Criminal damage to freshwater pearl beds

Scottish Natural Heritage (SNH) said "significant and lasting criminal damage" has been found at 75 per cent of pearl mussel sites surveyed.

This included illegal pearl fishing and unauthorised river works, which saw the destruction of entire populations of the protected species.

Yesterday, the Scottish Government backed Operation Caesar, a new crackdown on illegal attacks on the sensitive sites. Scotland has 21 designated sites for pearl mussels, with rivers here holding about half of the world's population of the species.

During the recent survey, seven out of nine Special Areas of Conservation (SACs) and Sites of Special Scientific Interest were found to be damaged, including three where recovery will be "extremely challenging".

In one river system in the west Highlands, one of the largest pearl mussel beds was found to have disappeared since the previous monitoring five years earlier, with no explanation other than destructive pearl fishing.

Fishing for the pearls is now outlawed and the mussels protected under the Wildlife and Countryside Act 1981. Crimes against them carry the possibility of prison sentences.

Environment minister Roseanna Cunningham said: "It is clear that the pearl mussel continues to suffer from indiscriminate and illegal ransacking by determined criminals. It is a UK wildlife crime priority and SNH has been tasked with co-ordinating action to try and halt this decline. This work will continue despite these setbacks.

"The Scottish Government is committed to protecting all our native species and to cracking down on the criminals."

Iain Sime, of SNH, described the findings as "shocking" and "appalling". He said: "It is clear that we must undertake urgent work to save this species from almost certain extinction in some areas.

"Unauthorised engineering in one river seems to have destroyed the most significant pearl mussel bed of around 900 animals in the lower reaches of the river.

"Another site has seen the killing, in less than a day, of 50 per cent of the mussels in the burn, making any recovery from the remaining animals extremely difficult."

The freshwater pearl mussel can live for 80-100 years but only matures after about ten-15 years. The rivers of the Highlands and the north-east hold the largest populations of the mussel in the UK, and Scotland is the species' global stronghold. However, they have been vanishing at a rate of two rivers a year since 1970. There are now thought to be only 61 breeding sites left. If the present rate of decline continues, it is estimated that surviving Scottish populations may only last for another 25 years.

Fishing for pearls sustained an industry up to the 19th century, but over-exploitation resulted in stocks being almost wiped out.

In 1998, the species was given full protection as numbers plummeted to critical levels. Criminals still raid mussel beds, ripping out mussels and opening and discarding the inedible flesh in their search for pearls.

Chief Inspector Matthew Reiss, of Northern Constabulary, appealed to walkers and fishermen to look out for any suspicious activity.