Flagging kelp: potent symbol of loss of mauri in the Bay of Islands

John Booth
3 February 2015

Today, the reef off Te Akeake, the northwest extremity of Urupukapuka Island, displays a fringe of kelp at low tide level, and then again from about 8 metres depth. What you can’t quite make out are the thousands of puny kina busy rasping their way across the intervening area. (Photos: NZ Aerial Mapping; Salt Air)

Today, the reef off Te Akeake, the northwest extremity of Urupukapuka Island, displays a fringe of kelp at low tide level, and then again from about 8 metres depth. What you can’t quite make out are the thousands of puny kina busy rasping their way across the intervening area. (Photos: NZ Aerial Mapping; Salt Air)

Summary

Sea urchins (kina) have eaten out much of the shallow-water kelp of the Bay of Islands, defiling the Bay’s essential life force. There appears no other credible explanation for the kelp loss. Similar destruction has taken place in many other parts of New Zealand, as well as overseas. The experience is that sea urchins increase in abundance as their key predators become overfished; the sea urchins consume or destroy the kelp over the band of the urchins’ depth distribution; and this leads to the collapse of natural functioning of shallow-water reef ecosystems.

Marine reserves in New Zealand and elsewhere show that when fishing pressure on the predators of sea urchins is removed, the full canopy of kelp returns. No-take reserves lead to fully functioning kelp ecosystems—their dependent life forms and ecological processes re-established.

The imposition has been so great it will take decades to repair. But the sea’s mauri can be restored. [Read more…]

The Value of Mangroves in Whangateau Harbour

Whangateau Harbour in flood January 29, 2011

Whangateau Harbour in flood January 29, 2011

This is the submission by Dr Roger Grace to the Independent Hearings Panel in the matter of the Proposed Auckland Unitary Plan on behalf of the Environmental Defense Society and the Royal Forest and Bird Protection Society of New Zealand [Read more…]

Why Do We Need No-take Zones for Marine Spatial Plan?

Why Do We Need No-take Zones for Marine Spatial Plan Dr Roger Grace (1)

In New Zealand, when we talk of no-take zones in the sea we really mean marine reserves, set up under the Marine Reserves Act 1971. Although there are a few other ways of achieving full protection, the Marine Reserves Act is the specific piece of legislation designed for this purpose. It does have some short-comings, however, and to correct some of these a new Marine Reserves Bill has been prepared, but has been languishing in the storage cupboards of Parliament with no action for more than ten years. [Read more…]

Merry Christmas from Auckland Council

Merry Christmas from Auckland Council cutting pohutukawas

Merry Christmas from Auckland Council cutting pohutukawas

The six Pohutukawa trees on the corner of St Lukes Rd and Great North Rd (opposite MOTAT) are under threat from Auckland Transport’s plan to create an additional lane for the approach to the new motorway overbridge. These trees are over 80 years old and were originally planted as part of the Chamberlain Park Golf course. How much more land, amenity, natural heritage and pollution needs to be devoted to new roads. Please sign and share this petition to get Auckland Transport to come up with a plan that does not result in these trees being cut down. You can find the campaign to save the Pohutukawa 6 on Facebook https://www.facebook.com/savethepohutukawa6

Whangateau Harbour Important Nursery for Parore

Hundreds of young parore, mostly about a year old, were hovering under the Omaha Causeway Bridge this morning.  They were taking advantage of a calm spot in an eddy as the tide started racing out.

Hundreds of young parore shelter under the Omaha Causeway bridge as the tide begins to drop.  The western row of bridge support columns can be seen in the background.

Hundreds of young parore shelter under the Omaha Causeway Bridge as the tide begins to drop. The western row of bridge support columns can be seen in the background.

According to Mark Morrison from NIWA, who did his MSc thesis on parore, the Whangateau Harbour produces all the parore for the coast from Pakiri to Kawau Bay. There are two sandstone reefs in the Harbour which serve as nursery areas for parore. One is about 200 metres south of the Causeway bridge and can be seen from the bridge when the tide is low. The other is on the Point Wells side of Horseshoe Island and is a popular snorkeling area alongside the channel. Masses of necklace weed grow on the reefs providing a sheltered habitat for the young parore.

In late January hundreds of recently settled parore only 20mm long shelter amongst the branches of mangrove trees when the tide is in. Here they continue to pick plankton organisms from the water, at the same time as beginning their herbivorous life by nipping at micro-algae growing on the mangrove branches.

Juvenile parore only 20mm long sheltering among the branches of large mangrove trees in the southern part of Whangateau Harbour.  The barnacles on the branches at left give you an idea of the scale.

Juvenile parore only 20mm long sheltering among the branches of large mangrove trees in the southern part of Whangateau Harbour. The barnacles on the branches at left give you an idea of the scale.

The tiny parore settle from their planktonic larval stage at about 12mm long and can be found schooling in estuaries and the lower parts of creeks when they are hardly recognizable just developing their stripes.

This tiny parore only 12mm long is just beginning to show its stripes.

This tiny parore only 12mm long is just beginning to show its stripes.

More Aucklanders Visit Marine Reserves Than Go Fishing!

The Auckland Council People’s Panel is a large group of many thousands of the Auckland public interested in providing feedback to Council about various issues which Council has an influence over or interest in.  Frequent questionnaires are published seeking the views of the panelists on a wide variety of topics.  A recent one was on Auckland’s Natural Environment.  Full results of this survey can be seen at  People’s Panel survey – Protecting & Improving Auckland’s Natural
Environment 

Tawharanui Marine Reserve on a quiet day.  Beaches and coasts were of greatest interest to panelists.

Tawharanui Marine Reserve on a quiet day. Beaches and coasts were of greatest interest to panelists.

The following I found fascinating in response to Question 5B, “In the last 12 months have you done any of the following activities in Auckland?”

Visited a beach 92%
Visited a marine reserve in Auckland 39%
Fished in the ocean 24%

[Read more…]

Hundreds of Trevally Shelter in the Shade

Hiding in the shade of the Omaha jetty floating pontoon this afternoon were hundreds of trevally of all sizes. They were accompanied by smaller numbers of parore and mullet, all station-keeping under the pontoon in the outgoing current.

Trevally

The water was beautifully clear about two hours after high tide, as there had been no rain and little wind for several days, the water offshore is really clear at present, and the vast numbers of cockles in the harbour would have finally “polished” the water of any remaining plankton and sediment.

I have seen trevally like this under the pontoon before, but they have usually stayed only a couple of days before moving on. But when they are there they are a lovely sight.

Today I just held my Go Pro camera in the water over the side of the pontoon, but it would be great to snorkel quietly over to the pontoon and take a closer look.