The giant sunfish or bumphead sunfish (Mola alexandrini),[4] (also known as the Ramsay's sunfish, southern sunfish, southern ocean sunfish, short sunfish or bump-head sunfish in various parts of the world),[5] is a fish belonging to the family Molidae. It is closely related to the more widely known Mola mola, and is found in the Southern Hemisphere.[6] With a specimen found dead near the Azores in 2021 weighing in at 2744 kg (6049 lb) it is the largest extant bony fish species in terms of maximum recorded mass by a wide margin. It can be found basking on its side occasionally near the surface, which is thought to be used to re-heat themselves after diving in cold water for prey, recharge their oxygen stores, and attract gulls to free them of parasites.[3]
In December 2017, it was demonstrated that Mola alexandrini may be a senior synonym of Mola ramsayi(Giglioli 1883) through both historically and newly published morphological data.[7] In July 2020, building upon this scientific learning, the larval forms of these species were discovered for the first time and confirmed with DNA analyses by Australian and New Zealander scientific teams.[8][9][10][11]
The ocean sunfish are in the genus Mola, currently composed of three species: Mola mola, Mola alexandrini, Mola tecta.[12] Also known as the southern ocean sunfish or southern sunfish, Mola alexandrini are commonly found in the epipelagic zone of the ocean, where enough light penetrates for photosynthesis to occur, although recent studies also suggest they may also be more common in deep waters.[13][14]
Taxidermy with a total length of 3m (9.8ft) and a height of 3.5m (11ft) in Aqua World
Mola alexandrini has a relatively small mouth, and its teeth are fused into a parrot-like beak. It can reach up to 3.3m (11ft) in length and 2,700 kilograms (6,000lb) in mass, making it the heaviest bony fish.[16][17] Their bodies are flat and round, with large fins that they swish back and forth to propel themselves with as they swim horizontally. Their skin has rough denticles and a leathery texture, with brown and gray coloring with pale blotches; at death, their scales turn white.[4] The body has a thick white subcutaneous gelatinous layer that is smooth to the touch, with a laterally compressed body covered in small rectangular scales.[7] Both molaspecies have no caudal bones, ribs, or pelvic fins, and have fused vertebrae, leaving only their median fins to propel themselves.[18]Mola alexandrini can be distinguished from Mola mola by its smaller number of ossicles and lack of a vertical band of denticles at its base.[5] In Mola, the lower jaws are intact while the upper jaws are slightly forked.[19] On the head, the lateral lines have small, white, rounded otoconia. On the sides are small gill openings covered by a soft gill membrane and gill rakers, which are covered under a subcutaneous gelatinous layer. All fins are spineless and triangular. Pectoral fins are small and rounded, located midlaterally fitting into shallow grooves on sides of the bod, and dorsal fins are located on both sides of the anal fin.[7]
M. alexandrini can be distinguished by its unique characteristics of head bump, a chin bump, rectangular body scales, and rounded clavus. Although adult sunfish look generally similar, they are distinguishable using seven characteristics: number of clavus fin rays, number of clavus ossicles, shape of clavus margin, presence of head bump, proportion of body length compared to body height,[20] shape of body scales,[21] and the presence of a chin bump.[22]
Alongside these species, there are no external differences between sexes; internally, however, the gonads differ in shape, with females having a single spherical ovary and males having a pair of elongated, rod-like testes.[7]
Overall, the maximum recorded weight of M. alexandrini is 2,744 kg (6049 lb) from a 325-cm-length (10.66 ft) specimen caught off the coast of Faial Island, Azores, Portugal in late 2021.[23] With these records, this specimen is currently regarded as the world's heaviest bony fish specimen. It exceeds by nearly half a ton (444 kg, 979 lb) the largest previously known specimen (2300 kg, 5070 lb), caught off Kamogawa, Japan in 1996.[24]
Distribution
Mola alexandrini has been found all over the globe and is widely distributed throughout the world's oceans, except for the polar regions.[7] These species have been collected from waters off Japan, Taiwan, the Galapagos Islands, New Zealand, Australia, Turkey, Oman, and Spain.[7] It can be found in the southwest Pacific, especially around Australia and New Zealand, and the southeast Pacific around Chile. Its range also extends to the southeast Atlantic near South Africa. During seasonal changes in climate on the Pacific side of Japan, M. alexandrini moves northwards in the summer and southwards in the winter.[25] Seasonal migration is driven by temperature differences and productive frontal areas.[26]
