Skippers behind one of Scotland's biggest fishing scams are due to be sentenced.

Seventeen fishermen face unlimited fines after admitting at a previous hearing that they made illegal landings of mackerel and herring worth £46.5m.

The "black fish" scam took place between January 1, 2002, and March 19, 2005, at fish processing company Shetland Catch in Lerwick, Shetland.

The company was convicted of helping the skippers land undeclared fish at its premises in Gremista. It is also scheduled to be sentenced on Friday at the High Court in Glasgow.

The offences, which broke sea-fishing regulations, were carried out to avoid the annual EU fishing quota allocated to boats.

Hamish Slater, 53, and Alexander Masson, 66, both from Fraserburgh; Alexander Wiseman, 60, from Banff; Robert Polson, 48, John Irvine, 68, William Williamson, 65, Laurence Irvine, 66, David Hutchison, 66, Thomas Eunson, 56, Allister Irvine, 63, Gary Williamson, 52, George Henry, 60, John Stewart, 57, George Anderson, 56, Colin Leask, 39 and Allen Anderson, 55, all from Shetland; and Victor Buschini, 51, from Poulton-le-Fylde, Lancashire, were all ordered to hand over almost £3m, under confiscation orders.

The convictions are a result of a seven-year investigation called Operation Trawler. It found that scales used on fish coming into Shetland Catch's factory were manipulated to provide false weights.

Company bosses were able to input fake wastage figures into a computer in the main factory, which was accessible to inspectors from the Scottish Fishing Protection Agency, now Marine Scotland, and would be deducted from the actual weight shown on the screen.

The proper weight was displayed on screens in the engineer's room and in a loft area, both off-limits to agency officials.