Generality
The Italian eel is the same species (Eel eel called "European eel") that colonizes the inland waters of the Old Continent, before migrating to the Sargasso Sea crossing the Mediterranean and then the Atlantic Ocean; it is a bony fish able to survive safely in both fresh and salt water .
The eel has very fatty but also very valuable meat and in the last 50-60 years its presence has been so reduced (for multifactorial causes) that it is classified among the species at risk of extinction.
Description
The eel has a smooth skin, completely covered with mucus and apparently free of scales (which are actually very small). The skin pigments of this fish change inter- and intra-individually based on the stage of sexual maturation and / or habitat.
The specimens caught in fresh or brackish waters have a brown or green color on the back, while the belly is yellow. The mature eel, that is, ready to make the migration, becomes black on the back and yellow on the belly; moreover, as the long journey for reproduction continues, it assumes quite different physical characteristics (which give it the name of "Argentine eel ") compared to freshwater specimens.
The freshwater or brackish "eel" has a long anal fin which joins first to the caudal one and then extends over to the back; the pectoral fins are rather reduced. The gills of the eel are small, the jaw is prognathic (even in the migrant specimen) and the eye seems quite underdeveloped. Having said that, we mention some morphological traits that vary in the Argentine eel: the micro-scales increase in size, the fins pectorals grow, as well as eyes, while the head thins considerably; everything suggests that it is an evolutionary process designed to improve its abyssal swimming capacity.
The European eel has very poor eyesight and uses it mainly in order to capture the light from which it hides (it is a mainly nocturnal fish that moves mainly with the absence of the moon), a sense that improves during migration; in hunting it mainly uses the sense of smell and probably the perception of vibrations in the fluid. For hunting, the eel makes use of powerful jaws equipped with small conical teeth useful for preying: worms, annelids, molluscs, crustaceans and fish of all kinds; it also has necrophagic and scavenger capabilities.
The eel reaches different sizes based on sex; the female can reach over one meter in length for 2 kilograms of weight (although based on the detection of some catches, it is conceivable that it exceeds 3 kg per 1.5m), while the male "should not" exceed the size of 50cm for 200g. In this regard there are conflicting opinions; for a long time the eel has been attributed a hermaphroditic ability that would have justified the presence of small males and large females. However, it is now more likely that the sexes are distinct and that the male is underdeveloped. This does not mean that some researchers have identified large male eels. To date there remains an obscure point on which, hopefully, greater clarity will be made.
Life cycle
The eel is a fish with an extremely complex behavior; the female spends most of its life cycle in fresh water (rivers, lakes and canals) or brackish (valleys and mouths), but when it reaches its reproductive maturity it undertakes long journeys towards the open sea ( 15-40km per day for over 6,000km) up to Sargassi (where, however, it meets with the African and American eel). As regards the male, some argue that it does NOT have a migratory behavior and is permanently stationed near the places of maturation (inland waters) or near the maritime coast , while other sources claim that he follows the female on her long journey (theory that goes with the hypothesis of hermaphroditism - it is not excluded that she changes sex during the journey). It has also been found that the eel matures in inland waters (fresh or brackish) for a period ranging from 8 to 18 years (more the female than the male), beyond which (mature or not) it reaches the sea and colonizes the tract coastal.
During the long journey, similarly to the salmon, the eel feeds in an insufficient manner, which is why it thins (slims) and undergoes the "atrophy of the digestive system"; it survives by virtue of the abundant stores of accumulated fat but, having reached the place , lays from 1 to 6 million eggs at a depth of about 1.000m and then dies. Although not reliable as a scientific bibliographic source, we still report the experience of the hard-working fishermen regarding the reproductive cycle of the eel; some, in cleaning of the catch, they affirm that (albeit rarely) it is possible to come across specimens containing fertile oviparous sacs. This statement seriously questions the hypothesis that the eel reproduces ONLY in the Sargasso. There are also reports of underwater experiences near the coasts that show a clear spawning and mating activity between the specimens (although this could precede the migration of the "eel).
The eel fry observed in the Sargasso Sea (more like maggots and sayings leptocephalus), for a first period they move passively following the current; then, once they have developed just enough to swim, they begin the same journey as their parents but backwards, reaching the place of maturation and growth. NB. Tiny eels are mentioned first Czechs then ragani.
An endangered species
The eel has suffered (and still suffers) from human intervention; among the various penalizing factors we recall: intensive fishing (especially with nets and pots), the introduction into fresh water of various predatory alien species but, above all, the construction of insurmountable architectural barriers such as dams and locks.
The eel can be bred but reproduction in captivity is still a taboo of fish farming; in the presence of such a peculiar behavior, it is not easy to implement strategies or apply methods useful to favor its mating in captivity. This is one of the reasons why eel breeding is based on the capture of small specimens with relative growth in fish farming basins.
While focusing on the capture of Czechs and ragans to be bred in fish farming (intensive or valliculture), the progressive decrease in their density and the appearance of a parasitic crustacean called Jordanian argulus they significantly compromised the production volume.
Nutritional characteristics
Eel is a food of animal origin belonging to fishery products; the composition of this aquatic organism varies significantly in relation to: age, state of sexual maturation, environment of sampling, etc. On average, eel increases its its fat stock as the years go by even if an old eel caught in inland waters (before migration) compared to another caught in the middle of the journey, contains a completely different lipid fraction (higher than the second). The same goes for sex; the female, reaching larger sizes than the male, increases more her own adipose tissue stocks in view of maturation and migration. It is however possible to affirm that the eel belongs to the category of fatty fish.
The quantity of fats present in the eel dramatically increases its energy intake, which is almost impossible to systematically contextualize in a low-calorie slimming diet.
The fatness of the eel is accompanied by considerable quantities of cholesterol which make it unsuitable for feeding against hypercholesterolemia. On the other hand, the eel provides excellent quantities of vit. A and vit. E fat-soluble, and essential polyunsaturated fatty acids (ω ‰ -3). Proteins are abundant and of high biological value.
Eel contains good amounts of iron and B vitamins: thiamin, riboflavin and niacin (B1, B2 and PP).
NB: As explained in this article, the culinary preparation of excellence for eel is grilled; with this system the fish can drain up to 50% of its own weight (water and fat), which drastically reduces the intake of lipids, cholesterol, essential fatty acids and fat-soluble vitamins.
