Northland Lakes Ecological Status 2009

Northland Regional Council (NRC) engaged NIWA to assist achievement of its goal “to prevent deterioration in water quality and loss of biodiversity value in Northland lakes”.

This report presents a summary of information gathered on 80 Northland lakes. The core information in this report is a ‘living’ document to be added to and modified to incorporate changes in lake values as they change. This information is key for the NRC Lakes Strategy as it is essential for managers to know what they are managing and monitor responses to management initiatives.

The report was updated in 2009 by:

1. Re-surveying the Waitahora Lagoon and Lakes Ngakaketa North, Morehurehu, Te Kahika, Waihopo, and Rotokawau (Waipapakauri), with vegetation descriptions, ecological observations, and LakeSPI.
2. Re-surveying Lake Swan and establishing a baseline assessment protocol as this lake was scheduled for invasive weed eradication using grass carp. Grass carp were introduced into Lake Swan in May 2009 by NRC.
3. Rapid assessment of Lake Heather submerged vegetation prior to intiation of a grass carp eradication programme by NRC.
4. Weed surveillance monitoring of Lakes Ngatu, Waiporohita, Kai-iwi, Taharoa, Waikere, Humuhumu, Swan and Rotokawau (all at-risk, high priority water bodies).