Learn About Dolphins
Dolphin Watch Guide & Information
Bottlenose dolphins live in small groups called pods. They live in temperate and tropical regions, mostly along coastal areas and mid ocean. The size and appearance of bottlenose dolphins vary according to whether they live inshore or offshore and can dive down to a depth of 300 metres, and hold their breath for 10 to 15 minutes.
How Dolphins Communicate
Dolphins use two means of communication: vocalisation and echolocation. Vocalisation is used to communicate with other dolphins. Echolocation is used for detecting objects in the water.
A clicking noise is sent from the dolphin’s forehead (melon) that rebounds off an object and back through the dolphins jaw bone, where it is interpreted in the dolphin’s brain.
The dolphin knows how far away the object is by how long it takes for the echo to return, and how large the object is by the strength of the echo.
Echolocation from a dolphin is so sensitive it can detect the heart beat of a child inside a mother’s womb, yet can increase the strength of the echo to stun small fish.
Dolphins belong to an order of aquatic mammals known as cetaceans. There are 37 species of dolphin and porpoise world wide.
Thirteen species of dolphin’s live in Australian waters, though only one type of dolphin lives in one area all its life, the Bottlenose Dolphin, of which 100-150 reside in Port Stephens.
All cetaceans are protected species.
Dolphin Watching Rules
- Two boats are allowed near the pod of dolphins at the same time.
- 30 minutes maximum time spent with each pod of dolphins.
- Do not disrupt or harass the dolphins.
- Let the dolphins come to the boat – do not chase the dolphins.
- Do not approach the dolphin from head-on or behind.
- Keep noise to a minimum.
- No feeding or touching
The female dolphin has a calf in the womb for 11 to 12 months. During the birth, 2 female dolphins act as midwives to assist with the delivery.
As soon as the calf is born, the mother will take it to the surface for its first breath of air. Within 24 hours the baby is suckling milk from its mother, and does so for 12 – 18 months.
The calf matures at the age of 6 and will live up to 30 to 40 years of age. The female dolphins will have a calf every 2-3 years and 6-8 calves in a lifetime.
Environment NSW Information about Bottlenose Dolphin
Australian Museum information about Bottlenose Dolphin
Excerpt : Snowgums to Sands
Just offshore a current of water moves south at a few kilometres an hour. This southerly current brings warmer water from the tropical north.
Twice a day, on the flood tide, some of this warm water is drawn into the port. High tide is a wonderful, renewing event. Clear, clean, salty water moves over the sand banks. Oyster racks are submerged.
Shallow rocky creeks fill with water and become navigable. The aerial roots of mangroves disappear under the unstoppable force. Predatory fish invade the sun-warmed land.
Water need only be waist-deep to find the bottlenose dolphin fishing. Air-breathing, warm-blooded, intelligent and friendly, this fellow mammal is one of the best-loved creatures of the sea. Any journey across the water usually involves a close encounter.
Dolphins love to ride a boat’s bow-wave. The pressure wave at the front of a boat gives them a boost. They dive, weave, kick and splash. This gives people a good chance to look at them. Dolphins are grey above and white below. If you see one that looks white it is probably swimming upside down. They do this when mating.
Man has a long association with this marine animal and there are plenty of dolphin stories. Forty years ago a local oyster farmer shot at a youthful, exuberant dolphin, which was on his lease knocking over the oyster racks. Old ‘Cutfin’ is still around today. You can still see one neat hole and one big chip where the two cartridges went through the dorsal fin.
Bottlenose dolphins normally live thirty to forty years under good conditions. ‘Nicky’ is another dolphin that has been around for forty-five years-still recognised by the characteristic nick on her fin. She is still breeding. Up until the 1950s fishermen would harpoon dolphins to use as bait in their crab traps. The fishermen knew that once they had killed, a dolphin from that pod would ever come near that boat again. The boat could be painted or modified but the dolphins would never be caught by that same boat again.
That was over forty years ago. Now, we treasure our dolphins. Charter boats run regular dolphin-watching cruises. Port Stephens’ dolphins are not fed or induced in any way to come to the boats. They do it out of curiosity. If they are not in the mood, they just swim away. When contact is made with the dolphins, there is always excitement. People rush to the sides and bow of the boat. The air is electric with wonder and anticipation.