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Shovelnose sturgeons are a freshwater species historically found in most portions of the Mississippi and Missouri river basins. This area ranges from Montana south to Louisiana, and from Pennsylvania west to New Mexico. However, shovelnose sturgeons are no longer found in Pennsylvania, New Mexico, and large parts of Kansas, Kentucky, and Tennessee where they were once abundant. The main cause for the restriction of range is the construction of dams on many of their native waterways.
Biogeographic Regions: nearctic (Native )
Eggs are deposited over cobble, gravel, or rock, becoming adhesive and attaching to the bottom substrates. After five to eight days, the eggs hatch and the young begin to search for food on the river bottom. Females grow significantly faster than males.
Development - Life Cycle: indeterminate growth
Shovelnose sturgeons are considered extirpated in three states, fully protected in four, and rare, or of special concern in eight states as of 1996. However, they are not currently listed as federally threatened or endangered.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: vulnerable
Shovelnose sturgeons search for food by manipulating their large barbels which have taste buds and electrorecptors. These barbels hang below the mouth and feel the bottom as the sturgeon swims. This allows them to sense when food or other obstacles are below.
Communication Channels: tactile
Perception Channels: tactile ; chemical
Rafinesque described this species as the 97th species described in his book, "Ichthyologia Ohiensis: Natural History of the Fishes Inhabiting the River Ohio and Its Tributary Streams," published in 1820.
There are no known adverse affects of shovelnose sturgeons on humans.
Shovelnose sturgeons have many benefits to humans. They have been commercially harvested since 1987, and the meat is considered a delicacy, especially when smoked. They are also considered a sport fish in 12 of the 24 states in which they occur. The roe is used as an acceptable caviar and it has also been introduced as a potential aquarium fish.
Positive Impacts: pet trade ; food
Scaphirhynchus platorynchus feed on invertebrates, stirring up and loosening bottom substrates. The shovelnose sturgeon harbors a newly discovered virus called the Missouri River Sturgeon Iridovirus or MRSIV. The shovelnose sturgeon is host to the hickory-nut Obovaria olivaria, and may possibly be hosts for other pearly mussels including commercial species. Lamprey also parasitize the fish.
Scaphirhynchus platorynchus are opportunistic feeders, eating mostly aquatic insects, mussels, worms and crustaceans. Altered stream flow can affect the sturgeon’s ability to find food and also influences the abundance of prey organisms. The barbels detect prey, and then the sucker type mouth easily picks up the food organisms. Most food is found over sand and gravel substrates.
Animal Foods: insects; mollusks; terrestrial worms; aquatic or marine worms
Foraging Behavior: filter-feeding
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods, Molluscivore , Vermivore)
Shovelnose sturgeons are primarily bottom dwellers, preferring high turbidity in large waters, and are usually found in pools downstream of sandbars or along the main channel border. The flowing freshwater is between 18-20 deg C. During low water or in the warm summer months, these sturgeons seek cooler, deep channel areas.
Average elevation: known to inhabit low elevations m.
Range depth: 2 to 7 m.
Average depth: 4 m.
Habitat Regions: temperate ; freshwater
Aquatic Biomes: benthic ; rivers and streams
The largest shovelnose sturgeon recorded weighed 13.72 lbs (6.2 kg). Most are not expected to live over 30 years of age.
Range lifespan
Status: wild: 61 (high) years.
Average lifespan
Status: captivity: 70 years.
Average lifespan
Status: wild: 30 years.
Shovelnose sturgeons have an elongated body with five rows of sharply keeled body plates: 14-19 dorsal plates, 38-47 lateral, 10-14 ventrolateral. They are olive to yellowish-brown in color on the top with lighter sides, and white on the bottom. The head contains bony plates with short spines at the tip of the snout and anterior to the eye. The snout is rounded and pointed up. The caudal peduncle is long, depressed, and fully armored. The tail is heterocercal, with the upper lobe containing long, thread-like filaments. All four barbels are evenly spaced under the jaw, unlike the related pallid sturgeon, which has barbels unevenly spaced under the jaw. The most readily distinguishing characteristic of the shovelnose is its small size and dark color. They rarely exceed 5 lbs (2.3 kg) or over 28 inches (70 cm)in length.
Range mass: .050 to 8.170 kg.
Average mass: 2.500 kg.
