Whalesucker

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Whalesucker
Remora australis.png
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Carangiformes
Family: Echeneidae
Genus: Remora
Species:
R. australis
Binomial name
Remora australis
Synonyms
  • Echeneis australis F. D. Bennett, 1840
  • Remilegia australis(F. D. Bennett, 1840)
  • Echeneis scutata Günther, 1860
  • Remora scutata(Günther, 1860)

The whalesucker (Remora australis) is a species of remora in the family Echeneidae, so named because it attaches itself exclusively to cetaceans. It is found worldwide in tropical and warm waters; in the Gulf of Mexico and western Atlantic Ocean, it occurs from Texas to Brazil, and in the eastern Pacific Ocean, it occurs from Vancouver Island to Chile. [2] It is the rarest member of the remora family, though this may reflect more the uncommon collection of cetaceans in the wild rather than the whalesucker's actual abundance. [3]

Contents

The adhesive disk atop the head of the whalesucker is the largest amongst the remoras, bearing 25–28 lamellae and measuring 47–59% of the standard length. The head itself measures 26–28% of the standard length. The dorsal fin rays number 23–26, the anal fin rays 24–26, and the pectoral fin rays 22–24. The jaws contain numerous large, stout canine teeth; the palatine and lingual patches are absent, and there are 17–20 gill rakers. The coloration is uniform brown, dark brown, or greyish-brown on the head, trunk, and fins. [4] Whalesuckers observed off Fernando de Noronha ranged from light grey to slate grey, with lighter fin margins. The smaller individuals are barred or blotched, while individuals over 35 cm (14 in) long have yellowish fins. [5] This species can reach 76 cm (30 in) in total length. [2]

The most common host of the whalesucker appears to be the blue whale. Chitinous material indicative of parasitic copepods or amphipods have been found in the stomachs of whalesuckers, suggesting a mutualistic relationship with their hosts. [3] Off Fernando de Noronha, whalesuckers down to small (4 to 9 cm [1.6 to 3.5 in]) juveniles are associated with spinner dolphins, and are likely recruited year-round from flotsam. The whalesuckers, no more than three to a host, usually attach to the flanks or belly of the dolphin, which may serve to minimize drag and facilitate feeding. When approached, they, especially small individuals, will shift to the opposite side of the host for protection. Whalesuckers impose a hydrodynamic cost to their host, their adhesive disks can abrade the skin, and they sometimes attach to inconvenient locations, such as near the blowhole or the genitals. The spinning behavior of dolphins, sharks, and other remora hosts has been proposed as a means of dislodging them. The whalesuckers feed on parasites and sloughed-off skin, and also forage on feces and vomit from the dolphins. [5]

Symbiotic Relationships: Blue Whale

The mutualistic relationship between the whalesucker (Remora australis) and the blue whale (Balaenoptera musculus) shows its mutualistic relationship with the adult spinner dolphin. [6] Remoras stick onto blue whales and stay attached when the whale surfaces, briefly emerging from the water themselves. Similar to its behavior with dolphins, whalesuckers are also known to change their position when feeding off blue whales, to avoid predation. [7]

While eliminating parasites, the whalesucker benefits from their symbiotic relationship with the whale by avoiding predators. The chance of mating also increases through habitual migration and food availability (i.e. parasites or food droppings). Meanwhile, the blue whale benefits from having parasites and detritus cleaned from its mouth and gill areas. [8] One of the most notable benefits the whalesucker receives from its relationship with blue whales is its reduction of drag when attached to its host, specifically when the remora attempts to stay close or stick to the blue whale while it is in movement. The speed of a median blue whale speed rests at about 2.1±0.5 m s−1 (7.6±1.8 km h−1) and at 3.9±0.8 m s−1 (14±2.9 km h−1), which is doubled for the remora given its small 1m stature. Whalesuckers can supposedly match the speed of the blue whales, with its supposed ability to skim and swim near the whale’s surface before attachment. It has been theorized that whalesuckers prefer to swim near blue whales to reduce drag, thus reducing separation and allowing the whalesucker to stay near its host. Using its adhesive disc, the whalesucker attaches directly behind the whale’s blowhole, directly on, behind, and above the pectoral fin, and next to or behind the dorsal fin. [9] This way, the whalesucker can keep itself constantly near the whale while resisting drag both while it swims freely, and when it attaches to its host. It has also been observed through this movement that it prefers to keep away from the ventral surface to avoid sea bird predators.

