Mangroves, Friend or Foe?

This is with reference to an article (edited here) by John Moran on NZFISHINGWORLD.co.nz regarding a small group of men affectionately known as The Mudlarks, who are doing their part to restore a special part of the Manukau harbour to its glory days

John Moran states that

'As a young buck growing up, my cobbers and I used to love mangroves. At high tide, we would paddle out in our leaking old duck punt and retrieve our precious net which invariably contained an assortment of fish.'

'In later years, when I became a super keen duck shooter, I used to select a large mangrove tree for the framework of a maimai or hide and after a bit of handsaw surgery a make shift floor was built from the cleared out tree centre with cheap car case plywood.

I loved everything about these harbour mangrove trees, but over the years my opinion has changed somewhat. During the early 1960's I shot from a decent maimai at Karaka in South Auckland, where we dug part of a bank out really close to the low tide mark, and trained the vegetation over a framework. Two of my mates built a very elaborate duck shack not far from my spot which must have cost plenty with all the treated and native timber used in the construction. It had a bunk house, galley and a three tier shooting platform. Sheer luxury! There were a few smallish mangroves nearby which afforded a nice bit of cover, but within a short space of time, these green invaders took charge and soon converted a once top duck shooting possie into a totally useless forest of mangroves that were of no use to man or beast'

Moran continues to say that this experience developed his interest in mangroves and that he has been in discussion with many people who swear that 'mangroves are aliens from hell and should be wiped off the face of the earth at all costs, then on the other side of the coin there is the brigade who treat mangroves with awe and reverence'.

Moran came across a DVD by Ruud Kleinpaste, "Bug Man", who said that there were over 50 tropical species of mangroves yet only one can tolerate New Zealand's unusual climate. Once established, this hardy species can grow anywhere from a half a metre to over eight metres in height and surprisingly thrives in fetid mud. One weird trait of this plant according to Rudd is that it has a shallow root system that spreads out 25 times the size of the plant drip line, where the roots from the parent plant and its neighbours all interlock and interwine under the mud which anchors and stabilises the forest it creates.

Moran continues to say that he came across an article in the New Zealand Geographic (Issue 67 Jan/Feb2004) on mangroves written by two ocean engineers. In the article were two aerial photographs of the Mangawhai Harbour, the first in 1946 and the second in 2001. These photos highlighted how invasive these plants had become. This article explained that other harbours between Auckland and Mangwhai experienced a 30 to 40 per cent in filling with mangroves and that research showed that the explosion of this plant coincided with introduction of top dressing and more intense farming practices leading to increased nutrient runoff into harbours.

The New Zealand Geographic stated that "New Zealand is the only country in the world where mangrove growth is expanding at such an explosive rate. That in itself is a big worry"

Moran comments that it is a belief that mangrove forests are an important habitat for a variety of marine life and many juvenile fish species which require the habitat of the mangroves to survive to adulthood. He questions then how does one account for the mangrove forests being left high and dry at low tide?

He continues that at a boat ramp in Waiuku, he met up with a fisherman, Ted Kitching, who was a retired mariner and an ornithologist and also is one of the original members of the "Mud Larks", a team of people who are dedicated to the removal of mangroves around Waiuku on the Manukau Harbour. with the purpose of clearing many clogged water access ways for boating. Moran says that he thought that it was almost impossible to obtain resource consent, but Ted explained that a resident of Waiuku organised a survey on public opinion of "mangroves and their environmental impact'. The resident prepared a "well thought out plan of attack and included drawings of a massive barge... to build as his nautical twelve wheeler truck" All this information was presented to the Waiuku Community Board, the Tamakae reserve Community and Franklin District Council. A resource consent was granted for the removal of 9.2 hectares of mangroves.

A hardcore group of mainly older men, all having a passion for clearing away the invasive mangroves began work immediately and gradually developed efficient systems to cut and transport the bundles of mangroves. This is the group which became known affectionately as "The Mudlarks"

At the time of John Moran writing this article, after one year's operation, the Mudlarks are just over one quarter through the stage one clearance allocation. Tests have confirmed that the chewed up mangroves are of good value for mulch or compost and the thicker timber from mature mangroves are excellent burning firewood.

Moran says that the Waiuku Mud Larks donate most of their leisure time to this tough operation. The Franklin District Council contributes to other running costs to ensure that this operation continues. Moran is aware that there is some opposition to the removal of mangroves but suggests to those that they look at a marine chart of the Harbour to realise that this operation is small in terms of any negative ecological effects this action may or may not have. He says that the 'basin at the bottom end of the township of Waiuku looks an absolute picture' now.

The Mudlarks are men in their sixties and seventies and even one in his eighties. Projects like these require younger people to assist and eventually take over.

If you wish to make contact for further information, the email address is

[email protected]