THE SECRETS UNDER THE OCEAN
DO YOU REALLY KNOW WHAT IS HIDDEN UNDER THE BLUE OCEAN?
WHAT IS THE OCEAN
the darks dephts
WHAT ARE THE SEACRETS HIDDEN IN THE DEEP AND DARK DEPHT?
THE SHARK, THE MOST DANGEROUS ANIMAL UNDER THE BLUE OCEAN. IT IS THE FIRST ENEMY OF AMERICAN FISHERMEN.
THE TSUNAMI REPRESENTS THE POWER OF THE OCEAN.
Shark meat is nutritious and is used for human food. In Asian cuisines a prized gelatinous soup is made from the fins of certain species; many of the millions of sharks landed annually are taken just for the fins, and finning is now believed to threaten such species. The flesh is also sold for poultry feed, and shark oils are used in industry; shark-liver oil was formerly used as a source of vitamin A. The rough skin is used as a sandpaper called shagreen, and tanned sharkskin is a durable leather.
Sharks are heavy fishes, possessing neither lungs nor swim bladders (see fish). Their skeletons are made of cartilage rather than bone, and this, along with large deposits of fat, partially solves their weight problem; nevertheless, most sharks must keep moving in order to breathe and to stay afloat. They are good swimmers; the wide spread of the pectoral fins and the upward curve of the tail fin provide lift, and the sweeping movements of the tail provide drive. Their tough hides are studded with minute, toothlike structures called denticles. Sharks have pointed snouts; their crescent-shaped mouths are set on the underside of the body and contain several rows of sharp, triangular teeth. They have respiratory organs called gills, usually five on each side, with individual gill slits opening on the body surface; these slits form a conspicuous row and lack the covering found over the gills of bony fishes. Like most fishes, sharks breathe by taking water in through the mouth and passing it out over the gills. Usually there are two additional respiratory openings on the head, called spiracles. A shark's intestine has a unique spiral valve, which increases the area of absorption. Fertilization is internal in sharks; the male has paired organs called claspers for introducing sperm into the cloaca of the female. Members of most species bear live young, but a few of the smaller sharks lay eggs containing much yolk and enclosed in horny shells. Compared to bony fishes, sharks tend to mature later and reproduce slowly.
THE DARKS DEPHTS
THE FANGTHOOTH FISH
The nightmarish fangtooth is among the deepest-living fish ever discovered.
THE FRILLED SHARK
Humans rarely encounter frilled sharks, which prefer to remain in the oceans' depths, up to 5,000 feet (1,500 meters) below the surface.
THE VAMPIRE SQUID
Vampire squid is an apt name for a creature that lurks in the lightless depths of the ocean.