Range length: 6.0 to 106.2 cm.
Average length: 91.0 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: female larger
Other fishes, such as catfishes and burbots, probably eat the young shovelnose sturgeons. The main predator of adult shovelnose sturgeons is man. Presently, about 25 tons of shovelnose sturgeon are harvested annually. Sixty percent come from the Mississippi River upstream of St. Louis, Missouri. They are harvested in late fall and early winter for both meat and highly valued roe. The alteration of large rivers, and construction of locks and dams for navigational purposes has contributed significantly to the decline of the species by blocking access to ancestral spawning grounds, and by eliminating its required habitat.
Known Predators:
Shovelnose sturgeons migrate upstream, sometimes as far as 540 km if unimpeded, in a search for acceptable reproduction habitat and mates. Due to proximate cues, such as day length, water flow, and water temperature, all adults of reproducing age gather at spawning sites in large numbers. Although these fish are usually bottom dwellers, they rise to the surface during this time. Commonly, the same sites are used for spawning over the years. Once at the spawning area, mating begins, and fertilization of eggs occurs.
Not all females spawn every year. The frequency is determined by food supply and ability to store adequate fat to produce mature gametes. Males however, always spawn if physically possible.
Mating System: polygynandrous (promiscuous)
Breeding begins when females are around seven years of age and the males are approximately five. Mature shovelnose sturgeons travel upstream to spawn over rocky substrates in flowing water between 17-21 deg C, usually downstream from a dam in April to early July. The male and female swim side by side while they release eggs and sperm. Once the eggs are fertilized, they adhere to the rocky substrates. It is very important that there is a continuous stream of water flowing over them, and that the substrate is not too fine, so that it does not settle over the eggs and suffocate them. After 5 to 8 days the dark gray eggs, measuring 2 to 3 mm in diameter, hatch. Within approximately three months, when the young are 15 to 20 cm, they are independent, and leave their natal habitat.
Breeding interval: Females do not spawn every year, and frequency is influenced by food supply and fat storage. If spawning does occur, once at the breeding location, breeding lasts for a few days, and then eggs are deposited.
Breeding season: April to early July
Average number of offspring: 50,000 eggs at one time for each female.
Range gestation period: 5 to 8 days.
Average gestation period: 7 days.
Average time to independence: 3 months.
Average age at sexual or reproductive maturity (female): 7 years.
Average age at sexual or reproductive maturity (male): 5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (External ); broadcast (group) spawning; oviparous
These sturgeons have to use a great deal of energy to swim upstream for long distances to spawning areas. Once at the spawning areas, and fertilization of eggs has occurred the female deposits approximately 50,000 eggs per spawning season. The parental involvement is very limited after eggs have been deposited. Both male and female return downstream to their original home range, leaving un-hatched eggs attached to bottom substrates at spawning areas to develop independently.
Parental Investment: pre-fertilization (Provisioning); pre-hatching/birth (Provisioning: Female)
Adi kürəkburun (lat. Scaphirhynchus platorynchus) — Nərəkimilər fəsiləsindən çay balığı növü. Kütləsi 2-3, bəzən isə 4,4 kq-a, uzunluğu isə 60-90 sm, bəzən 130 sm-ə çatır.
Der Schaufelstör (Scaphirhynchus platorynchus; engl.: shovelnose sturgeon, auch: hackleback, sand sturgeon, switchtail) ist eine stark gefährdete Fischart aus der Familie der Störe (Acipenseridae) in den Vereinigten Staaten. Sie ist die kleinste Art der Süßwasser-Störe und endemisch in Missouri und Mississippi River. Sie wird kommerziell befischt.[1]
Der deutsche und englische, sowie der wissenschaftliche Name beziehen sich auf das schaufelförmige Rostrum. Scaphirhynchus bedeutet übersetzt "Spatenschnautze" und platorynchus zusätzlich "breitschnauzig". Das Englische "Switchtail" bezieht sich auf einen langen Strahl der Schwanzflosse, der bei älteren Exemplaren allerdings oft verloren ist.
