Species Profile

Basking Shark Pacific population

Scientific Name: Cetorhinus maximus
Taxonomy Group: Fishes
COSEWIC Range: British Columbia, Pacific Ocean
COSEWIC Assessment Date and Status Change: April 2018
COSEWIC Status: Endangered
COSEWIC Status Criteria: A2ad; C2a(i); D1
COSEWIC Reason for Designation: In Canada, the species was once subject to directed fisheries and control programs. While such activities have long ceased, they reduced abundance to very low levels. The species is especially vulnerable to incidental fishing mortality because of its low intrinsic productivity. This species continues to suffer from human-induced mortality, primarily through entanglement with gear. Fisheries and Oceans Canada has engaged in research and monitoring to better understand the current status and the habitat requirements. There has also been increased public awareness. Despite the increase in overall attention to this species, there is no evidence of recovery and the designation of Endangered is still supported by the limited new information available since the last assessment.
COSEWIC History of Status Designation: Designated Endangered in April 2007. Status re-examined and confirmed in April 2018.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2010-02-23

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

Go to advanced search

Quick Links: | Description | Habitat | Biology | Threats | Protection | Recovery Initiatives | National Recovery Program | Documents

Description

The basking shark is the second largest fish in the world, with a maximum recorded size of 12.2 meters. This filter-feeder is named after its conspicuous behaviour of ‘basking’ (more accurately feeding) at the surface. The basking shark is typically blackish to grey-brown. It has an extremely large mouth with minute teeth, elongated gill slits, a pointed snout, and a crescent-shaped caudal fin. Gill openings have prominent gill rakers. It is the only species in its family, Cetorhinidae. The earliest fossil basking shark is 29 to 35 million years old.

Top

Distribution and Population

Basking sharks are found around the world in temperate coastal shelf waters and exist in Canada in both the Pacific and Atlantic Oceans. Along the North American Pacific coast, basking sharks were historically found off California in winter and spring and in particular areas off British Columbia in summer and fall, suggesting a seasonal north-south migration. Basking sharks have rarely been seen in North-American Pacific waters over the last fifteen years. Historically, however, large groupings were observed in nearshore waters along the west coast of Vancouver Island and in one location along the central mainland coast of British Columbia. Canada’s Pacific population of basking sharks has virtually disappeared. There are only six confirmed records of basking sharks in the Canadian Pacific since 1996, four of which are from trawl fishery observer records. Historical records indicate a widely spread population. The minimum historical population reconstructed from documented kills was at least 750 individuals, and possibly a few thousand, whereas the current population is extremely low. It is estimated that their rate of decline has exceeded 90 percent within about sixty years, or two to three generations.

Top

Habitat

Basking sharks are planktivores, and areas with high concentrations of zooplankton (small crustaceans and fish larvae drifting in the water column) appear to be their favoured habitat, typically including fronts where water masses meet, headlands, and around islands and bays with strong tidal flow. They spend much of their time near the surface, although there is recent evidence that basking sharks may also use deepwater habitats greater than 1000 meters.

Top

Biology

Basking sharks are slow-moving filter-feeders. Longevity is likely about 50 years, while maximum reported length is 12.2 meters. The species can be found alone or in groups and appears to be segregated based on sex. Size at birth probably ranges between 1.5 and 2 meters. Males are thought to reach maturity at between 12 and 16 years and females between 16 and 20 years. Gestation has been estimated at 2.6 to 3.5 years, the longest gestation known for any animal, with time between litters estimated at 2 to 4 years. Litter size is approximately six pups. The estimated annual reproduction rate is the lowest of any shark known. Basking sharks periodically shed their gill rakers (bristle-like structures at the back of their mouths used to filter food from the water) and are presently thought to cease feeding while they regenerate new ones over a 4-5 month period. Their massive livers, which can weigh one tonne, may act as a metabolic store that maintains energetic requirements while not feeding. Recent tagging has largely disproved the longstanding theory that basking sharks ‘hibernate’ in deep water over the winter. Adult basking sharks have no known predators but young individuals are most likely vulnerable to other large shark species. As an interesting oddity, on the Pacific coast basking sharks are considered by some scientists as the most plausible explanation for the repeated sightings of sea serpents, sea monsters, and the mythical Cadborosaurus (Caddy).

