A rockhopper penguin from Campbell Island. Over the past 60 years rockhopper populations in New Zealand’s sub-Antarctic islands have declined alarmingly. A NIWA study has begun to identify possible reasons for the decline. See “Declining rockhopper penguin populations in New Zealand” for more details.
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Brian Smith
Kevin Collier
Healthy populations of aquatic insects need a suitable environment on the stream bank as well as in the water.
Adult Zelandoperla decorata (a stonefly).
Adult Hydrobiosis parumbripennis (a caddisfly).
Microclimate control chamber.
Diurnal temperature ranges over 96 hours used in the study.
Predicted LT50 for adult stoneflies and caddisflies.
The term “aquatic insects” is collectively applied to the nymphs or larvae (young stages) of insects that spend part of their life cycle in water.
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Karen Robinson
John Zeldis
Alex Ross
Experiments are helping to establish the feeding preferences of farmed mussels.
Examples of some of the organisms found in mussel gut samples.
The feeding experiment. A series of buckets each contained one feeding mussel. Buckets containing seawater only were included as controls.
It has long been known that mussels are effective filterers of suspended material, including phytoplankton, bacteria, and non-nutritive material such as silt.
On this page
NIWA’s new executive team
New home for NIWA, Nelson
Sea and Learn 2002
NIWA’s National Centres
Perlan: gliding to new heights
New Zealand’s Sandy Coasts CD-ROM
Where did all the water go?
NIWA in the desert
New Zealand–French collaboration: a symposium
NIWA’s new executive team
The new executive team, which met for the first time under Chief Executive Rick Pridmore on 22 August, consists of three directors and seven general managers, each with various portfolio responsibilities.
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John Quinn
Mark Meleason
Regular monitoring of the growth of algal slimes is helping to identify trends in the overall health of our larger rivers.
Maharakeke Stream. (Photo: Chris Hickey)
Total periphyton cover at NRWQN sites.
Trends in annual periphyton cover at NRWQN sites from 1989 to 2001.
Downstream changes in periphyton cover.
Periphyton is the algae growing on the bed of streams and lakes.
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David Thompson
Paul Sagar
Feathers from museum specimens of rockhopper penguins are helping to throw light on the dramatic population decline of this bird in New Zealand’s sub-Antarctic islands since the 1940s.
Map showing the locations of Campbell Island, the Antipodes Islands and the Auckland Islands – breeding sites of rockhopper penguins in New Zealand.
Graph 1: Variation over time in δ15N (‰) for rockhopper penguins from Antipodes Island. Each dot represents an individual bird.
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Lionel Carter
Andrew Laing
Rob Bell
Occasionally huge storms from the south take us by surprise. Where do they come from and what are their characteristics?
Not a war scene, but the debris-strewn coast road between Island and Owhiro bays, 6 February 2002. (Photo: Bill and Suzanne Main)
Blue sky – white water: breaking waves fill Island Bay on Waitangi Day (6 February 2002).
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Niall Broekhuizen
Julie Hall
To give a realistic picture of the marine food web, models need to take into account the fact that small oceanic organisms can starve.
Simulated dynamics of algae, bacteria, active protozoa and cysts in the microbial food web.
We tend to think of large animals such as fish and whales as the main occupants of the deep ocean, but most marine organisms are tiny, often less than 0.2 mm long. There are literally billions of these organisms for every whale.
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Ian Hawes
Clive Howard-Williams
Management of pristine lakes such as Lake Taupo requires an understanding of how the various constituents of natural waters affect their optical properties – water colour and clarity.
Contributions to absorption in Lake Taupo water.
Modelled light in Lake Taupo at 10 m depth.
Water colour and clarity are both immediately evident to an observer and important in any assessment of water “quality”. Instinctively we look on clear blue water as better than turbid brown or green water.
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Dave Rowe
Gavin James
Gavin Macaulay
Ude Shankar
Management of lakes to protect fish can be improved by the use of GIS methods and new echo-sounding techniques.
Depth contours for Lake Taupo.
Change in the total area of smelt spawning habitat with lake level for Lake Taupo.
Typical echogram across Lake Rotoiti.
Profiles from one side of Lake Rotoiti to the other showing changes in the distribution and density of adult rainbow trout and large smelt over 3 days.
Changes to lakes such as greater water-level fluctuations, increased turbidity, or a decline in
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Mark Meleason
John Quinn
Rob Davies-Colley
Wood in streams isn’t debris: it plays an important role in shaping stream channels and providing diverse habitat for stream life.
The “plunge pool”, located immediately downstream of this log, was formed by the erosive force of the small waterfall on the streambed. (Venture Creek, South Westland)
Sediment, large wood, and small organic matter have accumulated behind the log being measured.
