Earlier this month the Sea World Research & Rescue Team assisted the NSW National Parks and Wildlife Service and Australian Seabird Rescue in freeing three bottlenose dolphins entrapped in Prospect Lake, Ballina, Northern New South Wales.

The dolphins, an adult female, juvenile and a new born male dolphin, are believed to have entered Prospect Lake approximately five days previously.

Sea World feared the dolphins could die as a result of low salinity levels in the lake if they were not rescued soon.

"There's a lot of fresh water in there as a result of recent rain and dolphins don't tolerate fresh water for long periods of time," Sea World Vet David Blyde said.

"Dolphins can survive for up to seven to 10 days in low salinity but after that they start to get dehydrated, suffer renal failure and eye and skin disease," He said.

Sea World Director of Marine Sciences Trevor Long said that tides and the number of animals entrapped did not favour any attempt to herd the animals out of the lake in the restricted timeframe.

Mr Long said that all aspects of the rescue were planned to limit the stress on the new born calf and its mother.

"We had to be extremely patient and wait for the animals to move into the shallow reaches of the lake before we could attempt a rescue," he said.

Mr Long said that Sea World employed the use of nets, divers, rescue staff and boats to catch and transfer the animals by vehicle to a release site.

Mr Long said that it was imperative for council to take action to ensure dolphins are not able to become entrapped in the lake in future, and has offered to work with council and other stakeholders to come up with solutions.

"The outcome this time was a positive one and we were all extremely pleased to see them swim off after the release, however we need to take action now to ensure this situation is avoided altogether," he said.