Megachasma pelagios 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Lamniformes Megachasmidae

Scientific Name: Megachasma pelagios Taylor, Compagno & Struhsaker, 1983
Common Name(s):
English Megamouth Shark
French Requin grande guele
Spanish Tiburón bocón, Tiburón bocudo
Taxonomic Source(s): Weigmann, S. 2016. Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeographical diversity. Journal of Fish Biology 88(3): 837-1037.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2015
Date Assessed: 2015-02-20
Assessor(s): Simpfendorfer, C. & Compagno, L.J.V.
Reviewer(s): Dulvy, N.K. & Kyne, P.M.
Contributor(s): Bigman, J.S.
Facilitator/Compiler(s): Kyne, P.M., Walls, R.H.L., Simpfendorfer, C. & Chin, A.
The Megamouth Shark (Megachasma pelagios) is a very large, pelagic filter-feeding shark distributed in pelagic habitats from approximately the surface down to 1,500 m in tropical waters worldwide. The colouration and catch records of the Megamouth Shark are suggestive of epipelagic rather than deepwater habitat, as is the composition of its liver oil. It is known from only 102 specimens (as of August 2015), and therefore appears to be very rarely encountered throughout its range, yet likely to be increasingly taken as bycatch in oceanic and offshore fisheries. Further research on its ecology and habitat use are required to better understand this species and the potential effects of fishing. Based on its wide range, at present it is assessed as Least Concern. Its increasing frequency of capture in Asia, particularly Taiwan, and its rarity and intrinsic sensitivity to overexploitation mean that captures in fisheries should be tracked carefully to ensure this species does not become threatened in the near future.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The Megamouth Shark is currently (August 2015) known from 102 specimens ( from tropical and temperate areas of all major oceans. Considerably more specimens are known from the Pacific Ocean in areas such as Taiwan, Japan, the Philippines, and Indonesia than elsewhere. It is probably wide-ranging and circumtropical in its distribution (Ebert et al. 2013).
Countries occurrence:
Australia (Western Australia); Brazil (Rio de Janeiro); China; Ecuador; Indonesia (Sulawesi); Japan; Mexico (Baja California, Baja California Sur); Peru; Philippines; Senegal; South Africa; Sri Lanka; Taiwan, Province of China; United States (California, Hawaiian Is.); Viet Nam
FAO Marine Fishing Areas:
Atlantic – eastern central; Atlantic – southwest; Atlantic – western central; Atlantic – southeast; Indian Ocean – western; Indian Ocean – eastern; Pacific – southeast; Pacific – northwest; Pacific – western central; Pacific – eastern central
Additional data:
Lower depth limit (metres):1500
Upper depth limit (metres):5
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This rare shark is known from 102 specimens (as of August 2015) since its discovery in 1976.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:A coastal and oceanic, pelagic and neritic species, it has been found in water as shallow as 5 m in a bay, 40 m deep on the continental shelf, and offshore in the pelagic zone at 8-1,500 m depth in water 348-4,600 m deep; some specimens have washed ashore (Yano et al. 1997, Ebert et al. 2013). The maximum reported size is 577 cm, although larger unsubstantiated sizes have been reported. The smallest known specimen was 177 cm, but it is unknown if this is close to the size at birth.
The only known prey of this species are epipelagic and mesopelagic euphausiid shrimp, copepods and jellyfish (Yano et al. 1997), and it has been suggested that the Megamouth Shark may follow vertical migrations of euphausiid prey during diel cycles (Compagno 2001). The feeding structures of this shark may allow it to feed on other pelagic invertebrates and even small fishes, but so far the stomach contents studied suggest that it primarily targets euphausiid shrimp (Compagno 2001). Observations made on a live-captured Megamouth Shark which was later tagged with an acoustic telemetric tag and tracked for two days, suggested it could breathe readily by gill-pumping and was not dependent on constant swimming like other lamnoid sharks. During the tracking period, the shark revealed a pattern of vertical, crepuscular migration in the epipelagic zone. The mode of reproduction is probably aplacental viviparous with uterine cannabilism or cannibal vivipary suspected in the form of oophagy (Ebert et al. 2013). A late immature or early adolescent female had two ovaries with many tiny oocytes, while an adult female had numerous larger oocytes. This is similar to the ovaries of other lamnoids.

