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Oruaiti School Programme, 2020

In 2020 Whitebait Connection Programme Coordinator Rosie worked with Oruaiti School for programme delivery. Their programme included field trips to the Oruaiti wetland and Lake Waiporohita for freshwater investigations. 

The Oruaiti River which connects to the Oruaiti wetland is in the Doubtless Bay catchment area. It starts in the northern Omahutu Forest, at the top of the catchment and the river opens out into Mangonui Harbour, at the bottom of the catchment. The catchment is mainly farmland, pine forest and native bush.

Here are the students results from their testing at the Oruaiti wetland: 

  •  Habitat Assessment - The students noticed that there was not much shade in areas of the wetland, that there were lots of aquatic plants and weeds that were blocking the sunlight from entering the water, and that there was no water flow
  • Water Temperature - 14 degrees celsius 
  • Electrical conductivity - 20 µS/cm
  • Clarity - 58cm 
  • pH - 6.5
  • Macroinvertebrates - flat mayfly nymphs, damselfly nymphs, dragonfly nymphs, woody cased caddisfly nymphs, mites, diving beetle larvae, diving beetles and mosquito larvae
  • Fish - common bullies and shortfin tuna 

Searching for macroinvertebrates at the Oruaiti wetland

As a comparison site, we tested the health of Lake Waiporohita. This dune lake is also in the Doubtless Bay catchment and has started to be restored through native tree plantings around the lake as well as limiting human activity in the lake. (No washing cars or using motorised boats in the lake)

Here are the students results from their testing at Lake Waiporohita: 

  • Clarity - 78cm 
  • pH - 6.5-7
  • Water temperature - 18 degrees celsius 
  • Electrical conductivity - 190 µS/cm
  • Macroinvertebrates - water strider, mosquito larvae exoskeletons, back swimmers and water boatmen
  • Gambusia (pest fish) were the only fish caught 
  • After much careful searching amongst the reeds, the students found a Southern Bell frog floating on the water surface. It appeared to be sick so hopefully it had lived to a ripe old age in the lake. These frogs are introduced from Australia and are the largest frogs in N.Z. Frogs are another indicator species we can use to determine the health of waterways

Macroinvertebrate sampling at Lake Waiporohita