Fishing boat skipper Iain Harcus has discovered the cool way to deliver his catch in perfect condition.

His vessel, the Orkney-based Aalskere, is only the second in Scotland to be fitted with equipment that chills fish with the sort of icy slush found in children's drinks.

The on board treatment leaves fish looking as if they have been dusted in snow and allows the catch to be delivered to market in the freshest possible state.

The £140,000 investment by Mr Harcus and fellow skipper Trevor Cumming has been backed by a £19,900 financial package from Orkney Enterprise.

Harvey Stevenson, development manager with the Kirkwall-based development agency, said: "We see food and drink as a hugely important sector within the Orkney economy.  This is a very new way to improve the handling and storage of the catch aboard one of Orkney's fishing fleet.

"It will result in improved quality when the fish are taken to market and that was something we were keen to support."

Mr Harcus said the decision to invest in the slush ice equipment - currently being fitted in Fraserburgh - followed the award of a prestigious contract from leading retailer Marks and Spencer.

The company, which sells produce aimed at the top end of the food market, was impressed by the quality of the Aalskere's catch and now buys all haddock landed by the vessel.

Mr Harcus said: "Given the state of the fishing industry it is vital you stay ahead of the game.  The Marks and Spencer contract is very important to us. They did not ask us to fit the new ice equipment but we felt it would help us improve still further on the quality of the fish we are supplying to them. They are delighted that we are making this investment."

The gear allows the catch to be bathed in soft, slushy ice as soon as it is brought on board.  Then, once gutted, the vessel's crew uses hoses to spray the catch with the slush ready for on board storage.

Mr Harcus explained: "It does not freeze the fish but quickly brings their temperature right down.  When they are put into storage, the water from the slush soon drains away and the fish are left looking as if they are covered in snow.

"Chilling the fish fast, from the moment they come on board, vastly improves the quality. With this system the fish should have an extra two to four days' shelf life compared to those that have been stored on conventional ice."

Two three-tonne capacity tanks are being fitted aboard the Aalskere. These store the slush ice, which is then pumped to hoses fitted throughout the vessel.

The 110ft whitefish boat supports 11 jobs and for the crew the equipment will mean relief from the old backbreaking task of keeping fish on ice.

"That meant smashing up big lumps of ice with axes," added Mr Harcus. "This should be a big improvement for the boys."