Lakes

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.

Three plants of an endemic submerged quillwort (Isoëtes) were recovered from Lake Ōmāpere by NIWA in 1998, prior to the lake weed (Egeria densa) dying off and the lake switching into an algal dominated turbid state. No further isoëtes plants have been observed in the lake since that time.

The ability to properly manage our freshwater resources requires a solid understanding of the flora and fauna which live in and interact with them.

John Clayton, a principal scientist in the fields of aquatic biodiversity and biosecurity based at NIWA's Hamilton office, has won a 2011 Kudos award for his leading role in the development of LakeSPI  (Lake Submerged Plant Indicators).

A regular newsletter that includes a seasonal review and outlook for New Zealand's water resources, and an update on some of NIWA's freshwater research.