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Encyclopedia > Otolith
Otolith
illustration of otolith organs showing detail of utricle, ococonia, endolymph, cupula, macula, hair cell filaments, and saccular nerve
Juvenile Herring. Length ca 30 mm, ca. 3 months old - still transparent, visible are the otoliths left of the eyes.
Gray's subject #232 1054
MeSH Otolithic+Membrane

An otolith, (oto-, ear + lithos, a stone), also called statoconium[1] or otoconium is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth. The saccule and utricle, in turn, together make the otolith organs. They are sensitive to gravity and linear acceleration. Because of their orientation in the head, the utricle is sensitive to a change in horizontal movement, and the saccule gives information about vertical acceleration (such as when in an elevator). http://www. ... Image File history File links Download high resolution version (2339x1453, 405 KB)herring juvenile image uwe kils gfdl self File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Species Clupea alba Clupea bentincki Clupea caspiopontica Clupea chrysotaenia Clupea elongata Clupea halec Clupea harengus Clupea inermis Clupea leachii Clupea lineolata Clupea minima Clupea mirabilis Clupea pallasii Clupea sardinacaroli Clupea sulcata Herrings are small oily fish of the genus Clupea found in the shallow, temperate waters of the North Atlantic... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Categories: Stub ... The utricle, larger than the saccule, is of an oblong form, compressed transversely, and occupies the upper and back part of the vestibule, lying in contact with the recessus ellipticus and the part below it. ... Inner ear The inner ear is the bony labyrinth, a system of passages comprising two main functional parts: the organ of hearing, or cochlea and the vestibular apparatus, the organ of balance that consists of three semicircular canals and the vestibule. ... For more uses of the word labyrinth, see Labyrinth (disambiguation) The labyrinth is a system of fluid passages in the inner ear, including both the cochlea which is part of the auditory system, and the vestibular system which provides the sense of balance. ... Gravity is a force of attraction that acts between bodies that have mass. ... Acceleration is the time rate of change of velocity and/or direction, and at any point on a velocity-time graph, it is given by the slope of the tangent to the curve at that point. ... The utricle, larger than the saccule, is of an oblong form, compressed transversely, and occupies the upper and back part of the vestibule, lying in contact with the recessus ellipticus and the part below it. ... Categories: Stub ... For other uses, see Elevator (disambiguation). ...

Contents

Mechanism

Otoliths are small particles, composed of a combination of a gelatinous matrix and calcium carbonate in the viscous fluid of the saccule and utricle. The inertia of these small particles causes them to stimulate hair cells when the head moves. The hair cells send signals down sensory nerve fibres, which are interpreted by the brain as motion. Calcium carbonate is a chemical compound, with the chemical formula CaCO3. ... This article is about inertia as it applies to local motion. ...


When the head is in a normal upright position, the otolith presses on the sensory hair cell receptors. This pushes the hair cell processes down and prevents them from moving side to side. However, when the head is tilted, the pull of gravity on statoconia shift the hair cell processes to the side, distorting them and sending a message to the central nervous system that the head is no longer level but now tilted. A diagram showing the CNS: 1. ...


In 1991, Martin Lenhardt of the University of Virginia discovered that people can hear ultrasonic speech, perhaps using the saccule as a hearing organ.[2] The University of Virginia (also called U.Va. ... Ultrasound is sound with a frequency greater than the upper limit of human hearing, approximately 20 kilohertz. ...


Significance in Ichthyology

Finfish (class Osteichthyes) have three pairs of otoliths - the sagittae (singular sagitta), lapilli (singular lapillus), and asterisci (singular asteriscus). The sagittae are largest, found just behind the eyes and approximately level with them vertically. The lapilli and asterisci (smallest of the three) are located within the semicircular canals. Orders See text The Actinopterygii are the ray-finned fish. ... Classes Actinopterygii Sarcopterygii Osteichthyes are a taxonomic superclass of fish, also called bony fish that includes the ray-finned fish (Actinopterygii) and lobe finned fish (Sarcopterygii). ...


The shapes and proportional sizes of the otoliths vary with fish species. In general, fish from highly structured habitats such as reefs or rocky bottoms (e.g. snappers, groupers, many drums and croakers) will have larger otoliths than fish that spend most of their time swimming at high speed in straight lines in the open ocean (e.g. tuna, mackerel, dolphinfish). Flying fish have unusually large otoliths, possibly due to their need for balance when launching themselves out of the water to "fly" in the air. Often, the fish species can be identified from distinct morphological characteristics of an isolated otolith. Genera Aphareus Aprion Apsilus Etelis Hemilutjanus Hoplopagrus Lipocheilus Lutjanus Macolor Ocyurus Paracaesio Pinjalo Pristipomoides Randallichthys Rhomboplites Symphorus Snapper can also refer to the Snapping turtle. ... Genera Acanthistius Alphestes Anyperidon Caprodon Cephalopholis Cromileptes Dermatolepis Epinephelus Gonioplectrus Gracila HypoplectrodesLiopropoma Mycteroperca Niphon Paranthias Plectropomus Saloptia Triso Variola For the computer program, see Grouper (Windows application). ... Genera See text. ... For other uses, see Tuna (disambiguation). ... Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. ... Binomial name Coryphaena hippurus Linnaeus, 1758 The Mahi-mahi (Coryphaena hippurus), also known as dolphin fish or dorado, are a species of surface-dwelling fish found in tropical and subtropical waters. ... Genera Cheilopogon Cypselurus Danichthys Exocoetus Fodiator Hirundichthys Oxyporhamphus Parexocoetus Prognichthys The Execoetidae or flyingfishes are a marine fish family comprising about 70 species grouped in 7 to 9 genera. ...