Habitat
Although members of the genus Mola are found in many oceans throughout the world, this species thrives best in the open ocean of tropical and temperate seas, preferring warmer temperatures ranging from 16.8 C to 25.6 C (62.24 F to 78.08 F), averaging 19.9 C (67.82 F) [7]. Many encounters with this species are linked to the influence of ocean currents.[27] Based on their immediate environment, sunfish have different movement patterns. During the nighttime, these species stay in the same areas, but during the daytime, they stay below the thermocline.[26] Vertical movement patterns correlated with thermocline depth, and they differed from December to May.[26]
Development
As M. alexandrini fry age, they undergo a number of physical changes. This includes a head bump forming from above the eyes to the front of the dorsal-fin base, and a chin bump developing from beneath the lower jaw to beneath the pectoral fins. Additionally, developing with age are lateral ridges from above the head and below the eyes to beyond the pectoral fins. Characteristics that distinguish Mola alexandrini from other species in genus Mola are clavus ossicles, a snout ossicle and a chin ossicle that develop further over time.[7] When eggs hatch, larva specimens range between 1.42 and 1.84 mm.[28] At 1.42 mm, they tend to display a globular shape. As they move into the pre-juvenile stage, specimens range between 5 mm to 59 mm. As they continue growing, their bodies take on the proportions of adults, including an elongated body. Once these species reach the juvenile stage, specimens are described to be as big as 305–750 mm in total length. As they mature, specimens reportedly reach 4000 mm with well-defined features, along with pigmentations of gray, olive, or black with a brown cast.[28]
Reproduction
Sunfish spawn in the outer circulation of the temperate Atlantic and Pacific Oceans, as well as in the Mediterranean Sea.[28] The optimal time for sunfish to spawn in the wild is not known, but research has shown that spawning in fall or winter, especially during the month of September, results in bigger fish.[28] Fertilization occurs when sperm and eggs are shed in the water.[29] Being that sunfish are so large, a single adult female can produce 300 million eggs.[29] Unfertilized eggs were measured at 0.42-0.45 mm in diameter.[28]
Lifespan
Just like many other fish, high mortality rates are common for eggs, larvae, pre-juveniles, and small juveniles due to predators.[30] There have been few reports on predation of Mola species however, predation by fish are from families Scombridae, Carangidae, Coryphaenidae, Xiphiidae, and Alepisauridae.[30] Although there is not much research on the lifespan of ocean sunfish, ocean sunfish reportedly take about 20 years to reach a length of 3 m (9.84 ft).[31]
Behavior
Sunfish swim by moving their dorsal and anal fins back and forth, both fins moving in the same direction at the same time.[29] Adults are reported to travel mainly alone or in pairs, and sometimes in groups.[28] Migrating from one place to another requires high tolerance and it is found that sunfish have high thermal tolerance undergoing quick and large temperature changes diving down the ocean several hundred meters.[27] Sometimes, sunfish come up to the shallow water to recover from hypoxia from feeding below the thermocline.[27] Like many other fish, sunfish adapt in response to the environment.[27] During the day, sunfish tend to dive deeper than they do at night.[26] During the nighttime, sunfish preferred temperatures between 18–24 C (64–75 F) while the fish moved to different areas during the day.[26] Vertical movements were correlated with temperature shifts.[26] Sunfish may dive deeper into cooler waters to cool the muscles or to repay oxygen debts.[26]
Diet
They mainly consume jellyfish, which are of low nutritional content but abundant, and they will also eat brittle stars, small fish, plankton, algae, salps, and mollusks.[3] Sunfish also feed on ctenophores, hydrozoans, and small crustaceans.[29] Juvenile sunfish feed in coastal areas in the coastal food web while larger sunfish dive deeper.[30] These species are active predators hunting in dynamic frontal systems.[27]
Predation
Predators include tiger sharks and orcas, though attacks are rare. Shark predation on all species of sunfish is sporadic, suggesting that ocean sunfish are of low quality or unpleasant for tiger sharks. With smart tactics, tiger sharks can stalk and ambush their prey and are able to bite through the thick gelatinous dermis.[30]
Ecosystem roles