Die Störe zeichnen sich aus durch reihig angeordnete Knochenplatten entlang der Seiten und vier Barteln auf der Unterseite des Rostrums. Diese Barteln stehen im selben Abstand zu Schnauzenspitze und zum Mund. Im Unterschied zum Weißen Schaufelstör (S. albus) hat der Schaufelstör keine Schuppen auf der Bauchseite. Schaufelstöre können 1 m Länge und 4,8 kg Gewicht erreichen. Die meisten Exemplare werden jedoch nur 50–85 cm lang und 2,5 kg schwer. Eine Besonderheit des Schaufelstörs ist ein langer dünner Flossenstrahl an der oberen Schwanzflossenlobus, der bei älteren Exemplaren jedoch häufig verloren geht. Die Farbe schwankt zwischen Hellbraun und Lederfarben mit einem weißen Bauch.[2] Die Störe werden wegen ihres wohlschmeckenden Fleisches und ihres Rogens, der zu erstklassigem Kaviar verarbeitet wird[3], kommerziell befischt.
Der Schaufelstör lässt sich von Wassertrübungen nur wenig beeinflussen. Der Missouri River und der Mississippi River transportieren andauernd große Anteile von Sedimenten. In diesen trüben Gewässern leben die Tiere vor allem in den Hauptarmen in Bodennähe und halten sich gerne in Gebieten mit schneller Strömung und Sand- oder Kiesgrund auf. Oft wandern die Fische über weite Entfernungen[4].
Die Störe ernähren sich von Insektenlarven (Köcherfliegen, Eintagsfliegen u. a.), sowie Krebstieren, Würmern und kleinen Fischen.[5] Sie sind auch Wirte von Glochidien (Larven) mehrerer Süßwasser-Mollusken, unter anderen Quadrula pustulosa (Pimpleback), Obovaria olivaria (Hickorynut) und Lampsilis teres (Yellow sandshell). Der Schaufelstör ist der einzige bekannte Wirt der Hickorynut-Muschel.[6]
Normalerweise wandern die Fische zwischen den Nahrungsgründen und den Brutplätzen in den großen Flüssen hin und her. Während sie sich das Jahr über eher am Grund der Gewässer aufhalten, kommen die Tiere zur Laichzeit näher an die Wasseroberfläche. Die Weibchen laichen nicht jedes Jahr, aber es gibt auch keine Aufzeichnungen über das Laichverhalten. Der Laich wird über kiesigem Grund in relativ schnell fließenden Gewässern abgesetzt. Die Jungtiere schlüpfen nach 3–5 Tagen mit ca. 1 cm Länge und die Larven treiben den Fluss hinunter, wo sie geeignete Lebensräume zum aufwachsen finden.[7] Carlson schreibt, dass das Wachstum relativ langsam ist. Die Tiere wachsen ca. 21,3 inch (54,1 cm) in fünf Jahren.
Der Rogen des Schaufelstörs wird als hackleback caviar verkauft. Da die Kaviarproduktion in Kaspischem Meer und Schwarzem Meer nachlässt, wird die Kaviarproduktion von Schaufelstör und Löffelstör kommerziell interessant.[8] Das Störfleisch wird weithin als Delikatesse angesehen und auch gerne geräuchert. Wilderei wird immer mehr zum Problem, zumal die Tiere 8–10 Jahre alt werden müssen um das erste Mal zu laichen. Teilweise werden Schaufelstöre auch als Aquarienfische gehalten.[6]
Der Schaufelstör wird wie der Weiße Schaufelstör vom Missouri River sturgeon iridovirus (MRSIV) parasitiert.
Der Schaufelstör (Scaphirhynchus platorynchus; engl.: shovelnose sturgeon, auch: hackleback, sand sturgeon, switchtail) ist eine stark gefährdete Fischart aus der Familie der Störe (Acipenseridae) in den Vereinigten Staaten. Sie ist die kleinste Art der Süßwasser-Störe und endemisch in Missouri und Mississippi River. Sie wird kommerziell befischt.
The shovelnose sturgeon (Scaphirhynchus platorynchus)[5] is the smallest species of freshwater sturgeon native to North America. It is often called hackleback, sand sturgeon, or switchtail. Switchtail refers to the long filament found on the upper lobe of the caudal fin (often broken off as adults). Shovelnose sturgeon are the most abundant sturgeon found in the Missouri River and Mississippi River systems, and were formerly a commercially fished sturgeon in the United States of America (Pflieger 1997). In 2010, they were listed as threatened under the U.S. Endangered Species Act due to their resemblance to the endangered pallid sturgeon (S. albus),[6] with which shovelnose sturgeon are sympatric.[6][7]
The sturgeons of the family Acipenseridae have bony scutes along the sides and back and four barbels on the underside of the rostrum. A total of 25 extant species of sturgeon are recognized, including 17 within the genus Acipenser. Sturgeon are distributed around the northern part of the Northern Hemisphere (holarctic distribution) and have marine, freshwater, and anadromous members. Sturgeons, including the shovelnose, are highly regarded for their flesh and their roe, from which premium grades of caviar are made (Barton 2007).