One of the whalesucker's most outstanding traits, shared among the Echeinedae family, is an adhesive disk. The adhesive disk is a round, oval, sucking disk located on the top of a remora’s head, with two layers of lamellae that allow for the remora to stick and unstick to the epidermal surfaces of larger fish, mainly cetaceans. Evolved from dorsal fin spines, the disc is thought to have evolved to allow individuals to attach to rough surfaces using their teeth. The average length of a whalesucker’s adhesive disc is about 11 to 19 cm. [10] There have been previous arguments that the morphology relating to the whalesucker’s origins belonged to the Opisthomyzonidae genus, which existed during the Oligocene era. However, this species has a fully formed disc, an equal-length jaw, a long head, a large body, and a short but deep caudal peduncle, which is the base of its forked caudal fin, a muscle in the tail that allows the fish to swim forward. [11] Recent studies of the Opithomyzonidae have found flaws in its perceived ancestry to the whalesucker due to its comparatively low six-to-eight-disc lamellae and lack of the adhesion disc’s migration to the fish’s skull. Additionally, there is a lack of consistency of timing between earlier ancestors of the whalesucker and the Opisthomyzon’s development of additional intercalary [ disambiguation needed ] bones and posterior laminae after the disc’s migration. It is more likely that the Opisthomyzon was the recent common ancestor of the Phtheirichthys family, the sister group to the extant remora. What is speculated, is that the changes in the disc’s length most likely occurred through performance-based natural selection through friction against surfaces of larger animals. [12] Each increase is said to help the remora attach to host organisms, and each species of fish diverged from one another to develop adhesive disks to attach to specific larger organisms based on their disk’s effectiveness. Specifically, each increase allows Echinidae species to develop better suction against tougher exteriors of sea mammals, including more dangerous species such as tiger sharks or hammerhead sharks. The behaviors of the whalesucker can be easily traced to other extant relatives within the Echinidae family. The closest relative of the whalesucker is the cobia, a.k.a. the black salmon (Rachycentron canadum). While the black salmon does not share the same feature of the adhesive disc as the whalesucker, both exhibited behaviors that enabled them to stay close to their host organisms for protection and resources. [13] The whalesucker’s true homologous origins may not be confirmed, its relationship to its phylogenetic relatives shows a similarity in both its morphology and behavior towards dolphins and blue whales.

Morphology

The whalesucker shares similar homologous structures to each living species of Echeneidae: each has a strong lower jaw, projecting forward and upward that becomes nearly horizontal to the surface of each remora’s adhesion disk. Additionally, remoras’ ability to move across the skin of their hosts allows them to shovel other parasites and detritus stuck on the host’s body into their mouth, which leavens extra effort made by the remora. [14] The functionality of the adhesion disc relies on friction and suction to keep the whalesucker attached to its host. Small spinules located in the lamellae (the layer of tissue in the whalesucker’s epidermal region), use friction by rotating the lamellae inside the disc to resist drag. A layer of thick epithelium (layer of cells that lines hollow organs and glands) seals the edge of the disc, lamellae, and median septum, which creates equalization of pressure and allows the whalesucker to attach to its neighbor. [15] However, whalesuckers can still lose their suction abilities through unequalization of pressure, as attaching to specific host organisms can render an unequal amount of force required for the fish to attach to its host, causing seep to emerge from outside of the disc, and lose its suction adhesion. The cranial veins of the remora also differ from other species of fish: they are larger and are placed ventral to the dorsal disc on the fish’s cranium. [16] As opposed to other species that merely rely on their jaw grip to latch onto prey, the interconnection between these veins, the brain, and the ventral surface of the remora allows it to work as a hydraulic press when using the adhesive disc to allow for pressurization equilibrium during attachment.

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The blue whale is a marine mammal and a baleen whale. Reaching a maximum confirmed length of 29.9 m (98 ft) and weighing up to 199 t, it is the largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda in the Indian Ocean and South Pacific Ocean, and B. m. indica in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies.

<span class="mw-page-title-main">Remora</span> Family (Echeneidae) of ray-finned fish

The remora, sometimes called suckerfish or sharksucker, is any of a family (Echeneidae) of ray-finned fish in the order Carangiformes. Depending on species, they grow to 30–110 cm (12–43 in) long. Their distinctive first dorsal fins take the form of a modified oval, sucker-like organ with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals. The disk is made up of stout, flexible membranes that can be raised and lowered to generate suction. By sliding backward, the remora can increase the suction, or it can release itself by swimming forward. Remoras sometimes attach to small boats, and have been observed attaching to divers as well. They swim well on their own, with a sinuous, or curved, motion.

<span class="mw-page-title-main">Fin whale</span> Large baleen whale species

The fin whale, also known as the finback whale or common rorqual, is a species of baleen whale and the second-longest cetacean after the blue whale. The biggest individual reportedly measured 26 m (85 ft) in length, with a maximum recorded weight of 77 to 81 tonnes. The fin whale's body is long, slender and brownish-gray in color, with a paler underside to appear less conspicuous from below (countershading).

