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Humpback anglerfish

January 06, 2023

The humpback anglerfish (Melanocetus johnsonii) is a species of black seadevils in the family of Melanocetidae, which means "black whale" in Greek.[1] The species is named after James Yate Johnson, the English naturalist who discovered the first specimen in Madeira in 1863.[2] The common names include anglerfish, viperfish and fangtoothfish.[2][3]

Humpback anglerfish
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Lophiiformes
Family: Melanocetidae
Genus: Melanocetus
Species:
M. johnsonii
Binomial name
Melanocetus johnsonii
Günther, 1864

Historical background

The first specimen of M. johnsonii was discovered by the English naturalist James Yates Johnson near Madeira, an archipelago off the coast of northwestern Africa, on December 24, 1863.[4] It was then brought to Albert Carl Ludwig Gotthilf Günther, keeper of zoology at the Natural History Museum in London, who described it as "a fish which proves to be the type of a new genus, not only on account of its extraordinary form, but also on account of the absence of pelvic fins."[4] Günther was the first to record the unique morphology of the species; he named it after Johnson, the initial collector. Early hypotheses about anglerfish behavior posited that their illicium and esca, the extended dorsal fin spine and bulbous apparatus that protrude from the snout, are used for luring prey. The Danish naturalist Christian Frederik Lütken was the first to suggest that this feature was central in feeding behavior.[5] Until the 1920s, male specimens without a luring apparatus had been thought to be distinct, and were placed in separate taxonomic categories than their female counterparts. In 1924, British ichthyologist Charles Tate Regan realized that a small fish attached to a larger anglerfish was actually a male in the process of reproduction, leading to the discovery of the sexual dimorphism that characterizes anglerfish.[5] Several specimens that were previously categorized as separate species, including M. ferox and M. krechi, have since been recognized as synonyms of M. johnsonii.[5]

Habitat

M. johnsonii inhabits the mesopelagic and bathypelagic zones, and is found most commonly at depths between 100 and 1,500 metres (330 and 4,920 ft).[5] Compared to other species in the genus, M. johnsonii is more likely to be found at shallower depths; 65% of recorded specimens were collected at depths at or above 1,000 metres (3,300 ft) below the surface of the water.[5] At these depths, there is little to no light penetrating from the surface photic zone. Because of this, the humpback anglerfish has evolved means of predation using bioluminescence based on the constraints of their habitat.[6]

M. johnsonii has the widest geographic distribution of all the species within the Melanocetus genus.[5] The species had been known to be widely distributed in the temperate and tropical ranges of all oceans, as well as in South China Sea and East China Sea.[1] Its southern geographic distribution was expanded in 2014 when the first specimen of M. johnsonii in Antarctic waters was obtained from the stomach of an Antarctic toothfish in the Ross Sea.[7] The specimen was identified by morphologic methods and further genetic analysis using the fish's pectoral fin clip which verified that the specimen belonged to M. johnsonii.[7] An individual specimen of M. johnsonii was found near Father Charles Canyon in British Columbia, extending its known northern distribution in the East Pacific and solidifying it as one of the most widely distributed anglerfish.[8]

Morphology

M. johnsonii is a black soft-bodied anglerfish that is dark brown or black in color.[9] Female humpback anglerfish have short, globular bodies, large heads with a widened mouth that is nearly vertical, and long pointed teeth capable of eating prey larger than themselves.[1][3] Numerous small skin spines are found under the dorsal fin.[9] Compared to other species within the genus, M. johnsonii has a longer illicium and fewer jaw teeth, but these teeth are relatively longer than those of other species.[9] Like all other anglerfish, females have a short dorsal fin spine (illicium) with a bulbous luring apparatus (esca) on the snout.[3][10] The esca has compressed posterior and anterior crests, noted when distinguishing it from other anglerfish.[1][10] Unlike other species in the genus, females of the species have a nearly straightened anterior margin of vomer.[5] Female M. johnsonii have small, subcutaneous eyes that may suggest their lack of dependency on visual sight for feeding and reproduction.[9]

