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Natural history: An Odd Place of Refuge

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The habit of the Shark Sucker, Echeneis or Remora, of taking shelter in the gill chamber or mouth cavity of its host. By E. W. Gudger Natural History 22 (1922):243-249.
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Study of remora fish could lead to new bio-adhesive

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When a shark is spotted in the ocean, humans and marine animals alike usually flee. But not the remora...

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Brief Summary

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Remoras, also called shark suckers, are a group of eight species in the mostly tropical and sub-tropical fish family Echeneidae. Remoras live primarily in the open ocean, and although they can swim on their own, they do not have a swim bladder so have trouble maneuvering long distances. Remoras can attach themselves to larger fish and marine animals and even boats using their first dorsal fin, which is modified into a characteristic flat sucking disk. Remoras are dependant on attaching to hosts in order keep water flowing across their gills, so that they get enough oxygen. Some remoras have a purely phoretic relationship with their hosts, that is, they interact with their host for the purpose of transport only, while other species will eat parasites from their host, thus providing a more mutually beneficial interaction. Most attach close to their hosts mouths and gill areas and eat the remains from their host’s meals. Some remoras will attach to many different species of fish, whales, sea turtles, rays, sharks, dugongs, and even boats. Others have much more specific host interactions, (for example the whalesucker, Remora australis, only attaches to cetaceans; the white suckerfish, Remorina albescens, rides in the mouth and gill chamber of manta rays.) Humans have used remoras for fishing by attaching them to a line and throwing them into the sea, then pulling in the line and harvesting the fish to which the remora has attached. Extensive information and nice pictures for the most common of the remoras, Echeneis naucrates, can be found at the Ichthyology at Florida Museum of Natural History web collections. (Froese and Pauly 2010; Wikipedia 2012)
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Remora

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This article is about the remora family. For the genus, see Remora (genus). For the rescue vehicle, see Australian Submarine Rescue Vehicle Remora.

The remoras /ˈrɛmərəz/, sometimes called suckerfish, are a family (Echeneidae) of ray-finned fish in the order Perciformes.[2][3] They grow to 7–75 cm (2.8 in–2 ft 5.5 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.[4] The disk is made up of stout, flexible membranes that can be raised and lowered to generate suction.[5] 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.

Characteristics

Remora front dorsal fins have evolved to enable them to adhere by suction to smooth surfaces and they spend their lives clinging to a host animal such as a whale, turtle, shark or ray. It is probably a mutualistic arrangement as the remora can move around on the host, removing ectoparasites and loose flakes of skin, while benefiting from the protection provided by the host, and the constant flow of water across its gills.[6] Although it was initially believed that remoras fed off particulate matter from the host's meals, this has been shown a falsehood; in reality their diets are composed primarily of host feces instead.[7]

Habitat

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Some remoras, such as this Echeneis naucrates, may attach themselves to scuba divers.

Remoras are tropical open-ocean dwellers, but are occasionally found in temperate or coastal waters if they have attached to large fish that have wandered into these areas. In the mid-Atlantic, spawning usually takes place in June and July; in the Mediterranean, it occurs in August and September. The sucking disc begins to show when the young fish are about 1 cm (0.4 in) long. When the remora reaches about 3 cm (1.2 in), the disc is fully formed and the remora can then attach to other animals. The remora's lower jaw projects beyond the upper, and the animal lacks a swim bladder.[2]

Some remoras associate with specific host species. They are commonly found attached to sharks, manta rays, whales, turtles, and dugongs (hence the common names "sharksucker" and "whalesucker"). Smaller remoras also fasten onto fish such as tuna and swordfish, and some small remoras travel in the mouths or gills of large manta rays, ocean sunfish, swordfish and sailfish.

The relationship between a remora and its host is most often taken to be one of commensalism, specifically phoresy.

Physiology

Research into the physiology of the remora has been of significant benefit to the understanding of ventilation costs in fish.

Remoras, like many other fishes, have two different modes of ventilation. Ram ventilation[8] is the process in which at higher speeds, the remora uses the force of the water moving past it to create movement of fluid in the gills. Alternatively, at lower speeds the remora will use a form of active ventilation,[8] in which the fish actively moves fluid through its gills. In order to use active ventilation, a fish must actively use energy to move the fluid; however, determining this energy cost is normally complicated due to the movement of the fish when using either method. As a result, the remora has proved invaluable in finding this cost difference (since they will stick to a shark or tube, and hence remain stationary despite the movement or lack thereof of water). Experimental data from studies on remora found that the associated cost for active ventilation created a 3.7–5.1% increased energy consumption in order to maintain the same quantity of fluid flow the fish obtained by using ram ventilation.[9]

Other research into the remora's physiology came about as a result of studies across multiple taxa, or using the remora as an out-group for certain evolutionary studies. Concerning the latter case, remoras were used as an outgroup when investigating tetrodotoxin resistance in remoras, pufferfish, and related species, finding remoras (specifically Echeneis naucrates) had a resistance of 6.1–5.5×108 M.[10]

Use for fishing

Some cultures use remoras to catch turtles. A cord or rope is fastened to the remora's tail, and when a turtle is sighted, the fish is released from the boat; it usually heads directly for the turtle and fastens itself to the turtle's shell, and then both remora and turtle are hauled in. Smaller turtles can be pulled completely into the boat by this method, while larger ones are hauled within harpooning range. This practice has been reported throughout the Indian Ocean, especially from eastern Africa near Zanzibar and Mozambique,[11] and from northern Australia near Cape York and Torres Strait.[12][13]

Similar reports come from Japan and from the Americas. Some of the first records of the "fishing fish" in the Western literature come from the accounts of the second voyage of Christopher Columbus. However, Leo Wiener considers the Columbus accounts to be apocryphal: what was taken for accounts of the Americas may have been, in fact, notes Columbus derived from accounts of the East Indies, his desired destination.[14]

Mythology

See also: Echeneis

In ancient times, the remora was believed to stop a ship from sailing. In Latin, remora means "delay", while the genus name Echeneis comes from Greek εχειν, echein ("to hold") and ναυς, naus ("a ship"). In a notable account by Pliny the Elder, the remora is blamed for the defeat of Mark Antony at the Battle of Actium and, indirectly, for the death of Caligula.[15] A modern version of the story is given by Jorge Luis Borges in Book of Imaginary Beings (1957).

