Lamberg caviar
The aquaculture of salmonids is the farming and harvesting of salmonids lamberg caviar controlled conditions for both commercial and recreational purposes. Salmonid aquaculture production grew over ten-fold during the 25 years from 1982 to 2007.
Much controversy exists about the ecological and health impacts of intensive salmonids aquaculture. Of particular concern are the impacts on wild salmon and other marine life. Very young fertilised salmon eggs, notice the developing eyes and vertebral column. Salmon egg hatching: In about 24 hr, it will be a fry without the yolk sac. The aquaculture or farming of salmonids can be contrasted with capturing wild salmonids using commercial fishing techniques. Salmonids are usually farmed in two stages and in some places maybe more.
First, the salmon are hatched from eggs and raised on land in freshwater tanks. Increasing the accumulated thermal units of water during incubation reduces time to hatching. The coastlines of these countries have suitable water temperatures and many areas well protected from storms. Chile is close to large forage fisheries which supply fish meal for salmon aquaculture. Modern salmonid farming systems are intensive.
Their ownership is often under the control of huge agribusiness corporations, operating mechanized assembly lines on an industrial scale. In 2003, nearly half of the world’s farmed salmon was produced by just five companies. This allows location of the hatchery to be independent of a significant fresh water supply and allows economical temperature control to both speed up and slow down the growth rate to match the needs of the net pens. Conventional hatchery systems operate flow-through, where spring water or other water sources flow into the hatchery. The eggs are then hatched in trays and the salmon smolts are produced in raceways. The waste products from the growing salmon fry and the feed are usually discharged into the local river. An alternative method to hatching in freshwater tanks is to use spawning channels.
These are artificial streams, usually parallel to an existing stream with concrete or rip-rap sides and gravel bottoms. Water from the adjacent stream is piped into the top of the channel, sometimes via a header pond to settle out sediment. Sea cages, also called sea pens or net pens, are usually made of mesh framed with steel or plastic. A large sea cage can contain up to 90,000 fish. They are usually placed side by side to form a system called a seafarm or seasite, with a floating wharf and walkways along the net boundaries. Additional nets can also surround the seafarm to keep out predatory marine mammals.
In contrast to closed or recirculating systems, the open net cages of salmonid farming lower production costs, but provide no effective barrier to the discharge of wastes, parasites, and disease into the surrounding coastal waters. Farmed salmon in open net cages can escape into wild habitats, for example, during storms. An emerging wave in aquaculture is applying the same farming methods used for salmonids to other carnivorous finfish species, such as cod, bluefin tuna, halibut, and snapper. However, this is likely to have the same environmental drawbacks as salmon farming. A second emerging wave in aquaculture is the development of copper alloys as netting materials.
Work continues on developing salmonid diet made from concentrated plant protein. As of 2014, an enzymatic process can be used to lower the carbohydrate content of barley, making it a high-protein fish feed suitable for salmon. However, commercial economic animal diets are determined by least-cost linear programming models that are effectively competing with similar models for chicken and pig feeds for the same feed ingredients, and these models show that fish meal is more useful in aquatic diets than in chicken diets, where they can make the chickens taste like fish. 4 kg of wild-caught fish are needed to produce 1 kg of salmon. The ratio may be reduced if non-fish sources are added. Wild salmon require about 10 kg of forage fish to produce 1 kg of salmon, as part of the normal trophic level energy transfer.
