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option4 Update #133

Massive Turbines for the Kaipara Harbour

by the option4 team
May 2010


This article was originally written for the NZ Fishing News magazine June 2010 edition.


If you are old enough to remember your mother using a mouli to vitamise chunky food then you probably grew up in the baby-boom era.

If not, a mouli was a small version of the machines now used to mince fish frames for burley.

Just imagine how efficiency increases with a similar machine over seven storeys high.

It is not surprising then that Crest Energy’s proposal to install 200 underwater turbines at the Kaipara Harbour entrance has more than just the locals choking.

At 24 metres high, 25 metres wide and 30 metres long these power-generators are massive.

The major concerns relate to the effects their swinging blades will have on the fisheries, the environment and access.

The Environment Court’s interim decision notes that Crest Energy said, “it would avoid any potential adverse effects as being of low, almost negligible probability, but some with possibly high impact, for instance on the rare and endangered Maui dolphin”.

West coasters have been through years of debate about harbour closures to protect these vulnerable dolphins.

It seems incredible now, after banning commercial fishing in this area, that the authorities will condone the installation of these turbines with unknown consequences.

(Click on image for larger view)

Even the scientists poorly understand the effects of having multiple generators rotating at about ten revolutions per minute creating electro-magnetic fields.

Another unknown is the impact on the nursery habitat of juvenile fish populations. The Kaipara currently sustains young fish utilising the horse mussel beds and subtidal seagrass meadows.

West coast snapper and fishing

In 2009 NIWA reported that around 98 percent of west coast North Island snapper originated as juveniles from the Kaipara. Given that the Snapper 8 population has been driven down to around 10 percent of its original biomass, with most of the old and large fish being removed, the potential effects of these generators cannot be ignored.

(Click on image for larger view)

It is proposed these turbines will be located in water at least 31 metres deep, leaving a minimum seven metres between the machine and the surface.

There is little evidence to prove whether this clearance is sufficient to enable migratory finfish patterns to continue.

While it would be convenient to ignore what is happening below the Kaipara’s surface and the cumulative effects on both the fisheries and the environment, a precautionary approach must be taken to ensure this known, significant juvenile habitat is protected.

Moreover, all fishing within the vicinity of the harbour entrance will be prohibited. The hugely popular fishing destination of The Graveyard will certainly become a ghost town, as all effort is likely to be displaced within the Harbour.

The impacts of shifting so much effort into the Kaipara’s upper reaches is likely to be noticed first by those communities who fish to sustain their families; and what chance will they have of having their concerns addressed a decade from now?

Not surprisingly, local Maori, Ngati Whatua and Te Uri o Hau have been vociferous in their opposition to the Crest Energy proposal.

It is time for New Zealanders of all ages and upbringing to demand tighter controls and higher environmental protection of this jewel, the Kaipara Harbour. It may feed our kids.
Environment Court interim decision information here. (Caution: Large file 4.6MB)
Read Crest Energy's Frequently Asked Questions here
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