The bid to free a Humpback whale calf tangled in ropes in Sydney Harbour has been abandoned for the night, after an adult whale accompanying it began behaving in an ‘‘erratic and defensive’’ manner.


Wildlife officers were alerted to the plight of the calf this afternoon, when the young whale was spotted with its mother in Middle Harbour with what appeared to be a rope and three buoys wrapped around its tail.


‘‘The officers decided it was too dangerous to attempt to free it this evening,’’ said a spokesman for the Office of Environment and Heritage, Roger Bell.


‘‘A third whale has joined the mother and calf, and the other whale has been showing erratic and defensive behaviour ... We don’t know how long it would take - a tail entanglement is a difficult one.’’


A National Parks and Wildlife crew went out in a boat to try and free the whale, but with the other whale behaving unpredictably nearby, decided a rescue attempt was too risky.The trio of whales has now passed out of the heads and were last seen travelling north-west at about 5pm.The whales were moving at about three to four knots, which was typical behaviour, and the entanglement did not seem to be slowing the calf down, he said.


A GPS reference had been taken at the position of the last sighting, and a search will be resumed tomorrow.A spokeswoman for the Sydney whale watch group Orcas said a keen member had spotted the pair off the eastern suburbs near the Macquarie lighthouse and called the Orcas hotline.


‘‘We've got a whole lot of rope and three buoys that it's dragging,’’ the spokeswoman told Macquarie Radio.


with AAP