River Guardians Dolphin Watch Project Swan River Trust Swan River Trust’s River Guardians Program PO Box 6740, Hay Street, East Perth WA 6892 Ph: 9278 099 Email: guardians@swanrivertrust.wa.gov.au
Dolphins in the Riverpark Threats and solutions
Caring for the Swan Canning Riverpark
Dolphins in the Riverpark Threats and solutions Information for teachers SWAN RIVER TRUST The Swan River Trust is a state government agency that protects, manages and enhances the Swan Canning Riverpark by working in partnership with government and the community.
Dr Hugh Finn photographing dolphins
RIVER GUARDIANS The River Guardians program engages the Perth community in activities that protect and restore the Swan Canning foreshores and waterways by involving and educating the community through events and activities with a river focus. www.riverguardians.com DOLPHIN WATCH PROJECT River Guardians Dolphin Watch was launched in April 2009. Dolphin Watch volunteers record details of dolphin sightings in the Swan and Canning rivers, now known as the Swan Canning Riverpark. Volunteers gather valuable scientific information on how dolphins use the Riverpark. Murdoch University’s Dr Hugh Finn and Curtin University’s Dr Chandra Salgado are leading this research into Perth’s river dolphins. Dolphin Watch is helping them build on previous research and aims to provide key information on dolphins in the Riverpark. The outcome of the study will be a comprehensive understanding of dolphin health in the Swan River and the effects of human activities on the mammals.
Dolphin Watcher Shirley Oliver with River Guardians Program Manager Marnie Giroud
Dolphin Watchers Trita and Peter Agar
Dolphin Watch volunteers, scientists and Swan River Trust staff aboard a Trust vessel
Dolphin background information CLASSIFICATION Classification: Scientific name: Common name:
Animalia – Chordata – Mammalia – Cetacea – Odontoceti - Delphinidae Tursiops aduncus Indian Ocean Bottlenose Dolphin
LIFE SPAN • Females – 40 years • Males – 30-35 years SIZE •
An average sized adult is 2.4m long and weighs 155kg
REPRODUCTION • Gestation is 12 months • Females have one calf about once every 4 years • Females can have 8 calves in their lifetime • A calf stays with its mother for 3-5 years • Females may first calve at around age 10-12 • Males may not mate successfully until much later because of intense competition for access to females SOCIAL STRUCTURE • Females have a network of female friends • Males usually bond closely to one another and form a long-term partnership known as an alliance • After weaning, juvenile dolphins spend several years learning about their environment and the dolphin society they inhabit. During these years, they learn important social and feeding skills that they will need in order to survive as adults.
HOME RANGE IN THE SWAN CANNING RIVERPARK • The ‘Swan’ dolphins split their time between the estuary and coastal areas such as Owen Anchorage off Coogee • They are often seen in the Canning River and some will occasionally travel into the upper reaches of the Swan River • Dolphin Watch volunteers help determine how far they travel upstream • The dolphins most commonly seen in the Riverpark use the rivers year-round and are thought
to be long-term residents. It is likely that their mothers were also ‘river’ dolphins COMMUNITY • There is an estimate of around 20 - 25 dolphins that live in the Swan Canning Riverpark STATUS • Common in their range • Protected by the Wildlife Conservation Act 1950
The dolphin with the white patch was named Kwillena by a Dolphin Watcher
Photo: Hugh Finn
THREATS Life can be stressful for dolphins in the urban Swan and Canning rivers. An adult needs to find more than 12-15kg of a fish a day but is on constant look-out for sharks. A female also has to look after a dependent calf for 3-5 years. Humans add to the stress that dolphins experience. So the best thing we can do is leave them alone. Threats to dolphins include: • entanglement in discarded fishing line • health effects from contaminants • loss of habitat and declines in food species • poor water quality from nutrient contamination • toxic algal blooms • disturbance from boat traffic • excessive underwater noise • people illegally feeding dolphins which can lead to boat strike and entanglement (dolphins often come close to boat owners who are feeding them)
HOW YOU CAN HELP DOLPHINS • Keep your distance - never approach a wild dolphin and make sure you keep at least 30 metres away if you’re in the water or 100 metres away if you’re in a boat. • Slow down for dolphins - dolphins often form resting groups in the middle reaches of the estuary, so keep an eye out for dolphins, and slow down if you spot any. • Never feed dolphins - it is illegal and leaves them vulnerable to entanglement, boat strikes, and disease. • Fish responsibly - dolphins, particularly calves, can get tangled in fishing line. Make sure you dispose of unwanted monofilament line carefully. Use biodegradable fishing line and take only what you need to maintain fish stocks. • Take rubbish home - rubbish such as plastic bags and fishing line can seriously injure or kill wildlife. • Report sick, stressed or injured dolphins - to the Department of Environment and Conservation’s Wildcare Helpline 9474 9055. INTERESTING FACTS • In Shark Bay, bottlenose dolphins use a feeding technique called “sponging”. To “sponge’, dolphins take a marine sponges off the sea floor and wear it on their beak (rostrum). The sponge provides protection while they probe around on the bottom for fish hidden in sand or under rocks. • Until recently, all bottlenose dolphins were considered members of one species. Now, scientists recognise two species: the Common Bottlenose dolphin (Tursiops truncatus) and the Indo-Pacific Bottlenose dolphin (Tursiops aduncus). In south west Western Australia, Common Bottlenose dolphins are generally found well offshore, while Indo-Pacific Bottlenose dolphins occur in coastal and estuarine areas. • In coastal and estuarine areas, bottlenose dolphins are generally observed in small groups of less than ten dolphins. In the open ocean, groups may number in the hundreds. • Scientists identify dolphins by permanent marks on their dorsal fins. These markings are scars and allow for dolphins to be monitored across their life-times. • Murdoch and Curtin universities work together with the Swan River Trust to monitor dolphins in the rivers. • River Guardians members can become Dolphin Watch volunteers and learn how to monitor dolphins in the rivers www.riverguardians.com
Dolphins in the Swan Canning Riverpark
Dolphins in the Riverpark Threats and solutions CURRICULUM LINKS Click on the hyperlinked learning area below to take you directly to the Curriculum Council’s Curriculum Resources.
