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Cultivation and farming of Atlantic Salmon

Sunday, December 19, 2010 · Category Environment · comments 0

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Most salmon we eat these days is cultivated salmon. Salmon farming has been taking place for at least fifteens years already, in countries such as Norway, Ireland, the Pharaoh Islands and Scotland. In 1998, there was more salmon farmed (900,000 tons) than caught in the wild (800,000). The demand for salmon has been increasing every year. Worldwide, 1.2 million tons of salmon were farmed in 2004 and more than twenty million kilograms in 2006 in the Netherlands.

History of cultivating Salmon

The farming of Atlantic salmon dates back to the 19th century, when hatchery techniques were developed in the United Kingdom. This first involved the production of immature fish to restock rivers for recreational fishing. In Norway in the 1960s, however, the first marine farms set up floating cages in fjords, with the aim of marketing adult salmon. Due to the success the market saturated in the 1990s

The process of cultivating Salmon

The reproduction of Atlantic salmon is fully controlled in fish farms. The eggs are removed from the females that are ready to lay and are fertilized by being mixed with the male’s milt. They are then placed in incubation tanks. The alevins emerge from the egg four to six weeks after fertilization.

Rearing of alevins

The rearing of alevins takes place in two stages, reflecting the salmon’s stages of development in fresh water.

Stage 1: In silos or trays - corresponding to the larval stage - the larvae absorb their yolk and become parr, at which point they are capable of feeding. The stage lasts four to six weeks.

Stage 2: The parr are transferred to fresh water tanks (or floating cages in a lake), where they will remain one to two years. During this time the fish become Salmon with all the biological characteristics that will enable them to live in sea water.

Fattening

The smolts are transferred to a sea site, where they are placed in a floating cage. They stay in the cage for around two years, the time it takes to reach commercial size (around 2 kg). The composition of the feed and the feeding rate, as well as the farm’s location and the harvesting and slaughter process, are all significant factors in the quality of the final product.

Salmon are carnivorous and are fed pellets made of fishmeal and fish oil (50 %), ingredients such as vegetable meals and extracts (cereals, beans, soy, etc.), vitamins, mineral salts and astaxanthin, the (natural or synthetic) pigment essential to their health that gives them their typical colour.

Problems with Salmon cultivation

There are a number of problems with farming salmon:

1. Illness and disease

The nurseries are a kind of bio-industry, whereby the salmon live very close together with all the dangers. Fish louse, a tick found on wild salmon, can easily spread and give the farmed salmon a diminished appetite and condition.

2. Waste causing drastic changes to marine flora and fauna

Louse is combated with heavy toxic insecticides, which also kill plankton. The fish farmers also use a cocktail of anti-biotics, hormone disorderlies, organophosphates and anti-fouling to prevent diseases and algae growth. All of these materials produce an enormous waste which is dumped in sea and causes drastic changes in the marine flora and fauna.

3. Use of artificial light for faster growth

To make the fish heavier more quickly, artificial light is used at night in the winter in several fjords, to keep the fish eating.

4. Mixing cultivated salmon with wild salmon

In addition, the mixing of wild salmon with those that have escaped is a problem. In 2005, more than 300,000 salmon escaped in Norway after a severe storm damaged a nursery basin. Sabotage activities a year later also helped a record number of salmon to escape, around 800,000 specimen. Unidentified people cut cables many times, which bonded the nursery basins together. Farmed salmon can carry over diseases. There are also major consequences when salmon are genetically manipulated in order to grow more quickly and then mix with wild salmon, as happened in a nursery in Canada.

5. The Salmon's Pink color

In 2003, the EC announced a limit to the use of canthaxanthine, a coloring put into fish food to give salmon the pink color. Wild salmon get this color naturally from eating shrimp, but farmed salmon are not fed shrimp. Too much coloring causes crystals to grow on the retinas of the eyes. Farmers have decided to switch over to astaxantime, a slightly more expensive coloring for which there a no regulations as of yet.

Happy Salmon eating.....I would say

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