Top

Threats

Historical targeted killing for liver oil (1941-1947), bycatch, and a directed eradication program by Canada’s Department of Fisheries and Oceans between 1945-1970, including the ramming of sharks with a blade-equipped boat, are believed to be responsible for basking sharks’ disappearance. At the time of this eradication program, basking sharks were considered a nuisance to commercial salmon fishing operations, including gillnetting and trolling. Eradication was aimed to reduce the nuisance factor. Currently, mortality incurred from fishing operations and vessel collisions are thought to be the largest threats to basking shark populations. Of all shark species, the basking shark appears to be the most vulnerable to human impacts. Characteristics making them vulnerable include late age of maturity, long gestation period, long periods between gestations, low productivity, sex segregated populations, overlapping habitats with commercial fisheries, nearshore/coastal habitat, surface behaviour, fearlessness around boats, and naturally small populations. The high value of basking shark fins has also promoted a lucrative trade to Asian countries.

Top

Protection

Federal Protection

The Basking Shark, Pacific population, is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

In Canada the species receives protection by broad regulations that prohibit finning of any shark species. They also receive protections under the Fisheries Act. Basking shark are being monitored using regular over-flights that visit areas where they have been abundant in the past. Given that there is no market for other parts of basking sharks in Canada, there is no directed exploitation. Directed kill of basking sharks is prohibited by European Community countries, United States, and New Zealand. Internationally, the IUCN Red List assessment has categorized basking sharks as Vulnerable globally and Endangered in the northeast Atlantic and north Pacific and even Critically Endangered in the case of Barkley Sound, B.C.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

Top

Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Basking Shark (Cetorhinus maximus) in Canadian Pacific waters
Status Final posting on SAR registry

Top

Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

23 record(s) found.

Reports on the Progress of Recovery Document Implementation

  • Report on the Progress of Recovery Strategy Implementation for the Basking Shark (Cetorhinus maximus) in Canada for the Period 2011 to 2016 (2018-09-13)

    The Pacific population of Basking Shark is threatened by various anthropogenic sources. The main threats identified for the Basking Shark include entanglement, collision with vessels, harassment from marine-based activities, and prey availability. The key factors limiting the recovery and survival of Basking Sharks are their long-life (~50 years), slow growth and maturation, and low fecundity, which lead to overall low productivity. The decline of the Pacific population of Basking Shark is primarily due to human-caused mortality, which occurred predominantly between 40 and 70 years ago. Even in the absence of human-induced mortality, Basking Shark populations grow very slowly.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Basking Shark (Cetorhinus maximus) Pacific population in Canada (2007-08-29)

    Basking sharks are named after their conspicuous behaviour of ‘basking’ (more accurately feeding) at the surface. The basking shark is distinguished from other sharks by its large size (second largest fish in the world), elongated gill slits, pointed snout, a large mouth with minute teeth, and a crescent-shaped caudal fin. Colouration is typically blackish to grey-brown. Gill openings have prominent gill rakers.
  • COSEWIC Status Appraisal Summary on the Basking Shark (Cetorhinus maximus) Pacific population in Canada (2020-01-16)

    In Canada, the species was once subject to directed fisheries and control programs. While such activities have long ceased, they reduced abundance to very low levels. The species is especially vulnerable to incidental fishing mortality because of its low intrinsic productivity. This species continues to suffer from human-induced mortality, primarily through entanglement with gear. Fisheries and Oceans Canada has engaged in research and monitoring to better understand the current status and the habitat requirements. There has also been increased public awareness. Despite the increase in overall attention to this species, there is no evidence of recovery and the designation of Endangered is still supported by the limited new information available since the last assessment. Note: This COSEWIC assessment was received by the Minister on October 15th, 2018.

