By Robin Street
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
(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
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.
Contributors
Robin Street (author), University of Michigan.

