Atlantic Salmon in the wild
The Atlantic salmon is so called because it is normally to be found in the rivers which run into the North Atlantic Ocean, both in Europe and on the east coasts of America and Canada. It hatches from an egg laid in gravel in a river, and spends the first one to two years of its life in freshwater.
When it is ready it then moves down a river to the sea, becoming what is known as a "smolt". It may then swim many thousands of
kilometres in the Atlantic Ocean in search of food. When it has been at sea for at least a year it starts to mature and becomes ready to reproduce. At this stage it returns to the river where it lived when it was young and swims back upstream until it reaches a suitable place to lay eggs.
Atlantic salmon have been continuing this life-cycle around the Atlantic Ocean for millions of years. However, man has recently transferred Atlantic salmon to places very far from the Atlantic Ocean, like the west coats of Canada and America, Chile, New Zealand and, of course, Australia. In most of these "foreign" countries the Atlantic salmon does not usually reproduce and multiply very well when released into the wild. However, it seems to survive and grow quite happily in fish farms.
Salmon Processing - typical factory operations
The following processes are as described by one of the processing factories in the Tasmanian industry. Some aspects may vary from one factory to another, as the technology involved is constantly evolving.
1. Fresh Fish
Fish arrive from the farm in ice slurry bins. They are tipped into the wet area processing line where they are gilled and gutted. A mini vacuum machine is used to suck out the kidney and any remaining gut.
The fish then pass through a washer which cleans the belly before being graded.
Fish are then either sold fresh or put into bins for freezing.
Fresh fish are packed over the packing scale and put into polystyrene boxes with ice. The boxes are put onto a refrigerated truck and taken to the airport.
2. Fish for freezing
Fish are hung on hooks on large racks and put into the blast freezer. The blast freezer runs at -40 degrees centigrade and it takes approximately 8 hours for the fish to freeze.
Once frozen, the fish are taken out and dipped in water to form a protective glaze. The fish that are frozen from January to mid February are dipped twice. This is because they are the best quality fish and will be kept in the freezer longest (approx 6-8 months) to be used either for smoking or to be sold frozen.
The fish are stored in bins in the freezer at -30 degrees centigrade.
3. Smoking
Fish are removed from the holding freezer and placed one by one into an insulated bin. The bin is then filled with water and left overnight to defrost.
The next morning the fish are filleted, their heads and tails taken off and refrozen to be sold, smoked, converted into mince or thrown away.
The fillets are then washed through the fillet washer, brined, in a salt/sugar solution. The fillets are then put on trolleys in the chiller (approx 3 degrees centigrade) and left for up to 12 hours before being smoked.
Cold smoked salmon is smoked using natural wood smoke (a mix of Tasmanian hardwoods). After being smoked, the fillets go back into the chiller until they are ready to be pin-boned and skinned.
After this they go back into the blast freezer for approximately 2 hours, to be frozen before slicing.
The product is then quality graded and packaged.
Most of the product is cold smoked, although some manufacturers also produce a hot smoked product. The difference is that the cold smoking is done at a low temperature (which does not cook the product) while hot smoking is done at a higher temperature and results in a cooked product.
Other products
The salmon can be used to produce a variety of other products - salmon steaks are a good example. There is likely to be a greater emphasis on ready to cook meals in the coming years.
Other products include salmon mince and caviar (salmon eggs), while waste product from the factories is generally used in organic fertiliser. Very little product is actually wasted in the entire production process.