Response Statements

  • Response Statement - Basking Shark, Pacific population (2007-12-04)

    This shark species is the only extant species in the family Cetorhinidae. It occurs circumglobally in temperate coastal shelf waters, and exists in Canada as two geographically isolated designatable units – Atlantic and Pacific. The species is vulnerable to incidental fishing mortality because of its low intrinsic productivity. Females do not mature until 16 to 20 years old, gestate between 2.6 and 3.5 years (the longest known gestation period for any vertebrate), and produce litters of only about 6 “pups”. These sharks are especially susceptible to entanglement in fishing gear and collision with boats because of their large size, surface behaviour and fearlessness around boats, and because their coastal distribution overlaps fishing and boating areas. Prior to 1970, large aggregations of these sharks were seasonally common in Pacific Canada, but only 6 sightings have been confirmed since 1996. This dramatic reduction in abundance is attributed to directed fisheries for liver oil (1941-1947) and an eradication program (until 1970) that killed hundreds, perhaps thousands of individuals between 1945 and 1970. The minimum historical population reconstructed from documented kills was at least 750 individuals, whereas the current population is virtually nil, implying a rate of decline exceeding 90% within < 2 generations.  The species is believed to migrate seasonally between Canada and California, where regional aggregations were also severely depleted by historic fisheries. Rescue from outside Canada is unlikely.
  • Response Statement - Basking Shark, Pacific population (2019-01-11)

    In Canada, the species was once subject to directed fisheries and control programs. While such activities have long ceased, they reduced abundance to very low levels. The species is especially vulnerable to incidental fishing mortality because of its low intrinsic productivity. This species continues to suffer from human-induced mortality, primarily through entanglement with gear. Fisheries and Oceans Canada has engaged in research and monitoring to better understand the current status and the habitat requirements. There has also been increased public awareness. Despite the increase in overall attention to this species, there is no evidence of recovery and the designation of Endangered is still supported by the limited new information available since the last assessment.

Recovery Strategies

Action Plans

  • Action Plan for the Basking Shark (Cetorhinus maximus) in Canadian Pacific waters (2020-02-21)

    The Pacific population of Basking Shark (Cetorhinus maximus) was listed as endangered under SARA in 2010. This action plan is considered one in a series of documents that are linked and should be taken into consideration together, including the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) status report, a recovery potential assessment, and the recovery strategy. This document is considered a partial action plan because current best available information is insufficient to identify critical habitat (DFO 2016). Identification of the habitat necessary to support survival and recovery of the population may be addressed in an amendment to the recovery strategy at a later date.
  • Multi-species Action Plan for Pacific Rim National Park Reserve of Canada (2017-08-24)

    Backed by the Insular Mountain Range of Vancouver Island and facing the open Pacific Ocean, Pacific Rim National Park Reserve of Canada (Pacific Rim NPR) protects and presents the rich natural and cultural heritage of Canada's west coast. Pacific Rim NPR consists of three distinct units, the Long Beach Unit, Broken Group Islands Unit, and West Coast Trail Unit, each offering a range of unique visitor experiences. With significant areas (51,216 ha in total) of old growth, temperate rainforest, coastal dune systems, wetlands and foreshore, and marine habitats, the park demonstrates the interconnectedness between land, sea, and people. These natural wonders are interwoven with the Nuu-chah-nulth First Nations culture (past and present), and that of European explorers and settlers.

Orders

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2007 (2007-08-30)

    2007 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report 2017 to 2018 (2018-10-15)

    Over the past year COSEWIC assessed a total of 90 wildlife species and 11 of these were assigned a status of Not at Risk. Of these 90, COSEWIC re-examined the status of 38 wildlife species; of these, the majority (87%) were reassessed at the same or lower level of risk. To date and with the submission of this report, COSEWIC’s assessments now include 771 wildlife species in various risk categories including 338 Endangered, 183 Threatened, 228 Special Concern, and 22 Extirpated (i.e. no longer found in the wild in Canada). In addition, 18 wildlife species have been assessed as Extinct, and a total of 59 wildlife species have also been designated as Data Deficient and 197 have been assessed and assigned Not at Risk status.

Permits and Related Agreements

  • Explanation for issuing permit(#DFO-18-PPAC-00013 ), persuant to the provisions of section 73 of SARA (2018-05-01)