The importance of ocean sunfish in marine food webs is unknown.[30] However, since ocean sunfish feed on gelatinous prey with a generalist diet, this suggests that these species play an important role in coastal food webs.[32] If sunfish were to be removed as bycatch, it can drive localized trophic cascades with top-down control being reduced.[33]
Economic importance for humans
Sunfish have economic value in tourism industries.[34] These fish make unpredictable appearances, but when they do appear, it is often a moment of excitement for tours and scuba divers.[34] In locations like the Galapagos Islands and the Alboran Coast in the Mediterranean, sunfish are spotted frequent enough to have sunfish tours.[27] Scuba diving tourism in Bali and the Nusa Penida islands has rapidly increased over the last few decades. Only a small number of fisheries target sunfish, including those in Taiwan and Japan. In Indonesia, sunfish are released, eaten by locals, used as bait, or end up at a fish market on rare occasions.[34]
Conservation status
The conservation status of M. alexandrini has not been evaluated, unlike M. mola. Fisheries around the world catch ocean sunfish as bycatch. M. mola was listed by the international Union for the Conservation of Nature (IUCN) as "vulnerable" due to the high level of estimated bycatch in South African longline fishery with an annual estimated 340,000 annual catches. Both M. mola and M. alexandrini were listed as "high risk" bycatch species in the longline fishery off eastern Australia. Threat levels are lower than what is stated on the IUCN listing in Australian, New Zealand, and South African fisheries. Currently, the Indonesian government's Ministry of Marine Affairs and Fisheries has placed sunfish on a plan for protection.[34]
Related Research Articles
Osteichthyes, commonly referred to as the bony fish, is a diverse superclass of vertebrate animals that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of extant fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, over 435 families and 28,000 species. It is the largest class of vertebrates in existence today.
The Tetraodontiformes are an order of highly derived ray-finned fish, also called the Plectognathi. Sometimes these are classified as a suborder of the order Perciformes. The Tetraodontiformes are represented by 10 extant families and at least 349 species overall; most are marine and dwell in and around tropical coral reefs, but a few species are found in freshwater streams and estuaries. They have no close relatives, and descend from a line of coral-dwelling species that emerged around 80 million years ago.
The ocean sunfish or common mola is one of the largest bony fish in the world. It was misidentified as the heaviest bony fish, which was actually a different species, Mola alexandrini. Adults typically weigh between 247 and 1,000 kg. The species belongs to the Mola genus, one of three in the Molidae family. It is native to tropical and temperate waters around the world. It resembles a fish head without a tail, and its main body is flattened laterally. Sunfish can be as tall as they are long when their dorsal and ventral fins are extended.
The Molidae comprise the family of the molas or ocean sunfishes, unusual fish whose bodies come to an end just behind the dorsal and anal fins, giving them a "half-fish" appearance. They are also the largest of the ray-finned bony fish, with the southern sunfish, Mola alexandrini, recorded at 4.6 m (15 ft) in length and 2,744 kg (6,049 lb) in weight.
Lancetfishes are large oceanic predatory fishes in the genus Alepisaurus in the monogeneric family Alepisauridae.
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 slender sunfish is a mola of the family Molidae, the only extant member of the genus Ranzania, found globally in tropical and temperate seas. Its length is up to 1 m (3.3 ft). Several stranding and mass stranding events have occurred on beaches near Albany, Western Australia.
The largetooth cookiecutter shark is a rare species of squaliform shark in the family Dalatiidae, reported from depths of 60–200 m (200–660 ft) at scattered locations in the Atlantic and Pacific Oceans. As its common name suggests, it is similar in appearance to the cookiecutter shark but has much larger lower teeth. This species reaches a maximum known length of 42 cm (17 in). The largetooth cookiecutter shark feeds by gouging out chunks of flesh from larger animals, including bony fishes, sharks, and marine mammals, and is able to take larger bites than I. brasiliensis. Little is known of its life history; it is thought to be a weaker swimmer than I. brasiliensis, and is presumably aplacental viviparous like the rest of its family. This shark is an infrequent bycatch of commercial trawl and longline fisheries, but is not thought to be much threatened by these activities.