Humpback anglerfish exhibit extreme sexual dimorphism, with larger sized females and dwarfed males.[1] Females have been found to grow up to 153 mm, while males only grow between 15.5 and 28 mm.[5] Males lack a luring apparatus, but have large eyes and nostrils which may be helpful for locating far dispersed mates.[5] While distinguishing characteristics of males in the genus are not well defined, M. johnsonii males usually have a relatively larger number of denticular teeth and dorsal and pectoral fin rays.[3] However, since only eight male specimens were obtained up to date, information concerning males is limited.[5]

Also, as there are many similarities in the morphological characteristics of M. johnsonii and M. rossi, one distinguishing feature is that M. johnsonii has black pigmentation on its upper body exterior while M. rossi does not.[7] Because of the numerous similarities between the two, it has been suggested that M. rossi may be a synonym of the M. johnsonii species.[5]

Feeding behavior

M. johnsonii females have large mouths filled with sharp teeth and huge stomachs that make them capable of eating nearly everything they encounter. Their stomachs are highly distensible and expand easily, allowing them to consume meals weighing more than themselves.[11] One M. johnsonii individual weighing 8.8 grams was retrieved using a trawl, and the specimen was found to have three snipe eels totaling 12.3 grams in its stomach.[11]

Since only 5% of nutrition produced by the photic zone in the open passes down to the deep ocean, there is not much food available in the deep sea.[6] M. johnsonii are ambush predators, meaning that they use a sit-and-wait predation strategy. Individuals of M. johnsonii have a low metabolic rate, even compared to organisms living at similar depths. To test this, experimenters used a trawl to retrieve eight M. johnsonii individuals, all with empty stomachs. The fish were kept alive in a laboratory and their aerobic metabolisms were measured. Researchers found that M. johnsonii is able to regulate its aerobic metabolism by adjusting its oxygen consumption, allowing it to live in hypoxic or anaerobic conditions for long periods of time.[11]

Females use the bulbous esca as a bioluminescent lure to attract prey.[12] The bioluminescence of M. johnsonii is caused by symbiont Enterovibrio escacola bacteria on the esca.[13][14] It was originally thought that E. escacola was an obligate symbiont of its host because its genome was reduced about 50% compared to an average free-living bacterium. Through genetic analysis and experimentation, it was determined that E. escacola and M. johnsonii are facultatively symbiotic, meaning that they can survive without each other when necessary.[11][14]

Reproduction

Searching for a mate for M. johnsonii is difficult because they live solitarily and far apart from each other in the deep sea.[6] Males have highly developed sensory organs that allow them to trace the scent of a female as it is minimally disrupted in the still waters of the deep sea.[15] Unlike in other species of anglerfish, males of M. johnsonii are non-parasitic.[15][12] This means that M. johnsonii males only temporarily attach onto the larger M. johnsonii female using a unique denticular apparatus before releasing their sperm.[5] Once this process is complete, males detach from the females to find other mates. Two cases of this phenomenon have been captured, one on the RRS Discovery in Ireland and the other on the R/V Tansei-Maru.[16] In both instances, there was no evidence of tissue fusion between the male and female anglerfish. The reproduction of black anglerfish is carried out by external fertilization; females release eggs into the water and males then immediately exert their sperm to capture and fertilize the eggs.[10] This unique reproduction process might explain why M. johnsonii males do not live on females for their entire life. Inspection of the morphology of male M. johnsonii supports this non-parasitic mating strategy. Most importantly, both M. johnsonii males and females are able to reach sexual maturity without the presence of the other sex. In parasitic ceratioids, metamorphosed males usually attach to the female before they reach sexual maturity.[16]

Conservation

M. johnsonii was classified as a "Least Concern" species on IUCN Red List of Threatened Species.[15] It is not a food source for humans and, therefore, is not hunted by humans. However, individuals may be collected as bycatch with trawling, and as commercial fisheries shift more toward deep sea resources, the species may become more affected by this catch.[15] The relatively small number of individuals currently recorded may be due to the scarcity of the species in the deep sea environment and the constraints of collecting such widely dispersed deep sea organisms.[12]

In the media

M. johnsonii was filmed in 2014 off of the coast of California by the Monterey Bay Aquarium Research Institute using their remotely operated submersible Doc Ricketts. The video shows a female M. johnsonii slowly swimming at a depth of about 1,900 feet in the Monterey Canyon.[17]