    This permit will apply to staff trained to complete opportunistic biosampling on Basking Sharks caught incidentally in trawl gear while aboard commercial groundfish vessels. The Company has considerable expertise in the provision of observers for at-sea monitoring in the north-east Pacific, with over 25,000 days at sea providing catch estimates, samples, tagging, and support for Fisheries and Oceans Canada's (DFO) research program. Staff are trained in the identification and handling of Basking Shark, in accordance with DFO's Shark Sampling Protocol (2011). The priority will be to return captured live Basking Sharks to the water as quickly as possible to reduce the chance of mortality. Live release will be monitored by observers to assess condition of shark when released and provide reporting to DFO. Depending on the condition of the live individual, external size measurements and a small clip of tissue (i.e. 1 cm square sample from any fin tip), for genetic analysis, will be collected to provide data and information on population structure. Staff will also apply appropriate handling procedures to reduce stress to live sharks. For Basking Sharks found dead, external size measurements and more detailed biosampling will occur; specifically: stomach contents and liver sampling; vertebrae (just behind gill slit area) removal; muscle sampling (from posterior base of dorsal fin at the attachment point to body); and, counting, sexing, measurements and sampling of pups (in the case of gravid females). Dead sharks will be counted and the data provided to DFO Science.
  • Explanation for issuing permit(#DFO-18-PPAC-00014), persuant to the provisions of section 73 of SARA (2018-05-01)

    This permit will apply to DFO Science staff trained to complete opportunistic biosampling on Basking Sharks caught incidentally during research surveys (e.g. directed groundfish surveys) while aboard DFO research vessels (RV). DFO Science Branch is responsible for the research of all elasmobranch species (including Basking Shark) in Canadian marine waters. Researchers are leading experts in their field and are trained to carry out biosampling in accordance with DFO's Shark Sampling Protocol (2011) on both live and dead sharks. The priority will be to return captured live Basking Sharks to the water as quickly as possible to reduce the chance of mortality. Live release will be monitored by at-sea observers to assess condition of shark when released and provide reporting to the DFO Lead Investigator. Depending on the condition of the live individual, external size measurements and a small clip of tissue (i.e.1 cm square sample from any fin tip), for genetic analysis, will be collected to provide data and information on population structure. Staff will also apply appropriate handling procedures to reduce stress to live sharks. For Basking Sharks found dead, sharks will be counted and the data provided to the DFO Lead Investigator. External size measurements and more detailed biosampling will occur on dead Basking Sharks; specifically: stomach content and liver sampling; vertebrae (just behind gill slit area) removal; muscle sampling (from posterior base of dorsal fin at the attachment point to body); and, counting, sexing, and measurements and sampling pups (in the case of gravid females).
  • Explanation for issuing permit(#DFO-18-PPAC-00015 ), persuant to the provisions of section 73 of SARA (2018-05-01)

    This permit will apply to the DFO Science Lead Investigator for satellite tagging of Basking Sharks either caught incidentally during a DFO Science research vessel (RV) survey or encountered based on sightings reported by members of the general public. The Lead Investigator has previous experience tagging sharks with satellite and conventional tags. The Lead Investigator is the head of the DFO Canadian Pacific Shark Research Lab and is a member of the Basking Shark Recovery Planning Team as well. Satellite tag information can provide long-term monitoring of a Basking Shark individual-with indication of death or changes in residency. Tagging locations will be within Pacific Canadian waters. For reported sightings, exact coordinates will depend upon where the reported locations are. Each shark encountered will be affixed with a single WC-MINIPAT 1XAA Argos-linked Pop-Up Archiving tag (Wildlife Computers©), inserted into the muscle to one side of the dorsal fin, perpendicular to the fin. Tagging will be carried out from a distance of up to 11' using a specially designed shark tagging pole with a 6'-11' telescoping handle and a Wilton dart applicator pin, 1/8" round. Each tag will be programmed to pop-off at a desired time (12 months maximum duration), at which time archived information (i.e. depth, temperature, ambient light levels through which location can be derived) will be available through the Argos- satellite system and CLS America. In the case of an incidental sighting aboard an RV, provided a trained scientist is aboard and the gear is available, tagging will be carried out right away. In the case of reported sightings of Basking Sharks, vessels/ platforms will be deployed in an attempt to locate and tag the shark, dependent upon if the shark can be reached in a timely manner. DFO 25 ft Lifetimer Vessel (Pallasi) CFV C06380BC, or another DFO registered vessels as available, will be utilized.
  • Explanation for issuing permit(#DFO-PAF SARA 178a), persuant to the provisions of section 73 of SARA (2010-07-08)

