Male dolphins are roaming large distances along the South West coast of Western Australia looking for sex while the females stay home, according to new research.

A study by Murdoch University's Cetacean Research Unit has looked at the home ranges of male and female Indo-Pacific bottlenose dolphins around Bunbury, and compared the areas roved regularly by the two sexes.

The female dolphin population moved around smaller areas, while the males traversed the coast in search of different female populations.

Researcher Kate Sprogis said her study of dolphin behaviour showed the males kept larger home ranges in a bid to find as many partners as possible, while the females lived in contained areas, partly to raise their young.

"The scientific term is a polyamorous species, and what I found is that the males in Bunbury are generally ranging over larger areas than the females," she said.

"We think that's because they want to cover as many female home ranges as possible ... to be able to pass their genes on to the next generation.

"For example some females might just use the Leschenault estuary and Koombana Bay, and some of their home ranges might be less than 40 kilometres square.

"Some males may use the bay but also along Back Beach and down to Busselton and offshore, so they may range across 180 kilometres square."

Dr Sprogis said the size of a dolphin's home range also differed according to location.

"The dolphins that are more resident in the bay area - in Koombana Bay and the Leschenault inlet and estuary - generally have a smaller home range area, whether they're male or female, versus the dolphins that use the coastal open beaches," she said.

The research put this down to food availability.

Dr Sprogis said the findings could be used to influence the way people and industry interact with the Bunbury dolphins, and should be considered in any coastal development and port expansion proposals.

She said the dolphins that use the areas near Bunbury's port, often females and calves, could be heavily impacted by industry and tourism.

"Some of the dolphins use 20 kilometre square home ranges, or 40 kilometres, which is not very big. So they will be interacting with vessels and tourism more often," Dr Sprogis said.

"Because they're residents they're not going to leave, because it's their home, whereas the other dolphins that use the coastal beaches and have larger home ranges aren't going to be as adversely impacted.

"The port wants to keep on developing. That's exactly where all the recreational boats are, that's exactly where the dolphin tourism is and that's exactly where the dolphins are illegally fed, so there's lots of begging dolphins in there."

The research was conducted as part of South West Marine Research Program.