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Kawhia Harbour News
The Kawhia Forum is now open for registration and participation.
Mauis dolphin sanctuary proposal
Dolphins prove they are priceless assets to New Zealand....(Stuff)
And yet more political governance issues that will effect our whenua. The Regional Council and Local Councils for Aotea and Kawhia are consulting with stakeholders of which Ngati Mahuta are but one. For details further please visit... www.ew.govt.nz/projects/shorefutures/index.htm
Foreign mussels in the Kawhia Harbour:
A member of the Kawhia Harbour Protection Society noticed birds feeding in specific areas on the mud flats. Curiosity about what caused them to be feeding in the same place each tide led him the edge of a massive mussel bed. Later two of us went out in a boat to determine the extent (hectares) and collect samples. Judging by the bed size they must have been there for more than a season.
The mussels are (not officially identified but reasonably certain to be) an exotic organism, Musculista senhousia , or Asian Date Mussel, or Carpet mussel. The 2cm shell is a pale green with amber zig zag lines across, anchored by a mass of attachment ‘hairs' that form a dense carpet, creating an oxygen depleted foundation, excluding most other marine life.
Sediments trapped amongst the mass of shell cover the greater part of the shells, leaving a small dark streak in the mud. The dark streak is the top of the shell where it opens to feed and circulate water. In places the dark marks make a mudbank look like a woven mat.
Biosecurity NZ told me they tend to make big beds that finally die, (probably by suffocation in sediments. In the meantime they will have established elsewhere to make yet another big bed.
The full impacts will not be known for a while. Control or removal is not practical with current technology or chemicals.
Carpet mussels were first seen near Auckland in the 1970's and have since spread to Whangarei, Waitemata, and Kaipara Harbours , Mahurangi, and Tamaki estuary. The Kawhia beds are the furthermost south. As the discussion continues we find they are in Aotea Harbour too.
We will keep you updated if we get any more information...John Dodgson - President KHPS
Update from John Dodgson - President of Kawhia Harbour Protection Society:
Greetings All, A quick note about some items that may be of interest.
Shores Future:
After the initial flurry of activity to collect information about what the community wanted included in the Shores Future, there has been little information released. There are three KHPS members who have been invited to join the Community Review Group waiting for the next move. Natasha and Jenni at EW are collating the information collected earlier and are in the midst of writing up the papers to present to the CRG for discussion. Jenni expects to present the papers to the CRG in December.
Update on the Asiatic Carpet Mussel:
Subsequent to telling NZ Biosecurity about the Asiatic Date Mussel (Musculista senhousia) in Aotea and Kawhia harbours I have obtained details of mussel invasion of the northern harbours. The Society has received several enquiries as to what we could do to control them in Kawhia.
To date there has been no mention of a practical control method. Chemicals that would affect the mussel would also damage desired species. Knowledge of biological controls is a realm yet to be explored. Mechanical control is not viable, both physically and economically. Apparently they grow rapidly, form dense mats, are short lived c 2 years, and colonise new areas as the mats die off. The mat is so dense as to form an anaerobic ( no oxygen) layer discouraging most other species.
Understanding the invader and how it grows and spreads, and recording the effects it has on established marine life could give some clues about what to expect in future. A recent drag in the Te Waitere channel with a scallop dredge brought up empty shells, seaweed and you guessed it, ADM. This indicates it is far more widespread than first thought.
There are a number of institutions who either have an interest or statutory obligation in coastal affairs. Finding the right one to undertake monitoring is an exercise. It is intended to ask each interest group, who is prepared to monitor the spread and effect of ADM in Kawhia and Aotea Harbours.
Sub-division in Aotea:
A 16 Lot subdivision adjacent to Aotea village, along the harbour margin, is apparently progressing without public notification despite KHPS drawing Council attention to the similarities to the Owhiro Rd subdivision that the Judicial Review determined should have been publicly notified. Otorohanga District Council subsequent to the Judicial Review indicated that all coastal subdivision consents would be publicly notified. If the consent process continues without notification a Judicial Review is the only way a Council decision can be challenged. Environment Court review of the decision is not possible because the challenger has not been part of the consent process. This project has all the hallmarks of problems in the future.
At the AGM:
In September our guest speaker drew attention to Spartina and Saltwater Paspalum, two salt tolerant, rapid growth, excluding plants that threaten the intertidal zone ecosystems within the harbour. Both are a much greater threat than the mangroves which are checked by colder temperatures.
A closer look at the Spartina growing in a wetland at Te Maika showed heavy stock browse and no chemical control as planned for in the DOC weed programme. The problem has been identified, money made available, consents applied for, yet the physical work did not happen. Over the summer it is intended to check the harbour edges and shallows to see how prevalent these two species are.
I am told that Canadian geese are building in numbers, breeding freely near Motutara peninsular. The gut system of a Canada goose is very primitive producing large quantities of faecal matter. The novelty of the goose rapidly decreases when they alight in flocks on farmland and start to feed and foul ground. Around Raglan harbour they are starting to cause concern as their numbers are rapidly increasing. Is this a warning?