Mussel beds installed in Mahurangi Harbour (Waihē) late 2017 are having a major upgrade this month from the Mussel Reef Restoration Trust (Revive our Gulf). Three 10 tonne mussel beds will be added to extend the previous five.
The mussel beds have been a success with excellent survival and rapidly forming reef structure. Divers have observed octopus and eagle rays in the mussel beds along with numerous species of juvenile fish and squid.
Auckland University Professor Andrew Jeffs is pleased with the progress “As well as the biodiversity benefits of mussel reefs we are also studying their ability to clean the water and stabilise the muddy seafloor”. Mussels are filter feeders that perform an important ecosystem service that was lost when they were fished to collapse in the late 1980’s. One adult mussel filters a bathtub of seawater per day, so the additional 30 tonnes of mussels will filter a lot of water.
The mussels have been donated by mussel farming company, North Island Mussels Limited (NIML), who are keen to see mussel beds restored to the Hauraki Gulf. NIML have been supporting the Revive Our Gulf project since 2013. NIML General Manager Daniel Ramsey says “Both North Island Mussels and our parent companies Sanford and Cedenco Foods are 100% committed to ensuring that mussel farming is a truly sustainable and environmentally friendly industry. We feel very proud and privileged to be involved with such a positive and worthwhile environmental activity by reinstating this highly treasured and uniquely New Zealand natural resource”.
Biosecurity staff from Auckland Council and Biosecurity NZ will oversee one of the deployments in order to better understand the complexity and cost of mussel restoration under current biosecurity requirements. The restoration work currently requires submerging the mussels in freshwater for an hour and a half to kill any unwanted marine organisms.
Logistics were supplied by global environmental not-for-profit organisation The Nature Conservancy. Co-ordinator Dr Carina Sim-Smith said “We’re connecting with the local community and iwi around the Auckland Region to help them restore the mauri (life force) of their local waters”. Mana Whenua, Ngati Manuhiri, have assisted in the restoration at Waihē (Mahurangi).
Volunteers from Revive Our Gulf enjoyed their day out on the water, mussel shoveller Stephen Horsley said “I’m proud to be part of something that’s a small step in returning the Hauraki Gulf to what it used to be”.