Dolphin bycatch is concerning conservationists (Image copyright Colin Wood/WDCS)

So far this year, 200 carcasses have been washed up on beaches in the county.

Conservation organisations say many are being caught in fishermen's' nets, while new research show they may also be affected by the sonar equipment from Royal Navy warships.

But by far the most common problem is with dolphins being stranded on beaches.

"The aim is to get to the carcass as quickly as possible Ruth Williams, Cornwall Wildlife Trust

Cornwall Wildlife Trust is hoping the hotline will allow experts to identify the cause of death quickly and speed up measures to reduce the numbers of fatalities.

Worst time

Anyone who sees a dolphin washed up can call the line to tell the Trust, which will offer advice on what to do and send volunteers to the scene.

The Trust is also running a session next weekend to teach people what to do if they spot a stranded dolphin.

Ruth Williams, from the Trust, said the worst time of year for dolphin deaths was December to March, during the bass fishing season when pair trawlers operate around the western approaches to the English Channel.

She said that better recording of deaths would help speed up measures to protect dolphins.

"The aim is to get to the carcass as quickly as possible. We have a whole network of people in the county to call on to record the dead dolphins.

"We need to find out a little bit more information on the death and if the carcass is in a good condition, that can give us the evidence we need to say whether the death is because of fishing bycatch or otherwise."

The hotline number is: 0845 2162626.