SATELLITE tracking, acoustic* tagging and unique genetic testing of great white sharks in Australian waters is helping scientists accurately predict whether populations of great whites are growing or getting smaller.
Great white sharks are listed as vulnerable under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. Vulnerable means in danger. When a particular species is thought to be in danger, a plan is put into place to protect them, so their numbers can recover.
But each summer, we hear about how many sharks are near beaches where people swim and surf. Some people believe there are a growing number of sharks and that their numbers should be controlled to protect people from shark attacks.
People who believe their numbers are growing and people who believe shark numbers are going down may have different opinions on whether shark fishing should be allowed or encouraged and what happens to a shark if it swims too close to people swimming at a beach.
There is no useful historical information to help make decisions like these. And scientists cannot count or study every shark in the ocean. The tracking, tagging and testing work is a way to make accurate guesses as to how many sharks there are now and how many there will be in the future. Then scientists and governments can make informed* decisions about whether sharks need to be protected or whether there are too many.
The scientists doing this shark research are from the CSIRO, which is the Australian government’s research and innovation* group. So far, tag-tracking has shown individual sharks swimming thousands of kilometres along the east coast through Victoria to New Zealand and between South Australia and northwest Western Australia. The process has identified two distinct population groups.
“Juvenile* white sharks move up and down the east coast from the Great Barrier Reef to southern Tasmania and are seasonally more common in Victorian waters over the mid-summer to autumn period,” CSIRO Oceans and Atmosphere senior research scientist Barry Bruce said.
The study has also shown a western population ranging from western Victoria to northwestern Western Australia.
“In general, white sharks tagged in eastern Australia stay in the east and those tagged in SA and WA stay west of Bass Strait,” he said.
First steps to estimate population size have been taken in eastern Australia where nursery* areas
have been targeted to estimate the number of juveniles, their survival and their genetic relatedness*.
Lots of information has been collected on the population west of Bass Strait, including the electronic tagging and tissue* sampling of more than 200 sharks. This field work will be
extended, and the data analysed*, during this project. Aerial* and vessel* surveys will also search for nursery areas to provide further options for monitoring*.
acoustic: relating to sound
informed: given or using information
innovation: doing something new or in a new way
genetic relatedness: shared genes; in the same family
tissue: from the body, such as skin or blood
aerial: in the air
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Activity 1: Great White Sharks!
Completing the activities using full sentence answers.
a) What are the benefits of being able to tag and track great white sharks?
b) Why might shark populations be getting smaller? Why is it important that they remain stable?
c) What information have the scientist found out already?
d) What do you think would be some of the difficulties of tagging and tracking Great White Sharks?
e) Who are the CSIRO? Try and find out what the letters in the acronym stands for.
Extension: Research more about the great white shark
Create a fact file. Include the following information.
Other interesting facts:
Labelled diagram of the animal:
Extra resources: Information about Sharks – either from books or the internet
Time: allow about 40 minutes to complete this task
Curriculum links: English, Science
Activity 2: Food Chain
Great white sharks are said to be at the top of the food chain. Yet they are listed as vulnerable! Research the food chain of the great white shark. Draw the food chain using pictures and labels. Be sure to include who preys on these sharks.
* A food chain shows how a living thing gets nutrients and how that living thing gets nutrients and so on. It usually finished with microscopic organisms or with plants that get energy from the sun. A very simple example is;
eagle – snakes – frog – insects – grass – sun.
Extension: Look at your food chain and discuss with a partner what would happen if sharks become extinct? What would happen to the next animal in this food chain? What would happen to the one after that?
Use and ‘If … then…’ statement to write what would happen on the food chain.
What would happen if there were too many sharks? How would the food chain change?
Write an ‘If … the…’ statement for this scenario as well.
Extra resources: Information about sharks – either from books or the internet
Time: allow at least 40 minutes to complete this task
Curriculum links: English, Science.
(Vocabulary, Connectives, Openers, Punctuation)
Describe the Animal!
Write a description-of-the-senses poem for a shark!
Time: allow at least 10 minutes to complete this task
Curriculum links: English, Big Write, VCOP
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