<span class="mw-page-title-main">Baleen whale</span> Whales that strain food from the water using baleen

Baleen whales, also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea, which use keratinaceous baleen plates in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae, Balaenopteridae (rorquals), Eschrichtiidae and Cetotheriidae. There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychians, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago.

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<span class="mw-page-title-main">Lamella (surface anatomy)</span> Anatomical structure

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<span class="mw-page-title-main">Slender suckerfish</span> Species of fish

The slender suckerfish or lousefish is a rare species of remora found around the world in tropical and subtropical seas, in areas like the Atlantic, Pacific, and Indian Ocean, from depths from 1 to 100 meters deep.

The spearfish remora is a species of remora with a worldwide distribution in tropical and subtropical seas. Remoras attach themselves to other fish with a sucker on the head and this fish is almost exclusively found living on billfishes or swordfishes, and sometimes on sharks.

Bioadhesives are natural polymeric materials that act as adhesives. The term is sometimes used more loosely to describe a glue formed synthetically from biological monomers such as sugars, or to mean a synthetic material designed to adhere to biological tissue.

<span class="mw-page-title-main">Epibiont</span> Organism that lives on surface of another living organism

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The white suckerfish or mantasucker is a species of remora in the family Echeneidae, a group of elongated marine fish with adhesive discs for attaching to larger organisms. They are known for their large lips and white color. The distribution of this species is worldwide in warm open seas: it is found in the western Indian Ocean including Réunion and Mauritius, in the eastern Pacific Ocean from San Francisco to Chile, and in the western and eastern central Atlantic Ocean from Florida and the Gulf of Mexico to Brazil and St. Paul's Rocks.

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The common remora is a pelagic marine fish belonging to the family Echeneidae. The dorsal fin, which has 22 to 26 soft rays, acts as a suction cup, creating a vacuum to allow the fish to attach to larger marine animals, such as whales, dolphins, sharks, and sea turtles.

<span class="mw-page-title-main">Marlin sucker</span> Species of fish

The marlin sucker or spear-fish remora is a species of remora found all over the world in tropical and temperate seas. It can reach up to 40 cm (16 in) in standard length. It normally lives attached to a larger fish; its host preference is for marlins and sailfishes, but it will attach to other large fish.

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<span class="mw-page-title-main">Sucker (zoology)</span> Specialised attachment organ of an animal

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Brooke E. Flammang is an American biologist at the New Jersey Institute of Technology. She specializes in functional morphology, biomechanics, and bioinspired technology of fishes. Flammang is a discoverer of the radialis muscle in shark tails. She also studies the adhesive disc of the remora, and the walking cavefish, Cryptotora thamicola. Her work has been profiled by major news outlets including The New York Times, The Washington Post, Wired, BBC Radio 5, Discovery Channel, and National Geographic Wild. She was named one of the "best shark scientists to follow" by Scientific American in 2014.

