{{מיון|
|שם=כריש ענק
|תמונה=250px
|ממלכה=בעלי חיים
|מערכה=מיתרניים
|מחלקה=דגי סחוס
|סדרה=כרישאים
|משפחה='''כריש ענקיים'''
|סוג='''Cetorhinus'''
|מין='''כריש ענק'''
|שם_מדעי=Cetorhinus maximus
|שימור=שימור VU
|תפוצה=250px  תפוצת הכריש הענק - בכחול.
}}
 
'''הכריש הענק''' (שם מדעי: '''Cetorhinus maximus'''), המוכר גם בשם "כריש עצם", הוא מין יחיד במשפחת הכריש-ענקיים (Cetorhinidae). הוא הכריש הלווייתן", והוא מצוי בכל האוקיינוסים ברחבי העולם ונמצא בסכנת הכחדה.

הפרט הגדול ביותר שנצפה בוודאות היה באורך של 12.27 מטר ושקל קרוב לשישה עשר טון. מזונו מורכב מקשרים. מאחר והוא ניזון מפלנקטון, הוא אינו מסוכן לבני האדם ולרוב מתרחק מקרבתם ומסירות.

{{Taxobox
| name = Basking shark
| fossil_range = Early Oligocene to Present<ref>{{cite journal
  | last = Sepkoski
  | first = Jack
  | authorlink =
  | coauthors =
  | title =  A compendium of fossil marine animal genera (Chondrichthyes entry)
  | journal = Bulletins of American Paleontology
  | volume = 364
  | issue =
  | pages = p.560
  | publisher =
  | location =
  | date = 2002
  | url = http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=575&rank=class
  | doi =
  | id =
  | accessdate = 2008-01-09 }}</ref>
| status = VU
| trend = not known 
| status_system = iucn2.3
| status_ref =<ref name="iucn"> Database entry includes justification for this species' status </ref>
| image = Basking Shark.jpg
| image_width = 200px
| regnum = Animalia
| phylum = Chordata
| classis = Chondrichthyes
| subclassis = Elasmobranchii
| ordo = Lamniformes
| familia = '''Cetorhinidae'''
| familia_authority = Gill, 1862
| genus = '''''Cetorhinus'''''
| genus_authority = Blainville, 1816
| species = '''''C. maximus'''''
| binomial = ''Cetorhinus maximus''
| binomial_authority = (Gunnerus, 1765)
| range_map = Basking shark distribution.gif
| range_map_width = 200px
| range_map_caption = Range (in blue)
}}
The '''basking shark''', ''Cetorhinus maximus'', is the second largest fish, after the whale shark. It is a cosmopolitan species — it is found in all the world's temperate oceans. It is a slow moving and generally harmless filter feeder.

Like other large sharks, basking sharks are at risk of extinction due to a combination of low resilience and overfishing to supply the worldwide market for the shark's fins, flesh and organs.

==Distribution and habitat==
The basking shark is a coastal-C (46 and 57°&nbsp;F). It is often seen close to land and will enter enclosed bays. The shark will follow concentrations of plankton in the water column and is therefore often visible on the surface. They are a highly migratory species leading to seasonal appearances in certain areas of the range.<ref name="FAO"></ref>

==Anatomy and appearance==
thumb|220px|right|Male basking shark 
The basking shark is one of the largest known sharks, second only to the whale shark. The largest specimen accurately measured was trapped in a herring net in the Bay of Fundy, Canada in 1851. Its total length was , and it weighed an estimated 19&nbsp;tons. There are reports from Norway of three basking sharks over 12&nbsp;m (the largest being 13.7&nbsp;m), but those are considered dubious since few if any sharks anywhere near such size have been caught in the area since. Normally the basking shark reaches a length of between  and a little over . Some specimens surpass 9 or even , but after years of hard fishing, specimens of this size have become exceedingly rare. 

These sharks possess the typical Behaviour).