The schooling bannerfish, also known as the false moorish idol, is a marine ray-finned fish, a butterflyfish from the family Chaetodontidae. It is native to the Indo-Pacific area.
A sunfish, also called a mola, is any fish in the genus Mola. The fish develop their truncated, bullet-like shape because the back fin, which is present at birth, never grows. Instead, it folds into itself as the creature matures, creating a rounded rudder called a clavus. Mola in Latin means "millstone" and describes the ocean sunfish's somewhat circular shape. They are a silvery color and have a rough skin texture.
The rainbow runner, also known as the rainbow yellowtail, Spanish jack and Hawaiian salmon, is a common species of pelagic marine fish of the jack family, Carangidae. The species is widespread throughout the tropical and subtropical waters of the world, inhabiting both coastal and offshore areas. The species is the only member of the genus Elagatis, which was created 15 years after its initial description, and is closely related to the amberjacks. The rainbow runner is easily distinguished by its body shape, and the brilliant colouration which gives the fish its name. It is a fast-swimming predator, taking small fish, cephalopods, and a wide variety of planktonic crustaceans. The species reaches sexual maturity around 60 cm (24 in), and spawning takes place at different times, with some populations spawning year round, while others only spawn at certain times of the year. The species is a well known game fish, taken by a variety of fishing methods, and is a well-regarded table fish. Large numbers of the species are taken as bycatch in tuna- and shark-fishing operations and marketed.
The coastal trevally, also known as the onion trevally, Japanese trevally or bluefin kingfish, is a species of inshore marine fish in the jack family Carangidae. The species is distributed throughout the tropical and subtropical waters of the Indian and west Pacific Oceans, from South Africa in the west to Japan and New Caledonia in the east, reaching as far south as Australia. The species is found on deep coastal reefs, both in schools and as solitary individuals, where they prey on small midwater organisms including crustaceans, small fish and cephalopods. The species is taken as bycatch in a number of fisheries throughout its range by a number of fishing methods and is of little commercial value, but is considered to be a good table fish. A mistype in the original volume in which Eduard Rüppell named the species led to the combination Carangoides caeruleopinnatus, which has incorrectly spread through the literature.
The duskyshoulder trevally or epaulet trevally, is a species of small inshore marine fish in the jack family, Carangidae. It is distributed through the eastern Indian and western Pacific Oceans, ranging from eastern India to northern Australia and Taiwan. It is relatively small by carangid standards, reaching only 27 cm maximum length, and can be distinguished by the large, black blotches on its shoulders. The duskyshoulder trevally is an inshore fish living in waters less than 50 m deep, over sandy substrates in bays and on the continental shelf. It is a predatory fish, taking demersal fishes, crustaceans, and cephalopods, with nothing known of its reproductive habits. It is of little value to fisheries, often taken as bycatch in prawn trawling operations.
The coachwhip trevally, also known as the oblong trevally or oblique-banded trevally, is a species of inshore marine fish classified in the jack family Carangidae. The coachwhip trevally is distributed through the Indo-west Pacific region, ranging from South Africa in the west to Fiji and Japan in the east. It is a moderately large fish, growing to a known maximum length of 46 cm and can be distinguished from similar species by an array of detailed morphological features including dentition, fin ray counts and scale patterns. The coachwhip trevally inhabits coastal waters throughout its range, known to prefer estuarine waters in a number of localities. Nothing is known of its diet or reproductive biology, and is of little importance to fisheries, occasionally taken as bycatch in trawl and hook and line fisheries.
The sharptail mola is a species of mola found circumglobally in tropical and temperate waters. It is similar in appearance to the ocean sunfish, but can be distinguished by the projection on its clavus (pseudo-tail). Other common names include sharpfin sunfish, point-tailed sunfish, and trunkfish. Rarely encountered, very little is known of the biology or life history of the sharptail mola. It has recently become important to commercial fisheries operating off eastern Taiwan. This species is the only member of its genus.
