GambaPosted on September 27, 2018 - Last modified: September 27, 2018
leg is the common name for numerous crustaceans of the order Decapoda. They have a flexible body and are eaten like shellfish. They can be confused with shrimp and prawns as they have a similar appearance. They are found on the seabed in all oceans.
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The following species are nicknamed as prawns:
- Chorizo prawn (Aristaeomorpha foliacea) - Also known as chorizo, Moorish prawn or Spanish prawn.
- Indian red prawn (Aristeomorpha woodmasoni)
- Genus Aristeus with several species known as pink prawns, red prawns, enlisted or striped prawns.
- Arabian red prawn (Aristeus alcocki)
- Mediterranean red prawn, red prawn, pink prawn or pink prawn (Aristeus antennatus)
- Purple prawn (Aristeus antillensis)
- Smooth red prawn (Aristeus semidentatus)
- Shrimp listed or enlisted (Aristeus varidens)
- Argentine leg (Artemesia longinaris)
- Speckled prawn or banana prawn (Metapenaeus monoceros)
- Genus Parapenaeopsis, with several species known as:
- Sandeel prawn (Parapenaeopsis hardwickii)
- Gamba kidi (Parapenaeopsis stylifera)
- Genus Parapenaeus with a species known as:
- White prawn or tall prawn (Parapenaeus longirostris)
- Genus Solanocera with several species known as:
- Bighead prawn (Solenocera melantho)
- Atlantic Prawn or Atlantic Mud Prawn (Solenocera membranacea)
- Genus Trachypenaeus with several species known as prawns.
Prawns are small in size and many of the species are microscopic, going completely unnoticed by other animals. All prawns are invertebrate animals, that is, they lack a backbone, but they do have a hard exoskeleton (known as a shell) that is normally transparent and colorless, which makes them more difficult to see in the water.
The characteristics may vary according to the species, in our case we will describe the Crangon crangon species known as the Common European Prawn. The prawn has its body divided into two main parts known as the head, the thorax and an elongated and narrow abdomen. Both the head and the thorax are fused forming the cephalothorax that is protected by the carapace, which is a harder and thicker shell than that of the rest of the body. Its function is to protect the gills.
From the shell also come the rostrum, the eyes, the whiskers and the legs. The rostrum (rōstrum from Latin meaning beak) is a rigid, pointed forward extension located at the front of the head similar to a beak or nose, which is used for attack or defense. It also helps stabilize the shrimp when swimming backwards. On either side of the rostrum are bulbous eyes on the stems. They are compound eyes with paronamic vision and are excellent at detecting movements. The two pairs of whiskers emerge from the head. One of the pairs is longer than the other and they are used as sensors that allow them to feel where they touch, as well as smell and taste things by taking chemical samples from the water. The long antennas help it to orient itself to its surroundings, while the short ones assess the suitability of the prey.
Eight pairs of appendages emerge from the cephalothorax. The first three are called maxillipeds. The first pair pumps water into the gill cavity. After the maxillipids come another five pairs of appendages called pereiopods. These form the ten legs of the decapods. The first two pairs of pereopods have claws or chela. The chela can grab the food and put it in the mouth. They can also be used for fighting and grooming. The remaining six legs are long and thin, and are used for walking or sitting.
The muscular abdomen is made up of six segments and has a skin that is thinner than the carapace. Each segment has a separately overlapping cover, which is usually transparent. The first five segments each have a pair of appendages called pleopods, in the lower part used to swim forward or for other different purposes such as: incubation of eggs, to breathe or to inseminate, varying according to the species. The sixth segment ends in the telson flanked by two pairs of appendages called the uropods. Uropods allow them to swim backwards, also functioning as rudders. The tail has an open fan appearance and is formed by the telson and the uropods. If a shrimp is scared, it can flex its tail in a quick motion that will allow it to flee backwards. This action is known as the caridoid escape reaction (lobterization).
Prawns are widespread and found in most coasts, estuaries, oceans, lakes and rivers around the world. There are so many different species of shrimp that there is a shrimp adapted to every existing habitat. The vast majority are marine animals but a quarter of them are found in fresh water. Marine species inhabit depths of up to 5.000 meters, from the tropics to the polar regions. They gather in schools (banks) to survive and are able to adapt to changes in water conditions.
Prawns are omnivorous animals that consume animals such as plants. They eat mainly algae and small fish and plankton. One of the species of prawns stuns its prey to hunt it by making a loud click in the water.
However, some species are specialized in filtering water using their bristly legs to capture the nutrients that the water carries.
Prawns are very abundant in the sea and together with their size they are ideal prey for many animals, both in and out of the water. They are foods of fish, Whales, dolphins, sharks, humans; crustaceans such as: crabs, sea urchins y sea stars; sea birds like puffins and many other species.
The female prawn can spawn millions of eggs as they hatch in a couple of weeks. Small prawns start out as plankton until they are large enough to hunt in groups.
Some species are capable of storing multiple mating sperm, being able to produce progeny with different paternities. In these species, the female makes a pre- and post-copulatory sperm selection.
State of conservation
It is difficult to determine the general conservation status of the prawn, as there are a large number of species that may or may not be threatened. However, prawns are frequently consumed as shellfish by humans in large quantities so we could determine that their status is vulnerable.
Relationship with humans
Humans have captured shrimp for food since the beginning of great civilizations, in 1985 Quitmyer and others found direct evidence of their capture dating back to 600 AD by finding remains of their jaw. Numerous forms of captures have been found, for example, in the unworthy peoples of North America they were captured using fishing prey and traps made of branches and Spanish moss. Other peoples used nets woven from whipped fiber from plants.
Currently the shrimp catch is carried out with large quantities of trawls that arrived with the internal combustion engine added to the boats. As the fishing methods were industrialized, changes were made, they stopped drying in the sun to leave them in canning for later in the XNUMXth century they were replaced by freezers.
Of all the species of prawns, there are about 20. All of them are decapods and the majority belong to the genus Dendrobranchiata. The most consumed species are:
Litopenaeus vannamei, Penaeus monodon, Acetes japonicus, Trachysalambria curvirostris,Fenneropenaeus chinensis, Fenneropenaeus merguiensis y Pandalus borealis.
Most of the prawns that are marketed are frozen and sold according to their presentation, classification, color and uniformity. Prawns have high levels of omega-3 fatty acids and low levels of mercury. Prawns are generally sold whole, although only the meat can also be sold. Like other shellfish, they are also high in calcium, iodine, and protein, but low in dietary energy. They also have high cholesterol, specifically 122 mg to 251 mg per 100 g. However, consumption is recommended for being healthy for the healthy system as it improves the ratio of LDL cholesterol to HDL cholesterol and reduces triglycerides.
Shrimp and other shellfish are among the most common food allergens. For Jews they are not kosher foods and therefore are prohibited.
The prawns began to be raised in specialized pools for human consumption when the demand for prawns exceeded the quantity supplied. Another reason was the prohibition of shrimp fishing because they made it difficult for other animals that were in danger of extinction such as the sea turtle to feed. Hatcheries began in the 1970s around the world, especially in China. In 2007, farmed shrimp production exceeded wild shrimp catch.
Freshwater prawns are very popular in home aquariums. Some are purely ornamental, while others are useful for algae control and debris removal. The most popular freshwater prawns are: bamboo prawn, Japanese swamp prawn (Caridina multidentata), the cherry shrimp (Neocaridine heteropod), and the ghost shrimp (Palaemonetes spp.)
Prawns are also included in salty aquariums, although they are less popular. The most popular species is the harlequin prawn (Hymenocera picta).