Importance of Scales

Serena Cuoghi
Title of Professor of Biology

Most fish, both marine and freshwater, have plates of variable size, shape and even thickness externally covering their skin. These hard formations of collagen and mineral salts are known as scales, which are classified according to their shape as: 1) ctenoids semicircular in shape and indented outer edge; 2) cycloids which are more rounded than the previous ones and with smooth edges; 3) ganoids, rhomboids that fit against each other very efficiently; 4) cosmoid and apparently the most ancient of all types; and lastly, 5) placoids, similar to quadrangular plates with a great hardness and an accommodation such that they make up an authentic armor, also highlighting that this type of scales is unique and exclusive to cartilaginous fish such as sharks and stripes.

However, fish are not the only animals covered by scales, reptiles also have them and with characteristics and composition very different from those of the first animal group, making it even more difficult to determine a specific evolutionary origin for them, however, this has not been an impediment to understand the importance of scales, both for the animals that protect themselves through them from adverse environmental conditions, the attacks of predators and the opportunism of ectoparasites, as well as for humans, who have found in these peculiar structures a whole source of rich nutrients that can be used for a wide variety of products, since while the fish scales have protein mainly collagen, reptiles such as crocodiles and chameleons have scales composed of keratin, another protein of great metabolic and commercial importance for the human.

Scratch resistant protection

In both fish and reptiles, the scales have the important function of providing extra protection to the animal's body, very possibly this is due to the fact of being animals exposed to constant friction as in the case of fish and to extreme, hostile and even thorny environments as in the case of reptiles. Be that as it may, the scales not only represent a physical protection mechanism, but also thermal protection, even more so for reptiles. who lack their own thermoregulation mechanism, needing to conserve as much heat as possible during absorption the day.

Unlike fish, in which the scales are completely independent of each other, the scales in reptiles are They are generated in the form of a tissue with bumps that completely covers the animal, just like the exoskeleton of the arthropods. Due to this, throughout the growth and adult life of reptiles, it is necessary to shed the entire layer of scales, both to allow its expansion towards the new dimensions of the animal, as well as for its maintenance in the face of the deterioration that it also experiences, a process that in fish occurs independently for each of its scales.

For most species, the size of the scales becomes invariable, so that as they grow, what happens is an increase in the amount of scales in order to keep the entire body of the animal.

Flaky Healthy

The collagen obtained by processing fish scales is widely used by the pharmaceutical sector, either through its distribution as a nutritional supplement, or as a basis for the manufacture of the billions of capsules in which the drugs are compressed in order to be ingested with greater ease.

On the other hand, this easily bioassimilable substance of vital importance has also found a wide range of uses to stand out within in the world of cosmetics, being present today in almost all body care and beauty products, emphasizing that the importance of the scales at an economic level, has transcended far above what could have been thought, on what was originally a waste of the industry fishery.

Despite all this economic inclusion, the item that possibly first popularized the use of fish scales, for the use of its collagen on a large scale scale, it was rather that of gastronomy and more precisely confectionery, thanks to the diffusion of the use of jellies obtained with the cooling of collagen, particularity that became very appetizing and practical when making combinations with foods of all kinds to create innovative presentations even of things as simple as a plate of fruit, thus providing such a simple technique and with such a pleasant result, that there are already thousands of industrial candies that also they use it.

References

Diez de Oñate, G., & Rodríguez Atá, R. (2001). Marine fish. series 4. Unesco.

Hickman, C. et al. (1998) Integral Principles of Zoology. 11th Ed. Madrid, Spain. McGraw-Hill Interamericana.

Villa, C. (1996). Biology. 8th Edition. Mexico. McGraw-Hill.