It is still a mystery how salmon can find the path leading to the river in which they were born. It seems to be a combination, among the many things, of astronomical navigation and electromagnetic flows, and also an extremely developed sense of smell. Almost all the species of salmon are born in sweet waters, then migrate to the valley towards the ocean, and finally go back to the place of their origin. The “wild” salmon is the best one, that is the fished one, because, thanks to the continuous movement, it has a more compact meat. Salmon meat is in fact very appreciated in the tables of the world and many are the recipes in which it is protagonist. With the term salmon are intended many species of fishes all belonging to the Salmonidae family.

	Salmon is one of the most appreciated fish in the tables of the world

 Atlantic Salmon (Salmo Solar), is the salmon living in the Atlantic ocean, simply known as “salmon”, the most common type in cooking. With a back of brown-green-blue color and silvery flanks, it can reach 80 cm in length. It is a predatory fish, very active and very aggressive, its ideal environment is the waters of Northern Atlantic ocean, cold and rich in oxygen. It is an anadromous fish, that is living most of the time in salt water and spawning the eggs in sweet waters. During its adult phase, it lives in the Northern Atlantic ocean, then, at the age of 2-6, it swims upstream the rivers of Northern America and Northern Europe in order to spawn eggs. It is the female who chooses the place, whereas the male fertilizes the eggs. Eggs hatch after a period from five to seven months, therefore some fry salmons, at least most of them, go to the sea, whereas others can stay for some years in sweet waters before beginning the journey to the sea. The few salmons who can survive to the period of reproduction, as they reach the sea, quickly recovers from the loss of weight, and within one or two years they are ready again for a new swim upstream of the river. Its meat, with a pink color, is very tasty and appreciated, for this reason Atlantic salmon is frequently bred in specific plants.

 Royal Salmon or Red King or Chinook, it is the Oncorhynchus Tshawytscha. It is the bigger of the family, can reach 150 centimeters in length and a weight of 20 kilograms. It lives in a pretty large area, it can be found in California (Monterey Bay), in the western coasts of the United States, Canada, Alaska and Siberia, as well as in the coasts of Japan. It can also be found in the Great Lakes of North America and in some areas of New Zealand, where it was introduced by man. Its compact meat, with a color ranging from pale pink to intense red, it is very appreciated by connoisseurs. Royal salmon, just like the Atlantic one, it is an “anadromous” fish and is an excellent traveler. After some years of age, it begins the journey to the sea, goes down the rivers and reaches estuaries, safe places rich of food, an ideal stop in order to let skin's physiology to adapt to the new concentrations of salt.

 The body of royal salmon is stretched and robust, with a green-blue back and silver flanks. The head is pointed, the mouth, with black gums, is full of pointed teeth: for this reason it is also known as “blackmouth”. During the reproduction period, royal salmon changes many parts of its body. One of them is the growth of the lower jaw, which block the mouth so it cannot close, therefore making eating impossible and forcing the salmon to a complete abstinence from food during the period of migration. Salmons swim upstream the river always in the same period of the year. Every salmon can, thanks to its sense of orientation guided by the sun, to find the right direction to the place of origin. The sense of smell, extremely developed, allows the salmon to recognize the water of the river where it is from.

 Silver Salmon, or Coho Salmon, it is known as Oncorhynchus Kisutch and can be found in the Pacific Ocean, along Siberian coasts, western coasts of Canada and United States down to Mexico, in the coasts of Japan and in North-Eastern Russia. It is very common during the sport fishing season, it is very appreciated in fish shops and in restaurants for its inviting red meat and moderate price. Red Salmon or Sockeye Salmon - known as Oncorhynchus Nerka according to scientific classification, with a green-blue back and silver flanks - it is common in the Pacific Ocean, from California to Japan. It can also be found in lakes and rivers having no access to the sea, in Alaska, Canada and in the North area of the United States. It is the most fished salmon from the industry and represents about two-thirds of total production. The aspect of its meat is compact with an intense red color, it is the most appreciated salmon in British Columbia and it has become the most common type of “canned salmon”.

 Pink Salmon, or Humpy, it is the Oncorhynchus Gorbuscha and the name derives from the color of its back. Of all the species living in the Pacific ocean, this is the smallest one, its length does not exceed 75 centimeters and its weight does not exceed 7 kilograms. Pink salmon has a maximum life span of two years, it has a green-blue back with large dark spots. The term Humpy comes from the slight hunch which it develops during the period of reproduction. Its meat is pale and with a delicate taste, however having a lower quality than others. During the month of July or August, pink salmons reach estuaries of rivers and begin to swim upstream, looking for a place to spawn eggs. The fry of pink salmon quickly go down to the estuary, rich of safe places and food, where they spend some weeks. After some time they enter the Pacific ocean where they will become adults.

