Business plans for three new ventures were backed by elected members in Lerwick Town Hall on Monday morning.
The most significant of the proposals is the new £5.6 million fishmarket for Scalloway.
But councillors were also given the chance to raise questions over the development of new turbines at the Hamars Ness (Fetlar) and Ulsta (Yell) ferry terminals and a new shed to help deal in the recycling of household waste.
The full business case for the fishmarket at the village harbour is expected to do much for the local fishing sector.
The document draws on figures from Marine Management Organisation, which show that around £33 million-worth of whitefish were landed in the isles last year – around 14 per cent of total Scottish landings.
In a four-year period from 2010, total fish landings rose by 60 per cent from 3,030 tonnes to over 4,800 tonnes, with the number of boxes being landed into Shetland “increasing significantly”.
Capital costs of the fishmarket are expected to be funded half from borrowing and half from EU grant funding – although the grant funding has not yet been secured because tenders for the works have not been received.
A report by head of capital programme Robert Sinclair states borrowing costs will be funded through the fees and charging structure within the harbour account.
However, the proposals raised questions from Shetland South councillor George Smith, who wondered whether the SIC should be ploughing money into a project that would mainly benefit businesses.
“We are the council, and we need to ensure our council resources are used in the best way possible – and this is a discretionary service,” Mr Smith said.
In a somewhat peculiar turn of phrase, chief executive Mark Boden likened the council to someone suffering from schizophrenia.
“The local authority has two broad duties,” he said. “One is to have a well-run council, with effective operational and financial management.
“The other issue is that the council exists to do things and achieve outcomes for its population.”
Mr Boden said it was a “valid objective” to generate wealth and employment.
“We have to weigh that in the balance, even though it’s not statutory.”
Mr Boden added that there was less risk in developing an existing operation such as the Scalloway fishmarket than investing in a venture which was brand new.
“We’re not starting off from a blank sheet of paper,” he said.
Meanwhile, the ferry terminal turbine project aims to see the development of a 10kW turbine at both Hamars Ness and Ulsta, connected to the local grid.
The “spend to save” project has been costed at £128,000 with a seven-year payback period.
The business justification case points to a cut in energy running costs of each ferry terminal by £163,580 over the 20-year life of the project.
But it says the savings could have been larger had it been possible to install a larger turbine. Instead, the project has been constrained by the limitations of the Shetland grid.
The third project concerns a sorting and storage shed for household waste recycling.
The building cost is estimated at £485,000, with the cost of machinery put at around £267,000.
Pending full council approval, the proposals will find their way into a five-year asset investment plan.