Change in the conservation status of indigenous marine species

  • Image, Conservation status of marine indigenous species.

    Marine mammals, seabirds, and shorebirds are indicator species for the state of our marine environment. A decreasing population can indicate that the ecosystem is degrading. New Zealand has a diverse range of marine species, many of which are endemic to (only breed in) New Zealand. They are apex species (near the top of the food chain) and can thrive only if their ecosystems are healthy.

    This measure reports on the number of indigenous marine species that have had a genuine change in conservation status between two monitoring periods (2008–11 and 2012–14). A change in a species’ conservation status reflects a change in its risk of extinction.

    We classified Changes in the conservation status of indigenous marine species as a case study.

    Key findings

    The conservation status of eight (9 percent) of the 92 seabird species and subspecies worsened between the 2008–11 and 2012–14 assessment periods.

    • Nationally critical
      • Antipodean wandering albatross (Diomedea antipodensis antipodensis)
      • Black-billed gull (Larus bulleri)
      • Chatham Island shag (Leucocarbo onslowi
      • Gibson's wandering albatross (Diomedea antipodensis gibsoni
      • Pitt Island shag (Stictocarbo featherstoni)
      • Salvin's mollymawk (Thalassarche salvini)
    • Nationally endangered
      • Fiordland crested penguin (Eudyptes pachyrhynchus)
    • Declining:
      • Erect-crested penguin (Eudyptes sclateri)
    • The conservation status of one (1 percent) of the 92 seabird species, the Bounty Island shag (Leucocarbo ranfurlyi), improved between the two listing cycles.
    • The conservation status of one (3 percent) of the 29 marine mammal species, the southern right whale (Eubalaena australis), improved between the two assessment periods, due to a population increase.
    Note: Excludes non-resident indigenous species (migrants and vagrants) that do not breed in New Zealand, as well as extinct species. The graph only includes species for which a genuine change of conservation status was determined.

    Definition and methodology

    The state of marine mammal, seabirds, and shorebirds populations is one of the indicators for healthy marine ecosystems. Decreasing populations can signal degradation of an ecosystem, although other factors (eg bycatch, ship strikes, or disease) may also cause populations to decrease.

    This is a measure of the number of indigenous marine species (mammals, seabirds, and shorebirds) that showed genuine changes in their conservation status between the two New Zealand Threat Classification System (NZTCS) listing cycles of 2008–11 and 2012–14. The conservation status of 92 seabirds, 14 shorebirds and 29 mammal species and subspecies were assessed.

    The NZTCS helps quantify the risk of all indigenous plants, animals, and fungi becoming extinct. It is used to monitor the status of individual species and report on the state of indigenous biodiversity. We use data for marine mammals, seabirds, and shorebirds.

    The Department of Conservation developed the NZTCS to provide a national system similar to the International Union for Conservation of Nature and Natural Resources (IUCN) Red List (Townsend et al, 2008). NZTCS classifications are made by independent expert panels. The panels classify taxa using combinations of one or more of the following criteria: total number of mature individuals in a taxon, population trend, total number of populations, number of mature individuals in the largest population, and area of occupancy of the total population.

    The analysis in this case study only considers changes in conservation status that are a result of a change in a species’ population numbers or distribution. It excludes changes in a species’ conservation status that are a result of changes in available information, the classification system, or taxonomy.

    Data quality

     Topic Classification   Relevance Accuracy 
     Biodiversity and ecosystem processes  Case study

     Image, Partial relevance.

    Image, High accuracy.


    Baker, CS, Chilvers, BL, Childerhouse, S, Constantine, R, Currey, R, Mattlin, R, van Helden, A, Hitchmough, R, & Rolfe, J (2016). Conservation status of New Zealand marine mammals, 2013 (PDF, 602kB). New Zealand Threat Classification Series 14.  Retrieved from

    Robertson, HA, Dowding, JE, Elliott, GP, Hitchmough, RA, Miskelly, CM, O’Donnell, CFJ, … Taylor, GA (2013). Conservation status of New Zealand birds, 2012 (PDF, 621kB). New Zealand Threat Classification Series 4. Retrieved from

    Townsend, AJ, de Lange, PJ, Duffy, CAJ, Miskelly, CM, Molloy, J, & Norton, DA (2008). New Zealand Threat Classification System manual (PDF, 478kB). Retrieved from


    Published October 27 2016

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