One of the finest examples of a medieval fish trap in Europe is going to be washed away before its secrets can be recorded, scientists have claimed.
A 700-year-old giant wooden weir, once used by monks, cannot be fully preserved because it is exposed to the forces of nature.
And with budget cuts hitting the Heritage Council there is no money to properly analyse and record the huge structure.
The ancient fishing trap -- described by experts as a harvesting machine -- had been buried for centuries and now sits 1.5km from land in the Fergus Estuary, Co Clare, on shifting mud banks and water channels.
Dr Aidan O'Sullivan, from the School of Archaeology at University College Dublin, said he had hoped to work with locals to analyse the site before it was washed away.
"There's nothing like it anywhere. In terms of preservation it's spectacular -- it's almost as though a medieval fisherman had walked off a few days beforehand," he said.
"There's nothing you can do to preserve it. The entire complex will be wiped out in five to 10 years' time. It's like a window in time.
"They are totally exposed to the forces of nature on the mudflats, after being buried for centuries beneath the mud."
Scientists and archaeologists have severely restricted timeframes to get out and record the 800m fish-catching structure with traps every 30m.
It can only be accessed by boat for a few short weeks in the summer when the tide is extremely low.
"The mudflats are too deep and dangerous to walk on," Dr O'Sullivan said.
The 1.2m-high fish weir is made from long wooden posts interwoven with wattle to a V-shape fence close to the low water mark.
Along the structure archaeologists have found ropes with knots holding it together and woven baskets which the fish were caught in. The first fences were built in the 13th century.
"It is almost as if someone had walked off and left these baskets there last year," Dr O'Sullivan said.
"They basically would have taken every fish out of the water.
"They would have been machines for harvesting."
The weir -- possibly owned by the Augustinian Abbey on Canon Island and used to feed the local lord -- succeeded in trapping fish in nets and baskets at the end of the fence as the tide went out.
"Medieval fishermen would have travelled out here by boat at low tide to build and repair the weirs and to remove the catch every day," Dr O'Sullivan said.