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Image Tuna sandwich trophic pyramid

TLF ID M008772

This image is a diagram known as a trophic pyramid. This example shows the levels of an ecosystem that support the growth of tuna, which might be consumed by a human in a tuna sandwich. The diagram shows six levels in the 'pyramid' from phytoplankton through to humans, and visually depicts the size of the biomass at each level of the pyramid.

Educational details

Educational value
  • In the tuna sandwich trophic pyramid, humans are fourth-level carnivores (or fifth-order consumers) when they eat tuna, and tuna are third-level carnivores (or fourth-order consumers). Tuna hunt fish such as mackerel (which makes up about 90 per cent of tuna's diet), molluscs (mainly squid) and crustaceans (such as lobster larvae in the zooplankton). Tuna are fast predators that hunt over a wide area.
  • In the tuna sandwich trophic pyramid, mackerel are the second-level carnivores (or third-order consumers). Their diet consists of zooplankton in summer, fish (such as blue whiting) and decapods (shrimp and lobster larvae) in autumn, and decapod larvae in winter. Whiting are the first-level carnivores (or second-order consumers). They hunt arthropods, fish, annelids (worms), cephalopods (such as squid), crustaceans (such as lobster larvae), polychaete worms and bivalves (such as mussels).
  • The animals that make up the zooplankton are herbivorous consumers (or first-order consumers). These animals (including tiny copepods, less than a centimetre long) are usually larger than the minute algae that make up the phytoplankton.
  • There is a 90 per cent loss of chemical and heat energy at each step in a trophic pyramid such as this. As much as 100 000 kg of producers ends up as 1 g of human via tuna. In contrast, 10 g of wheat ends up as 1 g human via wheat.
Year level

5; 6; 7

Learning area
  • Science

Other details

  • Contributor
  • Name: University of Waikato
  • Organization: University of Waikato
  • Description: content provider
  • Address: NEW ZEALAND
  • URL:
  • Publisher
  • Name: Education Services Australia Ltd
  • Organization: Education Services Australia Ltd
  • Description: Publisher
  • Address: VIC, AUSTRALIA
  • URL:
  • Resource metadata contributed by
  • Name: Education Services Australia Ltd
  • Organisation: Education Services Australia Ltd
  • Address: AUSTRALIA
  • URL:
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  • Generic
Learning Resource Type
  • Image
  • © Education Services Australia Ltd 2011 (except where otherwise indicated). You may copy, communicate and adapt this metadata for non-commercial educational purposes provided you retain all acknowledgements associated with the material.