A baby dolphin died after being 'struck by a power boat' off the coast of Cornwall.
It follows a series of disturbance incidents involving dolphins and power boats, jet skis and stand up paddle boards over the summer months.
The Dolphin died near Gunwalloe on the Lizard peninsula on 14 August .
A post-mortem of the dolphin carried out on Monday 14 September determined that the cause of death was head trauma, most likely caused by a boat strike.
The death came during a period in which the Trust and the Cornwall Marine and Coastal Code Group was receiving extremely high levels of disturbance reports from the public.
Cornwall Wildlife Trust said, "Use of marine vessels such as RIBS, jet skis and stand up paddleboards near marine life is harassing and chasing dolphins away from their territory and away from Cornish coastline."
The Trust is urging all water users to be more cautious and aware of their actions when at sea to protect marine life, and to prevent further incidents happening.
Abby Crosby, Marine Conservation Officer for Cornwall Wildlife Trust, says, “This baby dolphin represents the very reason we are working so hard in Cornwall to raise people’s awareness of the issue of marine wildlife disturbance by water users.
“This is a sad and avoidable incident resulting in the tragic death of a young dolphin.
"Not only is it a disaster for the conservation of this special animal, but the death of this young dolphin will have been incredibly traumatic for the mother and the rest of the family.
"Harassment can cause distress and make the animal change its natural behaviour.
"In the worst case it can lead to serious injuries, amputations and eventual death.
The Marine Disturbance Hotline can be called 24 hours a day, 7 days a week on 0345 2012626.