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Many people, especially those who live in harbourside communities around the top half of the North Island, will be well aware of the ever increasing infestation of mangroves in our harbours and estuaries. We are losing the areas that we used to swim in, catch fish such as snapper and flounder, boat and sail in and the other recreational activities that the harbours and estuaries provided.

A few years ago, marine birds were plentiful. There was a large supply of marine snails and small fish for them to feed on. Large fish could be seen chasing shoals of small fish.

However, those sights and activities are now very curtailed by the spread of mangroves. Take the Moanaanuanu Estuary in Whangamata. That was, until recent years, a clear expanse of water with sandy shores where the previously mentioned activities took place. Now it is difficult to see the channel in places. The snails, birds and fish have gone to be replaced by mud and slime. Very little lives under the mangroves.

Yes, there are some people who still subscribe to the previous foolish notion that mangroves are some sort of gift from the Gods, that they are havens for small fish and birdlife abounds. They are demonstrably wrong and even the person whose research started that notion, Professor Chapman, has admitted that his research related to mangroves in overseas countries, not the NZ situation. But nevertheless, these misguided people fail to recognise the situation and chant the nonsense like a mantra.

Thankfully, the vast majority of people realise that any plant can become a pest if it is growing in the wrong place. The vast majority of community of Whangamata (98.7% of over 1200 surveyed) want effective management of mangroves in the process of restoring the harbour. After years of obstinence, Waikato Regional Council (EW) is now moving down the path of mangrove management as a part of harbour and catchment restoration.

There is plenty of evidence that effective management produces excellent environmental and recreational benefits. The Whangamata community removed about 7 hectares of mangroves in the Maonaanuanu Estuary after being denied any proper response from authorities for years. Despite EW’s claim that there was not enough current to clear the area of mud and slime, the mud and slime has reduced from knee deep to no longer being detectable in many areas and sand has been exposed in others. Birds have returned. This morning (1st May) while checking the community’s rodent traps, Gary Lowe and I observed shoals of fish being chased by larger fish in the cleared area.

It is worth mentioning that the community has implemented a rodent control programme around the harbour. This is under the control of the Habourcare Inc. Bunnings were kind enough to sponsir materials for bait stations. Presently rats and mice are being caught in large quantities and the bait stations are being relieved of bait. We are about in bring in some traps for possums, stoats and weasels.

EW is presently moving towards mangrove management. A criteria has been developed and it merely needs to be applied correctly over the harbour. Council has resolved that all mangroves south of the “1944″ line are candidates for removal. The “1944″ line is a line drawn from the forestry HQ across the harbour at the northern reaches of the harbour.

There are some areas of mangroves in the “candidate” area that we need to get some more information before removal can be justified. However, it is clear that there are good reasons that the vast majority of mangroves in the area designated can be removed and good environmental benefits will be obtained.

It is envisaged that removal will be by way of a start/stop adaptive management regime. An area is cleared and testing is subsequently done. Provided no adverse effects are found, the next stage is cleared and further testing is done. No adverse effects – move onto the next area and so on. Very logical and rational.

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