Aquaculture for all

Monitoring Threat in New Zealand's Rivers

Crustaceans Biosecurity Welfare +9 more

NEW ZEALAND - Two decades of monitoring of river water quality by NIWA has provided important information that is helping to care for New Zealands iconic rivers, but farm pollution is now hampering the shellfish aquaculture industry.

Nitrogen and phosphorus levels have increased at many sites due largely to ‘diffuse pollution’ from pastoral farming – with increased stocking rates and use of fertilisers, and conversion of land used for sheep/beef farming to dairy or deer farms.

“We have used the Network to measure carbon travelling down New Zealand rivers – and found that this flow to the sea of carbon, coming ultimately from soils, is the equivalent of about 40% of New Zealand’s fossil fuel carbon emissions. We’ve also recently combined river quality data with satellite images of coastal areas to track river plumes. These can affect coastal water quality and could impact on marine reefs and shellfish aquaculture,” Dr Davies-Colley says.

However, overall New Zealand’s river water quality is in good condition by international standards, especially rivers in native forest and high country areas.

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