Estuaries

Latest news

Mangroves: to clear or not to clear?

19 May 2017

NIWA scientists have written a guide for managing mangroves, prompted by a desire for people to learn more about mangrove ecosystems, and what happens when they are removed.

Paradise for eels? Getting to know the secrets of NZ's new icon

Feature story

9 May 2017

As New Zealand's "Mr Eel", Niwa's Dr Don Jellyman has heard every tall tale. And some of them may be true.

Muddy sinks

Feature story

22 February 2017

New Zealand’s mangrove swamps and coastal marshes may be particularly adept at absorbing and storing the carbon we emit.

Citizen science monitoring of water a win-win, research shows

Media Release

12 December 2016

New research has revealed that citizen science monitoring of water is a win-win for scientists and volunteers—one gains access to new data, and the other the skills and confidence to become involved in discussions over what is happening to their streams.

Our work

Historical changes in juvenile fish habitats

NIWA is looking for people who have had a long association with the Hauraki Gulf or Marlborough Sounds to help them with a research project on juvenile fish habitats.

Predicting long-term sedimentation and heavy metal accumulation in estuaries

NIWA has developed an Urban Stormwater Contaminant (USC) model to enable urban planners to predict sedimentation and heavy metal accumulation in estuaries and identify problem areas in order to target mitigation measures.

The New Zealand Estuary Trophic Index

Excessive nutrient input (eutrophication) threatens many New Zealand estuaries causing ecological problems, such as algal blooms and poor physical and chemical conditions for estuarine life.

Estuarine water quality: the CLUES estuary tool

Many of New Zealand's rivers fail to meet national guidelines for nutrient levels. NIWA has developed the Catchment Land Use & Environmental Sustainability (CLUES) estuary tool to predict the effects of land use on estuarine nutrient concentrations.

Latest videos

The world's most mysterious fish

A video about The world's most mysterious fish. NIWA researchers are working with iwi to try to unlock the secrets of New Zealand tuna—freshwater eels. Every year tiny, glass eels wash in on the tide at river mouths along our coast. But where do they come from and how do they get there?

Ngā Waihotanga Iho - The Estuary Monitoring Toolkit

The main purpose of Ngā Waihotanga Iho is to provide tools for the public to measure environmental changes that occur in estuaries over time. These changes may occur due to natural processes and/or human activities. Ngā Waihotanga Iho is divided into six modules, each monitoring different aspects of your estuary.

Restoration of aquatic ecosystems

This project aims to increase our knowledge of aquatic ecosystems and their restoration, and apply this to degraded streams, rivers, lakes and estuaries.

The world's most mysterious fish

You’re not imagining it – our seas really are warming

The seawater in the New Zealand region is significantly warmer than it was 30 years ago. All indications are that the warming trend will continue.

Slowing the mud invasion

New Zealand's estuaries were once sandy, forest-lined gems.

Freshwater Update 76, March 2018

Freshwater Update 76 brings you the latest information from our Freshwater & Estuaries Centre, with articles ranging from spring and river water condition to urban waters, didymo and aquatic plant scientists.

The New Zealand Estuary Trophic Index

Excessive nutrient input (eutrophication) threatens many New Zealand estuaries causing ecological problems, such as algal blooms and poor physical and chemical conditions for estuarine life.

Protecting and restoring seagrass – what have we achieved and where to next?

The extent of NZ’s seagrass meadows has declined substantially in the last 50 years. This has been most evident in estuaries strongly affected by human activities. But seagrass meadows can be restored and NZ has a local example to prove it.

Using new laser technology to measure bank erosion

Fine sediment is NZ’s most widespread contaminant, degrading ecosystems and impairing recreational, cultural and aesthetic values in our rivers, estuaries, and coastal seas.

Compound Specific Stable Isotope tracing of sediment sources - tools to manage a sticky problem in New Zealand’s freshwaters and estuaries

Fine sediment is New Zealand’s most widespread water contaminant, degrading ecosystems, infilling dams and reservoirs and impairing recreational, cultural and aesthetic values in our rivers, estuaries and coastal seas.

Mangroves: to clear or not to clear?

Media Release

19 May 2017

NIWA scientists have written a guide for managing mangroves, prompted by a desire for people to learn more about mangrove ecosystems, and what happens when they are removed.

Paradise for eels? Getting to know the secrets of NZ's new icon

Feature story

9 May 2017

As New Zealand's "Mr Eel", Niwa's Dr Don Jellyman has heard every tall tale. And some of them may be true.

Toolkit development

A number of individuals, organisations and hapū have contributed to the development of Ngā Waihotanga Iho.

Getting started

This section outlines some practical matters you need to consider before using any of the modules.

Managing mangrove expansion

This manual aims to provide the guidance needed to manage mangrove expansion, while maintaining the ecological integrity of estuaries and harbours.

Muddy sinks

Feature story

22 February 2017

New Zealand’s mangrove swamps and coastal marshes may be particularly adept at absorbing and storing the carbon we emit.

Monitoring and maintenance of kōura

Once you have identified the problem, and applied the necessary tools for restoring kōura to your stream, the next phase of your project is to monitor the site to see whether restoration works.

Applying the right tools to restore kōura to lakes and streams

The tools available for restoring kōura to lakes and streams depend on what is causing kōura to decline.

Why are kōura rare or absent in your waterway?

Habitat and biological factors factors affect why kōura rare or absent in your waterway.

Are kōura present in your waterway?

First, determine if kōura should be present in your stream.

Identifying the problem for kōura

Identifying the factors causing kōura numbers to decline will allow you to determine which restoration tools you need to employ.

Guide to restoring kōura (freshwater crayfish) in lakes, rivers and streams

Habitat degradation and the introduction of exotic plant and fish species have adversely affected kōura populations throughout New Zealand. However, there are a number of measures that we can use to restore kōura populations in lakes, rivers and streams.