    Authorized representatives of DFO will carry out opportunistic satellite tagging of adult Basking sharks in order to provide information on their seasonal movements/migratory patterns. The ultimate goal of the activities is to assist in the recovery of the Basking shark by informing critical habitat studies.
  • Explanation for issuing permit(#DFO-PAF SARA 223), persuant to the provisions of section 73 of SARA (2011-06-03)

    Authorized representatives of Archipelago Marine Research (AMR) will carry out opportunistic biosampling, key morphometric measurements and genetic analysis when basking sharks are caught incidentally in trawl gear in order to collect information on basking sharks. The ultimate goal of the activities is to assist in the recovery of this species by gaining population, life history, diet, feeding characteristics, and contaminant analysis information.
  • Explanation for issuing permit(#DFO-PAF SARA 224), persuant to the provisions of section 73 of SARA (2011-06-03)

    Authorized representatives of the Department of Fisheries and Oceans will carry out opportunistic biosampling, key morphometric measurements and genetic analysis when basking sharks are caught incidentally during RV surveys in order to collect information on basking sharks. The ultimate goal of the activities is to assist in the recovery of this species by gaining population, life history, diet, feeding characteristics, and contaminant analysis information.
  • Explanation for issuing permit(#DFO-PAF SARA 306), persuant to the provisions of section 73 of SARA (2011-01-01)

    Authorized Vessel Masters and representatives of the following fisheries: Crab, Geoduck and Horse Clam, Groundfish Trawl, Halibut, Prawn and Shrimp by trap, Sablefish, Salmon Gill Net, Salmon Seine, Salmon Troll, Schedule II Species and Shrimp trawl will engage in fishing activities that are conducted under licenses issued under the Fisheries Act. Activities will have minimal effects on this species at risk as per the pre-conditions outlined below. There are no directed fisheries for Basking Sharks in Canadian waters. However, they may be incidentally caught in the above fisheries. 3363 licences have been issued to fishers involved in these fishing activities.
  • Explanation for issuing permit(#DFO-PAF SARA 307), persuant to the provisions of section 73 of SARA (2012-01-01)

    Authorized Vessel Masters and representatives of the following fisheries: Crab, Geoduck and Horse Clam, Groundfish Trawl, Halibut, Prawn and Shrimp by trap, Sablefish, Salmon Gill Net, Salmon Seine, Salmon Troll, Schedule II Species and Shrimp trawl will engage in fishing activities that are conducted under licenses issued under the Fisheries Act. Activities will have minimal effects on this species at risk as per the pre-conditions outlined below. There are no directed fisheries for Basking Sharks in Canadian waters. However, they may be incidentally caught in the above fisheries. 3544 licences have been issued to fishers involved in these fishing activities.
  • Explanation for issuing permit(#DFO-PAF SARA 308), persuant to the provisions of section 73 of SARA (2013-01-01)

    Authorized Vessel Masters and representatives of the following fisheries: Crab, Geoduck and Horse Clam, Groundfish Trawl, Halibut, Prawn and Shrimp by trap, Sablefish, Salmon Gill Net, Salmon Seine, Salmon Troll, Schedule II Species and Shrimp trawl will engage in fishing activities that are conducted under licenses issued under the Fisheries Act. Activities will have minimal effects on this species at risk as per the pre-conditions outlined below. There are no directed fisheries for Basking Sharks in Canadian waters. However, they may be incidentally caught in the above fisheries. 3031 licences have been issued to fishers involved in these fishing activities.
  • Explanation for issuing permit(#DFO-PAF SARA 349), persuant to the provisions of section 73 of SARA (2014-10-16)

    Authorized representatives of Fisheries and Oceans Canada will carry out opportunistic biosampling on incidentally captured Basking Sharks in order to collect information about the species. The ultimate goal of the activities are to assist in the recovery of this species by collecting data on population structure, life history characteristics, diet and feeding characteristics, contaminant analysis and reproductive hormone analysis.
  • Explanation for issuing permit(#DFO-PAF SARA 350), persuant to the provisions of section 73 of SARA (2014-10-21)

    Authorized representatives of Archipelago Marine Research will carry out opportunistic biosampling on incidentally captured Basking Sharks in order to collect information about the species. The ultimate goal of the activities are to assist in the recovery of this species by collecting data on population structure, life history characteristics, diet and feeding characteristics, contaminant analysis and reproductive hormone analysis.
Date modified: