Archive for September, 2008:
Blue Shark
Blue Shark
With its streamlined body and long, wing-like pectoral fins, the blue shark is a long-range cruiser and voracious feeder that sometimes attacks swimmers. But it mostly travels the open oceans, far from land, commonly migrating 3000km (1900 miles) or more with the seasons. The longest journey on record is nearly 6000km (about 3700 miles), and its maximum speed 69km/h (43mph). It usually travels near the surface, its dorsal and tail fins often projecting. It has big eyes that help it to spot prey - which is scarce in mid-ocean and finger-like gill-rakers to filter any small fish and other creatures from water passing from its mouth out through its gills.
Scientific name : Prionace glauca
Classification : Order Carchariniformes (ground or whaler sharks)
Family : Carcharhinidae
Size : Up to about 4m (13ft) long; up to 206kg (4551b)
Distribution : Worldwide, in temperate and tropical zones
Habitat : Mostly open ocean, near surface, but sometimes inshore
Diet : Fish (especially schooling species); squid and other invertebrates
Reproduction : Viviparous; often 50 or more young, born after 9-12 month gestation
Frilled Shark
Frilled Shark
With its slim body and fins, the frilled shark looks more like a giant eel than a typical typical shark. It is a deep-water species, rarely seen except in the nets of deep-sea trawlers, and may be responsible for some stories of `sea-serpents’. Like a few other species of the related order Hexanchiformes (the cow sharks; within which some biologists also place the frilled shark), it has six gill-slits - resembling a frilled collar - on each side; most sharks have five. The mouth opening is at the very front of its head, rather than being underslung as in most sharks; inside it has about 300 teeth, each three-pointed like a trident. It probably strikes snake-like at its prey.
Scientific name : Chlamydoselachus anguineus
Classification : Order Chlamydoselachiformes (frilled sharks) or Hexanchiformes
Family : Chlamydoselachidae
Size : Male up to 2m (6.5ft) long; female up to 1.5m (5ft)
Distribution : Worldwide, in temperate and tropical zones
Habitat : Offshore waters, to 1200m (4000ft) deep
Diet : Mainly deep-sea squid and fish
Reproduction : Ovoviviparous; 4-12 young born after up to 3.5-year gestation