Scientists from Murdoch University in Perth, Western Australia, are studying the urban dolphins in the city's Swan Canning Riverpark.
The research team's ongoing survey aims to find out which areas of the river the dolphins are using the most, and therefore which areas might need greater protection.
Watch the video and answer the questions below. The activity is suitable for intermediate students.
1 Why is Swan Canning Riverpark a challenging area for the dolphins?
2 Why can the population of dolphins decrease very quickly?
3 How long will dolphins stay at the surface? And underwater?
4 What happened in 2009?
5 How many dolphins usually die in a year?
6 What is good news?
7 Name one threat dolphins face in Swan Canning Riverpark.
You can check your answers by reading the transcript below.
For the population living in the Swan Canning Riverpark, it’s about 25, 30 individuals. It is a very challenging area for these dolphins because the Swan Canning Riverpark is an urbanized area. They have a very high risk of danger in the river and if we do not make personal … the population can decrease very quickly, especially because it’s a very small number.
We are trying to… Ah! We have dolphin! So at the moment they are foraging, so you will see them at the surface for just a little bit, but diving for quite a few minutes until they come back at the surface.
First of all, looking at which area the dolphins are using in the river, and from that we’re going to see if that area need a little bit more protection.
Back in 2009 we had six dolphins dead in the river in a very short time, so that just basically it’s the population of resident dolphins in Swan Canning Riverpark just decreased in a very high proportion.
Generally you count about one dead per year. This time was six in the year, so we call that an unusual event of mortality. The population numbers is back to what it was ten years ago. It is a good news, but you have to keep in mind that is still an urbanised area, so it’s still very challenging for any individuals, dolphins individuals to live in an urbanized area, and they have a high risk of danger like entanglements with fishing lines, speed boats with any recreational boats around.