Human-caused threats to marine habitats

  • Image, Threats to marine habitats.

    Human activities can harm marine habitats. The activities can affect the habitats directly (eg seabed trawling) or indirectly (eg sediment or contaminant run-off from arable land or built environments). Threats can be local (eg sedimentation in an estuary) or global (eg worldwide carbon dioxide (CO2) emissions driving ocean acidification).

    We classified Human-caused threats to marine habitats as supporting information.

    Key findings

    Human activities can severely affect the marine environment.

    • Ocean acidification is the greatest human threat to New Zealand marine habitats.
    • Other major threats are:
      • climate change (especially higher sea temperatures)
      • fishing (especially bottom trawling)
      • inputs from rivers (especially sediment).
    • Threats also include invasive species, algal blooms, and pollution.
    • Shallow habitats are more vulnerable than those deeper than 50m, and can be affected by more serious threats (up to 52 threats, compared with five threats for deep-water habitats).
    • Coastal reef, sand, and mud habitats are the most threatened habitats.

    Definition and methodology

    This information is based on a study in which 45 experts were asked to assess the impacts of 65 threats on 62 habitats (343 assessments in total), using five vulnerability criteria (MacDiarmid et al, 2012).

    Data quality

     Topic Classification   Relevance Accuracy 
    Resource use and management, and other human activities Supporting information



    See Data quality information for more detail.


    MacDiarmid, A, McKenzie, A, Sturman, J, Beaumont, J, Mikaloff-Fletcher, S, & Dunne, J (2012). Assessment of anthropogenic threats to New Zealand marine habitats. New Zealand Aquatic Environment and Biodiversity Report No. 93. Available from

    Archived pages

    See Human-caused threats to marine habitats (archived October 2016). 


    Updated 27 October 2016


Related content

Access data files

Fisheries impacts data


Related indicators

Threats to marine habitats


Related links

Our marine environment 2016

Environment Aotearoa 2015

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