Source: NIWA – National Institute of Water and Atmospheric Research
You can’t take a trip to the Marlborough Sounds and fail to notice the patchwork of buoys bobbing in the blue waters. Suspended under these buoys are kilometres of lines, each in turn with their own much smaller lines trailing beneath. These lines, less than a millimetre in diameter, are the anchoring byssal threads (or beards) of green-lipped mussels.
Historically, wild green-lipped mussels were gathered direct from the Sounds’ seabed and shorelines. However, since the 70’s, land-use changes and harvesting have contributed to the reduction of these natural beds.
Marlborough is still a highly productive green-lipped mussel region, but it’s the farmed mussels which are now bringing in the money. With hundreds of farms throughout the Sounds, this region calls itself the ‘Green-lipped Mussel Capital of the World’.
These hardy filter-feeders do well on mussel lines, benefitting from the cleaner water and reduced predation that comes with elevation. The lines also provide easy access for marine farmers to check and harvest their stock. With relatively low impact on the environment, mussel lines yield a nutritious treat a little over 18 months from seeding.
With the aquaculture industry prospering, mussel farm owners decided it was time to give back to the environment, donating some of their farmed stock to rewild the once-native beds that their industry was built upon.
Auckland University PhD candidates Emilee Benjamin and Trevyn Toone have been working closely with NIWA researchers, MPI, local farmers and iwi to identify the best ways to restore wild mussel beds in Pelorus Sound.
Over the past three years they’ve been monitoring mussel and ecosystem health in the newly reseeded beds. It’s early days yet but they are already seeing signs of success.