Estuary’s fish life under investigation
Fishing boats working in the Avon-Heathcote Estuary recently are not commercial fishing. They are the first of several annual fish studies commissioned by the City Council.
NIWA, the National Institute of Water and Atmospheric Research, has been contracted to do research to help the Council better understand the impact on the estuary’s ecology and water quality of stormwater treatment improvements, recreational activity and the planned ocean outfall pipeline.
The research will give the Council baseline information about species, numbers and size of fish in the estuary. Further surveys will show the effect of moving the city’s treated wastewater to the new ocean outfall, Council Parks and Waterways planner Eric Banks says.
In this year’s survey NIWA staff will catch, count, identify and release fish. They will repeat the exercise each November for the next two years and, depending on budget, for three years after the pipeline starts operating.
Natural climate-induced fluctuations in fish numbers and changes in commercial fishing practices will be taken into account, Mr Banks says.
The estuary is a nursery area for many fish, particularly the commercially important flounder. It is also a migration route for freshwater eels, lamprey, common smelt and brown trout.
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