Letter to the editor

 

I add further comments re the ecological health of Mangawhai Harbour (MHRS).

Since 1991 the dedicated volunteers of the Mangawhai Harbour Restoration Society have worked tirelessly to restore our harbour to its near original structure and ecological health. It is on record that the serious negative geomorphyl impact of sand mining destroyed the harbour’s geographical shape and turned it into an ecoligal wasteland.

The negative ecological impact of New Zealand mangrove proliferation is well documented. I list my expert advisers as Dr de Lange, emeritus professor Waikato University who studied the infestation of northern New Zealand waterways by this species for 40 years. As well we have in our community Andre and Robin La Bonte and Mark Farnsworth who have committed many years of study and practical action in an effort to control the mangrove pest.

Dr de Lange advised that the negative impacts of mangrove proliferation are as follows:

(a) Aggregation of pollutants washed into harbours and estuaries off roadways, unburnt hydrocarbons from vehicles, heavy metals used in manufacturing tyres.

(b) Aggregating farm run-off fertilisers and faecal waste from farm animals.

(c) Developing root structures preventing the natural tidal and water flows in our harbours.

The toxic nature and fertilising impact of the pollutants is obvious to see.

I chaired the MHRS to stop the issuing of further sand mining licences to commercial operators. If licences for the next 30 years had been issued the best advice we had was that our harbour would have been destroyed within this time, including the habitat for our fairy terns and our way of life.

Graham Mackenzie
Mangawhai