Iwi fear effects of dredging on shellfish beds

Iwi are concerned about the environmental impact a plan to dredge Tauranga Harbour will have on centuries-old shellfish beds.

Port of Tauranga has lodged a resource consent to clear 15 million cubic metres of sand, silt and rock from the shipping channel, to allow ships of up to 350m to dock.

A port report on the environmental effects of the dredging said disruption to pipi beds in the harbour would be minimal, as the resource was healthy and well stocked.

But Te Runanga o Ngaiterangi Iwi Trust chief executive Brian Dickson said he was not convinced, and had received no assurance that a key gathering area - known as Te Paritaha o Te Awanui - would be unaffected.

"We do understand that it is going to bring some economic benefits but whether it's sustainable in terms of our customary fisheries is unclear. There are some tensions there as a starting point.

"This ... is a real taonga. It's been handed down to us and it's been our source of sustenance since mai ra ano [forever]."

His tribe wanted independent research to verify the operation's effects on the harbour.

He said Ngati Ranginui and Ngati Pukenga would join his tribe in filing a joint objection to the proposed work.

Ngati Ranginui member Patrick Nicholas said many marae relied on the legally protected pipi beds for food at major hui and tangi. Customary fishing practices saw certain hapu gathering at different places, and the dredging would almost certainly affect that, he said.

"Where are they going to go? Into places where other hapu are? That affects many."

Concerns have also been raised about possible erosion at Matakana Island as a result of the dredging, and the effects on the marine environment in the 9sq km dumping area.

Port chief executive Mark Cairns was unavailable for comment, but an earlier port report to iwi said there would be "very little loss" of pipi and what was lost would be "limited to a narrow band at most 100 metres wide at the northern end of Centre Bank [a main gathering area]."

In its consent application, the port argued that it needed to accommodate a trend towards larger ships. If it failed to do so, New Zealand "risked" becoming a feeder port to Australia, which would mean delays in getting exports to international markets.

It said international "mega" shipping companies were moving towards vessels that could handle the equivalent of 15,000, 6.1m containers on major shipping routes, with 7000-container ships being moved on to secondary routes such as Australasian ports.

Currently New Zealand handled ships with 2500- to 3000-container capacity.