This list of megamouth shark specimens and sightings includes recorded human encounters with Megachasma pelagios, popularly known as the megamouth shark. A similar list is published by the Ichthyology Department of the Florida Museum of Natural History at the University of Florida. [1]
Records are listed chronologically in ascending order and numbered accordingly.
| # | Date | Location | Sex | Size | Method of capture | Disposition | References | Notes |
|---|---|---|---|---|---|---|---|---|
| 1 | 15 November 1976 | 25 miles (40 km) off Kāne'ohe, Oahu, Hawaii ( 21°51′N157°46′W / 21.850°N 157.767°W ) | Male | TL: 4.46 m; PCL: 3.091 m (69.3% TL); WT: 750 kg | Became entangled in the sea anchor of a United States Navy ship | Deposited at the Bernice Pauahi Bishop Museum | Dunford (1976); Taylor (1977); Cressey & Boyle (1978); Johnson (1978); Taylor et al. (1983); [Anonymous] (1983a, b, c, d, e, f); Maisey (1985); Wood (1986); Gallagher (N.d.) | Holotype and first recorded specimen. First examined by Leighton Taylor, who dubbed it "megamouth". |
| 2 | 29 November 1984 | Catalina Island, California | Male | TL: 4.49 m | "Caught" | Deposited at the Natural History Museum of Los Angeles County | [Anonymous] (1984a, b); Lavenberg & Seigel (1985); Diamond (1985); Maisey (1985); Wood (1986) | |
| 3 | 18 August 1988 | Mandurah, Western Australia | Male | TL: 5.15 m; PCL: 3.43 m (66.6% TL) | Found washed ashore | Deposited at Western Australian Museum | Berra & Hutchins (1988); [Anonymous] (1988a, b); Nielsen (1988); Berra & Hutchins (1990); Berra & Hutchins (1991) | |
| 4 | 23 January 1989 | Hamamatsu, Shizuoka, Japan | Male | TL: 4+ m | Found washed ashore | Discarded | Nakaya (1989a); Nakaya (1989b) | |
| 5 | June 1989 | Yaizu, Shizuoka, Japan | Female? | TL: ~4.9 m | Caught in net | Released alive | Miya et al. (1992); Mollet (2012) | Most likely a female according to John Morrissey. |
| 6 | 21 October 1990 | Dana Point, California | Male | TL: 4.94 m | Found entangled in a drift gillnet | Tracked | Haight (1990a); Haight (1990b); [Anonymous] (1990a, b, c, d); [Anonymous] (1991a, b); Lavenberg (1991); Nelson et al. (1997) | Specimen was taken alive, then fitted with two ultrasonic transmitters and tracked for two days. The shark was observed to move close to the surface at night and deeper during the day. |
| 7 | 29 November 1994 | Hakata Bay, Fukuoka, Japan ( 34°40′N130°50′E / 34.667°N 130.833°E ) | Immature female | TL: 4.71 m; PCL: 3.136 m (66.6% TL) | "Stranded" | Deposited at Marine World Uminonakamichi (Fukuoka, Japan) | Castro (1994); Takada (1994); Takada (1995); Clark & Castro (1995); Castro et al. (1997); Nakaya et al. (1997); Takada et al. (1997); Tanaka & Yano (1997); Yabumoto et al. (1997); Yamaguchi & Nakaya (1997); Yano et al. (1997a); Yano et al. (1997b); Yano et al. (1997c); Goto (1999) | First confirmed female; much studied. Numerous papers on this specimen were published in Biology of the Megamouth Shark (1997). |
| 8 | 4 May 1995 | 40 miles (64 km) off Dakar, Senegal ( 15°08′N18°22′W / 15.133°N 18.367°W ) | Immature male | TL: ~1.8 m | Caught in purse seine of French tuna fishing ship | Discarded | Séret (1995) | First recorded specimen from the Atlantic Ocean and smallest known specimen at the time. |
| 9 | 18 September 1995 | southern Brazil | Immature male | TL: 1.9 m; WT: 24.4 kg | Caught by commercial longline vessel | Deposited at Instituto de Pesca in São Paulo, Brazil | Castro & Gadig (1995); Amorim et al. (1995); Amorim et al. (2000) | |
| 10 | 30 April 1997 | 12 miles (19 km) south of Mikizaki, Owase, Mie, Japan ( 33°44′N136°16′E / 33.733°N 136.267°E ) at 150 m depth | Female | TL: 5.44 m; WT: 1,040 kg | Caught by fishermen | Deposited at Toba Aquarium | Yano et al. (1997d); Ito et al. (1999) | External brain form and cranial nerves studied in detail. |