Society and Environment - Place and Space - Sustainability requires community cooperation Science - Life and Living - Interdependence of living things Science - Earth and Beyond - Sustainability of life and wise resource use Values - Environmental Responsibility - 5.4 Diversity of species The Arts - Students generate arts works that communicate ideas. English - Reading English - Listening and Speaking Progress
LEVEL This activity is aimed at primary and middle school but may be adapted across all levels.
ACTIVITY AIM Learn about Indo-Pacific Bottlenose dolphins living in the Swan Canning Riverpark. Investigate the threats to dolphins living in the Riverpark and workshop solutions.
REFERENCES 1. 2. 3. 4.
www.riverguardians.com www.cffr.murdoch.edu.au/mucru/ Curtin University of Technology – www.cmst.curtin.edu.au Conservation biology of bottlenose dolphins (tursiops Sp.) in Perth metropolitan waters, Hugh Finn, Doctoral candidate, Murdoch University, 2005 5. Bottlenose dolphins (Tursiops sp.) in the Swan River, Western Australia: community size and composition, residency patterns, and social structure, Hong Nam Lo, Honours candidate, Department of Environmental and Aquatic Science 6. Bottlenose dolphins (Tursiops sp.) – a Study of Patterns in Spatial and Temporal use of the Swan River, Western Australia, Kimberly Moiler, Honours candidate, Department of Environmental Biology, Curtin University 7. Dolphin Discovery Centre - www.dolphindiscovery.com.au
MATERIALS: • • • •
inflatable dolphins x 4 (you can purchase from Toys R Us or Clark Rubber) sticky note pads x 4 red and blue textas x 8 dolphin background information (included)
ACTIVITY: Threats and solutions Activity steps
Time
There are many options for students to discover information on dolphins. You may like to choose from the following list: • read the dolphin background information; • write or distribute information as notes for students; • ask students to research information as a set assignment; • show a video on dolphins; or • visit Dolphin Discovery Centre in Bunbury www.dolphindiscovery.com.au, Naturaliste Marine Discovery Centre www.nmdc.com.au or the Aquarium of Western Australia www.aqwa.com.au/main.asp
Varies depending on activity chosen
2
•
Explain that scientists call small groups of dolphins ‘pods’. Organise students into four groups and ask each group to come up with a name for their dolphin ‘pod’
3 minutes
3
• •
Hand out post it notes and textas Explain that scientists often name dolphins according to physical characteristics they can see on the skin or dorsal fin of dolphins including nicks, cuts and scars from other dolphins and predators such as sharks Ask each group to name their dolphin according to the physical characteristics they can see (e.g. ‘Spot’ because there are spots on the dolphin.) Ask each group to identify threats to dolphins in the rivers and write each threat in red on a separate sticky note Stick each sticky note with a threat to the inflatable dolphin
1
•
•
4
•
•
Materials
Curriculum link
• dolphin background information provided • internet • excursion • video • library resources
Science - Life and Living Interdependence of living things
10 minutes
• • • •
post it notes red textas black textas inflatable dolphins
English - Listening and Speaking Progress
10 - 15 minutes
• • • •
post it notes red texta black texta inflatable dolphins
Science - Earth and Beyond Sustainability of life and wise resource use
English - Reading
5
•
•
6
•
7
•
8
•
9
•
Rotate the dolphins from one group to the next (ask one student from each group to take their dolphin to the next pod – clockwise works best) Write a solution for each of the threats (written and attached to the dolphin from the previous group) in black texta and attach to the sticky note threat Invite one person from each group to hand in all sticky note threats from their group. Stick the threat to the board and continue to collect threats from each group. Group the double-ups into themes such as fishing (fishing line rubbish, fishing hooks). Read out the threats and solutions and discuss. Discuss any threats/solutions not identified with the information sheet included with this pack. Make a poster/write a story/or conduct a presentation on how to keep our rivers and dolphins healthy
Conduct the Dolphin Quiz with students included with this pack.
