Atmospheric analysis

NIWA has been using advanced scientific instruments to measure atmospheric trace gases and isotopes for over 50 years.

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    Tuna - defining your research questions

    Defining your research questions is the first place to start when designing a survey.
  • Tuna - monitoring

    In this section, we look at defining your research questions, site selection and timing, sampling methods, and considerations for data collection.
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    Tuna - acknowledgements

    Since NIWA was established as a Crown Research Institute in 1992, the organisation has been fortunate to receive funding to undertake research that continues to increase our understanding of a fascinating and incredibly important taonga freshwater fish.
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    Tuna - databases and resources

  • Tuna - solutions for restoration and enhancement

    Shortfin and longfin eels are an important resource from both a human/cultural use and biodiversity perspective.
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    Tuna aquaculture - international

    Worldwide production of eels is estimated to be worth over $US 1 billion annually, with 233,589 tonnes of eel produced each year.
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    Tuna - barriers to migration

    One of the greatest threats to indigenous fish species which follow a catadromous life cycle (i.e., starting life at sea but then migrating into freshwater) are barriers that prevent or delay migrations between freshwater and marine environments.
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    Tuna - loss of habitat

    Much of the habitat that was formerly available to eels has been lost through practices like the wetland drainage and river channelling.
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    Tuna - pressures on New Zealand populations

    Freshwater eel populations around the world are in steep decline.
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    Tuna - growth

    New Zealand longfins are one of the largest eel species in the world.
  • Tuna - biology and ecology

    Freshwater eels have an unusual life cycle which sees them travelling between the ocean, estuaries and freshwaters.
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    TAN1116 voyage log - technical updates