| 11 | 20 February 1998 | Macajalar Bay, Cagayan de Oro, Philippines | Male | TL: ~5.49 m | Caught by three fishermen | Consumed | Baldo & Elizaga (1998); Elizaga (1998a); Elizaga (1998b); Reyes (1998); Morrissey & Elizaga (1999); Amorim et al. (2000) | |
| 12 | 23 April 1998 | Atawa, Mie, Japan | Female | TL: 5.2–5.49 m | "Captured" | Discarded | Yano et al. (1998); Amorim et al. (2000); Burgess (N.d.) | |
| 13 | 30 August 1998 | Manado, North Sulawesi, Indonesia ( 1°46′0″N124°50′3″E / 1.76667°N 124.83417°E ) | Female? | TL: ~5 m | Observed being attacked by sperm whales | Swam away | Pecchioni & Benoldi (1999); Amorim et al. (2000) | |
| 14 | 1 October 1999 | 30 miles (48 km) west of San Diego, California | Female | TL: ~17 ft (5.2 m) | Caught in a drift gillnet | Released alive in good condition | Petersen (1999) | Four colour photographs taken. Water temperature was 67.2 °F (19.56 °C). |
| 15 | 19 October 2001 | 42 miles (68 km) northwest of San Diego, California | Male | TL: ~18 ft (5.5 m) | Caught in a drift gillnet | Released alive in good condition | Petersen (2001) | Tissue biopsy collected. Water temperature was 65.8 °F (18.78 °C). |
| 16 | 18 January 2002 | eastern Indian Ocean ( 2°17.9′S88°12.7′E / 2.2983°S 88.2117°E ) at 150 m depth | Immature male | TL: 2.35 m; WT(estimate): >120 kg | Caught in tuna purse seine | Discarded | Boonyapiwat & Vidthayanon (2002) | Caught by M/V Seafdec. Sea surface temperature was 26.8 °C. |
| 17 | 20 April 2002 | Nature's Valley near Plettenberg Bay, approximately 400 km east of Cape Town, South Africa ( 33°59′S23°34′E / 33.983°S 23.567°E ) | Female | TL: 3.5 m; WT: 300 kg | Found washed ashore | Deposited at Port Elizabeth Museum | [Anonymous] (2002); Sanchez (2002); Smale (2002); Smale et al. (2002) | Collected from the beach by Vic Cockcroft of the Centre for Dolphin Studies. Tissue samples taken. Specimen was examined, measured and dissected by Malcolm Smale and Leonard Compagno. Mould of the animal was used for educational displays. |
| 18 | 6 January 2003 | Tablon, Cagayan de Oro, Philippines | ? | TL: 4.97 m; BD: 1.01 m | Caught by fisherman | Consumed | Yasay (2003) | Caught by fisherman Eldiposo Pabaida. Personnel of the Bureau of Fisheries and Aquatic Resources 10 (BFAR 10) measured the specimen and took several photographs. |
| 19 | 26 May 2003 | Dana Point, California | ? | TL(estimate): 20–25 ft (6–7.6 m); WT (estimate): 5 tons | Sighted at sea | Released | Robbins (2003) | Sighted by Scott Caldwell from the Leslie Anne. A rope was temporarily tied around the animal's tail, preventing escape. No photographs taken; unconfirmed sighting. |
| 20 | 3 July 2003 | 800 m off Ki-Lei-Bi, Hualien County, Taiwan | Male | TL: ~2.5 m; WT: 490 kg | Caught in net | Consumed | Mollet (2004) | Caught by fisherman Li. Specimen bought by local seafood store. Stomach was found to be empty. |
| 21 | 7 August 2003 | Omaezaki, Shizuoka, Japan | Male | TL: 4.3 m | ? | Deposited at Tokai University | Furuta (2003); Burgess (N.d.) | Prepared for display by taxidermist. |
| 22 | 8 March 2004 | 41.6 nautical miles (77.0 km) off Posorja Port, Guayas, Ecuador ( 2°54.374′S81°14.858′W / 2.906233°S 81.247633°W ) | Male | TL: 4.2 m; WT: ~600 kg | Caught in trammel net | Sent to market | Romero & Cruz (2004) | Caught by small fishing vessel that was unable to bring it aboard. Assisted by the Ecuadorian tuna fish ship Betty Elizabeth. Animal was alive at time of capture and regurgitated food consisting mainly of Engraulis ringens . Surface temperature of the sea was 23.6 °C. |
| 23 | 13 March 2004 | Gapang Beach, northern tip of Sumatra | Immature male | TL: 1.767 m; WT: 13.82 kg | Found washed ashore | Deposited at Cibinong Museum | Lumba Lumba Dive Centre (2004); White et al. (2004) | Smallest recorded specimen. On public display. |
