On the question about the number of teeth of a white shark cannot be answered unequivocally because they are located in several rows. Their number is variable, and depends on the size of the animal, its age. Some time back the tooth is in the gum, taking a vertical position only when the free space because, unlike the teeth of mammals, they do not have long roots and they are able to move about freely in the gums. Upper teeth, by the way, arranged in one row and larger than the lower. But the lower teeth are more acute.
The modern great white shark teeth have a triangular shape and as sharp as blades. Such teeth easily cut through large pieces of meat with large fish or mammals, or to bite prey in half. The porbeagle teeth tone, acute and recurved for grasping and retaining a nimble and slippery prey. In benthic species, feeding on molluscs and crabs, the teeth are thick and blunt – these tools comfortable to chew solid calcareous shell and the shell. The teeth are in the mouth and in the throat of many series – one thousand and even more. Working teeth are in the front row. They easily fall off, and his successor shall be nominated from the depths of the jaws of the all-new series is a real “factory tooth”. Continue reading
The Carp Family (Cyprinidae).
Gold, or Chinese, crucian carp (Carassius auratus) found in the wild in Korea, China and Japan. This crucian carp in nature has a Golden hue, especially in shallow, well warmed by the sun waters.
Of all aquarium fish, goldfish have the longest history . Goldfish, a domesticated form of the Golden carp was first bred in China over 1500 years ago, where these, taking advantage of the variability of carp in coloration and in the shape of the body, engaged in the culture of ornamental carp. Goldfish bred in garden ponds and reservoirs in the estates of the nobility and wealthy people. It was the first time goldfish imported in the mid-eighteenth century. Currently widespread many varieties of goldfish.
Main color of body and fins reddish-Golden, the back is darker than the abdomen . Other types of coloring: pale pink, red, white, black, black-blue, yellow, dark bronze, fiery red. The body of a gold fish is elongated, slightly compressed laterally. In ponds goldfish can grow up to 35 cm, but in a normal aquarium its size is much smaller. To distinguish males from females only during the spawning season. Then the female has a rounded abdomen, while the males have pectoral fins and the gills there are a white “rash”. Continue reading
An important reserve in increasing fish productivity is the introduction of fish culture in the practice of the method of joint cultivation of fishes of several kinds . that most fully use feed resources of the reservoir. Practice confirms the possibility of growing in a variety of combinations that reduce competition for food fish such as carp, carp, white and variegated silver carp, white Amur, etc.
Silver carp . With the introduction into farms of joint cultivation of fishes of the composition of the productivity of fish in ponds is 20 – 30 kg/ha water area. When grown with carp and herbivorous fish in pond farms of the southern areas by herbivorous fish receive an additional fish for at least 6 – 10 t/ ha, in ponds in the forest-steppe up to 3 – 5 kg/ha.
The silver carp eats all types of algae that occur in fresh water. Its power is supplied by filtering phytoplankton through a kind of arranged Gill apparatus. In Biotechnics of artificial breeding using the method of pituitary injections, where to produce offspring using the pituitary glands of fish / kg females. The ripening females after hypophyseal injections depends on the temperature conditions in the spawning basins. When ripe, the prevailing temperature of 21 – 26 degrees Celsius. Continue reading