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    • Rights: The University of Waikato
    Published 3 December 2007 Referencing Hub media
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    Andrew Stewart is discussing the adaptations1 of the Antarctic silverfish2.

    Points of interest for teachers:

    • Students may want to discuss why the icefish does not have red blood.
    • Why is more oxygen3 dissolved in the Antarctic waters?
    • Consider the range of adaptations that icefish have developed.

    Transcript

    ANDREW STEWART
    These particular fishes are found no where else in the planet4 except in Antarctic waters. They’re completely unique to Antarctica, they’re known as ice fishes. Now one of the really amazing things about them is they have no blood at all in them – they have no red blood cells. As you can see the gills are white and when you open them up the stomach5 is white, the liver6 is white, everything is white, there is nothing red or pigmented. There is no haemoglobin7 at all and that’s because the Antarctic waters are so cold that sufficient oxygen can be dissolved in it that they don’t need a carrier to carry oxygen around their body. There are a number of other characters too, such as they have a much larger heart and they can also absorb some oxygen across their skin. So this makes them a particularly interesting and unique group of fishes found nowhere else in the world.

    1. adaptation: A change in the structure or function of something. In biology, a change in a species, as a result of natural selection. Individuals with a particular feature (adaptation) are more likely to survive and reproduce than individuals without this feature.
    2. silverfish: A 5 cm long fish that is especially common in the Ross Sea.
    3. oxygen: A non-metal – symbol O, atomic number 8. Oxygen is a gas found in the air. It is needed for aerobic cellular respiration in cells.
    4. planet: In our Solar System, a planet is defined as an object that orbits the Sun, is big enough for its own gravity to make it ball-shaped and keeps space around it clear of smaller objects.
    5. stomach: An organ of digestion with a sac-like shape located between the oesophagus and the small intestine. It temporarily stores food, mixes and churns it with gastric juice and allows digestion of some of the protein content of food to take place.
    6. liver: A vital organ situated beside the stomach. It is the body’s largest internal organ and plays a major role in metabolism as well as other important and complex functions.
    7. haemoglobin: The oxygen-carrying substance in red blood cells.

    Appears in

    ARTICLE

    Week 3: Diversity of Ross Sea fish

    The Antarctic fish fauna is relatively small, with only around 325 species known and only about 135 reported to be found in the Ross Sea region. By comparison, coral reefs support very large fish ...

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      adaptation

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      2. A change in the structure or function of something. In biology, a change in a species, as a result of natural selection. Individuals with a particular feature (adaptation) are more likely to survive and reproduce than individuals without this feature.

      planet

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      3. In our Solar System, a planet is defined as an object that orbits the Sun, is big enough for its own gravity to make it ball-shaped and keeps space around it clear of smaller objects.

      haemoglobin

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      4. The oxygen-carrying substance in red blood cells.

      silverfish

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      5. A 5 cm long fish that is especially common in the Ross Sea.

      stomach

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      6. An organ of digestion with a sac-like shape located between the oesophagus and the small intestine. It temporarily stores food, mixes and churns it with gastric juice and allows digestion of some of the protein content of food to take place.

      oxygen

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      7. A non-metal – symbol O, atomic number 8. Oxygen is a gas found in the air. It is needed for aerobic cellular respiration in cells.

      liver

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      8. A vital organ situated beside the stomach. It is the body’s largest internal organ and plays a major role in metabolism as well as other important and complex functions.

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