| 24 | 19 April 2004 | Ichihara, Tokyo Bay, Japan | Female | TL: 5.63 m; WT: 2,679 lb (1,215 kg) | Found washed ashore | Taxidermy specimen displayed at the Natural History Museum and Institute | Osedo (2004) | Survived several days before dying from stress. Identified by Masaki Miya, curator of fishes at the National History Museum and Institute in Chiba. |
| 25 | 23 April 2004 | off Ajiro, Shizuoka, Japan | Female | TL: ~4.9 m | Caught by fishermen | Discarded | Furuta (2004) | Japanese newspaper article mentions total length of 5.5-5.6 m and weight of "1", implying over 1 ton. |
| 26 | 4 November 2004 | Barangay Namocon, Tigbauan, Iloilo, Philippines | Female | TL: 5.04 m; WT: ~1 ton | Stranded on beach | Preserved in tank at SEAFDEC Museum | [Anonymous] (2004); Bagarinao (2004) | Stranded alive at around 5 pm and died at around 10 pm. Removed from the beach by 16 fishermen. Preserved in 10% formalin in a 1-ton fiberglass tank. |
| 27 | 23 January 2005 | off Kisei cho Nishiki, Mie, Japan, at 200 m depth | Female | TL: 5.28 m | Caught in purse seine | Deposited at Toba Aquarium | Furuta (2005) | Prepared by taxidermist for display at the aquarium. |
| 28 | 30 January 2005 | Macajalar Bay, Cagayan de Oro, Philippines | Female? | TL: 4.17 m; WT: ~1,000 kg | Caught in net | Buried | Elizaga (2005a); Elizaga (2005b); Lumingkit et al. (2005); Ellorin (2005) | Caught by fisherman Sofronio Casañares. It pulled Casañares's paddle-driven banca for around an hour before stopping, apparently due to exhaustion. Specimen was dissected prior to burial. |
| 29 | ~25 April 2005 | Hualien Port, Hualien County, Taiwan | ? | WT: 580 kg | Caught by ocean sunfish driftnetters | Sold at market for human consumption | Wang & Yang (2005a) | Described by fishermen as "big mouthed shark with no teeth". |
| 30 | 2 May 2005 | Hualien Port, Hualien County, Taiwan | ? | WT: 580 kg | Caught by ocean sunfish driftnetters | Sold at market for human consumption | Wang & Yang (2005b) | Described by fishermen as "big mouthed shark with no teeth". |
| 31 | 4 May 2005 | Hualien Port, Hualien County, Taiwan | Female | TL: 7.09 m?; WT: 689 kg | Caught by ocean sunfish driftnetter | Dissected at Taipei Zoo/Academia Sinica | Wang & Yang (2005c) | Presumed to be pregnant based on swollen belly. Measured by Shih-Chu Yang. One ectoparasite collected from specimen. |
| 32 | 5 May 2005 | off Hualien County, Taiwan | Female | WT: 807 kg | Caught by fishermen | Dissected at Taipei Zoo | Wang & Yang (2005d) | Likely to have been pregnant. Sold directly to Kwung-Tsao Shao of the Academia Sinica. |
| 33 | 5 June 2005 | off Hualien County, Taiwan | ? | WT: 400–500 kg | Caught by fishermen | ? | Lin (2005) | Fifth megamouth shark caught in the area within two and a half months. |
| 34 | 26 January 2006 | 4 km off Bayawan, Negros Oriental, Philippines | Female | TL: 5 m; WT (estimate): 1 ton/750 kg | Accidentally caught in fishing net | Buried | [Anonymous] (2006); Sala (2006) | Towed by pumpboat of the Bayawan city government to the city's boulevard, but died before it could be released. Very small shrimp found in stomach. |
| 35 | 12 March 2006 | Barra, Macabalan, Cagayan de Oro, Philippines | Female | TL: 7 ft 5 in (2.26 m); WT: 60–80 kg | Accidentally caught in gillnet | ? | Cabig (2006) | Identified by Edward B. Yasay. Animal died before Yasay could study it. |
| 36 | 23 March 2006 | "China Sea" | ? | TL: 4.7 m; WT: 650 kg | Caught by fishermen | ? | Lin (2006) | Photograph taken. |
| 37 | 2 May 2006 | Sagami Bay, Yugawara, Kanagawa Prefecture, Japan | Female | TL: 5.7 m | Found alive in a fixed shore net | Dissected and exhibited at the Aburatsubo Marine Park in Kanagawa | Burgess (2006); Mollet (2012) | Could not be initially landed due to adverse wind conditions. Animal was filmed on third day and died soon afterwards. |
