Impact of new organisms on Marlborough seafood

UC researcher looking at impact of new organisms on Marlborough seafood

October 31, 2012

A University of Canterbury (UC) researcher will be spending this summer looking at the potential spread of new organisms around the Marlborough Sounds and will gauge what this means for New Zealand’s seafood industry.

UC biology masters student Ashleigh Watts, who will be based in Nelson next year, said her research will enhance current knowledge about the regional spread of non-native (foreign) species around aquaculture structures and provide new insight into an important area of invasive ecology.

``My research will help local aquaculture industries and regional councils worldwide in developing appropriate pest management strategies for these economically valuable areas, ultimately contributing to the preservation of the marine environment for future generations.

``Non-native species that have been deliberately or accidentally introduced into an area outside their native range are an important part of human mediated global change that threatens native biodiversity and generates significant biological and economic harm.

``For example, mussel farms in Prince Edward Island, Canada, have been directly impacted by non-native species growing on mussel lines and reducing the growth, productivity and quality of the mussels, leading to reduced revenue for mussel growers.

``In addition, some marine organisms in Portsmouth Harbour, USA, produce harmful chemicals, which prevent the offspring of native organisms finding a place to live, thereby, reducing local biodiversity.

``During the last two centuries and particularly the last 50 years, accelerating levels of global-shipping and yachting have increased the spread of non-native species. Considerable effort has been dedicated toward developing management strategies to prevent new species arriving, but ‘leaky’ borders make this an overwhelming task,’’ Watts said.

It was critical for pest management to try to understand how the organisms were spreading around New Zealand after they arrived. In marine environments, currents and headlands and other oceanographic features restrict exchange between water masses and therefore can also restrict, or enhance, the natural spread of new organisms.

However, aquaculture structures such as mussel farms provide an artificial habitat for fouling communities and were often infected by non-native species and exposed to high levels of vessel traffic, potentially increasing the spread of new species.

Tunicates, primitive invertebrates that attach to hard surfaces, have been identified as significant pests to aquaculture in New Zealand and in many other countries, increasing processing and production costs.

``My masters’ project will investigate the effects of mussel aquaculture on the regional spread of non-native species and the feasibility of management for these aquaculture systems in the Marlborough Sounds and potentially in the Nelson Harbour.

``This will be achieved by using ecological, mathematical and genetic tools to understand how didemnum vexillum, a non-native sea squirt, is making its way around the Marlborough Sounds.

Watts’ project will be conducted under the guidance of UC’s Dr Sharyn Goldstien and Dr Grant Hopkins from the Cawthron Institute in Nelson.
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