Environment, Farming

Scientists’ mussel seabed solution

Mussels are extensively farmed in the Marlborough Sounds. Photo: Supplied.

Hopes to bring wild mussels back to the Sounds and boost marine diversity have moved a step closer.

An international team of experts are calling for Marlborough District Council to approve plans to create two new mussel beds in the Pelorus Sound.

And marine scientists hope the Marlborough project could spark mussel bed restoration initiatives in other parts of New Zealand.

The move comes after three years of investigation into the best way to create new seabed habitats.

Large areas of mussel beds were destroyed last century as land clearance and ongoing run off from farmland altered the nature of the seabed.

A report prepared for council by marine scientist Dr Andrew Jeffs says dropping clean shells to create a habitat for two new mussel beds in

the Pelorus Sound could stop further deterioration.

“For a number of years there has been concern, including from MDC, about the decline of wild shellfish beds in areas of the Marlborough Sounds.

“Studies in other areas have shown that mussel beds are extremely productive, support high biodiversity, act as nurseries for fin-fish species, and help to remove suspended sediment from the water column and stabilise the seabed,” the report says.

Scientists plan to drop clean shells to act as anchors for live mussels in a bid to test whether coarser seabed substrate will prove a better habitat than silt.

The multi-million-dollar project has attracted significant co-funding and specialist technical support from an overseas environmental NGO, The Nature Conservancy.

“One possibility for the lack of natural recovery of wild mussel populations in the Marlborough Sounds is the inability of mussels to re-establish naturally on this changed seabed substrate,” Andrew says.

“Mussels require sediment particles of at least 2 mm in diameter in order to attach their anchoring threads which hold them upright on the seafloor so they can feed,” he says.

The shell material and live mussels will be actively monitored by researchers.

The Marine Farming Association worked with other community groups, the University of Auckland and NIWA to develop the research plan.

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