| 38 | 16 November 2006 | Tortugas Bay, Baja California, Mexico | Immature female | TL: 2.149 m; WT: 27 kg | Accidentally caught by commercial shark boat | On display at the Regional Fisheries Center of Ensenada | Castillo-Géniz (2006) | Accidentally caught by crew of the commercial shark boat F/V Corina del Mar. Examined on November 28 by team of technicians and students led by José Leonardo Castillo-Géniz. Samples taken of stomach contents, teeth, and dermal denticles. |
| 39 | 29 May 2007 | Barangay Tungkop, Minglanilla, Cebu, Philippines | ? | TL: 8.2 ft (2.5 m); WT: ~40–50 kg | Found wounded near shore | ? | Parco (2007a); Parco (2007b) | Found alive with head wound; died after several hours. |
| 40 | 7 June 2007 | Sagami Bay, Japan | Female | TL: 5.4 m | Caught in net | Released alive | Mollet (2012) | Photographed, filmed and tagged prior to release. |
| 41 | 9 July 2007 | 700 km east of Ibaraki Prefecture, Japan | Female | TL: 3.6–4 m; WT: 360–450 kg | Caught in purse seine | Deposited at Okinawa Churaumi Aquarium | [Anonymous] (2007); Lin (2007); [Anonymous] (2011a, b, c) | Brought to Ishinomaki port and fish market in Miyagi Prefecture. Frozen and transferred to Okinawa Churaumi Aquarium. Dissected at Okinawa Churaumi Aquarium between March 1–3, 2011, in preparation for plastination. During dissection, internal organs were removed, vertebrae sampled for age determination, and head subjected to a CT scan. |
| 42 | 27 September 2007 | Hinunangan, Philippines | ? | TL: 2.74 m | Found dead on beach | ? | Tajonera (2009a) | Weight unknown. Photographed by Marlou Pan. |
| 43 | around 30 June 2008 | off Taiwan | ? | WT: 200+ kg | "Captured" | ? | Mollet (2012); Burgess (N.d.) | Reported by Victor Lin. No photograph and no length or sex data available. |
| 44 | 10 July 2008 | off eastern Taiwan | Female? | TL (estimate): ~5–5.5 m; WT: 870 kg | "Caught" | ? | Mollet (2012); Burgess (N.d.) | Claimed to be 9 m long in media reports. |
| 45 | 5 September 2008 | Hinunangan, Philippines | ? | TL: 2.13 m | Found stranded alive | Pushed back into water, presumably swam away | Tajonera (2009b) | No photographs taken. Identified by AT-Fisheries. |
| 46 | 30 March 2009 | off eastern coast of Burias Island, Philippines, at ~200 m depth | Male | TL: 4 m; WT: ~400–500 kg | Caught in gillnet by fishermen targeting Rastrelliger kanagurta and Auxis rochei | Consumed | Aca (2009); Dell'Amore (2009) | Died during capture. Tied up and towed to Barangay Dancalan, Donsol, Sorsogon. Identified by Elson Aca of WWF. Cuts found near left side of mouth. Several shrimp larvae found in stomach. |
| 47 | 9 June 2009 | off eastern Taiwan | Female? | TL: 3.90 m; WT: 350 kg | Caught by fishermen from Taitung County | Preserved at local shark museum | Lin (2009) | Bought by local shark museum to be mounted for display. |
| 48 | 9 July 2009 | Praia Grande, Cabo Frio, Rio de Janeiro, Brazil | Male | TL: 5.39 m | Found dead on beach | Partially consumed by locals | Lima et al. (2009); Gomes & Buttigieg (2009); Mollet (2012) | Appeared to have died of natural causes. Autopsy revealed empty stomach. |
| 49 | 9 July 2009 | 700 km off Ibaraki Prefecture, Japan | Female | TL: 4 m; WT (estimate): 450 kg | "Caught" | Flesh sold at market for consumption at Ishinomaki | [2] | |
| 50 | 6 November 2009 | 18 miles (29 km) southwest of Islas San Benito, Mexico | ? | TL: 2 m | Caught in fishing net | ? | Camacho (2009) | Caught by Ensenada fishermen on vessel Famtasma del Mar, captained by Eden Ruvicel. |
| 51 | 25 April 2010 | Taiwan Strait, off southeastern China | Male | TL (estimate): ≥4 m; WT (estimate): >1000 kg; WT(skin): 100–200 kg | "Caught" | Flesh cut into chunks and sold at market for consumption; skin and jaw saved; to be donated to educational facility | Lin (2010a) | Photographs taken of skinned specimen only. |
