Our playful residents
A Mandurah dolphin cruise is our region’s most popular tourist attraction. The Peel-Harvey Estuary is lucky enough to be home to more than 80 resident dolphins. There are another 30 who live in the Dawesville Cut and hundreds more along our coast who also occasionally visit our inland waterways.
Mandurah’s waterways are the ideal home for dolphins due to the abundance of fish. In addition, the shallow, warm, protected water is great for birthing. The large population of dolphins in the region shows how healthy our waterways are.
The dolphins that inhabit the Peel-Harvey and adjacent coastal waters are Indo-Pacific Bottlenose Dolphins and ours is Western Australia’s largest residential population of the species.
The size of an adult dolphin in Mandurah ranges from 2.3 to 2.6 metres long and they weigh up to 220kg. At birth they are approximately 1 metre in length, weighing up to 20kg.
Bottlenose dolphins can live to over 40 years of age. In fact, we have a number of dolphins in Mandurah older than 25 years, who we often see on our dolphin cruises including Nikki, Bendy Wendy Fourteen, Bitts, Blake, Jack Daniels, Frankenstein, Twenty Two and Zero One.
Safety in numbers
Dolphins live together in groups. They can have as little as 2 dolphins in their group, up to more than a thousand. Here in Mandurah, we typically see group sizes of 2 to 15 and sometimes up to 30 on our dolphin cruise. Swimming in numbers offers social benefits as well as protection from predators such as sharks.
Our dolphins live in a fission-fusion society, which basically means that individuals come and go, groups form and break apart on a daily basis, with no matriarch or ‘dominant female’ in the group. Few dolphin species actually live in a matriarchal society (orca, pilot whales), where related individuals will stay together as a family group known as a ‘pod’.
Females are usually seen together and have a network of female friends, while males usually bond closely to one other male and form a long-term partnership known as an ‘alliance’, where they feed, pursue females and do everything together. Males may also venture alone for periods of time.
Beautiful baby dolphins
Females have a baby which is called a ‘calf’ every 2 to 3 years in Mandurah. The calf will stay by its mother’s side for up to 3 years and suckle her milk for the first 18 months, just like human babies do. At about 6 years of age, the males will venture off from their mother and form strong bonds with other males, while the females usually continue to associate with their mother and their birth pod.
Bottlenose dolphins predominantly take part in mating when the water temperature is above 20/21 degrees. Here in Mandurah, that is usually from November to June each year.
With a 12-month pregnancy term, most calves are also born during the mating season. In 2017 we spotted 5 new calves on our dolphin cruises – Splash, Sea, Speckle, Nikaila and Andrew, on top of 10 new calves in 2016.
Energetic and cheeky
Dolphins are very social animals who have a very playful and cheeky manner about them. The most obvious sign of socialising between dolphins is body contact. Examples of body contact include rubbing their bodies against each other, stroking each other with their tail flukes or fins, and nudging each other. Other physical socialising can include tail slapping, leaping into the air, chasing each other or throwing around objects such as seaweed and octopus in a playful manner.
They’re also social with animals outside their species. Off Mandurah’s coast they have been observed playing with whales as the whales migrate down the west coast to the Southern Ocean.
They are very curious creatures and like to socialise with humans too. We often see them on our dolphin cruise surfing on the wake of boats, swimming around vessels and looking at people observing them.
Food, glorious food
Mandurah’s dolphins predominantly eat fish. The amount of food they eat depends on the season. During summer, water conditions are warm and they do not need to maintain a thick blubber layer, so the dolphins usually consume between 6 to 8kg per day. In winter, they do a lot of feeding to maintain a thick blubber layer for the colder, winter conditions, consuming between 10 to 14kg a day!
Here in Mandurah we have observed some extraordinary feeding techniques, while on our dolphin cruises. Small fish, like Garfish, are caught with rapid chases. Sometimes the dolphins swimming belly-up (snacking) while the fish tries to escape at the surface. Salmon is usually pursued against rock walls, Mullet chased in the shallows and often stunned with an impressive tail whack, while an octopus may get tossed up into the air.
Stranded in the shallows
Mandurah is identified as a dolphin stranding hotspot. The Estuary is very shallow and the dolphins can get caught out by the tide. When a dolphin strands, if not attended to quickly, it can be fatal. Fortunately, in Mandurah, we have the Mandurah Dolphin Rescue Group which monitors our dolphin population and goes to the aid of any dolphins in trouble.
If you see a dolphin, or any other wildlife is sick, injured or in distress, please call the WILDCARE helpline on 08 9474 9055.
All of our dolphins are identified by marks and notches on their dorsal fin and/or body. You can download the Mandurah Dolphin Fin Book which outlines the key characteristics of all of our dolphins or may purchase a hard copy at our Gift Shop.