groups together to examine and identify pests that threaten aquatic ecosystems.

It aims to predict and prevent further invasions.

She is in New Zealand because, despite the obvious differences in ecosystem, several species of pest are found both here and in Canada.

She has been talking with boat owners in Nelson, Golden Bay and Waikawa, and looking at the bottom of their vessels with an underwater camera in an attempt to understand boat fouling by marine pests.

She is also interested in finding out whether there is a pattern based on the type of vessel or how it is used.

As well as being costly for boat owners to clean off, some sea squirts have the potential to affect farmed mussel spat by smothering the mussels or stripping the growing lines due to the additional weight.

Ms Lacoursiere-Roussel said she had carried out similar work on boats in Nova Scotia, and her work in Nelson was part of an attempt to understand how species from different parts of the world become established elsewhere. "The best way to stop the spread is to understand the spread."

It was also a good way to learn lessons from previous pest invasions, such as with Didemnum, which is well established in New Zealand but has not reached Canada's east coast.

New Zealand was one of the first countries to study marine invasions and the effects of boating and shipping, and she hoped to glean valuable knowledge here. "We have the same species so we can do it all together."

She is joined in her work by Cawthron Institute marine biosecurity team senior scientist Barrie Forrest.

- © Fairfax NZ News