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  • Environmental DNA (eDNA) has revolutionised how scientists monitor ecosystems and identify the species that live in them. eDNA is genetic material found in hair, scales, skin and even faeces (poo) that are naturally shed by living things into the environment.

    Rights: The University of Waikato Te Whare Wānanga o Waikato

    DNA sequence for tuna and brown trout

    When ‘fishing for eDNA’, students discover what is living in a lake by matching a short DNA sequence with the species it comes from.

    Note: These are simulated DNA sequences rather than the actual sequence.

    Every living thing has a DNA barcode – a short unique DNA sequence. Just like we scan barcodes to identify products in our shopping trolley, scientists look for DNA barcodes in samples of water from a lake, seawater, mud, ice or soil. They use the eDNA to identify individual organisms and monitor what’s living in a lake and even in the surrounding ecosystem.

    This energetic activity simulates scientists fishing for (collecting) eDNA sequences from a lake system – housed in a plastic container outside – perhaps the school’s sports field or quad. Students match the eDNA sequences they collect with reference images and collate the data in a graph. Students are encouraged to peer review their results to build an accurate body of evidence.

    eDNA explorers – discovering life in the lakes of Aotearoa

    This animated video provides a simple explanation of eDNA and how it helps us discover what is living in a lake.

    Select here to view video transcript, questions for discussion and copyright information.

    In this activity, students use a magnetic fishing rod to collect information about the presence and population size of organisms living in their lake ecosystem. They use reference images to interpret and match the eDNA sequences and create a data collection chart of what’s living in the lake and the land around it and how abundant they are. Note: The activity uses simulated DNA sequences for each species.

    By the end of this activity, students should be able to:

    • begin to recognise that all living things have a unique DNA barcode
    • begin to recognise that scientists can use these barcodes to identify what is living in a particular location
    • make inferences about why the DNA of non-aquatic species like cows or pine trees might be in a lake
    • make inferences about the condition of the lake as an ecosystem (its health)
    • discuss some of the advantages and disadvantages of using eDNA for ecosystem monitoring.

    Download the Word file (see link below).

    Download the eDNA sequences and species cards PDF file (see link below).

    Download the species tokens and data collection chart PDF file (see link below).

    Nature of science

    When building a body of knowledge, scientists use peer review to ensure data accuracy and quality control. During this activity, students review their research by ensuring the sequence cards are accurately matched to the corresponding images and the results are accurately recorded in the data table. These actions support students to practise the science capabilities ‘Critique evidence’ and ‘Use evidence’.

    Related content

    Lakes380 – Our lakes’ health: past, present, future uses eDNA and other methods to document lake health around Aotearoa. Find out what the data tells us.

    Find out how students used DNA barcodes to identify food sources in wētā frass (poo). Schools are using this information to create wētā-friendly habitats!

    The article What is PCR? explains the process by which millions of copies of a specific DNA sequence are produced from a small sample.

    Read about the steps in DNA extraction.

    Activity ideas

    Use this activity to explore your local lake.

    Use this activity to extract DNA from a tomato.

    Use these activities to monitor species in your local environment:

    Useful links

    Lakes380 – Our lakes’ health: past, present, future is a 5-year research project that will enrich our understanding of the environmental, social and cultural histories of 10% of New Zealand’s 3,800 lakes (>1 ha). This involves collecting and analysing lake sediments and water samples as well as interviews and field visits.

    Visit the Environmental Protection Authority’s Wai Tuwhera o te Taiao – Open Waters Aotearoa programme. The programme provides eDNA testing kits and resources to community groups, iwi, hapū, school and kura.

    Watch these animated YouTube videos for simple explanations of eDNA: Illumina’s What is Environmental DNA (eDNA)? and World Wildlife Fund’s Environmental DNA.

    New Zealand’s Biological Heritage National Science Challenge uses eDNA for environmental monitoring. It has supported the creation of a nationwide database to integrate and share eDNA data.

    Wilderlab provides advanced lab testing services for eDNA monitoring in Aotearoa. Wilderlab has an interactive map with publicly available eDNA data. This is a useful resource for scientists, conservationists, educators and anyone else with an interest in biodiversity, water quality and biosecurity in Aotearoa.

    This The Conversation article looks at the application of eDNA to develop a new index to measure river health using the Taxon-Independent Community Index.


    This resource has been developed in collaboration with Lakes380 – Our lakes’ health: past, present, future (C05X1707), Cawthron Institute and GNS Science. The concept for this activity was conceived by Georgia Thomson-Laing (Cawthron Institute) and was developed through the Lakes380 Education Workshops funded by the Cawthron Institute Trust Board.

    Rights: Crown Copyright, Cawthron Institute and GNS Science

    Lakes380 – Our lakes’ health: past, present, future

    Lakes380 is a national project to gain in-depth understanding of the current and historical health of lakes in Aotearoa New Zealand. The project was co-led by GNS Science and Cawthron Institute and funded by the New Zealand Ministry of Business, Innovation and Employment (C05X1707;

      Published 9 February 2023, Updated 13 March 2023 Referencing Hub articles
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