Guentherus is a genus of jellynose fishes, belonging to the Ateleopodidae family, with two recognized species:
The longrakered trevally, also known as the cale cale trevally and heavyjawed kingfish, is a species of marine fish in the jack and horse mackerel family Carangidae. The longrakered trevally is distributed throughout the tropical and subtropical waters of the Indian and west Pacific Oceans, from Mozambique and Madagascar in the west, to Japan and northern Australia in the east. A large species growing to a recorded length of 1 m, the longrakered trevally is distinguished by is protruding lower jaw, elongated gill rakers and lack of villiform teeth on its tongue. It is an inshore species, restricted to coastal and estuarine regions, where it preys on fishes and crustaceans. Little is known of the species reproductive cycle or growth. The longrakered trevally is of minor importance to fisheries and is often taken as bycatch in finfish and prawn trawls, as well as by recreational fishermen.
Mola tecta, the hoodwinker sunfish, belongs to the family Molidae and genus Mola. It is closely related to the more widely known ocean sunfish. The Latin word "tecta" means hidden. The word "hidden" was adopted for the name because the fish has blended in among other species of sunfish for a long time and has only been discovered recently. Discovered on a beach near Christchurch, New Zealand, in 2015, it was the first new species of sunfish to be identified in 130 years. Mola tecta are mostly discovered in the temperate region of the Southern Hemisphere in the water near Australia, New Zealand, Southern Chile and Southern Africa. It was first described by Marianne Nyegaard, a marine scientist who studied ocean sunfish for her PhD.
Marianne Nyegaard is a Danish marine biologist who specializes in the study of ocean sunfish. She is known for identifying the ocean sunfish species Mola tecta.
↑ Yasemi, M.; Nazari Bejgan, A. R. (2013) The first record of southern ocean sunfish, Mola ramsayi from Northern Oman Sea, Iran. Iranian Journal of Fisheries Sciences, 13, 242–246.
↑ Matsuura, K., 2002. Molidae. Molas (ocean sunfishes, headfishes). In Carpenter, K. E. (ed.)
↑ Phillips, N. D.; Harrod, C.; Gates, A. R.; Thys, T. M.; Houghton, J. D. R. (2015) Seeking the sun in deep, dark places: mesopelagic sightings of ocean sunfishes (Molidae). Journal of FishBiology, 4, 1118–1126.
↑ Thys, T. M.; Hays, G. C.; Houghton, J. D. R. The Ocean Sunfishes: Evolution, Biology and Conservation. CRC Press, 2020, p. 29.
↑ Kuta, Sarah (19 October 2022). "This 6,000-Pound Sunfish Is the Largest Bony Fish on Record". Smithsonian Magazine. Retrieved 20 October 2022. Weighing in at roughly 6,050 pounds—the size of a large SUV—the fish was 882 pounds heavier than the reigning bony fish world record-holder, a 5,070-pound sunfish discovered off the coast of Japan in 1996 ... They are related to ocean sunfish (Mola mola) but can be twice as heavy.
↑ Tierney M. Thys; Jonathan Whitney; Alex Hearn; Kevin C. Weng; Cesar Pen Aherrera; L. Jawad; J. Alfaro-Shigueto; J.C. Mangel; Stephen A. Karl (2013). "First record of the southern ocean sunfish, Mola ramsayi, in the Galapagos Marine Reserve". Marine Biodiversity Records. 6: 1–4. doi:10.1017/S1755267213000377.
↑ Yoshita, Y.; Yamanoue, Y.; Sagara, K.; Nishibori, M.; Kuniyoshi, H.; Umino, T., Sakai, Y.; Hashimoto, H.; Gushima, K. (2009) "Phylogenetic relationships of two Mola sunfshes (Tetraodontiformes: Molidae) occurring around the coasts of Japan, with notes on their geographical distribution and morphological characteristics". Ichthyology Research, 56, 232–244.
↑ Sawai, E.; Yamanoue, Y.; Jawad, L.; Al-Mamry, J.; Sakai, Y. (2017) "Molecular and morphological identification of Mola sunfsh specimens (Actinopterygii: Tetraodontiformes: Molidae) from the Indian Ocean". Species Divers, 2, 99–104.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
