Student studies water pests
Canterbury University student Ashleigh Watts is studying marine pests that invade mussel farms in Pelorus Sound.
Miss Watts, a descendent of the Jackson whalers, is trying to identify patterns in the way the pests grow and spread. Her work should help the aquaculture industry predict the outcome if any new pests invade and plan an effective response, she said.
Working in the Marlborough Sounds felt like returning home, Miss Watts said. She has spent many summers at her family's property at Te Awaiti Bay in Tory Channel where her ancestors were whalers and farmers.
In 1828, her great-great-great-grandfather James Hayter Jackson founded Tory Channel shore whaling station, Te Awaiti, where he was buried. Her granddad is Reg Jackson, who was a gunner for the Perano whalers and a farmer on Arapawa Island.
Months spent on boats in the Marlborough Sounds and diving with her late father meant she felt at home on the Sanford and Spat New Zealand boats where she did her research, Miss Watts said.
About half her time was spent at sea and half at research organisation the Cawthron Institute in Nelson which was supporting her research.
As mussel lines were hauled out of the water she recorded the location and density of fouling organisms, including sea squirts, seaweed, tube worms, barnacles and blue mussels.
Valueless blue mussels tended to latch on to marketable greenshell mussels, she said. This weakened their attachment, sometimes causing whole crops to fall off when longlines were lifted.
"There have been instances where workers have had to scrape blue mussels off full lines and re-seed them," she said.
Scraping hard pests such as barnacles and tube worms from mussels damaged the shells which reduced their value. Soft sea squirts could be easily removed but when abundant, could damage or strip lines.
Her research included identifying different pest distributions up and down Pelorus Sound, Miss Watts said.
For example, blue mussels might be more common in the outer Pelorus and sea squirts in the inner sound.
She was investigating potential influences such as water salinity, pH, algae species present, seasonal variations and also didemnum genetics to see whether populations are closely-related.
Increased global shipping and yachting had increased the world-wide spread of non-native marine pests, Miss Watts said. To control new pests, it was critical to understand how organisms spread.
After six summer and two winter months collecting data, Miss Watts would publish her results in a thesis completing a master's degree in marine ecology.
A music as well as science graduate, Miss Watts sings opera and fronts Christchurch covers band Ashleigh and the Classics.
- The Marlborough Express
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