MARINE experts have shepherded to safety a dolphin stranded in a small suburban lake in northern NSW.

The bottlenose dolphin had entered Prospect Lake at Ballina on an incoming tide eight days ago in search of fish.

But the noise and vibrations of a road bridge close to the lake’s entrance had deterred the mammal from turning back to safety in the Richmond River and eventually, the sea.

Stephen McCourt, marine sciences manager for Gold Coast theme park Sea World, said fears for the dolphin’s health grew because the lake, surrounded by housing developments, had a low level of salinity and only limited stocks of small fish.

He said two boats and seven staff from Sea World came to Ballina yesterday to help NSW National Parks and Wildlife Service personnel herd the dolphin out of the lake and into a narrow creek without stressing it by netting and transporting it by road.

“The plan was to net the animal near the entrance and try to drive it back under the road bridge,” Mr McCourt said today.

“It used to go to the entrance on a daily basis but would not go out.”

Faced with the choice of negotiating the nets and boats blocking its path to the lake or swimming under the bridge to the creek, it chose the latter option, Mr McCourt said.

“When it was presented with nets, boats and people behind it today or the road bridge, it chose the road bridge, which is a great outcome,” he said.

“It was pursued with a small inflatable boat down the narrow creek and back into the Richmond River.”

The dolphin, the sex of which remains unknown, was one of several which had been seen in the lake in the past, Mr McCourt said, adding that one had died there.

“That’s why we felt, with the invitation of NSW National Parks, that early intervention was the most appropriate outcome,” he said.