Lakes

NIWA researchers are out on Lake Whakatipu for the next week mapping the lake floor for the first time.

The condition of many NZ lakes is under threat from land-use changes and the invasion of alien aquatic plants.

NIWA discusses, in depth, this year's most asked question—what is happening to our fresh waterways?

To prepare for changes in climate, our freshwater and oceans decision-makers need information on species vulnerability to climate change.

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.

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

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

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

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

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.

This research project aimed to understand the causes behind differences in mercury in trout and other organisms in the Bay of Plenty/Te Arawa lakes—in particular what features of each lake explain why mercury in trout is higher in some lakes than in other lakes.

NIWA researchers have spent part of the last month keeping a close eye on the bottom of Lake Tekapo to find out what it looks like and what is going on below the lake bed.