| 52 | 19 June 2010 | off eastern Taiwan | ? | WT (estimate): ~770 kg | "Caught" | Flesh sold at market for consumption; jaw saved | Lin (2010b); Mollet (2012) | Purchased by fish dealer in northeastern Taiwan "in poor condition, described as tattered and broken or perhaps even cut open". Photographs taken of jaw and flesh chunks only. |
| 53 | 14 January 2011 | 500 m off Owase, Mie, Japan | ? | TL (estimate): 5 m | "Bycaught and fled by itself" | ? | [3] | Found being entrapped in a set net in early morning, and on 15th, an aquarium at Osaka tried to purchase the individual alive and make it the first exhibition of live animal in the world, but the shark was found missing in 6am, likely to surpass the net rather than breaking through it. |
| 54 | 12 June 2011 | Bahía de Vizcaíno, off western Baja California peninsula, Mexico | Immature male | TL: 3 m | "Caught" | ? | Falcón (2011) | Sent to Ensenada, Mexico, to be sliced into pieces, examined, and photographed. Gill and muscle structure studied by researchers from Mexico and the Scripps Institution of Oceanography. Captured by same vessel that caught specimen #38. |
| 55 | 1 July 2011 | Odawara(Sagami Bay), Kanagawa Prefecture, Japan | Female | TL: ~3 m | ? | Deposited at Kanagawa Prefectural Museum of Natural History | Mollet (2012); Burgess (N.d.) | Information and photographs provided by Alex Buttigieg (Mollet, 2012). While some fishermen claimed that another shark shored at Ishibashi area nearby was even bigger, the others consider that this report was of the same individual. [4] |
| 56 | January 2012 | "Sea of China" | ? | TL: 5.65–5.70 m; WT: 1,150–1,250 kg | ? | ? | Mollet (2012) | Information and photographs provided by Victor Lin (Mollet, 2012). |
| 57 | 16 October 2012 | off eastern Taiwan | Female | TL (estimate): 6 m [4.29 m without tail]; WT (estimate): 800–900 kg | "Caught" | Organs preserved and donated to unspecified university; meat sold | Lin (2012) | Tail broke off during recovery. Total intact length estimated by fish dealer who purchased specimen. |
| 58 | 14 April 2014 | off Shizuoka, Japan | Female | TL: 4.4 meters; WT (estimate): not reported | "Caught" | Autopsy scheduled for May 2014 | NHK News Web [5] | Specimen will be studied at Tokai University Marine Science Museum, Shizuoka, Japan |
| 59 | 24 December 2014 | off Futo, Itō, Shizuoka, Japan | ? | ? ("Massive") | Entrapped in set nets and was released | The shark was released because it was too big to bring ashore. | Fujii M. 伊豆東海岸定置網へのメガマウスザメ混獲事例より. 板鰓類研究会報. No. 51. | |
| 60 | 28 January 2015 | off Albay, Philippines | Male | ? | Washed ashore | Preserved on ice pending necropsy and display | Washington Post | |
| 61 | 2 June 2015 | Nghệ An Province, Vietnam | ? | TL (estimate): 5 m; WT (estimate): 800–900 kg | Washed ashore | Xác cá 'khủng' trôi dạt vào bờ biển Nghệ An | ||
| 62 | 18 April 2016 | 5 km off Owase, Mie, Japan | ? | TL: 5 m; WT: 1,000 kg | Bycatch in seine nets | Purchased with a successful bid by a local fishmonger, then was delivered to a national research institute, kept in a fledge | 体長５メートル、メガマウス水揚げ 尾鷲港（三重県） | publisher=Chunichi Shimbun and Chūkyō Television Broadcasting |
The megamouth shark is a species of deepwater shark. It is rarely seen by humans and is the smallest of the three extant filter-feeding sharks alongside the relatively larger whale shark and basking shark. Since its discovery in 1976, fewer than 100 specimens have been observed or caught. Like the other two planktivorous sharks, it swims with its mouth wide open, filtering water for plankton and jellyfish. It is recognizable from its large head with rubbery lips. The megamouth is so unlike any other type of shark that it is usually considered to be the sole extant species in the family Megachasmidae, though some scientists have suggested it may belong in the family Cetorhinidae.
