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Harbour issues

Mangroves, biosecurity, loss of sea grass habitat, sea lettuce and sedimentation are all issues that are affecting water quality and our ability to enjoy the harbour.

The way we use and manage land and go about our daily business can affect all of those things.

Recreational and commercial vessels from all over New Zealand and the world enter Tauranga Harbour every week, bringing the risk of marine pests with them.

Find out more about specific Tauranga Harbour issues

Learn how you can help care for Tauranga Harbour

There are many simple steps you can take to care for Tauranga Harbour: at home, work, around your garden or farm, and of course, on and around the water.

Find out what you can do to make a difference.

Harbour health

In 2011, Manaaki Taha Moana (a project funded by Ministry of Science and Innovation) prepared a comprehensive report on the health of Tauranga Harbour, which summarised all of the known monitoring and research on the harbour. The report has also identified gaps in knowledge and priorities for field research. This report is available at the Manaaki Taha Moana website.

In summary the report does not identify any significant trends for water quality or benthic communities, however it does express concern at:

  • The 34% decline in seagrass over 40 years, with losses of up to 90% in subtidal areas (areas not exposed by the tide). 
  • The increase in mangrove coverage by 160% over the last 60 years.  Ongoing sedimentation has been identified as the primary cause of mangrove spread.
  • Sea lettuce blooms and the visual and odour effects of accumulations on nearby residents and harbour users and also the effects of accumulations on the ecology of the harbour.
  • The decline of some fish species, shellfish species, effects of toxic phytoplankton, and the ongoing risk of establishment of invasive species in the harbour.

Other sources of information about the state of the harbour environment are: