Conservationists admit they have no clear answers as to why dead dolphins and porpoises are washing up on Dorset beaches.

There have been a number of reports of carcasses on the county's shores this winter, the most recent being at Stair Hole, Lulworth and at Chesil Cove, Portland at the weekend.

Other sightings have been made on Portland – including a rare white-beaked dolphin – Bowleaze Cove in Weymouth and along the Purbeck coast, which has led to coastguard teams going out to take measurements.

Dorset Wildlife Trust (DWT) says it has been made aware of a number of reports of dead dolphins and porpoises, and has been receiving information about sightings since early November.

The cause of death is unknown – although higher numbers are often recorded at this time of year with stronger winds, bigger swells and larger waves more likely to wash carcasses ashore.

DWT is urging people to report sightings.

DWT’s Chesil Centre Officer, Sarah Hodgson, said, “There are many reasons that could cause these animals to die, either simply due to natural causes or as a result of human activity such as by-catch from commercial fisheries, entanglement from ghost fishing-gear or pollution. However, without in-depth examinations we can only speculate.”

The strandings have been either common dolphins or harbour porpoises but a rare white-beaked dolphin, measuring more than nine feet in length, was recently discovered at Hallelujah Bay on Portland.

Sarah Hodgson said: “Whilst it is unusual to see a white-beaked dolphin, we are aware that there is a small population of these dolphins which are resident in Lyme Bay. We have passed details and photos to MARINElife who have been researching this local population."

DWT says it is important that these sightings are reported as soon as possible to enable organisations to assess and record the carcass before it decomposes. In some instances, experts from the Cetacean Strandings Investigation Programme (CSIP) may undertake a post-mortem examination to try to determine the cause of death.

Anyone who finds a marine mammal washed up should report it as soon as possible by calling 01305 264620 or emailing It is helpful if you can include a photograph of the animal but not to touch it as they can carry diseases. Once it has been reported a DWT representative will be able to complete a strandings report to send to CSIP for their national database and potentially further investigation.