Dolphins are a common sight in Cardigan Bay

People in Borth, near Aberystwyth, are demanding action against the riders, who they claim have no regard for bathers either.

More than 50 locals held a meeting on Monday and confronted Ceredigion County Council about the problem.

The council said it was looking into the matter.

One of the residents opposed to the water bike users is John Hefin who lives just feet away from the beach.

"This problem goes back to the early 1990s and it seems to have got worse and worse since then," he said.

Cardigan Bay is the largest bay in the UK and an important part of Wales' coastal heritage Borth resident John Hefin

"But we seem to be going round in circles just like the water bikes.

"These people have been seen chasing dolphins which is totally irresponsible.

"One guest to Borth wrote to the community council and complained that one whizzed passed him and his children without realising the danger.

"The machines are very noisy and with health and safety the way it is, I'm sure there must be grounds to prevent them travelling so close to the shore."

Mr Hefin added: "Buoys have been put out as a means of informing powered boats that they must stay away from the shore but they seem to take no notice of them.

"As Borth doesn't have a harbour we can't impose any more restrictions than that at the moment.

"Cardigan Bay is the largest bay in the UK and an important part of Wales' coastal heritage.

"There needs to be co-operation between Pembrokeshire, Ceredigion and Gwynedd on this issue so as to ensure that this valuable asset is preserved."

More than 50 people attended a meeting to discuss the problem

A spokeswoman for the council said: "Ceredigion County Council continue to look into the matter and further internal discussions are to be held in the wake of the consultation with the community at Borth."

Terry Leadbetter of Marine Life Rescue, in Milford Haven, said the actions of water bikers was both "irresponsible" and "unnecessary."

"Dolphins are protected under the Wildlife Act so these machines shouldn't be interfering with the mammals," he added.

"Dolphins get disorientated by the noise which can affect their navigation. This is especially hazardous for young calves who rely on their parents for two years.

"If they become disorientated and lose contact with their mothers they could die."

He added: "It's a ludicrous situation and dangerous for both parties involved, although I rarely hear of a dolphin being hit.

"That's probably because they're more intelligent than most of the people riding these machines.

"Bottlenose dolphins are found in Cardigan Bay and they can weigh about 1,000 kilos (one tonne) so if a water bike hits one the rider will know about it.

"Dolphins can be protective as well and I wouldn't like a one-tonne dolphin charging at me at 50mph which is the speed some of them can reach."

Its estimated there is a resident population of just 127 dolphins in Cardigan Bay, but during the summer numbers can rise to 400.