They can reach 1 metre (39 in) in length and up to 4.8 kilograms (11 lb) in weight but 50–85 centimetres (20–33 in) and 2.5 kilograms (5.5 lb) is more common.
The scientific name Scaphirhynchus, Greek, means "spade snout", and platorynchus, Greek, means "broad snout". The shovelnose sturgeon is characterized by a long slender filament on the upper lobe of the caudal fin. They have a flattened rostrum (modified snout) that is also shovel-shaped. There are four fringed barbels on the ventral side of the rostrum that can be found in a straight line, which is equidistant from the mouth opening to the tip of the snout, unlike pallid sturgeon. The belly of the shovelnose sturgeon is covered with scale-like plates, which is another distinguishing factor from pallid sturgeon who have primarily scaleless bellies. Coloration of the shovelnose sturgeon ranges from a light-brown to buff with a white belly (Pflieger 1997).
The shovelnose sturgeon, as its distribution represents, is impacted very little by turbidity. The Missouri River and the Mississippi River systems tend to carry high sediment loads. Here the sturgeon inhabits the open channel or main channel areas of the large rivers. It lives on the bottom, often in areas with swift current and sand or gravel bottom. As with many riverine fish species, the shovelnose sturgeon does not have a restricted home range and may travel long distances (Pflieger 1997).
The shovelnose sturgeon feeds on the bottom, using its highly protrusible mouth to suck up its food. The diet is mainly aquatic insect larvae, consisting principally of mayflies, true flies (Diptera), and caddisflies. The sturgeon also feed on crustaceans, worms, and small fish (Carlson et al. 1985;Held 1969). As a result, to bottom feeding it is a host to the glochidia (larvae) of several species of freshwater mollusc, including Quadrula pustulosa (pimpleback), Obovaria olivaria (hickorynut) and Lampsilis teres (yellow sandshell). It is the only known host of the hickorynut mussel.[7]
A typical sturgeon's life history includes a migration from feeding grounds to breeding grounds in large rivers. During spawning, behavior changes and swimming near the surface occurs. Females do not spawn every year and spawning chronology is not readily evident. Spawning takes place over gravel in fairly swift water. Eggs hatch after 3 to 5 days, and the larvae—about 1 cm long—drift downstream to suitable rearing areas in the river (Barton 2007). Carlson et al. (1985) found that the growth of the shovelnose sturgeon is relatively slow, reaching 21.3 inches (54 cm) in five years.
The roe of the shovelnose sturgeon was marketed as "hackleback" caviar. As old-world sources of Caspian and Black Sea sturgeon caviar became overfished, especially in the wake of the collapse of the Soviet Union, roe from shovelnose sturgeon became commercially important.[7] The flesh of the sturgeon is widely considered a delicacy, especially smoked sturgeon. Poaching of the shovelnose sturgeon is becoming a problem, as they must be 8–10 years old before spawning can occur, and females do not become gravid every year. There has some interest in marketing the shovelnose sturgeon as an aquarium species.[7] In 2010, the shovelnose sturgeon was listed as threatened under the U.S. Endangered Species Act due to its resemblance to the endangered pallid sturgeon (Scaphirhynchus albus),[6] with which shovelnose sturgeon are sympatric.[6][7]
The shovelnose sturgeon (Scaphirhynchus platorynchus) is the smallest species of freshwater sturgeon native to North America. It is often called hackleback, sand sturgeon, or switchtail. Switchtail refers to the long filament found on the upper lobe of the caudal fin (often broken off as adults). Shovelnose sturgeon are the most abundant sturgeon found in the Missouri River and Mississippi River systems, and were formerly a commercially fished sturgeon in the United States of America (Pflieger 1997). In 2010, they were listed as threatened under the U.S. Endangered Species Act due to their resemblance to the endangered pallid sturgeon (S. albus), with which shovelnose sturgeon are sympatric.
