Scientists believe they may have partly explained the mystery of the growing number of dead seals being washed up on UK shores exhibiting horrific "corkscrew" injuries.

Experts at the Sea Mammal Research Unit at St Andrews University suspect that female harbour seals are being attracted by the low-frequency hum of ships' propellers that mirror the mating call of a breeding male.

Acoustic tests appear to confirm the fatal attraction theory resulting in the mammals being sucked through the ducted blades of working boats.

Dr David Thompson, the researcher leading the investigation, said it was necessary to determine what types of propellers were causing the injuries before measures could be put in place with the marine industry to prevent them.

"What we have found is that in the summer the deaths are almost exclusively adult female harbour seals and in the winter mostly juvenile grey seals," he said.