Fish otoliths accrete layers of calcium carbonate and gelatinous matrix throughout their lives. The accretion rate varies with growth of the fish - often less growth in winter and more in summer - which results in the appearance of rings that resemble tree rings. By counting the rings, it is possible to determine the age of the fish in years.[3] Typically the sagitta is used, as it is largest,[4] but sometimes lapilli are used if they have a more convenient shape. The asteriscus, which is smallest of the three, is rarely used in age and growth studies. Calcium carbonate is a chemical compound, with the chemical formula CaCO3. ... The growth rings of an unknown tree species, at Bristol Zoo, England Pinus taeda Cross section showing annual rings, Cheraw, South Carolina Pine stump showing growth rings Dendrochronology or tree-ring dating is the method of scientific dating based on the analysis of tree-ring growth patterns. ...


In addition, in most species the accretion of calcium carbonate and gelatinous matrix alternates on a daily cycle. It is therefore also possible to determine fish age in days. This latter information is often obtained under a microscope, and provides significant data to early life history studies.


By measuring the thickness of individual rings, it is possible (at least in some species) to estimate fish growth because fish growth is directly proportional to otolith growth. Otoliths, unlike scales, do not reabsorb during times of decreased energy making it even more useful tool to age a fish. Fish never stop growing entirely, though growth rate in mature fish is much reduced. Rings corresponding to later parts of the life cycle tend to be closer together as a result.


Age and growth studies of fish are important for understanding such things as timing and magnitude of spawning, recruitment and habitat use, larval and juvenile duration, and population age structure. Such knowledge is in turn important for designing appropriate fisheries management policies. It has been suggested that this article or section be merged into Population dynamics. ... A fishery (plural: fisheries) is an organized effort by humans to catch fish or other aquatic species, an activity known as fishing. ...


The composition of fish otoliths are proving useful to fisheries scientists. The calcium carbonate that composes the otolith is primarily derived from the water. As the otolith grows, new calcium carbonate, mainly aragonite, crystals form. As with any crystal structure, lattice vacancies will exist during crystal formation allowing trace elements from the water to bind with the otolith. Studying the trace elemental composition or isotopic signatures of trace elements within a fish otolith gives insight to the water bodies fish have previously occupied. The most studied trace and isotopic signatures are strontium due to the same charge and similar ionic radius to calcium; however, scientists can study multiple trace elements within an otolith to discriminate more specific signatures. A common tool used to measure trace elements in an otolith is a laser ablation inductively coupled plasma mass spectrometer. This tool can measure a variety of trace elements simultaneously. A secondary ion mass spectrometer can also be used. This instrument can allow for greater chemical resolution but can only measure one trace element at a time. Dr. Steven Campana is one of the leading researchers in the study of otolith trace elemental and isotopic composition. The hope of this research is to provide scientists with valuable information on where fish have traveled. Combined with otolith annuli, scientists can add how old fish were when they traveled through different water bodies. All this information can be used to determine fish life cycles so that fisheries scientists can make informed decisions about fish stocks.


Significance in Paleontology

After the death and decomposition of a fish, otoliths are dispersed, buried and eventually fossilized. They are one of the many microfossils which can be found though a micropalaeontological analysis of a fine sediment. Their stratigraphic significance is minimal, but can still be used to characterize a level or interval. For other uses, see Fossil (disambiguation). ... For other uses of the term, see Fossil (disambiguation) Fossils are the mineralized remains of animals or plants or other artifacts such as footprints. ...


The composition of fossilized otoliths can also yield information about the ancient environment. Most notably, stable oxygen isotopes can be used to calculate the water temperature. There are even efforts to study stable oxygen isotopes in modern fish to infer El Nino and La Nina effects.


References

  1. ^ Dorland's Illustrated Medical Dictionary
  2. ^ Lenhardt (1991-07-05). "Human ultrasonic speech perception". Science 253 (5015): 82-5. Retrieved on 2007-02-02. 
  3. ^ Quality control of age data at the Alaska Fisheries Science Center (PDF) Daniel K. Kimura, Delsa M. Anderl, Marine and Freshwater Research, 2005, 56, 783–789. Retrieved 2007-04-07.
  4. ^ Fish Age and Growth with Otoliths Tennessee Wildlife Resources Agency. Retrieved 2007-04-07.

  Results from FactBites:
 
Otolith - Wikipedia, the free encyclopedia (372 words)
An otolith, (oto-, ear + lithos, a stone) or otoconium is a structure in the saccule or utricle of the inner ear.
The otolith organs (the utricle and the saccule) are structures in the inner ear, specifically in the vestibular labyrinth, that are sensitive to gravity and linear acceleration.
Otoliths are small particles of calcium carbonate in the viscous fluid of the saccule and utricle.
Determination of growth in bony fishes from otolith microstructure. (2109 words)
Increments on the edge of the otolith, however, are often masked by the optical distortion produced by the angle of refraction between the edge and the medium, which makes it difficult to count marginal increments.
After determining the otolith growth rate, the age would be determined by dividing otolith size by the rate of growth.
Otolith rings in tropical species are rather less clearly defined than in cold-water fish: the predominance of transparent zones requires methods which can bring out the contrast between the opaque and the hyaline rings.
  More results at FactBites »

 
 

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