 Keta Salmon, or Chum Salmon, it is known as Oncorhynchus Keta as well as Dog Salmon, because of the big teeth it develops during the spawning period. It lives in the Pacific Ocean, from California to Korea and in the Bering Strait. After having been canned, it takes the name of keta salmon. Its meat has an aspect from pale red to average intense red, with a low quantity of saturated fats. Danube Salmon, also known as Hucho Hucho, lives in the Danube river and in its northern tributaries. It is a massive fish and very strong, excellent predator, it likes to stay in the surface of the stream, always ready to catch its prey. The reproduction period is springtime. In March and April, Danube salmons swim upstream in search of calm waters with gravely floors, where the female spawns eggs. Japanese Salmon, according to scientific classification Oncorhynchus Masou, is common in Korea, Taiwan and Japan.

 Fish, as it is commonly known, it is good for the health thanks to the presence of that particular type of fats known as “Omega 3”. It is a polyunsaturated fatty acid the body cannot make itself, for this reason it is defined as essential, and it must be provided through the assumption of food. These “good” fats have a repairing function of cellular membrane, delaying the aging of every organ. According to experts, in normal conditions, it is advised a daily intake of 700 mg of Omega 3, a quantity which can be provided by 30 grams of salmon.

 Just like any type of fish, before purchasing a salmon it is good to make sure the eye is “alive” and convex, pink and wet gills, brilliant meat. The central part is the best one and in case it was bought in steaks, meat must adhere to the central bone and with an uniform color. In case it is bought sliced, meat must be well adherent to the cartilage. Bred salmon can be found in shops all year long, its meat has a less strong taste and a darker color. Less valuable salmons have a curved jaw curved upward like a hook. When bought raw, in steaks, fillets or whole, salmon must be washed and dried with a cloth, wrapped in cooking paper or a clean cloth and kept in the fridge, consumed within 24 hours. In case of smoked salmon, it must be kept in fridge until expiration date and it is suggested to take it out from the fridge at least 10-15 minutes before serving. The consumption of salmon, because of its high content in fats, it is not advised to kids below 2 years of age.

 In shops can be found excellent smoked salmon, most of the time coming from Norway or Scotland. The first thing to check is the expiration date, the aspect of the meat must be uniform and slightly shading off into orange. In case the color is too dark, this could probably mean it is too salty, whereas in case the surface is oily, this could indicate a non perfect smoking technique. In packages are usually found emblems emphasizing the quality of the product: indeed they simply have a merely “commercial” meaning, whereas it is too frequent the lack of information about the smoking technique. The most appreciated salmon is the one smoked with aromatic wood, mainly juniper, laurel and rosemary. Smoking techniques provide for the disposition of the salmons in horizontal or vertical position, the latter producing a better meat. Smoked salmon is not advised to kids below 4-5 years of age.

 In the traditional processing, the head and tail of salmon were eliminated, then the skin was separated from the meat and the two flanks were spread of salt, then allowed to rest for a whole day. After having removed the salt, the flanks were hung and allowed to dry for 24 hours more, before proceeding with the smoking process. The “smoking room” consists in a closed room in which are laid, in specific mats layered at variable heights, salmon flanks, in the bottom are laid wood chips which, burning with no flame, make a lot of smoke which will pass through hung flanks. Salmons remain in this smoking room for 10-11 hours at a temperature of 30-32° C. Industrial processing uses different techniques. Cold smoking lasts about 12 hours at a temperature not higher than 20° C and in specific containers made of aromatic wood. Warm smoking provides for an initial temperature of 120° C for the first 20 minutes, then it is lowered to 80° C for 2 hours, while continuously making sure the internal temperature of flanks is kept at about 75° C.

 The industrial processing also make use of liquid smoke, directly sprayed on salmon's flanks or soaked in a solution of liquid smoke and water. Modern technology has also introduced the so called “electrostatic smoking”, realized with liquid smoke particles electrostatically charged and which then stick to salmon's flanks. These innovative processes ensure a smoking with no noxious agent produced by the smoke, however in package's labels the smoking technique is never indicated.

 Expiration date of smoked salmon changes from country to country. In some countries, like Italy, it is permitted a period of 8-12 weeks, definitely too long, whereas in France the expiration date must not exceed 21 days. In countries where the expiration date is set to definitely long times, it is always advised to consume salmon at least 30 days in advance before the expiration date. Most of the times the choice of salmon is done according to the color of its meat. Producers are well aware of this, therefore they use food enriched with carotenoids in order to obtain a more inviting color. Besides the hue of color it is also advised to check homogeneity, as a homogeneous color indicates a higher quality. Another aspect to be considered is the presence of blood stains: they indicate a low quality processing technique.