Harm can be unvoluntarily caused by dolphins lovers to these beloved marine mammals

IT'S an increasingly common summer sight: scores of holidaymakers piling into tour boats to watch dolphins cavorting in NSW's bays and inlets.

But research has found dolphin-loving Australian tourists may be harming the very objects of their affection, by robbing them of opportunities to socialise, forage, raise young and rest.

The international study, presented at a conference before Christmas, suggests too many tour boats can reduce the number of dolphins using a waterway and can lower the reproductive success of the animals that remain.

It has prompted calls for restrictions on the number of operators and tours in dolphin hotspots and a licensing system to ensure boats do the right thing.

But the tourism industry at the state's most popular dolphin viewing location at Port Stephens has questioned the impact humans have, saying there is no evidence local numbers of the marine mammals are waning or that they are under stress.

Lars Bejder, a researcher with Canada's Dalhousie University, studied the impact of tourism on resident dolphins in Shark Bay in Western Australia.

He presented the results of his research to the Biennial Conference on the Biology of Marine Mammals in San Diego last month.

Dr Bejder said the study looked at the number of Pacific bottlenose dolphins in part of the bay over almost 14 years as the number of tour boats went from zero to one and then two.

The introduction of one tour operator in the area had no detectable impact on the number of dolphins.

But his study found that, in 4 years after the number of operators increased from one to two, there was a fall of nearly 15 per cent in the number of dolphins in the study area.

His research also suggested tourism had an impact on the number of young dolphins being born and surviving.

The more time female dolphins spent in contact with tour vessels, the less likely they were to be able to successfully rear young.

"Tourism activity was likely to be the more significant contributor to the decline in numbers and . . . the reduced reproductive success of females," he wrote.

In his findings, he warned a similar trend would devastate the dolphin population at locations such as Port Stephens.

He said West Australian wildlife authorities were considering his findings and he hoped they would take action to protect the dolphins.

Master's degree research by marine scientist Simon Allen has previously shown Port Stephens dolphins changed their behaviour and group structure when approached by tour boats.

The area has about 80 resident dolphins, which are viewed by more than 250,000 tourists each year, ferried by nine permanent and up to six occasional tour boat operators.

"If the tourism industry in Port Stephens is not managed very carefully, we may end up with 15 boats watching the same 30 dolphins," he said.

With the State Government two months ago declaring Port Stephens part of a marine park, Mr Allen wants a licensing system for operators, limits on the number of interactions each day by tours and no-go zones for boats.

However, Port Stephens tour operators believed dolphins in the area were already coping well with tourism.

Frank Future, a long-standing tourism operator and member of the Port Stephens Commercial Dolphin Watching Association, said tour boats maintained a respectful distance from the animals.
"The population seems to be quite steady," he said. "There hasn't been any diseases that might come from a breakdown in their immune system [indicating stress]."

But he agreed a cap on operators could prevent overtaxing the animals and ensure the long-term sustainability of the industry.

"The whole town feeds off them. They are an iconic attraction."

The area has about 80 resident dolphins, which are viewed by more than 250,000 tourists each year, ferried by nine permanent and up to six occasional tour boat operators.

"If the tourism industry in Port Stephens is not managed very carefully, we may end up with 15 boats watching the same 30 dolphins," he said.

With the State Government two months ago declaring Port Stephens part of a marine park, Mr Allen wants a licensing system for operators, limits on the number of interactions each day by tours and no-go zones for boats.

However, Port Stephens tour operators believed dolphins in the area were already coping well with tourism.

Frank Future, a long-standing tourism operator and member of the Port Stephens Commercial Dolphin Watching Association, said tour boats maintained a respectful distance from the animals.
"The population seems to be quite steady," he said. "There hasn't been any diseases that might come from a breakdown in their immune system [indicating stress]."

But he agreed a cap on operators could prevent overtaxing the animals and ensure the long-term sustainability of the industry.

"The whole town feeds off them. They are an iconic attraction."