Scaphirhynchus platorynchus Scaphirhynchus generoko animalia da. Arrainen barruko Actinopterygii klasean sailkatzen da, Acipenseridae familian.
Scaphirhynchus platorynchus Scaphirhynchus generoko animalia da. Arrainen barruko Actinopterygii klasean sailkatzen da, Acipenseridae familian.
Esturgeon scaphirhynque
Scaphirhynchus platorynchus, communément appelé Esturgeon scaphirhynque, est une espèce de poissons appartenant à l'ordre des Acipenseriformes. C'est la plus petite espèce d'esturgeon d'eau douce endémique d'Amérique du Nord. C'est aussi le plus abondant des esturgeons, et on le rencontre dans les bassins du Missouri et du Mississippi. C'est aussi le seul esturgeon pêché pour son commerce aux États-Unis.
Le nom scientifique Scaphirhynchus, vient du grec signifiant « museau en forme de bêche », et platorynchus vient également du grec et signifie « large museau ». L'Esturgeon scaphirhynque se caractérise par un long filament sur le lobe supérieur de sa nageoire caudale. Il a un rostre aplati également en forme de bêche, qui présente quatre barbillons sous sa face ventrale. Ces barbillons sont situés à équidistance entre l'ouverture de la bouche et l'extrémité du museau, à la différence de ceux du Scaphirhynque blanc. Son ventre est recouvert de plaques semblables à des écailles, une autre différence avec le Scaphirhynque blanc. Sa couleur va du brun clair au chamoisé, avec un ventre blanc[1].
L'Esturgeon scaphirhynque, comme on peut le remarquer avec son aire de répartition, n'est pas dérangé par la turbidité de l'eau. Les eaux du Missouri et du Mississippi sont en effet chargées en sédiments. On rencontre cet esturgeon dans le fond de ces fleuves, souvent dans des zones au courant rapide et avec un fond sableux ou caillouteux.
L'Esturgeon scaphirhynque se nourrit dans le fond de la rivière, utilisant son museau pour dénicher sa nourriture. Son alimentation est principalement composée de larves d'insectes, notamment d'éphéméroptères, de diptères et de trichoptères. L'Esturgeon scaphirhynque se nourrit également de crustacés, de vers et de petits poissons. Comme il se nourrit au fond de l'eau, c'est un hôte pour les larves de plusieurs mollusques d'eau douce comme Quadrula pustulosa, Obovaria olivaria et Lampsilis teres.
Esturgeon scaphirhynque
Scaphirhynchus platorynchus, communément appelé Esturgeon scaphirhynque, est une espèce de poissons appartenant à l'ordre des Acipenseriformes. C'est la plus petite espèce d'esturgeon d'eau douce endémique d'Amérique du Nord. C'est aussi le plus abondant des esturgeons, et on le rencontre dans les bassins du Missouri et du Mississippi. C'est aussi le seul esturgeon pêché pour son commerce aux États-Unis.
Scaphirhynchus platorynchus Rafinesque, 1820, noto in italiano come storione naso a pala, è un pesce d'acqua dolce della famiglia Acipenseridae.
Questa specie si trova lungo tutto il corso dei fiumi Mississippi e Missouri e in vaste porzioni dei loro maggiori affluenti.[3] La specie di Scaphirhynchus, precedentemente indicata come storione naso a pala nei sistemi di drenaggio della baia di Mobile in Alabama da Smith-Vaniz nel 1968, è stata riclassificata da Williams and Clemmer nel 1991 con storione dell'Alabama (Scaphirhynchus suttkusi).[4] L'unica popolazione nota e confermata di storione naso a pala in Alabama, in una porzione del fiume Tennessee pare essere ora estinta. Una distinta sottopopolazione si trovava un tempo nel Rio Grande, Nuovo Messico,[5] ma un solo esemplare di questa sottopopolazione è ad ora noto.[6]
L'alterazione dei grandi fiumi con la costruzione di chiuse e dighe per la navigazione ha contribuito sensibilmente al declino di questa specie impedendogli l'accesso alle aree riproduttive. inoltre, molti degli habitat originari dello storione naso a pala sono stati alterati dallo sviluppo di progetti di impiego di risorse idriche per l'irrigazione, la fornitura d'acqua e la produzione di elettricità.[8]
Seppure le uova di storione naso a pala sono utilizzate come un caviale accettabile, l'eccessivo sfruttamento di esso non risulta ancora essere uno dei problemi principali per questa specie, forse per le sue ridotte dimensioni rispetto a Acipenser fulvescens e Scaphirhynchus albus, le altre due specie di storione presenti nel medesimo areale. Lo storione naso a pala è ancora localmente abbondante in alcune aree dove l'habitat rimane ancora pressoché inalterato.
