basking shark:
2008/03/09 03:59:41.504 GMT-4
By Robin Street
Kingdom:
AnimaliaPhylum:
ChordataSubphylum:
VertebrataClass:
ChondrichthyesOrder:
LamniformesFamily:
CetorhinidaeGenus:
CetorhinusSpecies: Cetorhinus maximus
Geographic Range
North and South Atlantic and Pacific Oceans.
Biogeographic Regions:
oceanic islands (
native );
atlantic ocean (
native );
pacific ocean (
native ).
Habitat
Basking sharks inhabit subpolar and temperate seas moving southward during the winter. They prefer surface waters of the open sea, straying inland only to breed in the summer.
Aquatic Biomes:
coastal .
Physical Description
Mass3900 kg (average)(8580 lbs)
The basking shark has a conical snout, enormous gills, dark bristle-like gill rakers, and a crescent-shaped tail. Teeth are small and numerous(about one hundred per row) with a single conical cusp usually curved backwards, and similar in both jaws. Color is grayish brown to black above, often with blotches of a lighter color, and pale with blotches on the belly. Average size of this shark ranges from 7-9 m.
Some key physical features:
bilateral symmetry .
Reproduction
Age at sexual or reproductive maturity (female)2920 days (average) [
External Source: AnAge]
Age at sexual or reproductive maturity (male)2920 days (average) [
External Source: AnAge]
Basking sharks are believed to be ovoviviperous. Females mature at 4-5m. Embryos supposedly measure between 1.5-1.8m in length.
Behavior
This is a migratory speciesal though its seasonal movements aren't well known. They dwell in northern waters as long as the plankton population is abundant, moving south in the winter. Though they are largely oceanic sharks, they can be found off the coast of Iceland and northern Europe during the summer where they mate.
Key behaviors:
natatorial ;
motile .
Food Habits
To capture food, this shark swims with its mouth open widely, gillrakers straining plankton from the water. The absence of basking sharks in the winter has led to the belief that they hibernate in deep waters until the following summer and, since they lose their gill rakers in winter, possibly cease to feed during this time.
Economic Importance for Humans: Negative
In some areas, this shark is considered to be a nuisance because it gets tangled in floating nets while basking on the surface. Occasionally, they have been known to ram small boats, presumably by accident.
Economic Importance for Humans: Positive
This fish was once used for its liver oil and was thus virtually endangered for some time. It is still used in lesser amounts for fish meal and animal feed.
Conservation Status
No special status.
BASKING SHARKCetorhinus maximus
Go to a
Basking Shark PrintoutThe basking shark (Cetorhinus maximus) is a huge filter feeding shark which grows to be up to about 33 feet (10 m) long. It is the second-largest shark (after the
whale shark). The basking shark is also called the sunfish, the bone shark, the elephant shark, the sailfish shark, and the big mouth shark.
GENERAL DESCRIPTIONThis huge, bulky, filter-feeder is grayish brown to black to bluish on the upper surface and off-white or darker on its belly. It has a huge mouth which it uses to collect tiny food that floats in the water. A sluggish swimmer with huge gills and dark, bristle-like gill rakers, it filters its food from the water. The snout is short and conical.
SIZEFemale basking sharks are up to 33 feet (10 m) long; males are up to 30 feet (9 m) long. This enormous shark weighs up to 4 tons. It is the second largest fish in the world; the
whale shark is the largest. TEETHBasking sharks have hundreds of teeth (each having a single cusp, curving backwards) but they are tiny and are of little use.
DIET AND FEEDING HABITSBasking sharks are filter feeders that sieve small animals from the water. As the basking shark swims with its mouth open, masses of water filled with prey flow through its mouth. The prey includes plankton, baby fish, and fish eggs. After closing its mouth, the shark uses gill rakers that filter the nourishment from the water. Gill rakers are bristly structures (the thousands of bristles are about 4 inches or 10 cm long) in the shark's mouth that trap the small organisms which the shark then swallows. The water is expelled through the shark's 5 pairs of gill slits. The shark can process over 1500 gallons (6000 liters) of water each hour.
SOCIAL GROUPSBasking sharks travel alone, in pairs, or in schools (groups) of up to 100 members.
HABITATBasking sharks live in coastal temperate waters. They spend most of their time at the surface, hence their nickname the "sunfish."
DISTRIBUTIONBasking sharks are found off the coasts of western North America from Baja to southern Alaska, off the east coast of the US and southern Canada, along the Gulf Stream, to the entire coastline of Europe, off the southern coast of Australia, off South Africa, New Zealand, most of southern South America, the Red Sea, and the coastlines of China and Japan.
SWIMMINGBasking sharks are slow swimmers, going no more than 3 mph (5 kph). They swim by moving their entire bodies from side to side (not just their tails, like some other sharks do).
REPRODUCTIONBasking sharks reach sexual maturity at about 2-4 years old. They mate in the summer off the coasts of Iceland and northern Europe. The gestation period is about 3.5 years. They probably reproduce via
aplacental viviparity. Females give birth to 1-2 live young. which are about 5.5 feet (1.7 m) long. These are the largest shark pups.
Like all sharks, fertilization of the eggs occurs within the female. The eggs hatch within the female and are nourished by eating unfertilized eggs in the womb. There is no placenta to nourish the babies - they must fend for themselves, even before birth. They swim away from the mother immediately after birth, there is no maternal care-giving. SHARK ATTACKSBasking sharks are not aggressive and are generally harmless to people. MIGRATIONBasking sharks migrate seasonally, eating in cool northern waters, moving south during the winter. POPULATION COUNTThe number of basking sharks is unknown, but it may be decreasing since the basking shark is hunted for its meat, fins and oil.
BASKING SHARK CLASSIFICATION
Kingdom Animalia (animals)Phylum ChordataSubphylum Vertebrata (vertebrates)Class Chondrichthyes (cartilaginous fish)Subclass Elasmobranchii (sharks and rays)Order
LamniformesFamily CetorhinidaeGenus Cetorhinus Species maximus