Donald Turtle and his 72-year-old wife Joan, were fined £3,300 each plus £1,000 fines.
Their son, John, skipper of their boat, The Ben Loyal, was fined £11,000 plus costs of almost £5,000.
"We have worked so hard all our lives to afford our own home," said Donald.
"Standing in that courtroom you couldn't shake the feeling that it could all be taken away from you in an instant."
The couple have already paid more than £12,000 in solicitors' costs over the last six years.
Mrs Turtle said the last six years of stress had taken its toll on her health, forcing her to take anti-depressant medication and making her increasingly reclusive. "What are we actually guilty of? We're guilty of marketing fish that should have been dumped dead overboard. As a Christian I think its a moral crime to do that and I can't understand why the churches aren't shouting about it," she said.
Following the court case a senior Marine Fisheries Agency spokesman said theirs was an environmental and financial crime.
"Quota was available for these species of fish throughout the investigation period," he said.
"This deception was done for financial gain – not to avoid discarding fish.
"And these activities both endangered fish stocks and penalised legal fishermen by depressing prices.
"The investigation by fishery officers was detailed and painstaking due to the well organised nature of this deception. The defendants denied their offending to the last moment which led to protracted legal proceedings."
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