Scaphirhynchus platorynchus Rafinesque, 1820, noto in italiano come storione naso a pala, è un pesce d'acqua dolce della famiglia Acipenseridae.
Scaphirhynchus platorynchus is een straalvinnige vissensoort uit de familie van de steuren (Acipenseridae).[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1820 door Rafinesque.
Bronnen, noten en/of referenties
Multimedia w Wikimedia Commons Łopatonos amerykański[3] (Scaphirhynchus platorynchus) – gatunek ryby jesiotrokształtnej z rodziny jesiotrowatych (Acipenseridae).
Ameryka Północna, w dolnym biegu Missisipi, od Zatoki Hudsona po Arkansas.
Podobny do jesiotrów, pysk łopatowato spłaszczony, trzon ogona silnie wydłużony. Osiąga długość 100 cm i masę 3 kg (maksymalnie 4,88 kg[4]). Występuje w wodach słodkich.
Żywi się bezkręgowcami dennymi, zwłaszcza larwami owadów.
Łopatonos amerykański (Scaphirhynchus platorynchus) – gatunek ryby jesiotrokształtnej z rodziny jesiotrowatych (Acipenseridae).
Mississippiskovelstör[3] (Scaphirhynchus platorynchus) är en art av familjen störfiskar som finns i Nordamerika och som främst utmärker sig genom sin ringa storlek.
En sötvattensfisk med avlång kropp utan fjäll men med 5 rader tydligt kölade benplattor längs kroppen. Även huvudet har benplattor; de på nosen och framför ögat har korta taggar. Nosen är lång, platt och skovelliknande, samt har 4 fransade skäggtömmar på undersidan, framför den tandlösa munnen. Denna kan fisken skjuta fram och använda för att suga upp byten. Stjärtfenan har två lober: Den övre, större har långa, trådliknande utskott som ofta bryts av hos äldre individer. Ryggfenan har 30 till 36 mjukstrålar, analfenan 18 till 23.[4][5] Kroppen är ljusbrun på ryggen och sidorna, vit på buken.[6] Arten är en liten stör; som mest kan den bli 100 cm lång och väga 4,88 kg,[7] men det är ovanligt att de blir så stora; vanligen blir de inte mycket längre än 70 cm[5]
Mississippiskovelstören är mestadels solitär (utom i samband med parningen)[5] och lever på bottnen av större, grumliga floder med stark ström och sand- eller grusbotten. Däremot undvker den lugnvatten i sjöar och dammar. Även om den normalt föredrar strömmande vatten, söker den under vårflodens högvatten skydd bakom dammar och andra hinder.[4] Under större delen av året föredrar den vatten med en temperatur av 18 – 20 °C. Vid lågvatten eller under de varmaste sommarmånaderna söker den emellertid djupare, svalare vatten. Deras revir är stort, och de kan simma långa sträckor i samband med födosöket, som mest 20 km per dag. Under detta använder den framför allt skäggtömmarna för att orientera sig i det ofta grumliga vattnet.[5] Födan består av larver av vatteninsekter, speciellt dagsländor, nattsländor och myggor, musslor, maskar och kräftdjur. Arten kan bli 43 år gammal.[7]
Honan blir könsmogen kring 7 års ålder, hanen vid ungefär 5 år. Leken sker från april till tidigt i juli när vattnet når en temperatur mellan 19 och 21 ºC, då flera fiskar vandrar uppströms för att leka nära ytan i strömt vatten[4] över sten- eller grusbotten. Under parningssäsongen kan vaje hona avge upp till 50 000 ägg, som hanen befruktar medan han simmar sida vid sida med honan. Äggen, som är mörkgrå och 2 till 3 mm stora, klibbar fast vid bottenmaterialet och kläcks efter 5 till 8 dagar. Efter ungefär 3 månader och en längd på 15 till 20 cm, lämnar ungfiskarna födelseomrdet och simmar neråt.[5] Alla individer leker inte varje år; tätheten i parningarna är beroende av hur välnärda de vuxna fiskarna är. Uppgifter finns om att det även förekommer en lekperiod under hösten i Mississippiflodens mellersta lopp.[6]
