موضوع بالانجليزي عن سمك القرش

موضوع بالانجليزي عن سمك القرش

تعبير انجليزي عن whale shark

معلومات عن القرش الحوتي

موضوع انجليزي عن سمك القرش قصير

موضوع عن الاسماك بالانجليزي

معلومات عن سمك القرش بالانجليزي

معلومات بسيطه عن القرش بالانجليزي

وصف القرش بالانجليزي

معنى كلمة سمك القرش بالانجليزي

معلومات عن سمك القرش الابيض

موضوع انجليزي عن سمك القرش قصير

موضوع تعبير عن سمك القرش

معلومات بسيطه عن القرش بالانجليزي

وصف القرش بالانجليزي

موضوع عن الاسماك بالانجليزي

معلومات عن سمك القرش الابيض

تعبير انجليزي لفل 4

تعبير الانجليزية للسنة 4 متوسط

تعبير انجليزي طويل

تعبير انجليزي حر

تعبير انجليزي صف ثاني متوسط

تعبير انجليزي صف ثالث متوسط

تعبير انجليزي صف اول متوسط

تعبير انجليزي صغير وسهل

تعبير انجليزي صف عاشر

معنى كلمة سمك القرش بالانجليزي

معلومات عن الحوت الازرق بالانجليزي

موضوع عن الاخطبوط بالانجليزي

موضوع عن الاسماك بالانجليزي

information about fish

paragraph about fishing

موضوع انجليزي عن سمك القرش

موضوع عن السمك

تعبير عن صيد السمك بالانجليزي

انواع السمك بالانجليزي

موضوع انجليزي عن سمك القرش قصير

 معلومات عن سمك القرش بالانجليزي

معلومات بسيطه عن القرش بالانجليزي

موضوع انجليزي عن سمك القرش قصير

موضوع عن الاسماك بالانجليزي

موضوع تعبير عن سمك القرش

تعبير انجليزي 100 كلمة

تعبير انجليزي 150 كلمة

تعبير انجليزي 102

تعبير انجليزي للصف 11

تعبير انجليزي للصف 12

تعبير انجليزي صف 11

تعبير انجليزي متوقع 2014

تعبير انجليزي متوقع 2015

مواضيع تعبير انجليزي توجيهي 2014

مواضيع تعبير انجليزي للتوجيهي 2012

مواضيع تعبير انجليزي توجيهي 2015

مواضيع تعبير انجليزي للتوجيهي 2014

مواضيع تعبير انجليزي توجيهي 2016

مواضيع تعبير انجليزي توجيهي 2013

مواضيع تعبير انجليزي للتوجيهي 2015

معنى كلمة سمك القرش بالانجليزي

معلومات عن سمك القرش الابيض

موضوع عن الاخطبوط بالانجليزي

معلومات عن الحوت الازرق بالانجليزي

search about The Great White Shark بحث عن اسماك القرش ...

سمك القرش في الإنجليزية, ترجمة, العربية-الإنجليزية قاموس - ...

تم

The whale shark (Rhincodon typus) is a cartilaginous fish, the only member of the genus Rhincodon and the only present species of the Rhincodontidae family. Exceptionally reaching 20 meters in length, for a mass of 34 tons, this shark is considered the largest fish currently living on Earth. However, its observable size is in practice generally between 4 and 14 meters.

Massive, moving quite slowly and without aggressiveness, this shark is perfectly harmless to man. Like the blue whale, its equivalent in mammals of the maritime megafauna, this sea giant feeds mainly on plankton, algae and microscopic animals, which it absorbs by its broad mouth.

Easily recognizable with its checkered livery, the whale shark is found in open seas and tropical and warm oceans. Its lifetime is estimated to be between 100 and 150 years1 even though the oldest specimen collected was about 70 years old2. Although there are no precise data on its total population, the species is considered to be at risk.

