Almost an entire fishing port's trawler fleet has been fined over £122,800 for breaching government fishing regulations and putting stocks at risk.
The fishermen did not accurately record their catches
Ten North Yorkshire trawler captains - 90% of Whitby's fleet - were in the dock at Hull Crown Court after pleading guilty to 55 charges.
The men, who earn between £8,000 and £20,000, failed to submit declarations which properly recorded their catches.
Their barrister said the port's fishing industry was "on its knees".
Among the defendants was Arnold Locker, from the National Federation of Fishermen's Organisations, who has previously lobbied on behalf of the industry at 10 Downing Street.
Simon Phillips, prosecuting on behalf of the Department of the Environment, Fisheries and Rural Affairs (Defra) said the amounts of black market fish landed was valued at £475,000, but the defendants admitted only £149,000.
He said the investigation into the fleet began in 2003 when suspicions were aroused that recordings of landings had dropped 35%.
The scam was to land fish and sell it at auction but not declare the whole catch to fisheries inspection. The fish was legitimately sold at a dockside auction, but the exact amount hidden from view by book-keeping.
Evidence had been gathered by boarding ships at sea, raiding offices and seizing computer drives.
At one point Captain Steven Veart lost his cool, snatching a log book off a fisheries officer and throwing it out into the sea from his vessel, the Christina, at the Whitby quayside.
He said he was annoyed "by a job's worth, bureaucrat".
Barrister for all the defendants, Ian Lawrie, told Judge Simon Jack that in court was the entire fishing fleet of Whitby with boats above 10 metres.
"It is a sad reflection of the perilous state of the white fishing industry of a town. It is literally on its knees. How it got there is a long process."
He said the men were in dire straights caused by a reduction in quotas, an unfair playing field of subsidies and a decommission scheme which would land some of the men in massive debt.
The captains and details of their fines
Steven Veart, 42, the master of Christina - £10,000
Richard Marsay, 37, master of the Nicholas M - £9,000
James Locker, 25, master of Our Lass - £4,050
Andrew Locker, 27, master of the Rebecca - £3,750
Arnold Locker, 52, master of the Defiant - £6,000
John Hall, 57, the master of Abbey Lee - £3,000
David Locker, 44, master of Orion II - £4,500
Richard Brewer, 51, master of Ocean Rose £4,500
Mark Cole, 24, master and joint owner of the Good Intent - £4,500
James Robert Cole, of Whitby, master and joint owner of the Good Intent - £12,000
Locker Trawlers Ltd owners of the Abbey Lee, Christina, Defiant, Orion II, Nicholas M, Our Lass and Rebecca pleaded guilty to 21 offences for seven trawlers - £52,500
Arrivain Fishing Company Ltd, owners of Ocean Rose, pleaded guilty to three offences - £9,000
Robert Cole, 62, master and joint owner of the Good Intent, of Helerdale Road, Whitby, was not in court and pleaded not guilty to three offences of not accurately recording fish landed. The judge agreed his charges should be left on file and not proceeded with.