Use and Trade [top]

Use and Trade: This species is not generally used when caught. However there have been reports that the flesh is eaten.

Threats [top]

Major Threat(s): The Megamouth Shark is taken as rare, incidental bycatch of various high-seas and coastal fisheries, including commercial drift gillnets, set fish traps, and pelagic longlines, purse-seines, and pelagic trawls. So far, most specimens have been utilized by museums and oceanaria for research and display. The increasing reports of captures from Southeast Asia suggest some potential effects of fisheries. However, the lack of catch data and life history information makes it difficult to understand the effects of these catches. Dulvy et al. (2014) predicted, based on its body size and depth distribution, that the Megamouth Shark had a high likelihood of being threatened with an elevated risk of extinction if it was subjected to significant fisheries. There is evidence that the Megamouth Shark is frequently captured in Taiwanese gillnet fisheries (D. Ebert, pers. comm., 2015) and there have been recent captures in the Philippines and Sri Lanka (Fernando et al. 2015) raising concern that the level of capture may lead to global population decline.

Conservation Actions [top]

Conservation Actions: There are no species-specific regulations or management in place for this species.

Classifications [top]

9. Marine Neritic -> 9.1. Marine Neritic - Pelagic
suitability:Suitable season:resident 
10. Marine Oceanic -> 10.1. Marine Oceanic - Epipelagic (0-200m)
suitability:Suitable season:resident 
10. Marine Oceanic -> 10.2. Marine Oceanic - Mesopelagic (200-1000m)
suitability:Suitable season:resident 
10. Marine Oceanic -> 10.3. Marine Oceanic - Bathypelagic (1000-4000m)
suitability:Suitable season:resident 

In-Place Research, Monitoring and Planning
  Action Recovery plan:No
  Systematic monitoring scheme:No
In-Place Land/Water Protection and Management
  Conservation sites identified:No
  Occur in at least one PA:Unknown
  Area based regional management plan:No
  Invasive species control or prevention:Not Applicable
In-Place Species Management
  Harvest management plan:No
  Subject to ex-situ conservation:No
In-Place Education
  Subject to recent education and awareness programmes:No
  Included in international legislation:No
  Subject to any international management/trade controls:No
5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.1. Intentional use: (subsistence/small scale) [harvest]
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.3. Unintentional effects: (subsistence/small scale) [harvest]
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
3. Monitoring -> 3.1. Population trends
3. Monitoring -> 3.2. Harvest level trends

Bibliography [top]

Compagno, L.J.V. 2001. Sharks of the World. An annotated and illustrated catalogue of the shark species known to date. Volume 2. Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). FAO, Rome.

Dulvy, N.K., Fowler, S.L., Musick, J.A., Cavanagh, R.D., Kyne, P.M., Harrison, L.R., Carlson, J.K., Davidson, L.N.K., Fordham, S.V., Francis, M.P., Pollock, C.M., Simpfendorfer, C.A., Burgess, G.H., Carpenter, K.E., Compagno, L.J.V., Ebert, D.A., Gibson, C., Heupel, M.R., Livingstone, S.R., Sanciangco, J.C., Stevens, J.D., Valenti, S. and White, W.T. 2014. Extinction risk and conservation of the world’s sharks and rays. eLife 3: e00590.

Ebert, D.A., Fowler, S. and Compagno, L. 2013. Sharks of the World. Wild Nature Press, Plymouth.

Fernando, D., Perera, N. and Ebert, D.A. 2015. First record of the megamouth shark, Megachasma pelagios, (Chondrichthyes: Lamniformes: Megachasmidae) from Sri Lanka, northern Indian Ocean. Marine Biodiversity Records 8.

IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: (Accessed: 19 November 2015).

Yano, K., Morissey, J.F., Yabumoto, Y. and Nakaya, K. 1997. Biology of the Megamouth Shark. Tokai University Press, Tokyo, Japan.

Citation: Simpfendorfer, C. & Compagno, L.J.V. 2015. Megachasma pelagios. The IUCN Red List of Threatened Species 2015: e.T39338A2900476. . Downloaded on 15 October 2018.
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