References

  1. ^ a b c d e Froese, R., Pauly D., Eds. (2015) Melanocetus johnsonii. FishBase.
  2. ^ a b Fitch, J.E., Lavenberg R.J. (1968). Deep-water teleostean fishes of California. University of California Press, 115.
  3. ^ a b c d Humpback Blackdevil, Melanocetus johnsonii Gunther, 1864. Australian Museum.
  4. ^ a b Günther, A.C.L.G. (1865). On a new genus of pediculate fish from the Sea of Madeira. The Annals and magazine of natural history; zoology, botany, and geology, 15(3), 332–334. Retrieved from https://www.biodiversitylibrary.org/part/61580#/summary
  5. ^ a b c d e f g h i j k l Pietsch, T. W. (2009). Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea (1 ed.). University of California Press. p. 365. ISBN 978-0-520-25542-5. JSTOR 10.1525/j.ctt1ppb32.
  6. ^ a b c Ryan, P. (2006). Deep-sea creatures - The bathypelagic zone. Te Ara - the Encyclopedia of New Zealand. Retrieved from http://www.TeAra.govt.nz/en/deep-sea-creatures/page-3
  7. ^ a b c Orlov, A. M., et al. (2015). First record of humpback anglerfish (Melanocetus johnsonii) (Melanocetidae) in Antarctic waters. Polar Research, 34(1),1-5. doi:10.3402/polar.v34.25356
  8. ^ Weil, J., et al. (2015). First records and range extensions of deep-sea anglerfishes (families: oneirodidae, melanocetidae, Ceratiidae) in British Columbia, Canada. Northwestern Naturalist: A Journal of Vertebrate Biology, 96(2), 133–143. doi:10.1898/1051-1733-96.2.133
  9. ^ a b c d Pietsch, T., Van Duzer, J. (1980). Systematics and Distribution of Ceratioid Anglerfishes of the Family Melanocetidae with the Description of a New Species from the Eastern North Pacific Ocean. Fishery Bulletin, 78(1), 59–87. Retrieved from https://spo.nmfs.noaa.gov/sites/default/files/pdf-content/1980/781/pietsch.pdf
  10. ^ a b c Quigley, D.T. (2014). Ceratioid Anglerfishes. Sherkin Comment, 1(58), 7. http://www.sherkinmarine.ie/SherkinComment58.pdf
  11. ^ a b c d Cowles, D.L., Childress, J.J. (1995). Aerobic metabolism of the anglerfish Melanocetus johnsoni, a deep-pelagic marine sit-and-wait predator. Deep Sea Research Part I: Oceanographic Research Papers,42(9), 1631–1638. doi:10.1016/0967-0637(95)00061-A
  12. ^ a b c Humpback anglerfish. Ocean Animal Encyclopedia. [1] Oceana.
  13. ^ Szakmány, C. (2013). Luminescence in Nature and in the Education. Physics Competitions, 15(1), 58–64. http://wettbewerbe.ipn.uni-kiel.de/ipho/wfphc/data/journal/PhysicsCompetitions_Vol_15_No_1u2_2013_09.pdf
  14. ^ a b Baker, Lydia J.; Freed, Lindsay L.; Easson, Cole G.; Lopez, Jose V.; Fenolio, Danté; Sutton, Tracey T.; Nyholm, Spencer V.; Hendry, Tory A. (1 October 2019). "Diverse deep-sea anglerfishes share a genetically reduced luminous symbiont that is acquired from the environment". eLife. 2019 (8): e47606. doi:10.7554/eLife.47606. PMC 6773444. PMID 31571583.
  15. ^ a b c d Arnold, R. (2015). Melanocetus johnsonii. The IUCN Red List of Threatened Species 2015. Retrieved from https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T18127840A21911455.en.
  16. ^ a b Pietsch, T.W. (2005). Dimorphism, parasitism, and sex revisited: modes of reproduction among deep-sea ceratioid anglerfishes (Teleostei: Lophiiformes). Ichthyological Research, 52(3), 207–236. doi:10.1007/s10228-005-0286-2
  17. ^ Fessenden, Marissa. "The Black Sea Devil, a Rare Deep-Sea Anglerfish, Filmed for the First Time". Smithsonian Magazine. Retrieved 2020-03-11

External links

 
Wikimedia Commons has media related to Melanocetus johnsonii.

January 06, 2023
humpback, anglerfish, humpback, anglerfish, melanocetus, johnsonii, species, black, seadevils, family, melanocetidae, which, means, black, whale, greek, species, named, after, james, yate, johnson, english, naturalist, discovered, first, specimen, madeira, 186. The humpback anglerfish Melanocetus johnsonii is a species of black seadevils in the family of Melanocetidae which means black whale in Greek 1 The species is named after James Yate Johnson the English naturalist who discovered the first specimen in Madeira in 1863 2 The common names include anglerfish viperfish and fangtoothfish 2 3 Humpback anglerfishConservation statusLeast Concern IUCN 3 1 Scientific classificationKingdom AnimaliaPhylum ChordataClass ActinopterygiiOrder LophiiformesFamily MelanocetidaeGenus MelanocetusSpecies M johnsoniiBinomial nameMelanocetus johnsoniiGunther 1864 Contents 1 Historical background 2 Habitat 3 Morphology 4 Feeding behavior 5 Reproduction 6 Conservation 7 In the media 8 References 9 External linksHistorical background EditThe first specimen of M johnsonii was discovered by the English naturalist James Yates Johnson near Madeira an archipelago off the coast of northwestern Africa on December 24 1863 4 It was then brought to Albert Carl Ludwig Gotthilf Gunther keeper of zoology at the Natural History Museum in London who described it as a fish which proves to be the type of a new genus not only on account of its extraordinary form but also on account of the absence of pelvic fins 4 Gunther was the first to record the unique morphology of the species he named it after Johnson the initial collector Early hypotheses about anglerfish behavior posited that their illicium and esca the extended dorsal fin spine and bulbous apparatus that protrude from the snout are used for luring prey The Danish naturalist Christian Frederik Lutken was the first to suggest that this feature was central in feeding behavior 5 Until the 1920s male specimens without a luring apparatus had been thought to be distinct and were placed in separate taxonomic categories than their female counterparts In 1924 British ichthyologist Charles Tate Regan realized that a small fish attached to a larger anglerfish was actually a male in the process of reproduction leading to the discovery of the sexual dimorphism that characterizes anglerfish 5 Several specimens that were previously categorized as separate species including M ferox and M krechi have since been recognized as synonyms of M johnsonii 5 Habitat EditM johnsonii inhabits the mesopelagic and bathypelagic zones and is found most commonly at depths between 100 and 1 500 metres 330 and 4 920 ft 5 Compared to other species in the genus M johnsonii is more likely to be found at shallower depths 65 of recorded specimens were collected at depths at or above 1 000 metres 3 300 ft below the surface of the water 5 At these depths there is little to no light penetrating from the surface photic zone Because of this the humpback anglerfish has evolved means of predation using bioluminescence based on the constraints of their habitat 6 M johnsonii has the widest geographic distribution of all the species within the Melanocetus genus 5 The species had been known to be widely distributed in the temperate and tropical ranges of all oceans as well as in South China Sea and East China Sea 1 Its southern geographic distribution was expanded in 2014 when the first specimen of M johnsonii in Antarctic waters was obtained from the stomach of an Antarctic toothfish in the Ross Sea 7 The specimen was identified by morphologic methods and further genetic analysis using the fish s pectoral fin clip which verified that the specimen belonged to M johnsonii 7 An individual specimen of M johnsonii was found near Father Charles Canyon in British Columbia extending its known northern distribution in the East Pacific and solidifying it as one of the most widely distributed anglerfish 8 Morphology EditM johnsonii is a black soft bodied anglerfish that is dark brown or black in color 9 Female humpback anglerfish have short globular bodies large heads with a widened mouth that is nearly vertical and long pointed teeth capable of eating prey larger than themselves 1 3 Numerous small skin spines are found under the dorsal fin 9 Compared to other species within the genus M johnsonii has a longer illicium and fewer jaw teeth but these teeth are relatively longer than those of other species 9 Like all other