In 2020 Whitebait Connection Programme Coordinator Rosie delivered a school programme to Kaeo School. This programme included field trips to the upstream and downstream areas of the Kaeo River for freshwater investigations. The Kaeo River is in the Whangaroa catchment area. It starts in the Puketi Forest, at the top of the catchment and the river opens out into Whangaroa Harbour, at the bottom of the catchment. The catchment is mainly farmland, pine forest and native bush.
Here are the students results and findings from their testing at the downstream site:
- Habitat Assessment - The students noticed that there was not much shade over the river, and there was a lot of erosion as there were no trees to hold the bank in place and stop soil and sediment from washing into the river.
- Electrical Conductivity - 150 µS/cm
- Water Temperature - 16 degrees celsius
- Clarity - 75cm
- pH - 7
- Macroinvertebrates - flat mayfly nymphs, woody cased caddisfly larvae, pond skaters, freshwater shrimp, mites, midge larvae, worms and snails
- Fish - Common bullies and elver (juvenile tuna/eels) were caught
In May 2019, Whangaroa College students sampled the same area of Kaeo River. They found 4 adult Inanga, 120 Gambusia, (a pest fish), 48 Freshwater Shrimp and 2 Common Bully fish. The electrical conductivity was 340 µS/cm, the temperature was 14.3°C, the water clarity was 83 cm and the pH was 7.
The second water testing site was much further upstream, located in the middle of the Whangaroa catchment. Waiare Stream flows into the Kaeo River close to where we were testing.
Here are the students results and findings from their testing at the upstream site:
- Clarity - 81cm
- pH - 7
- Water Temperature - 16 degrees celsius
- Electrical Conductivity - 140 µS/cm
- Macroinvertebrates - dobsonfly larvae, flat mayfly nymphs, woody-cased caddisfly larvae, stony-cased caddisfly larvae, dragonfly nymoh, damselfly nymph, adult diving beetles, freshwater shrimp, water spider, cranefly larvae, mosquito larvae, pond skater, midge larvae, snails and worms
- Fish - adult inanga, juvenile inanga, common bullies and redfin bullies
Overall, the upper Kaeo River appeared in better condition than the lower Kaeo River. The electrical conductivity, temperature and pH of both waterways were similar, however the upper Kaeo River had a much better habitat assessment, with more instream water features as well as more trees growing along the river bank. This will prevent erosion and provide cooler areas of the water for freshwater creatures during summer. Erosion of sediment into a waterway will increase water temperatures and decrease the water clarity.