Mississippiskovelstören finns i USA i Mississippi och Missourifloderna och deras större bifloder, inklusive den lägre Ohiofloden, där de går upp till Pennsylvania. Uppgifter om att den skulle finnas i Alabama i floder som mynnar ut i Mobile Bay förefaller bero på förväxling med släktingen Scaphirhynchus suttkusi, som före 1991 räknades till denna art. Däremot har det funnits en underpopulation i Alabama, men denna är utdöd. Räknat efter delstater finns den i Montana, North Dakota, South Dakota, Minnesota, Wisconsin, Wyoming, Nebraska, Iowa, Illinois, Indiana, Kansas, Missouri, Kentucky, Oklahoma, Arkansas, Tennessee, Texas, Louisiana och Mississippi. Förutom Alabama har den även funnits i West Virginia, Ohio, Pennsylvania och New Mexico, men är numera utdöd där.[1]
Arten fiskas framför allt för köttets skull, som anses vara en läckerhet, inte minst rökt. Man gör även kaviar av rommen.[5] Kommersiellt fiske är tillåtet i 7 stater (Illinois, Indiana, Iowa, Kentucky, Tennessee, Missouri och Wisconsin; till år 2000 ingick även Arkansas[1]). 1997 var den totala årliga fångsten 22 680 kg.[6] Den får även sportfiskas i 12 stater.[5]
Mississippiskovelstören är klassificerad som starkt hotad ("EN", underklassificering "A3d"+"4ac") av IUCN och beståndet minskar. Främsta orsakerna är flodregleringar och dammbyggnation, som förhindrar tillträdet till lekområdena, och dessutom påverkar födotillgången. Däremot anses inte överfiske vara något hot.[1]
Mississippiskovelstör (Scaphirhynchus platorynchus) är en art av familjen störfiskar som finns i Nordamerika och som främst utmärker sig genom sin ringa storlek.
Cá tầm mũi xẻng, Scaphirhynchus platorynchus, là loài cá tầm nhỏ nhất có nguồn gốc từ Hoa Kỳ. Cá tầm mũi xẻng là loài cá tầm phong phúng nhất, được tìm thấy trong các hệ thống sông Missouri và sông Mississippi. Cá tầm mũi xẻng bị đánh bắt thương mại chỉ ở Hoa Kỳ (Pflieger 1997).
Bài viết Lớp Cá vây tia này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Cá tầm mũi xẻng, Scaphirhynchus platorynchus, là loài cá tầm nhỏ nhất có nguồn gốc từ Hoa Kỳ. Cá tầm mũi xẻng là loài cá tầm phong phúng nhất, được tìm thấy trong các hệ thống sông Missouri và sông Mississippi. Cá tầm mũi xẻng bị đánh bắt thương mại chỉ ở Hoa Kỳ (Pflieger 1997).
Scaphirhynchus platorynchus Rafinesque, 1820
Охранный статус
Обыкновенный лопатонос[1] (лат. Scaphirhynchus platorynchus) — речная рыба семейства осетровых. Максимальная длина тела 100 см, обычно 60—90 см; максимальный вес 4,88 кг, обычно 2—3 кг; максимальная продолжительность жизни 43 года[2]. Характеризуются очень длинным уплощённым хвостовым стеблем, одетым, как панцирем, костными пластинками; хвостовая нить отсутствует или мала; плавательный пузырь большой, глаза маленькие.По характеру питания — бентофаг. Лопатоносы в США имеют небольшое промысловое значение.
Обыкновенный лопатонос (лат. Scaphirhynchus platorynchus) — речная рыба семейства осетровых. Максимальная длина тела 100 см, обычно 60—90 см; максимальный вес 4,88 кг, обычно 2—3 кг; максимальная продолжительность жизни 43 года. Характеризуются очень длинным уплощённым хвостовым стеблем, одетым, как панцирем, костными пластинками; хвостовая нить отсутствует или мала; плавательный пузырь большой, глаза маленькие.По характеру питания — бентофаг. Лопатоносы в США имеют небольшое промысловое значение.