The Lamniformes are an order of sharks commonly known as mackerel sharks. It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark.
The goblin shark is a rare species of deep-sea shark. Sometimes called a "living fossil", it is the only extant representative of the family Mitsukurinidae, a lineage some 125 million years old. This pink-skinned animal has a distinctive profile with an elongated, flat snout, and highly protrusible jaws containing prominent nail-like teeth. It is usually between 3 and 4 m long when mature, though it can grow considerably larger such as one captured in 2000 that is thought to have measured 6 m (20 ft). Goblin sharks are benthopelagic creatures that inhabit upper continental slopes, submarine canyons, and seamounts throughout the world at depths greater than 100 m (330 ft), with adults found deeper than juveniles. Some researchers believe that these sharks could also dive to depths of up to 1,300 m (4,270 ft), for short periods of time.
The blacktip reef shark is a species of requiem shark, in the family Carcharhinidae, which can be easily identified by the prominent black tips on its fins. Among the most abundant sharks inhabiting the tropical coral reefs of the Indian and Pacific Oceans, this species prefers shallow, inshore waters. Its exposed first dorsal fin is a common sight in the region. The blacktip reef shark is usually found over reef ledges and sandy flats, though it has also been known to enter brackish and freshwater environments. It typically attains a length of 1.6 m (5.2 ft). Like other sharks, the females are larger than the males.
Megachasma is a genus of sharks. It is usually considered to be the sole genus in the distinct family Megachasmidae, though suggestion has been made that it may belong in the family Cetorhinidae, of which the basking shark is currently the sole extant member. Megachasma is known from a single living species, Megachasma pelagios.
The guitarfish, also referred to as shovelnose rays, are a family, Rhinobatidae, of rays. The guitarfish are known for an elongated body with a flattened head and trunk and small, ray-like wings. The combined range of the various species is tropical, subtropical, and warm temperate waters worldwide.
The longfin mako shark is a species of mackerel shark in the family Lamnidae, with a probable worldwide distribution in temperate and tropical waters. An uncommon species, it is typically lumped together under the name "mako" with its better-known relative, the shortfin mako shark. The longfin mako is a pelagic species found in moderately deep water, having been reported to a depth of 220 m (720 ft). Growing to a maximum length of 4.3 m (14 ft), the slimmer build and long, broad pectoral fins of this shark suggest that it is a slower and less active swimmer than the shortfin mako.
The blacktip shark is a species of requiem shark, and part of the family Carcharhinidae. It is common to coastal tropical and subtropical waters around the world, including brackish habitats. Genetic analyses have revealed substantial variation within this species, with populations from the western Atlantic Ocean isolated and distinct from those in the rest of its range. The blacktip shark has a stout, fusiform body with a pointed snout, long gill slits, and no ridge between the dorsal fins. Most individuals have black tips or edges on the pectoral, dorsal, pelvic, and caudal fins. It usually attains a length of 1.5 m (4.9 ft).
The pelagic thresher is a species of thresher shark, family Alopiidae; this group of sharks is characterized by the greatly elongated upper lobes of their caudal fins. The pelagic thresher occurs in the tropical and subtropical waters of the Indian and Pacific Oceans, usually far from shore, but occasionally entering coastal habitats. It is often confused with the common thresher, even in professional publications, but can be distinguished by the dark, rather than white, color over the bases of its pectoral fins. The smallest of the three thresher species, the pelagic thresher typically measures 3 m (10 ft) long.
