Seventeen Scottish skippers and a processing firm have received fines totalling almost £1m for their part in the UK's biggest fraud involving illegal catches of fish.
The men had admitted they were able to sell vast quantities of mackerel and herring by evading EU quotas.
Three firms, one in Shetland and two in Peterhead, were involved in the black fish fraud, worth almost £63m.
Judge Lord Turnbull said the scam was "an episode of shame" for the industry.
During hearings at the High Court in Glasgow, six more skippers also admitted their part in the illegal fish landing.
Stephen Bellamy, 49, from Fraserburgh, John Smith, 36, and James Smith 54, both from Peterhead, Ernest Simpson, 64, Allan Simpson, 42, both from Fraserburgh and Oswald McRonald, 63, from Banff, are due to be sentenced in May, along with four others.
Seventeen men who had previously admitted to being involved in the scam were fined a total of £720,000.
One of the processing companies, Alexander Buchan Limited, which operated a factory in the Aberdeenshire fishing town of Peterhead, was fined £240,000.
A second Peterhead processing plant, Fresh Catch, admitted landing £10.5m of illegal fish. Shetland Catch has already pleaded guilty to landing £47.5m of black fish. Both companies have still to be sentenced.
The convictions came as the result of a seven-year investigation, Operation Trawler, after the Scottish Fisheries Protection Agency (SFPA), now Marine Scotland, became suspicious about widespread illegal landing of fish within the pelagic fleet.
The 17 fishermen sentenced on Friday illegally landed mackerel and herring at the Shetland Catch factory in Lerwick over a three year period, between January 2002 and March 2005.
They offloaded thousands of tonnes of fish, much more than they were allowed under European rules to protect stocks.
The court has heard how logbooks were falsified and digital weighing scales at the factory were rigged to underestimate the weight of the fish being landed.
In Peterhead, at the Fresh Catch factory, fish was pumped ashore through secret underground pipes.
Fisheries officers and police raided the factories in 2005 after an investigation into the companies' accounts.
Sentencing the 17 skippers, judge Lord Turnbull said the scam was a "cynical and sophisticated" operation which had the "connivance of a number of different interested parties".
He described the men as normally law-abiding, but said the proceedings brought "embarrassment and shame" to them and their families.
He said: "No-one for example appears to have engaged in this exercise on account of struggling to cope financially with the costs of continued fishing within the quota levels allocated.
"Indeed, in contrast to some within the fishing industry, those engaged in fishing with the pelagic fleet appear to have been able to make very substantial sums over many years, providing very comfortable livings for themselves and their families."
He added: "The motivation was purely financial. Those who were already making a good living saw this as a way more income could be generated and were prepared to participate in deliberate lies and falsehoods."
Scottish Fisheries Secretary Richard Lochhead welcomed the fines imposed on the skippers and company.
He said: "There is no doubt that these illegal activities are a stark and shameful reminder of the culture that existed in some sectors of the fishing industry in past years but they do not reflect the much improved culture we see today."
Hamish Slater, 53, and Alexander Masson, 66, both from Fraserburgh, were fined £80,000 and £50,000 respectively, while Alexander Wiseman, 60, from Banff, was also fined £50,000.
Another 13 men from Shetland were fined for their role in the scam.
Robert Polson, 48, was fined £70,000; John Irvine, 68, was fined £80,000; William Williamson, 65, was fined £45,000; Laurence Irvine, 66, was fined £80,000; and both David Hutchison, 66, and 56-year-old Thomas Eunson were fined £40,000.
Allister Irvine, 63, and Gary Williamson, 52, were both fined £35,000; John Stewart, 57, was ordered to pay £15,000; and both George Henry, 60, and George Anderson, 56, must pay £12,000.
Colin Leask, 39, and Allen Anderson, 55, were each fined £3,000.
A £70,000 fine was imposed on Victor Buchini, 51, from Poulton-le-Fylde in Lancashire.
The seventeen men have already been forced to pay back almost £3m in profits they made from the scam.