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Ova
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Each year in March the maturing parent fish (called broodstock) are moved from a seawater farm to the hatchery. At the beginning of May the broodstock start to spawn. Eggs are collected, fertilised and laid out in special incubator trays in the hatchery building. The eggs are supplied with a constant flow of fresh, well oxygenated water which is heated to enhance fish development. It is also filtered to minimise silt settlement on the eggs and gill damage in young fish. |
Yolk sac fry
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The eggs start hatching in July, with the young fish initially absorbing nutrients from a large yolk-sac attached to their bodies. When they are ready to eat for the first time, they are moved into small tanks and provided with a specially prepared food, broken up into particles which are small enough for the fish to eat. The feed contains a balanced package of all of the nutrients the fish need, consisting mainly of fish meal, vegetable matter, added vitamins and minerals. |
Parr
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The fish eventually become too big for the hatchery tanks and are transferred to large tanks in the on-growing area, where they spend the majority of their lives before being transferred to sea. In the warmer months the salmon use more oxygen than the river can provide, which means that the oxygen levels have to be artificially boosted using specialised equipment. |
Smolt (70g)
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During the 8-16 months following hatching the salmon become smolts and are transferred to sea. Transfer is achieved by using pumps to load the fish into tanks of water on trucks. At this point they are also electronically counted. Oxygen is added to the tank water so that the fish can be safely transported. This occurs when the fish is approx 15 months old and weigh approximately 70g |
Transfer
~1.5 kg
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Once transferred from the hatchery, most of the fish are held in fish cages at "nursery" sites in brackish water (although in some cases this stage is skipped and the fish are placed directly into a full saltwater site). During this time, they are held in large cages, and grow quickly. After 6 to 9 months they have reached around 1.5kg, and are then transferred to marine sites for grading and on-growing to harvest size. The nursery sites are then rested (in much the same way as a farmer might fallow a field) prior to being used for the next intake of smolt. |
Harvest
3-4kg
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Once transferred to the grow out site, the fish are held for up to 15 months. They continue to grow rapidly in the cages in the sea water, until they are ready to be harvested. The typical harvest size is between 3kg and 4 kg. Once harvested, most fish farms again rest the site prior to using it again.
After harvesting the fish are sold either as fresh or frozen product. A large amount of the product is also smoked
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