The crocodile shark is a species of mackerel shark and the only extant member of the family Pseudocarchariidae. A specialized inhabitant of the mesopelagic zone, the crocodile shark can be found worldwide in tropical waters from the surface to a depth of 590 m (1,940 ft). It performs a diel vertical migration, staying below a depth of 200 m (660 ft) during the day and ascending into shallower water at night to feed. Typically measuring only 1 m (3.3 ft) in length, the crocodile shark is the smallest living mackerel shark. It can be distinguished by its elongated cigar-shaped body, extremely large eyes, and relatively small fins.
The tawny nurse shark is a species of carpet shark in the family Ginglymostomatidae, and the only extant member of the genus Nebrius.
The viper dogfish or viper shark is a rare species of dogfish shark in the family Etmopteridae, and the only extant member of its genus. It has been found in the Pacific Ocean off southern Japan, the Bonin Islands, Pacific Ocean off northern Taitung County and the Northwestern Hawaiian Islands. This species inhabits upper continental slopes and seamounts. It may migrate vertically, shifting between bottom waters 270–360 m (890–1,180 ft) deep during the day and upper waters less than 150 m (490 ft) deep at night. A slender, black shark reaching 54 cm (21 in) in length, the viper dogfish can be recognized by its narrow, triangular jaws and well-spaced, fang-like teeth. It also has two spined dorsal fins, dermal denticles with faceted crowns, and numerous light-emitting photophores concentrated on its ventral surface.
The Portuguese dogfish or Portuguese shark, is a species of sleeper shark of the family Somniosidae. This globally distributed species has been reported down to a depth of 3,675 m (12,057 ft), making it the deepest-living shark known. It inhabits lower continental slopes and abyssal plains, usually staying near the bottom. Stocky and dark brown in color, the Portuguese dogfish can be distinguished from similar-looking species by the small spines in front of its dorsal fins. Its dermal denticles are also unusual, resembling the scales of a bony fish. This species typically reaches 0.9–1 m (3.0–3.3 ft) in length; sharks in the Mediterranean Sea are much smaller and have distinct depth and food preferences.
The smalleye pygmy shark is a little-known species of squaliform shark in the family Dalatiidae, found in water 150–2,000 m (490–6,560 ft) deep near Japan, the Philippines, and Australia. It migrates vertically daily, spending the day in deep water and the night in shallower water. One of the smallest shark species, the smalleye pygmy shark is known to reach only 22 cm (8.7 in) long. It has a blackish, spindle-shaped body with relatively small eyes, and a spine preceding the first dorsal fin, but not the second. Bioluminescent photophores occur on its underside, which may serve to disguise its silhouette from predators. This species feeds on small squid, krill, shrimp, and bony fishes. It is aplacental viviparous. The International Union for Conservation of Nature has assessed it as Least Concern, citing its wide distribution and lack of threat from fisheries.
The Japanese roughshark is a rare species of shark in the family Oxynotidae, known only from a handful of specimens recovered from Suruga Bay and the Enshunada Sea off Japan. It is a benthic species that occurs at a depth of 150–350 m (490–1,150 ft). This shark is caught as bycatch by bottom trawlers throughout its entire limited range, and may be threatened given the declines in other bottom deep sea species in Suruga Bay.
The brown lanternshark or bristled lanternshark is a little-known species of deep-sea dogfish shark in the family Etmopteridae. It is found off Japan and New Zealand, and possibly also South Africa and Australia, typically deeper than 300 m (980 ft). This species can be distinguished from other lanternsharks by its coloration, which is a uniform dark gray or brown without the ventral surface being much darker and clearly delineated from the rest of the body. The brown lanternshark feeds on small bony fishes, cephalopods, and crustaceans. Reproduction is ovoviviparous, with females giving birth to 9–18 young. An unusually high proportion of individuals in Suruga Bay are hermaphrodites, with both male and female characteristics.
Weh Island, often known as Sabang after the city of which the island is administrated, is a small active volcanic island to the northwest of Sumatra, 45 minutes by fast regular ship or 2 hours by ferry from mainland, Banda Aceh. It was originally connected to the Sumatran mainland and became separated by sea after the volcano's last eruption in the Pleistocene era. The island is situated in the Andaman Sea.
The Jewett Sand Formation is a geologic formation in California, USA. It preserves fossils dating back to the Miocene Epoch of the Neogene period.
Megachasma applegatei is an extinct species of megamouth shark from the Oligocene to early Miocene of the Western United States. The type fossil was discovered in the San Joaquin Valley in 1973, but only described in 2014, when the species was named after its discoverer, Shelton Applegate.