Directors of the company, which runs what is thought to be Europe's largest pelagic fish factory at Lerwick on Shetland, said they were delighted with the profit for the year.
Accounts filed at Companies House for the 12 months to March 31 this year show turnover coming in at £63.63 million, almost 13 per cent behind the £73.05 million recorded for the previous financial year.
However pre-tax profits still surged 121 per cent from £1.4 million to £3.1 million which was put down to a buoyant mackerel season which offered good sales margins.
Writing in the accounts the directors said: "The company has benefited from its busiest winter mackerel season in over ten years."
No explanation was given for the drop in turnover but the directors noted herring sales were facing ongoing challenges although the company had a decent summer season in 2013.
Underlining its growing confidence Shetland Catch said it was planning its first major capital expenditure in almost eight years with a £1.5 million upgrade of its mackerel distribution system and packing lines.
The accounts note the company has £1.5 million to pay in relation to a levy imposed by the High Court as part of a 2012 investigation into over fishing.