anglerfish females have a short dorsal fin spine illicium with a bulbous luring apparatus esca on the snout 3 10 The esca has compressed posterior and anterior crests noted when distinguishing it from other anglerfish 1 10 Unlike other species in the genus females of the species have a nearly straightened anterior margin of vomer 5 Female M johnsonii have small subcutaneous eyes that may suggest their lack of dependency on visual sight for feeding and reproduction 9 Humpback anglerfish exhibit extreme sexual dimorphism with larger sized females and dwarfed males 1 Females have been found to grow up to 153 mm while males only grow between 15 5 and 28 mm 5 Males lack a luring apparatus but have large eyes and nostrils which may be helpful for locating far dispersed mates 5 While distinguishing characteristics of males in the genus are not well defined M johnsonii males usually have a relatively larger number of denticular teeth and dorsal and pectoral fin rays 3 However since only eight male specimens were obtained up to date information concerning males is limited 5 Also as there are many similarities in the morphological characteristics of M johnsonii and M rossi one distinguishing feature is that M johnsonii has black pigmentation on its upper body exterior while M rossi does not 7 Because of the numerous similarities between the two it has been suggested that M rossi may be a synonym of the M johnsonii species 5 Feeding behavior EditM johnsonii females have large mouths filled with sharp teeth and huge stomachs that make them capable of eating nearly everything they encounter Their stomachs are highly distensible and expand easily allowing them to consume meals weighing more than themselves 11 One M johnsonii individual weighing 8 8 grams was retrieved using a trawl and the specimen was found to have three snipe eels totaling 12 3 grams in its stomach 11 Since only 5 of nutrition produced by the photic zone in the open passes down to the deep ocean there is not much food available in the deep sea 6 M johnsonii are ambush predators meaning that they use a sit and wait predation strategy Individuals of M johnsonii have a low metabolic rate even compared to organisms living at similar depths To test this experimenters used a trawl to retrieve eight M johnsonii individuals all with empty stomachs The fish were kept alive in a laboratory and their aerobic metabolisms were measured Researchers found that M johnsonii is able to regulate its aerobic metabolism by adjusting its oxygen consumption allowing it to live in hypoxic or anaerobic conditions for long periods of time 11 Females use the bulbous esca as a bioluminescent lure to attract prey 12 The bioluminescence of M johnsonii is caused by symbiont Enterovibrio escacola bacteria on the esca 13 14 It was originally thought that E escacola was an obligate symbiont of its host because its genome was reduced about 50 compared to an average free living bacterium Through genetic analysis and experimentation it was determined that E escacola and M johnsonii are facultatively symbiotic meaning that they can survive without each other when necessary 11 14 Reproduction EditSearching for a mate for M johnsonii is difficult because they live solitarily and far apart from each other in the deep sea 6 Males have highly developed sensory organs that allow them to trace the scent of a female as it is minimally disrupted in the still waters of the deep sea 15 Unlike in other species of anglerfish males of M johnsonii are non parasitic 15 12 This means that M johnsonii males only temporarily attach onto the larger M johnsonii female using a unique denticular apparatus before releasing their sperm 5 Once this process is complete males detach from the females to find other mates Two cases of this phenomenon have been captured one on the RRS Discovery in Ireland and the other on the R V Tansei Maru 16 In both instances there was no evidence of tissue fusion between the male and female anglerfish The reproduction of black anglerfish is carried out by external fertilization females release eggs into the water and males then immediately exert their sperm to capture and fertilize the eggs 10 This unique reproduction process might explain why M johnsonii males do not live on females for their entire life Inspection of the morphology of male M johnsonii supports this non parasitic mating strategy Most importantly both M johnsonii males and females are able to reach sexual