Mr Carmichael found out that Orkney shellfish farmers have seen their rents double in the last five years.
The figures emerged after the MP questioned the Chancellor of the Exchequer how much rent the Crown estate was charging the fastest growing sector of the aquaculture industry.
His queries revealed that the income the Crown Estate has received from shellfish farmers UK wide has increased by 50 per cent since 2003.
Rents from Shetland shellfish farmers has increased from £15,000 in 2002/3 to £50,000 in 2006/7, a rise of 233 per cent. The figure in Orkney has grown from £1,100 to £2,500 during the same period.
Shellfish farm rents rocket
UK - The crown Estate Commission has come under fire once again from northern isles MP Alistair Carmichael, who accuses them of colossal greed for more than tripling seabed rents for shellfish farmers in Shetland.