Basking Shark

Cetorhinus maximus

elephant shark, bone shark, nurse fish, sunfish, sailfish, hoe-mother, requin pèlerin, squale pèlerin, squale géant, éléphant de mer, poisson à voiles

INTRODUCTION

The basking shark is the second largest shark and fish in the world, and it is the only member of the Cetorhinidae family. It is normally observed at the surface where it feeds alone or in a group. The basking shark is often found near the coast in northern and temperate waters. In Quebec and the Canadian maritime provinces, it ranges from Newfoundland in the north, to the St. Lawrence Estuary in the west. Despite its huge size, the basking shark poses no threat to humans. It feeds exclusively on plankton. It is not known where specimens observed in Canada spend the winter although basking sharks tagged in New England have been tracked as far south as Brazil. Various sources wrongly suggest that the basking shark hibernates on the sea floor during winter. This idea was debunked in 2003 when scientists of the Marine Biological Association (UK) discovered that the basking shark actually feeds on plankton at depths up to 900 m (3,000 ft) during the cold season. It is also the only shark that passively filter feeds, relying solely on forward movement to capture plankton at a speed of approximately 2 knots (3.7 kph; 2.3 mph).

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 24, 2016

RIGHT: Basking shark off Anticosti Island, Québec.

Photo © MICS

NAMES

Scientific Name: Cetorhinus maximus* (Gunnerus, 1765)

Cetorhinus: from the Greek [ketos] + [rhinos] = sea monster + nose

maximus: Latin = great

*sea monster with a big nose

 

Common Names: Basking shark, elephant shark, bone shark, nurse fish, sunfish, sailfish, hoe-mother, requin pèlerin (Fr.), squale pèlerin (Fr.), squale géant (Fr.), éléphant de mer (Fr.), poisson à voiles (Fr.)

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 23, 2016

SIZE AND APPEARANCE

Maximum length: Up to 12 m (40')

Average length: 6.5 m to 9 m (22' to 29')

Weight: Up to 4,500 kg (9,900 lbs)

 

The basking shark is the second largest shark and fish in the world, measuring up to 12 m (40 ft) in length. Seen from the surface, it is often mistaken for a whale. It can even completely leap out of the water in order to rid itself of parasites. This infrequent occurrence was reported in Percé Bay in July 2001. When it opens its mouth, its head takes on gigantic proportions. Its liver is equal to 25% of its body weight and helps maintain the buoyancy of this enormous fish.

BELOW: Basking shark in the Bay of Fundy, near Grand Manan Island. Photo © Jeffrey Gallant | GEERG.ca

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 23, 2016

DENTITION

Although it feeds on plankton, the basking shark has hundreds of little teeth.

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 23, 2016

DISTRIBUTION (QUEBEC AND MARITIME PROVINCES)

The basking shark is found in almost all of the worlds' oceans. In Eastern Canada, its habitat includes all of the maritime provinces, from the Bay of Fundy to Labrador. In Quebec, the basking shark is common throughout the Gulf of St. Lawrence, and it seasonally ventures into the St. Lawrence Estuary in the summer and fall. It is frequently observed off the Gaspé Peninsula, especially in the Bay of Chaleur. Specimens have even been accidentally captured by trawlers in mid-winter, which may be an indication that a certain number remain in the Gulf of St. Lawrence year-round.

 

ST. LAWRENCE: The presence of Cetorhinus maximus in the St. Lawrence Gulf and Estuary is neither recent nor is it related to climate change.

 

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AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 23, 2016

PREY

The basking shark feeds on zooplankton, which consists of very small fish and invertebrates. It can filter up to 1,500,000 litres of water per hour at swimming speeds up to 4 kph (2.5 mph). In the St. Lawrence, the basking shark thus feeds on the same source of seasonal food as the many baleen whales that share its summertime range from the mouth of the Saguenay Fjord to the waters of the gulf.

 

VERIFIED STOMACH CONTENTS

PlanKton : copepods, crustaceans, larvae, fish eggs

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 24, 2016

VIDEO: Basking shark feeding on plankton at the surface off South West Cornwall, United Kingdom.

REPRODUCTION

The basking shark is ovoviviparous. Embryos feed on a yolk sac and later on unfertilized ova (oophagy). Gestation is believed to last up to 48 months. Pups are born fully developed at 1.5 - 2 metres (4.9 - 6.6 ft). Litter size is approximately 6 pups (only one pregnant female has ever been captured) every four years. Mating and birthing are thought to occur in shallow water in the summer.

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 24, 2016

LIFE EXPECTANCY

May live up to 100 years.

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 23, 2016

ATTACKS

Intentional attacks attributed to the basking shark are nonexistant. In fact, most known incidents have involved humans getting too close and getting hit by the caudal fin (tail).

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 24, 2016

FISHERIES

The basking shark is not hunted in Canada or the U.S. A few fisheries still exist in Asian markets where the basking shark is hunted for its liver oil, meat, cartilage and fins. Large numbers are also caught as by-catch and for the illegal fin trade.

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 24, 2016

STATUS

Scientific Name: Cetorhinus maximus

Taxonomy Group: Fishes

Range: Atlantic Ocean

Last COSEWIC Assessment: November 2009

Last COSEWIC Designation: Special Concern

SARA Status: No schedule, No Status

 

Click HERE to go to the COSEWIC profile page on the Basking shark.

AUTHOR: Jeffrey Gallant

LAST MODIFIED: October 22, 2016

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