Auckland’s 11,117km2 of sea and roughly 1800km of coastline provide a variety of marine environments, which in turn support diverse marine life.

Auckland Council monitors the health of our marine environments through three main programmes: water quality (approximately 32 sites), sediment contamination (approximately 120 sites) and ecology (approximately 150 sites) covering all the major harbours and most of the smaller estuaries on the east coast.

We monitor a range of key indicators at our water sampling sites, including sediment, nutrients, and metals. These indicators alert us to changes in key water quality factors that have the potential to affect other aspects of the ecosystem, including human health.

Overall, water quality in the Auckland region has improved since the beginning of our sampling in the late 1980s. However, we are starting to see increasing trends in nutrient concentration and suspended sediment at some of our sites, suggesting that changes in land use in these areas is affecting water quality in our estuaries and harbours.

We monitor the health of ecological communities living in the sand or mud flats of estuaries and harbours, as well as on subtidal rocky reefs. We also collect information about the habitat so we can track changes in environmental conditions. The health of ecological communities in many of Auckland’s estuaries and harbours has declined since the 1990s. Many of these changes are attributed to increased sediment deposition, particularly of muddy sediment on sandy habitats. Species diversity has decreased at most sites accompanied by an increase in species that are mud tolerant. On subtidal rocky reefs, we have not seen any significant changes in the community since 2009. The biggest change at our sites has been the appearance of non-native species.

Currently the most degraded areas are close to the centre of Auckland, reflecting current and historic land use impacts. This impact footprint will continue to grow as urban Auckland expands.

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