A porpoise caught in an illegal salmon net would have died a "slow, painful" death, police have said.

Officers are hunting a poacher who set a 125 metre-long nylon net off the west coast of Lewis in the Western Isles.

A porpoise became entangled in the net and died. A dead salmon was also found

Police Scotland said they are working with conservation agencies and fishery groups in the area to find the culprit.

Wildlife crime officer Adrian Kay, who is based in nearby Benbecula, said: "It is clear that this porpoise, an intelligent animal, would have suffered a slow, painful death caught in this net.

"The poachers who set this net do not appear to have checked it regularly, allowing this salmon and porpoise to die trapped within it.

"The net was attached to a number of floats, one of which was white and was marked 'L1 LADY'. We urge anyone with any information about this crime to get in touch."

The porpoise and salmon were discovered after a member of the public reported the net.

David Maclennan, Western Isles manager for Scottish Natural Heritage, said: "This latest incident highlights the need for people to be vigilant about the use of illegal salmon nets in the area and to report cases to the authorities.

"As well as being illegal, this form of salmon netting poses a major threat to porpoises, dolphins, and basking sharks which often feed in the main netting areas. We are committed to working with fishery boards and the police to stamp out the practice."