The History Of Fishing

Life began in water more than 400 million years. Were some microscopic plants which began to feed on other, evolved in animals. It was here where there was already a division of species. Some of these primitive animals evolved to become jellyfish, worms, snails and other invertebrates. The other part developed a backbone giving rise to the first vertebrates: fish. They developed fins and began to breathe through gills (although a small part it was for lungs). Finally, some of the existing fish species came ashore causing, over time, to the great variety of terrestrial species today.
Fish farming today is of great importance, since it is a food rich in proteins, both for animals and for humans. It is also a way to solve problems in generating employment. Venezuela is a country rich in water which has many possibilities for the development and intensification of agricultural production and in this case for fish culture.

     FISH


The fish originated from other chordates to the beginning of the Cambrian. No one knows for certain exactly where to draw their origin, the most primitive group of fish known up to the ostracoderms, from which descended the modern agnathans (which includes the lampreys and mixines).


One of the most important developmental achievements was the development of jaws from gill arches, as primitive fish allowed to feed on larger pieces, capturing prey, crushing. Within the first jawed fish are the placoderms, which appeared towards the end of Silurian. Terrestrial vertebrates diverged from lobe-finned fish, related to the coelacanth or dipnoos.


Aquatic vertebrates are generally ectothermic, covered mostly equipped with scales and fins, which allow movement in the aquatic environment, and gills, which capture the dissolved oxygen in water.

Fish are abundant in both saltwater and fresh water, being able to find species from mountain streams (eg roach) and in the depths of the ocean (eg eels Swallow). The specialty of zoology that deals specifically with fish is called ichthyology. The world of fish has a lot of variety in the forms as they are adapted to swimming, lifestyle and environment in which each species is developed.

Fusiform body shape, the predominant tendency of most fish species, obey the law: maximum swimming speed with minimum energy expenditure, in some however, the fusiform shape may be missing, and is then replaced by a series of morphological adaptations able to compensate for their body shape. The fish are found in all aquatic environments of the world, except those that contain harmful or toxic elements.


Fins: They are fundamental in swimming ability, especially the flow with maintaining stability in the water. The paired fins located on either side of the body are: the pectoral fins (behind the head) and the ventral. The median fins (only one) are the anal, caudal and dorsal. The study of the wings is a good way to identify fish.

The adipose fin (if present) is located just behind the dorsal fin and before the flow characteristic is their lack of bones or radios. Some say that the gonopodium is an example of adipose fin, while others see it as an organ. (All depends on your point of view).

Role of Fins:
The fins have different functions, but all basically serve for locomotion and balance. The caudal fin acts as a kind of rudder and, thanks to the body or the caudal peduncle, is also involved in propulsion. Fish are in great speed is because they have a tail fin crescent-shaped.

The dorsal and anal fins are folded along the body when the fish swims. Its function corresponds to that of the keel of a boat at low speed.

The paired fins help to stabilize the fish when it encentra between two stools. When nothing, these flaps are retracted and also help to slow.

The Scales:
Arranged like tiles on a roof lining skin scales of fish. As the flaps, their shape may serve to differentiate one species from another.

VARIETIES OF FISH IN RIVERS
FRESHWATER
The diversity of fish living in freshwater environments of Venezuela is one of the most important natural heritage features of the country's first known figure on the freshwater fishes of Venezuela was provided by Magus (1970) who indicates 521 species ( 422 primary, 52 secondary and 47 peripheral), Taphorn and colleagues (1997) listed a total of 1,065 species, Lassus and colleagues (2004) present a list of 1,198 species of fish in inland waters of Venezuela, Lassus and colleagues (2005) A total of 995 recorded species of fish to the Orinoco River basin (Colombia and Venezuela). In recent years new species have been described for Venezuela appreciably, which allows us to indicate that we are closer to knowing the exact number of freshwater fish living in Venezuela. Venezuela is the second or third country in the Nontropical region, after Brazil and Colombia very closely in terms of richness of freshwater fish. However, what matters is not the place it occupies in the hierarchy list or honor roll of species richness, but the place it occupies in the commitment to humanity to protect and conserve all species in the country.

The freshwater fishes of Venezuela are divided into seven major river basins: The basin of the Orinoco, Cuyuni River Basin (part of the Essequibo River basin), the Black River Basin (linking the basins of Orinoco and Amazon River), the basin of the Gulf of Praia, Caribbean Sea basin (it may indicate that the main river basins are individuals: Tuy, Tocuyo Aroa, Unare, etc..), the basin of Lake Maracaibo and the Lake of Valencia. Several species are unique or endemic to each basin, but also the species do not live evenly across the basin. Each species is located where the ecological, physiological and historical permits. Thus we have no species native to the Andean foothills, the Guiana Shield and the plains region, but all water bodies in these regions may belong to the great Orinoco River basin.

The freshwater fish can be divided into primary, secondary and peripheral. The so-called primary freshwater fish species are those whose ancestors or similar or related groups also live in fresh water. These species do not tolerate any degree of salinity. The so-called secondary freshwater fish species are those whose ancestors or similar or related groups are in the marine environment.