Gallery

Timeline

See also

References

  1. ^ Friedman, Matt, et al. "An early fossil remora (Echeneoidea) reveals the evolutionary assembly of the adhesion disc." Proc. R. Soc. B 280.1766 (2013): 20131200.
  2. ^ a b Froese, Rainer, and Daniel Pauly, eds. (2013). "Echeneidae" in FishBase. April 2013 version.
  3. ^ "Echeneidae". Integrated Taxonomic Information System. Retrieved 20 March 2006..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
  4. ^ "Sharksucker fish's strange disc explained". Natural History Museum. 28 January 2013. Archived from the original on 1 February 2013. Retrieved 5 February 2013.
  5. ^ Beer, Amy-Jane. Derek Hall. (2012). The Illustrated World Encyclopedia of Marine Fish & Sea Creatures. Leicestershire: Lorenz Books. p. 235. ISBN 978-0-7548-2290-5.
  6. ^ Jackson, John (30 November 2012). "How does the Remora develop its sucker?". National History Museum. Retrieved 2 January 2016.
  7. ^ Williams, E. H.; Mignucci-Giannoni, A. A.; Bunkley-Williams, L.; Bonde, R. K.; Self-Sullivan, C.; Preen, A.; Cockcroft, V. G. (2003). "Echeneid-sirenian associations, with information on sharksucker diet". Journal of Fish Biology. 63 (5): 1176. CiteSeerX 10.1.1.619.4020. doi:10.1046/j.1095-8649.2003.00236.x.
  8. ^ a b Willmer, Pat; Stone, Graham; Johnston, Ian (2009-03-12). Environmental Physiology of Animals. John Wiley & Sons. ISBN 9781444309225.
  9. ^ Steffensen, J. F.; Lomholt, J. P. (1983-03-01). "Energetic cost of active branchial ventilation in the sharksucker, Echeneis naucrates". Journal of Experimental Biology. 103 (1): 185–192. ISSN 0022-0949. PMID 6854201.
  10. ^ Kidokoro, Yoshiaki; Grinnell, Alan D.; Eaton, Douglas C. (1974). "Tetrodotoxin sensitivity of muscle action potentials in pufferfishes and related fishes". Journal of Comparative Physiology. 89: 59. doi:10.1007/BF00696163.
  11. ^ Gudger, E. W. (1919). "On the Use of the Sucking-Fish for Catching Fish and Turtles: Studies in Echeneis or Remora, II., Part 1". The American Naturalist. 53 (627): 289–311. doi:10.1086/279716. JSTOR 2455925.
  12. ^ Gudger, E. W. (1919). "On the Use of the Sucking-Fish for Catching Fish and Turtles: Studies in Echeneis or Remora, II., Part 2". The American Naturalist. 53 (628): 446–467. doi:10.1086/279724. JSTOR 2456185.
  13. ^ MacGillivray, John (1852). Narrative of the Voyage of H.M.S. Rattlesnake, Commanded By the Late Captain Owen Stanley, R.N., F.R.S. Etc. During the Years 1846–1850. 2. London: Lords Commissioners of the Admiralty. (Dr. Gudger's accounts are more authoritative, but this source is noted as an early account that Gudger appears to have missed.)
  14. ^ Wiener, Leo (1921). "Once more the sucking-fish". The American Naturalist. 55 (637): 165–174. doi:10.1086/279802. JSTOR 2456418.
  15. ^ Pliny the Elder. "Book 32, Chapter 1". Natural History. (cited in Gudger, E. W. (1930). "Some old time figures of the shipholder, Echeneis or Remora, holding the ship". Isis. 13 (2): 340–352. doi:10.1086/346461. JSTOR 224651.)

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Remora: Brief Summary

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This article is about the remora family. For the genus, see Remora (genus). For the rescue vehicle, see Australian Submarine Rescue Vehicle Remora.

The remoras /ˈrɛmərəz/, sometimes called suckerfish, are a family (Echeneidae) of ray-finned fish in the order Perciformes. They grow to 7–75 cm (2.8 in–2 ft 5.5 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.

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Description

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Distribution: Atlantic, Indian and Pacific. Elongate body, with the head flattened and bearing a sucking disc having 10-28 transverse movable lamina (disc said to have evolved from a spinous dorsal fin). Mandible jutted. Scales small and cycloid. Spines absent in dorsal and anal fins. About 18-40 soft rays each in dorsal and anal fins. No swim bladder. Branchiostegal rays 8-11. With the sucking disc, the remora hitches to larger animals such as sharks, bony fishes, turtles or mammals. Some species reportedly show considerable host specificity. About 1 m maximum length (reported for Echeines naucrates); the smallest species measuring 17 cm.
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MASDEA (1997).
i18n: Contributor
Edward Vanden Berghe [email]