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  • Weddell seals and orca are among the top predators in the Ross Sea region of Antarctica, and more than half of the Weddell seal population can be found in the Ross Sea. Information about changes in population numbers could give important insights into the health and functioning of the Antarctica ecosystem.

    Rights: Public domain

    Weddell seal and her young pup

    A Weddell seal (Leptonychotes weddellii) and her young pup. During the breeding season, females rearing their pups gather in colonies along cracks in the ‘fast ice’ – sea ice adjacent to land or ice shelves that is continuous except for small cracks caused by tidal action.

    Toothfish are an important food source for Weddell seals (see Antarctic marine ecosystem). They are a high-energy food source for the seals, particularly during the breeding season when both male and female seals lose an enormous amount of weight. The abundance of toothfish seems to be linked to how well seals recover from their breeding season, which impacts on the success of future breeding seasons.

    It is really difficult to count seals – they tend to live in remote hard-to-reach locations where weather conditions are extreme, and they spend a lot of their time in the water. During summer, they haul themselves out onto the ice for some time each day. Scientists need to understand the typical pattern of seal numbers out on the ice so they can reliably estimate the population size.

    To enlist help, scientists set up an online citizen science project. Although this project has since finished, the full results from ScienceAdvances can be seen here.

    Rights: Zooniverse

    Zooniverse logo

    Zooniverse is a platform for citizen science projects that bring together researchers and volunteers to assist with data analysis and image identification.


    Reach: Worldwide

    Nature of science focus: Online citizen science (OCS) projects can be used to develop any of the Nature of Science (NoS) substrands. Identify aspects of NoS that your students need to get better at or understand more fully, and then frame your unit to be very clear about these things when you do them.

    Science capability focus: Gather and interpret data

    Science focus: Ecology

    Some suggested science concepts:

    • All animals occupy specific habitats and niches.
    • All animals have adaptive features – structural (tapered bodies, blubber, large lungs), physiological (slowing heart rate when diving to conserve oxygen, large blood volume) or behavioural (basking in the Sun to warm up, creating breathing holes in the ice) – that enable them to survive.
    • Animals respond to changes in their environment, both natural and humaninduced.
    • Energy is transferred through food webs.

    Many concepts could be learned – focusing on a few can often be more powerful. Develop your learning outcomes and success criteria from these concepts as well as the Nature of Science strand and the science capabilities.

    Some examples of learning outcomes:

    Students can:

    • describe an animal’s habitat and niche
    • relate an animal’s structural or behavioural features to how the animal survives
    • observe closely to identify the presence and number of seals in images
    • discuss the benefits and challenges of setting up an online citizen science project like the Weddell sea seal count.

    About Zooniverse’s Weddell seal count project

    Participants in this OCS project support scientists by helping to analyse approximately 10,000 images taken by two land-based automated cameras on Turtle Rock, Erebus Bay. These cameras took pictures every 10 minutes over the period from 27 November 2014 through to 1 January 2015.

    Scientists are looking for changes in population numbers so they can assess if the Weddell seals are being adversely affected by human fishing for toothfish or by the ice melting away beneath them due to climate change.

    Participation in the project can be done at any time using a computer to access the images and identify and count the number of seals. The tutorial images are effective in training your eye to decide if what you see is indeed a seal or not or a mother and pup (baby seal). Mothers and pups are counted separately from individual seal counts. There are three classifications: pups very close to their mothers, pups away from their mothers and individual seals.

    The website is well set up and easy to follow. Additional information and tutorials are available if required. After you have counted the seals in an image, another one appears. You can also ask questions about the image if you are unsure, and you can contact the scientists through the ‘talk’ feature. Here you’ll also find other people’s comments and observations.

    This OCS project lends itself to developing an appreciation for an amazing environment and its inhabitants. It will also help develop students’ ability to carefully observe. Some useful conversations can be had around why scientists need assistance in categorising all of these photos/videos and how they make sure that the data collection is reliable.


    This project is no longer collecting data.

    In September 2021, insights from the first global population estimate of Weddell seals in Antarctica were published. Scientists estimated there are about 202,000 female seals, which is less than expected. The research suggests that fast ice (where ice is anchored to the shore), ocean depth and distances to penguin colonies explains the spatial spread of these seals. The authors say Weddell seals – along with penguins – could be used as an indicator of environmental changes in the area.

    • Full report here from ScienceAdvances
    • Watch this YouTube video of Dr Michelle LaRue talking about the global population count of Weddell seals in Antarctica.

    Nature of science

    Using OCS projects like this one in teaching and learning provides opportunities to discuss how scientists might use the collective data from photos to monitor species numbers. Students can also consider the opportunities and challenges in setting up an OCS project like this one.

    Related content

    Find out more about different types of seals, and count the crabeater seals in Antarctica as part of another online citizen science project.

    For other online citizen science projects logging the distribution of species, see Kea Database and Instant Wild.

    eBird, New Zealand Garden Bird Survey, Marine Metre Squared and iNaturalist enable you to log your data rather than asking you to interpret images captured by the project.

    In Taranaki’s Project Hotspot, citizen scientists are asked to log sightings of coastal species. Using hidden cameras, researchers from Victoria University of Wellington asked citizens to help investigate the number of invasive mammals in Wellington – see Invasive animals in cities.

    Who’s eating who? by Bronwen Wall in the Ministry of Education’s Connected series level 4, 2012, looks at Antarctic food webs and animal adaptations for life in an icy ecosystem. Teacher support material is also available.

    Here are some planning tips for when you intend to use a citizen science project with your students.

    Useful links

    The Ministry of Education’s Building Science Concepts series includes Book 39: Is it an Animal? Introducing the Animal Kingdom and Book 55: Mammals: Investigating a group of animals

    For more on adaptations of Weddell seals, see Cool Antarctica.

      Published 29 March 2019, Updated 25 September 2021 Referencing Hub articles
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