The broodstock fish are stripped of their roe and milt. The fertilized eggs are placed in the hatchery, where they take 60 days at a maximum water temperature of 8 °C to hatch out.
When the eggshell breaks, the eggs hatch out, yielding fry with yolk-sacs on their stomachs. The yolk-sac is the fry’s “lunch-box” for the first few weeks of its life before start-feeding, when it gradually begins to take dry feed.
After about one year in a hatchery tank, the salmon have grown enough to be set out in seawater. At this point they have already undergone physiological changes that enable them to live in the sea. An average smolt weighs 80-100 g when it is released into the sea. Smolt used to be set out in the spring, but this now also takes place at other times of the year.
Ongrowing in the sea
After just over two years in the sea cages, the salmon have grown to a weight of about 5 kg. The rate of growth depends, among other factors, on the water temperature.
Well-boats are used to transport both smolt from the hatchery to the ongrowing farms and fully grown live salmon from farms to the slaughterhouse. All salmon are slaughtered in specialised fish-processing plants. They are anaesthetised before they are slaughtered and are then immediately cleaned, sorted, chilled and processed for further transport. Some fish are smoked or turned into fillets or “table-ready” products, but most are sold as cleaned whole salmon.
2 years to grow, 2 hours to process It takes in average 2 years to grow a salmon and only 2 hours through the processing plant at a core and storage temperature at 2°C. When the fish has reached a weight of 4–6 kg it is ready for processing. The salmon is taken by well boat to the fish-processing facility, where it is stunned, gutted, washed and sorted by size and quality.
Around every 48 minutes, every day all year round, a trailer fully loaded with salmon from the Lerøy Seafood Group crosses the Norwegian border on its way to the market. In addition, salmon is also exported on board its own salmon aircraft. Several companies are now also evaluating the use of sea transport to carry salmon from processing plants to market.