Dogs worrying horses and sheep at Northam Burrows
Dogs not kept on a lead are continuing to worry ponies and sheep at a North Devon Site of Special Scientific Interest (SSSI).
Torridge District Council said nine sheep had been killed and 17 injured this year on Northam Burrows near Westward Ho! beach.
Park rangers said ground nesting birds were also being disturbed.
The council has been working with the local police to encourage owners to keep their dogs under control.
Pc Dick Rowlands, from Devon and Cornwall Police, said: "We are active on the Burrows and take these matters seriously.
"We do investigate and have prosecuted dog owners whose dogs are not kept under control."
Signs listing the number of animals injured or killed by dogs have been erected on the Burrows to encourage dog owners to behave responsibly.
Northam Burrows is part of the newly-designated United Nations Biosphere reserve in North Devon.