Cut

The size of whale sharks has been the subject of a number of more or less justified assertions. According to observations made in the Indian Ocean, the size of the whale shark is almost always between 4 and 14 m (95% of the observations), with a maximum of observations between 5.50 and 10 m (71% of the cases ) 5. It can therefore reach a maximum practical length of about 14 m, although the maximum size of 20 m, for a weight of about 34 t was reported once in 19992. The whale shark is the largest fish existing today, and only Leedsichthys and Megalo gifts, now missing, would have passed it. In the rest of the animal kingdom, however, it is smaller than the blue whale, a mammal that can reach 30 meters for 170 tons.

Skin

The whale shark's skin is completely white, while the back of the shark is gray, darker than most sharks, with many light spots and horizontal and vertical white or yellow lines forming a checkerboard . These tasks allow the identification of individuals by photo-identification: fact sheets, sorts of identity cards, are associated with animals, and are then used by researchers to identify and count whale sharks6. Galapagos and Australia7 have already been observed and even filmed an albino whale shark8. As in the rest of the animal kingdom, these individuals are extremely rare.

The skin of the whale shark is thicker and harder than that of any other species in the world, reaching up to 15 cm in thickness, and is covered with dermal denticles. It is his principal defense.

fins

The first dorsal fin has a generally triangular shape. The tip is rounded in juveniles and becomes more upright and angular with age. Its faces have the same livery in checkerboard as the body. The second dorsal fin is smaller.

The powerful pectoral fins have a false shape. The upper surface is dark and dotted with spots while the underside is white.

The caudal fin is heterocercal, the upper lobe being much larger than the lower lobe (the asymmetry becomes less pronounced in adults). It provides the driving force. However, the whale shark is not an effective swimmer, it uses all its body to swim and moves at an average speed of 5 km / h, a relatively slow speed for a fish.

Food

This giant of the seas does not share that name with the whales. It also follows the same diet. Indeed, the whale shark feeds only on small prey such as plankton and krill, but also algae, small crustaceans, small squid or fish of less than 10 cm (mackerel, ... ). An analysis of the stomach contents of a specimen caught off the coast of India in 1961 revealed a wide variety of ingested, including large quantities of zooplankton, partially digested fish remains, crustaceans, molluscs and small amounts of algae, suggesting undoubtedly an omnivorous diet. However, it is necessary to be less categorical because, because of its filtering behavior, the absorption of algae may be involuntary. It is one of only four known species of sharks that, like whales, filter their food by swimming slowly in waters rich in plankton ... mouth gaping. The water rushes into it, loaded with foods of all sizes and comes out of nutrients.

To compensate for the small size of its prey, it must swallow large amounts of food (nearly one tonne of plankton per day). To do this, it filters, thanks to its large gaps, the water which engulfs in its immense mouth. Its numerous rows of teeth, a few millimeters long, play no part in the diet. Instead, the shark draws water, closes the mouth and expels the water through its gills. During the slight delay between the closing of the mouth and the opening of the gill slits, the food is trapped against the dermal denticles lining the gill blades and the pharynx. This unique modification of the gills prevents the passage of solids larger than 2 mm in size, but leaves the liquid to flow. The particles isolated by this "sieve" are then swallowed. Whale sharks were caught "coughing." This is assumed to be a means of removing the accumulation of particles in the gills11.

Only four members of the elasmobranch family are reputed to be filterers6:

• the whale shark;

• the big-mouth shark;

• the basking shark;

• the manta ray.

In its feeding behavior, the whale shark uses two techniques: it can "filter", in the manner of the blue whale or "gober", in a similar way to tarpon. Thus, the animal is not content to filter the water during its movements when the concentration of planktonic food is low. Immobile, it can also rapidly aspirate large quantities of liquid, which is more suitable for catching larger prey or compact planktonic clouds12.

Solitary individuals have been observed feeding passively, swimming gaping mouths, or sometimes vertically encamped in the sea and opening their mouths to suck prey, when they are numerous. The latter method is used on banks of small crustaceans (krill), squid, anchovies or sardines13.

In group hunting, whale sharks feed, at dusk or at night, by filtering surface water with open mouth and distended jaw, or by "gobbling" the prey dynamically.