maturity without the presence of the other sex In parasitic ceratioids metamorphosed males usually attach to the female before they reach sexual maturity 16 Conservation EditM johnsonii was classified as a Least Concern species on IUCN Red List of Threatened Species 15 It is not a food source for humans and therefore is not hunted by humans However individuals may be collected as bycatch with trawling and as commercial fisheries shift more toward deep sea resources the species may become more affected by this catch 15 The relatively small number of individuals currently recorded may be due to the scarcity of the species in the deep sea environment and the constraints of collecting such widely dispersed deep sea organisms 12 In the media EditM johnsonii was filmed in 2014 off of the coast of California by the Monterey Bay Aquarium Research Institute using their remotely operated submersible Doc Ricketts The video shows a female M johnsonii slowly swimming at a depth of about 1 900 feet in the Monterey Canyon 17 References Edit a b c d e Froese R Pauly D Eds 2015 Melanocetus johnsonii FishBase a b Fitch J E Lavenberg R J 1968 Deep water teleostean fishes of California University of California Press 115 a b c d Humpback Blackdevil Melanocetus johnsonii Gunther 1864 Australian Museum a b Gunther A C L G 1865 On a new genus of pediculate fish from the Sea of Madeira The Annals and magazine of natural history zoology botany and geology 15 3 332 334 Retrieved from https www biodiversitylibrary org part 61580 summary a b c d e f g h i j k l Pietsch T W 2009 Oceanic Anglerfishes Extraordinary Diversity in the Deep Sea 1 ed University of California Press p 365 ISBN 978 0 520 25542 5 JSTOR 10 1525 j ctt1ppb32 a b c Ryan P 2006 Deep sea creatures The bathypelagic zone Te Ara the Encyclopedia of New Zealand Retrieved from http www TeAra govt nz en deep sea creatures page 3 a b c Orlov A M et al 2015 First record of humpback anglerfish Melanocetus johnsonii Melanocetidae in Antarctic waters Polar Research 34 1 1 5 doi 10 3402 polar v34 25356 Weil J et al 2015 First records and range extensions of deep sea anglerfishes families oneirodidae melanocetidae Ceratiidae in British Columbia Canada Northwestern Naturalist A Journal of Vertebrate Biology 96 2 133 143 doi 10 1898 1051 1733 96 2 133 a b c d Pietsch T Van Duzer J 1980 Systematics and Distribution of Ceratioid Anglerfishes of the Family Melanocetidae with the Description of a New Species from the Eastern North Pacific Ocean Fishery Bulletin 78 1 59 87 Retrieved from https spo nmfs noaa gov sites default files pdf content 1980 781 pietsch pdf a b c Quigley D T 2014 Ceratioid Anglerfishes Sherkin Comment 1 58 7 http www sherkinmarine ie SherkinComment58 pdf a b c d Cowles D L Childress J J 1995 Aerobic metabolism of the anglerfish Melanocetus johnsoni a deep pelagic marine sit and wait predator Deep Sea Research Part I Oceanographic Research Papers 42 9 1631 1638 doi 10 1016 0967 0637 95 00061 A a b c Humpback anglerfish Ocean Animal Encyclopedia 1 Oceana Szakmany C 2013 Luminescence in Nature and in the Education Physics Competitions 15 1 58 64 http wettbewerbe ipn uni kiel de ipho wfphc data journal PhysicsCompetitions Vol 15 No 1u2 2013 09 pdf a b Baker Lydia J Freed Lindsay L Easson Cole G Lopez Jose V Fenolio Dante Sutton Tracey T Nyholm Spencer V Hendry Tory A 1 October 2019 Diverse deep sea anglerfishes share a genetically reduced luminous symbiont that is acquired from the environment eLife 2019 8 e47606 doi 10 7554 eLife 47606 PMC 6773444 PMID 31571583 a b c d Arnold R 2015 Melanocetus johnsonii The IUCN Red List of Threatened Species 2015 Retrieved from https dx doi org 10 2305 IUCN UK 2015 4 RLTS T18127840A21911455 en a b Pietsch T W 2005 Dimorphism parasitism and sex revisited modes of reproduction among deep sea ceratioid anglerfishes Teleostei Lophiiformes Ichthyological Research 52 3 207 236 doi 10 1007 s10228 005 0286 2 Fessenden Marissa The Black Sea Devil a Rare Deep Sea Anglerfish Filmed for the First Time Smithsonian Magazine Retrieved 2020 03 11External links Edit Wikimedia Commons has media related to Melanocetus johnsonii Melanocetus johnsonii Marine Species Identification Portal Melanocetus johnsonii specimen Museum of New Zealand Te Papa Tongarewa Retrieved from https en wikipedia org w index php title Humpback anglerfish amp oldid 1120753974, wikipedia, wiki, book, books, library,

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