Other distinctive characteristics of the basking shark include a strongly keeled caudal peduncle, highly textured skin covered in placoid scales and a layer of mucus, a pointed snout (which is distinctly hooked in younger specimens), and a lunate caudal fin. In large individuals the dorsal fin may flop over when above the surface. Colouration is highly variable (and likely dependent on observation conditions and the condition of the animal itself): commonly, the colouring is dark brown to black or blue dorsally fading to a dull white ventrally. The sharks are often noticeably scarred, possibly through encounters with lampreys or cookiecutter sharks. The basking shark's liver, which may account for 25% of its body weight, runs the entire length of the abdominal cavity and is thought to play a role in buoyancy regulation and long-term energy storage.

In females, only the right ovary appears to be functional: if so, this is a unique characteristic among sharks.

==Diet==
The basking shark is a passive zooplankton, small fish and invertebrates from up to 2,000 tons of water per hour.<ref name="FLMNH"></ref> Unlike the megamouth shark and whale shark, the basking shark does not appear to actively seek its quarry, but it does possess large olfactory bulbs that may guide it in the right direction. Unlike the other large filter feeders, it relies only on the water that is pushed through the gills by swimming; the megamouth shark and whale shark can suck or pump water through their gills.<ref name="FLMNH"/>

== Behaviour ==
thumb|right|250px|Head of a basking shark.
Studies in 2003  have disproved the idea that basking sharks hibernate and have shown that they are active throughout the year.<ref>http://www.baskingsharks.org/view_folder.asp?folderid=6230&level2id=6212&rootid=6212&depth=2&level1=&toptab=1</ref> In winter, basking sharks move to deeper water (depths of up to 900 m) feeding on deep water plankton. Satellite tagging confirmed that basking sharks move thousands of kilometres during the winter months locating plankton blooms. It was also found that basking sharks shed and renew their gillrakers in an ongoing process, rather than over one short period.

They feed at or close to the surface with their mouths wide open and gill rakers erect. They are slow-moving sharks (feeding at about 2&nbsp;knots) and do not attempt to evade approaching boats (unlike great white sharks). They are harmless to humans if left alone and will not be attracted to chum.

Basking sharks are social animals and form schools segregated by sex, usually in small numbers (3 or 4) but reportedly up to 100 individuals.<ref name="FAO" />  Their social behaviour is thought to follow visual cues, as although the basking shark's eyes are small, they are fully developed and have been known to visually inspect boats, possibly mistaking them for conspecifics.<ref name=ELASMO></ref> Females are thought to seek out shallow water to give birth.

These sharks have few predators, but orcas and tiger sharks are known to feed on them, and the aforementioned lampreys are often seen attached to them, although it is unlikely that they are able to cut through the shark's thick skin.<ref name="FAO" />

Even though the basking shark is large and slow it can breach and has been reported jumping fully out of the water.<ref name="PSRF"></ref> This behaviour could be an attempt to dislodge parasites or comensals.<ref name="FAO" /> There are doubts as to the accuracy of these observations - since the basking shark has a recorded top swimming speed of  and has not been observed to jump, even under the stress of harpooning.<ref name="FAO" />

== Reproduction ==
Basking sharks are ovoviviparous: the developing embryos first rely on a ova produced by the mother (a behaviour known as oophagy). Gestation is thought to span over a year (but perhaps 2 or 3 years), with a small though unknown number of young born fully developed at 1.5&ndash;2&nbsp;m (5&ndash;6.5&nbsp;ft). Only one pregnant female is known to have been caught; she was carrying 6 unborn young.<ref name="Trust">{{cite web|
author=The Shark Trust| 
title=Basking Shark Factsheet | 
publisher=The Shark Trust| 
accessdate=2006-07-07| 
url=http://www.sharktrust.org/do_download.asp?did=26369}}</ref>
Mating is thought to occur in early summer and birthing in late summer, following the female's movement into shallow coastal waters.

The onset of maturity in basking sharks is not known but is thought to be between the age of 6 and 13 and at a length of between 4.6 and 6&nbsp;m. Breeding frequency is also unknown, but is thought to be 2 to 4 years.