Vol.11 No.2 - June 2003

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Di Tracey
Helen Neil
Dennis Gordon
Steve O'Shea
How old is a coral? Finding the answer requires some rather complex steps.
Di Tracey holding a branch of a large (broken) tree of bubblegum coral (Paragorgia arborea), radiocarbon-dated at 300–500 years old. This species is among the most impressive octocorals and some of the largest specimens have been trawled from New Zealand waters.

Answers to the photo quiz
Photo A: A classic banded kokopu community stream: small, bush-covered, low elevation with pool habitat. A few redfin bullies and shortfin eels were also present.
Photo B: Shortfin eel, but if you guessed inanga you were not far off. Because the site is in Northland, this type of habitat is more likely to contain a shortfin eel community than inanga. Also present were Crans bully, with a few longfin eels and redfin bullies.
Photo C: Torrentfish. This open, gravel riffle close to the sea is classic torrentfish habitat.

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Malcolm Green
Waves at the edge of an estuary can cause surprisingly large amounts of sediment to disperse over quite long distances: what are the implications for the estuary ecosystem?
Diagram of waves at high tide and low tide.
When out in a boat in the middle of a large estuary, we see wide expanses of deep water and we feel strong tidal currents. When we walk along the shoreline of the same estuary, however, we wade through shallow water that creeps sluggishly up and down the intertidal flats.

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Lorna Pelly
Gavin Fisher
A comparison between some renewable energy options for New Zealand and Scotland shows up some interesting similarities and differences.
Windfarm at Hau Nui, near Martinborough. (Photo: Alan Blacklock)
Comparison of electricity production resources in 11 countries. (Source: CIA World Factbook, 2002)
The energy crisis in New Zealand in early winter 2003 demonstrated the danger of committing the majority of the national energy production to one resource, particularly one that can be affected by the climate.

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John Booth
Steve Chiswell
Russ Bradford
Barry Bruce
The rock lobster fishery on both sides of the Tasman should benefit from specialised sampling equipment.
Two final-stage phyllosoma larvae of the red rock lobster Jasus edwardsii (upper) together with a final-stage phyllosoma larva of the prawn killer Ibacus alticrenatus.
Russ Bradford with the multiple codend device secured to the end of the 60-m long fine-meshed net.
The New Zealand red rock lobster Jasus edwardsii has among the longest larval development known for any marine creature.

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Jody Richardson
Ian Jowett
Can you tell which fish communities inhabit the streams in the photographs? Read on – and then try our test!
A: a tributary of the Waikato River near Huntly. The catchment is 100% native bush and the stream is 1–2 m wide. Although over 100 km inland, the site is only 20 m above sea level, and there are no barriers to migration.
B: a medium-sized, low-gradient river in Northland. The catchment is mostly farmland and the riverbed is mud.

On this page
NIWA makes atmospheric measurements in Arctic Norway
Global lessons from Māori success in fisheries?
Deep-sea experiments suggest spring food shortages
IPCC Chair visits NIWA
Supply and demand at the papakāinga
The hunt for small snapper
Kyoto conference discusses effects of climate change on the world’s lakes
NIWA makes atmospheric measurements in Arctic Norway
During February and March, a three-week campaign measuring the chemicals involved in stratospheric ozone depletion was held at the Rocket Range in Andoya, Norway.

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Cindy Baker
Jacques Boubée
Experimental work is helping to identify the types of fish ramps that will most likely help migratory fish get past low barriers in streams.
Ramp surfaces tested.
Proportion of inanga juveniles successfully negotiating each ramp type.
Proportion of adult inanga successfully negotiating each ramp type.
Proportion of redfin bullies successfully negotiating each ramp type.
Close to half our native freshwater fish are diadromous, with part of their life cycle spent at sea and part in fresh water.

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Alistair Dunn
Neil Andrew
Computer modelling of apparently simple interactions in a reef environment has shown that these systems can change in a surprisingly complex way.
A kina barren.
The transition cycle showing sample pictures of the transitions between states for a simulated population of kelp and kina.
Relative numbers of kelp and kina over time from a single simulation.
When it comes to biodiversity, reefs (ridges of rock, sand, coral or other hard materials lying at or near the surface of the ocean) are often thought of as stable systems unless catas

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Penehuro Lefale
Is there a role for indigenous knowledge of weather and climate in improving scientific understanding of future changes in the climate?
Damage from Tropical Cyclone Val, Samoa,1991
Recreational activities for Pacific children depend on historic knowledge of their environment
Long before the advent of complex numerical climate models, indigenous communities have used changes in their environments to predict changes in the weather and climate.

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Michael Ellwood
Michelle Kelly
Deep-sea sponges have the potential to provide unusually detailed information about ocean, and thus climate variations in the past.
Sclerosponge showing mushroom-like growth form. Note hints of the internal ring formation on stalk as sponge grows up and out. (Photo from Bergquist, P.R. (1978). Sponges. Hutchinson & Co., London.)
Mushroom-like sclerosponges (yellow-orange) in a marine cave in Palau, Micronesia.