Mussels put back in fragile waters
BioMarine oyster barges, with huge bags of live mussels on board, have headed out into Mahurangi Harbour in the Hauraki Gulf several times over the past month.
Rather than going to the company’s oyster farms, they have headed to five different locations, where the mussels were shovelled over the side.
They are part of an ambitious project that could eventually see the harbour floor once again carpeted with mussel beds and ultimately help restore some of the massive mussel beds that once covered 1200 square kilometres of the Hauraki Gulf sea floor.
A boom and bust commercial trawling industry in the gulf saw the once extensive beds collapse around the 1950s.
But even after the mussel fishery was closed, the beds never recovered.
Mussels have an important role, cleaning the water as they filter feed and providing a safe habitat for young fish.
Mussel beds carry 10 times the number of fish found on barren sea floor.
Gulf in decline
The seminal 2011 State of the Environment report on the Hauraki Gulf Marine Park showed the gulf was in a continued state of decline.
The following year a group was formed to look at the possibility of restoring some of the beds.
Some test beds were established in the gulf using young mussels donated by commercial mussel farmers on the Coromandel.
Techniques are still being refined, but the aim is to slowly restore the beds as funds become available.
Small trial beds of about one tonne of mussels each were set in place a year ago in the harbour and maha Bay.
Their success has now seen these 10-tonne beds formed, onetime Arkles Bay resident, and project leader Peter van Kampen said.
The mussels were again trucked up from the Coromandel before being loaded on to the barges and shovelled out by Revive our Gulf volunteers.
Taken off commercial mussel ropes, some of the shellfish will be damaged and may not survive the trip.
They were also submerged in fresh water for about 90 seconds to kill any attached foreign invasive marine pests like fan worm, club sea squirt, or undaria kelp, van Kemp said.
Over the first month the shellfish will congregate together and form large beds.
‘‘By next June it’s hoped the mussels will be spawning and the beds will become self sustaining,’’ van Kampen said.
While there are no direct ¯benefitsO to his business, BioMarine owner Jim Dollimore is right behind the restoration project.
‘‘We’ve let the gulf decline a lot,’’ Dollimore said.
‘‘In my father’s generation the sea was seen as infinite and all sorts of things went into it.
‘‘Now we’re starting to look after it, and these restoration projects are starting to happen.’’