10 - 15 minutes
• • •
post it notes black texta inflatable dolphins
Science - Earth and Beyond Sustainability of life and wise resource use
10 minutes
•
board or wall
Science - Earth and Beyond Sustainability of life and wise resource use English - Listening and Speaking Progress
10 minutes
40 – 60 mins (This activity could also be extended to become a large assessment piece)
• • • •
10 minutes
•
art materials A3 poster paper computers
quiz sheets
Science - Earth and Beyond Sustainability of life and wise resource use Society and Environment - Place and Space - Sustainability requires community cooperation The Arts - Students generate arts works that communicate ideas. English - Listening and Speaking Progress Society and Environment - Place and Space - Sustainability requires community cooperation
Assessment Activity steps 1, 8 and 9 can be used as assessment tasks at your discretion.
Threats and solutions Keep your distance – never approach a wild dolphin and make sure you keep at least 30 metres away if you’re in the water or 100 metres if you’re in a boat. Brake for dolphins - dolphins often form resting groups in the middle reaches of the estuary, so keep an eye out for dolphins, and slow down if you spot any. Never feed dolphins – it is illegal and leaves them vulnerable to entanglement, boat strikes and disease. Fish responsibly – dolphins, particularly calves, can get tangled in fishing line. Make sure you dispose of unwanted monofilament line carefully, use biodegradable fishing line and take only what you need to maintain fish stocks.
Take your rubbish home - rubbish such as plastic bags and fishing line can seriously injure or kill wildlife. Take your rubbish home with you and pick up rubbish when you see it. Prevent pollution - many rivers, estuaries and coastal waters near large human population centres show signs of nutrient overloading and heavy metal contamination. Toxic algal blooms are increasingly common in estuaries and bays. There are many ways you can help reduce pollution in the rivers: 1. Fertilise wise at home – never over-water and only apply fertiliser when it’s needed in spring or early autumn 2. Wash your car on the lawn to keep detergents out of the stormwater drainage system 3. Grow local native plants in your garden 4. Pick up your dog’s waste. It’s full of nutrients which can feed algal blooms 5. Dispose of your paint, oil and chemicals appropriately – ask your local council for help 6. Use phosphorous-free detergents to wash your clothes Weeds in your garden - keep garden weeds away from drains, they may end up as invasive weeds in the rivers. Compost leaves and clippings so they don’t contribute to nutrient overload in the rivers
Discarded fishing line wrapped around the tail fin of this dolphin potentially caused this animal to die
Name:
DOLPHIN QUIZ Q.
What species of dolphins do we have in the Riverpark?
________________________________________________________________________________ Q.
How many calves (baby dolphins) can a female dolphin have in her lifetime?
________________________________________________________________________________
Q.
Why shouldn’t you feed dolphins in the wild?
________________________________________________________________________________ ________________________________________________________________________________
Q.
How can you fish responsibly?
________________________________________________________________________________ ________________________________________________________________________________ Q.
What can you do at home to help keep our rivers and dolphins healthy?
________________________________________________________________________________ ________________________________________________________________________________
DOLPHIN QUIZ ANSWERS Q.
What species of dolphins do we have in the Riverpark? Tursiops adunctus or Indo Pacific Bottlenose dolphins
Q.
How many calves (baby dolphins) can a female dolphin have in her lifetime? 8
Q.
Why shouldn’t you feed dolphins in the wild? It is illegal and leaves them vulnerable to entanglement, boat strikes, and disease when they approach humans and boats
Q.
How can you fish responsibly? Provide two answers. • dolphins, particularly calves, can get tangled in fishing line. Make sure you dispose of unwanted monofilament line carefully • use biodegradable fishing line; and • take only what you need to maintain fish stocks
Q.
What can you do at home to help keep our rivers and dolphins healthy? Provide at least four points. • fertilise wise at home – never over-water and only apply fertiliser when it’s needed in spring or early autumn. • wash your car on the lawn to keep detergents out of the stormwater drainage system • grow local native plants in your garden • take your rubbish home with you and pick up rubbish when you see it • pick up your dog’s waste, because it’s full of nutrients which can feed algal blooms • dispose of your paint, oil and chemicals appropriately – ask your local council for help • use phosphorous-free detergents to wash your clothes. Phosphorous is one of the main nutrients that feed algal blooms • compost your leaves and clippings. If washed into stormwater drains, they can contribute to nutrient overload in the rivers. • keep garden weeds away from drains. They may end up in the rivers as invasive weeds.