The silky shark is a species of requiem shark, family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found in tropical waters worldwide. Highly mobile and migratory, this shark is most often found over the edge of the continental shelf to a depth of 50 m (160 ft). The silky shark has a slender, streamlined body and typically grows to 2.5 m (8.2 ft) long. A swift, inquisitive and persistent hunter, it feeds mainly on bony fishes and cephalopods, and has been known to drive them into compacted schools before launching open-mouthed, slashing attacks. This species often trails schools of tuna, a favored prey. The silky shark has an extremely acute sense of hearing, allowing it to localize the low-frequency sound generated by other feeding animals, and by extension, sources of food. Due to their abundance, they form a major component of commercial and artisanal shark fisheries in many countries. Data now suggest that silky shark numbers are declining around the world, which prompted the International Union for Conservation of Nature to reassess its conservation status from Least Concern to Near Threatened in 2007.
The parts of a tree are the roots, trunk(s), branches, twigs and leaves. Tree stems consist mainly of support and transport tissues (xylem and phloem). Wood consists of xylem cells, and bark is made of phloem and other tissues external to the vascular cambium. Trees may be grouped into exogenous and endogenous trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of trees (all conifers, and almost all broadleaf trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the monocotyledons (e.g., palms and dragon trees), but also cacti, grow by addition of new material inwards.
The silky shark is a species of requiem shark, family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found in tropical waters worldwide. Highly mobile and migratory, this shark is most often found over the edge of the continental shelf to a depth of 50 m (160 ft). The silky shark has a slender, streamlined body and typically grows to 2.5 m (8.2 ft) long. A swift, inquisitive and persistent hunter, it feeds mainly on bony fishes and cephalopods, and has been known to drive them into compacted schools before launching open-mouthed, slashing attacks. This species often trails schools of tuna, a favored prey. The silky shark has an extremely acute sense of hearing, allowing it to localize the low-frequency sound generated by other feeding animals, and by extension, sources of food. Due to their abundance, they form a major component of commercial and artisanal shark fisheries in many countries. Data now suggest that silky shark numbers are declining around the world, which prompted the International Union for Conservation of Nature to reassess its conservation status from Least Concern to Near Threatened in 2007.
