Clarence River, a favourite area for Bottlenose dolphins

BOTTLENOSE dolphins prefer the Clarence River to other rivers in the region because it has cleaner water, new research shows.

Christine Fury, a researcher with Southern Cross University's Whale Research Centre, has been studying local estuarine dolphins for three years and uncovered some fascinating facts.

She found the Clarence River is the number one choice of home for the dolphins, while the Richmond River, which runs through Ballina, is the second most popular.

She estimated that 71 dolphins usually live in the Clarence River, compared with about 34 in the Richmond River.

"The Clarence River is the most popular because it is the largest estuarine river system in NSW and therefore has a greater volume of water," she said.

"It also has less urban and agricultural development. Both these factors mean the water quality is better."

Rockfish Cruises owner Di Jones said she frequently saw bottlenose dolphins, while conducting cruises on the Clarence River.

"We generally do get a few," she said.

"There's a big pod that lives in the Iluka Harbour that seems to travel around."

She said another good spot to see bottlenose dolphins was in the sheltered area beside the breakwater wall at Yamba, but noticed that they tended to scarper when the water was murky after rain.

In conducting the research, Ms Fury said she discovered bottlenose dolphins' favourite fish was mullet, followed by whiting.

She also discovered that, like humans, dolphins have distinct personalities, with the more gregarious and inquisitive dolphins having the best chance of long-term survival.