A new campaign to save Scotland's threatened native oysters has been launched by Scottish Natural Heritage.
Oyster sales peak at three times of the year
People in the west of Scotland have been urged to look out for poachers in the run-up to the festive period, a peak season for oyster consumption.
The native oyster once supported a prolific fishery in several parts of Scotland, but there are now only a few isolated populations on the west coast.
Their biggest threat is said to be unlawful harvesting from sea lochs.
The new leaflet and poster will alert people to the decline and list ways the public can help.
These include reporting unlawful harvesting to the police and informing Scottish Natural Heritage (SNH) of any sightings.
Christmas is one of three peak times for oyster consumption in Scotland, alongside St Valentine's Day and the start of the season in September.
Although the bulk of these sales are for farmed oysters, SNH said unlawful gathering of native oysters "undoubtedly supplies these markets".
In the past, over-harvesting, diseases and chemical pollution were all factors in the native oyster's decline but unlawful harvesting is now the main threat to the species in Scotland.
Strathclyde Police, Argyll and Bute Council and the Crown Estate have joined SNH in the new information campaign.
The Crown Estate, which returns its profits to the Treasury, manages one of the largest property portfolios in the UK, valued at more than £5bn.
Its marine estate includes more than half of Britain's foreshore and estuaries and almost the entire seabed surrounding the UK.
Jane Dodd, marine adviser for SNH, said: "Many people are unaware of the plight of our native oyster or that it is unlawful to gather them without permission from the Crown Estate.
"This campaign aims to raise awareness about the problem and encourage people to help by reporting any unlawful collection or other threats to the native oyster, as well as helping us to monitor populations by letting us know if you spot them."
Superintendent Raymond Park of Argyll and Bute's sub-division of Strathclyde Police, said: "For the campaign to be successful, it is important that those outwith the immediate natural heritage community should understand the issues.
"That's why we will be making the campaign literature available at the public counters of many of our police stations."
David Stewart, renewables manager at the Crown Estate, said the scheme was vital in ensuring the long-term future of the species in Scotland.
He said: "The wide distribution of information on this UK Biodiversity Action Species should ensure its protection and hopefully restoration on the west coast."
The native oyster, also known as the flat or common oyster, grows wild in the shallow coastal waters of Scotland.
At peak production the Firth of Forth fishery produced 30 million oysters per year which were exported to England and the continent.
Extreme pressure from harvesting and illegal poaching caused the fishery to close entirely by 1920.