A whale has drowned off the coast of Scotland after becoming tangled in rope.

The 22ft-long northern bottlenose's body was discovered at Ardentinny in Argyll last weekend.

It had suffered an injured tail and a large amount of seawater was found in its stomach.

The one-ton mammal was too large to retrieve so biologists removed its head for the National Museum of Scotland.

It is believed to be the first time a beaked whale has died of entanglement in Scotland in at least 25 years. Northern bottlenose strandings are rare.

Mariel ten Doeschate from the Scottish Marine Animal Strandings Scheme said: "It's hard to tell what kind of rope caused the entanglement as it was not attached anymore.

"The lesions were around 10mm to 15mm deep, which is consistent with creel rope.

"Given the state of the carcase, it is very likely to have happened in Scottish waters."

Ms ten Doeschate added: "Entanglement is known to be a global problem, particularly for large whales.

"Nevertheless this is the first northern bottlenose whale, or indeed any beaked whale species, where we have diagnosed entanglement as the cause of death since the start of the scheme in 1992.

"By examining cases such as this, we are however able to better understand how and where animals become entangled, hopefully leading to the development of pragmatic mitigation measures to minimize the problem in the future."