References

  1. ↑ Collette, B.; Smith-Vaniz, W.F.; Williams, J.T.; Pina Amargos, F. & Curtis, M. (2017) [errata version of 2015 assessment]. "Remora australis". IUCN Red List of Threatened Species . 2015: e.T198650A115342516. doi: 10.2305/IUCN.UK.2015-4.RLTS.T198650A16644012.en .
  2. 1 2 Froese, Rainer; Pauly, Daniel (eds.). "Remora australis". FishBase . April 2013 version.
  3. 1 2 O'Toole, B (Apr 2002). "Phylogeny of the species of the superfamily Echeneoidea (Perciformes: Carangoidei: Echeneidae, Rachycentridae, and Coryphaenidae), with an interpretation of echeneid hitchhiking behaviour". Canadian Journal of Zoology. 80 (4): 596–823. doi:10.1139/z02-031.
  4. ↑ Lachner, E.A. (1986). "Echeneididae". In Whitehead, P.J.P; et al. (eds.). Fishes of the North-eastern Atlantic and the Mediterranean. Paris: United Nations Educational, Scientific and Cultural Organization. ISBN   92-3-002309-4.
  5. 1 2 Silva-Jr., J. M. and Sazima, I. (2006). Whalesuckers on spinner dolphins: an underwater view. JMBA2-Biodiversity Records: 1-6.
  6. ↑ Wingert, Natália; Milmann, Lucas; Baumgarten, Melina; Danilewicz, Daniel; Sazima, Ivan; Ott, Paulo H. (15 November 2021). "Relationships Between Common Bottlenose Dolphins (Tursiops truncatus) and Whalesuckers (Remora australis) at a Remote Archipelago in the Equatorial Atlantic Ocean". Aquatic Mammals: 585–598. doi:10.1578/AM.47.6.2021.585.
  7. ↑ Flammang, Brooke E.; Marras, Simone; Anderson, Erik J.; Lehmkuhl, Oriol; Mukherjee, Abhishek; Cade, David E.; Beckert, Michael; Nadler, Jason H.; Houzeaux, Guillaume; Vázquez, Mariano; Amplo, Haley E.; Calambokidis, John; Friedlaender, Ari S.; Goldbogen, Jeremy A. (15 October 2020). "Remoras pick where they stick on blue whales". Journal of Experimental Biology. 223 (20). doi:10.1242/jeb.226654. PMID   33115921.
  8. ↑ Flammang, Brooke E.; Marras, Simone; Anderson, Erik J.; Lehmkuhl, Oriol; Mukherjee, Abhishek; Cade, David E.; Beckert, Michael; Nadler, Jason H.; Houzeaux, Guillaume; Vázquez, Mariano; Amplo, Haley E.; Calambokidis, John; Friedlaender, Ari S.; Goldbogen, Jeremy A. (15 October 2020). "Remoras pick where they stick on blue whales". Journal of Experimental Biology. 223 (20). doi:10.1242/jeb.226654. PMID   33115921.
  9. ↑ Flammang, Brooke E.; Marras, Simone; Anderson, Erik J.; Lehmkuhl, Oriol; Mukherjee, Abhishek; Cade, David E.; Beckert, Michael; Nadler, Jason H.; Houzeaux, Guillaume; Vázquez, Mariano; Amplo, Haley E.; Calambokidis, John; Friedlaender, Ari S.; Goldbogen, Jeremy A. (15 October 2020). "Remoras pick where they stick on blue whales". Journal of Experimental Biology. 223 (20). doi:10.1242/jeb.226654. PMID   33115921.
  10. ↑ Wang, Yueping; Yang, Xingbang; Chen, Yufeng; Wainwright, Dylan K.; Kenaley, Christopher P.; Gong, Zheyuan; Liu, Zemin; Liu, Huan; Guan, Juan; Wang, Tianmiao; Weaver, James C.; Wood, Robert J.; Wen, Li (27 September 2017). "A biorobotic adhesive disc for underwater hitchhiking inspired by the remora suckerfish". Science Robotics. 2 (10). doi:10.1126/scirobotics.aan8072. PMID   33157888.
  11. ↑ Friedman, Matt; Johanson, Zerina; Harrington, Richard C.; Near, Thomas J.; Graham, Mark R. (7 September 2013). "An early fossil remora (Echeneoidea) reveals the evolutionary assembly of the adhesion disc". Proceedings of the Royal Society B: Biological Sciences. 280 (1766): 20131200. doi:10.1098/rspb.2013.1200. PMC   3730593 . PMID   23864599.
  12. ↑ Gamel, Kaelyn M; Garner, Austin M; Flammang, Brooke E (29 August 2019). "Bioinspired remora adhesive disc offers insight into evolution". Bioinspiration & Biomimetics. 14 (5): 056014. Bibcode:2019BiBi...14e6014G. doi:10.1088/1748-3190/ab3895. PMID   31382254.
  13. ↑ Gamel, Kaelyn M; Garner, Austin M; Flammang, Brooke E (29 August 2019). "Bioinspired remora adhesive disc offers insight into evolution". Bioinspiration & Biomimetics. 14 (5): 056014. Bibcode:2019BiBi...14e6014G. doi:10.1088/1748-3190/ab3895. PMID   31382254.
  14. ↑ Flammang, Brooke E.; Marras, Simone; Anderson, Erik J.; Lehmkuhl, Oriol; Mukherjee, Abhishek; Cade, David E.; Beckert, Michael; Nadler, Jason H.; Houzeaux, Guillaume; Vázquez, Mariano; Amplo, Haley E.; Calambokidis, John; Friedlaender, Ari S.; Goldbogen, Jeremy A. (15 October 2020). "Remoras pick where they stick on blue whales". Journal of Experimental Biology. 223 (20). doi:10.1242/jeb.226654. PMID   33115921.
  15. ↑ Flammang, Brooke E.; Kenaley, Christopher P. (19 July 2017). "Remora cranial vein morphology and its functional implications for attachment". Scientific Reports. 7 (1): 5914. Bibcode:2017NatSR...7.5914F. doi:10.1038/s41598-017-06429-z. PMC   5517627 . PMID   28725032.
  16. ↑ Flammang, Brooke E.; Kenaley, Christopher P. (19 July 2017). "Remora cranial vein morphology and its functional implications for attachment". Scientific Reports. 7 (1): 5914. Bibcode:2017NatSR...7.5914F. doi:10.1038/s41598-017-06429-z. PMC   5517627 . PMID   28725032.
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