Sea Sturgeon Research Articles

Standardized Sperm Cryofreezing Technique for Caspian Sea Sturgeons (Huso huso, Acipenser persicus, Acipenser stellatus, Acipenser nudiventris)

Sturgeons, considered `living fossils,` face extinction due to various factors, according to the International Union for Conservation of Nature's Red List. The present study describes a uniform sperm cryopreservation method for the endangered Caspian Sea sturgeon species, which are beluga (Huso huso), Persian (Acipenser persicus), stellate (Acipenser stellatus), and ship (Acipenser nudiventris) sturgeons for both artificial reproduction and ex-situ conservation attempts. For this aim, sperm samples were diluted 1:1 in extender composed of 118 mM Tris buffer (pH=8) and 23.4 mM sucrose-based extender containing 15% DMSO and equilibrated for one hour at 4°C. Then, sperm samples were placed into 0.50-ml straws and multi-stage cooling was applied to freeze with the help of a programmable freezer with an accuracy of ±0.1C/min, and finally stored in liquid nitrogen (-196C) tank. Thawing was performed at 40°C water baths for 25 s. The results indicated that storage for two years resulted in a 24.7% fertilization rate for the stellate sturgeon, while the Persian sturgeon had a remarkable rate of 58.2% after five years storage.

Under-actuated USV path following control under multiple constraints

The path following control of an under-actuated unmanned surface vehicle (USV) under the constraints of rudder angle, rudder velocity, and rudder response time in the disturbing environment is studied, and a cascaded path following control system based on guidance law and heading control law is designed. First, the guidance law is designed on the basis of integral line-of-sight, while the tracking error state is introduced to design a variable gain disturbance observer, which not only ensures the stability of the convergence section but also takes into account the tracking accuracy of the stable section. The stability of the system is analyzed. Subsequently, the rudder maneuverability constraint and rudder effect delay are further imposed after fully considering the limited range of rudder angle, rudder velocity, and rudder response time in the process of path following. In addition, the heading control law is, therefore, designed on the basis of the rolling optimization strategy, which effectively reduces the oscillation while ensuring the convergence speed. The stability of the control law is further proved. Thereafter, a simulation experiment proves the effectiveness and advancement of the algorithm designed in this paper. In the end, based on the software and hardware design of the control system, “Sea Sturgeon” USV is used for the lake test of the proposed control algorithm to verify its feasibility in practical engineering applications.

Marking fin spine of juvenile sturgeon (acipenseriformes: acipenseridae) using oxytetracycline and the comparing of growth performance

ABSTRACT This study aimed to describe and validate the formation of the rings in the spine of the pectoral fin and to determine the coherence of the OTC mark with the rings of three species of Caspian Sea sturgeon, the Persian sturgeon (Acipenser persicus), the Starry sturgeon (Acipenser stellatus) and Ship sturgeon (Acipenser nudiventris). Validation was achieved by comparing the total radius of the fin spine of fish of known age after one and two years of growth with the measured radius of the first and second rings in the zone. There was no overlap between the measured radius for the first year and the increase for the second. The Ship sturgeon showed the largest width of the second ring followed by the Persian sturgeon and Stellate sturgeon. The results indicate that the highest growth parameter belongs to the juvenile Ship sturgeon. This research showed that chemically marking the fin spines of juvenile Acipenseridae leads to unbiased estimates and contributes to the knowledge of the population dynamics of these species. The study found that the combination of the dial ring of the pectoral fin spine with growth validated the age estimation in juvenile sturgeon Ship, Persian, and Starry sturgeon.

Detection of white sturgeon iridovirus (WSIV) in sturgeons (Actinopterygii: Acipenseriformes: Acipenseridae) from aquaculture facilities located in Poland, Germany, and Italy

Background. White sturgeon iridovirus (WSIV) is one of the most serious threats for sturgeon aquaculture as the mortality in juvenile individuals can reach 95%. At the turn of the century WSIV was reported among hatchery-raised white sturgeon, Acipenser transmontanus Richardson, 1836,  in North America, Russian sturgeon , Acipenser gueldenstaedtii Brandt et Ratzeburg, 1833, in northern Europe but also pallid sturgeon, Scaphirhynchus albus (Forbes et Richardson, 1905) and shovelnose sturgeon, Scaphirhynchus platorynchus (Rafinesque, 1820) in North and South Dakota. The clinical signs of infection include cessation of feeding and edematous and pale gills. Those pathological changes lead to respiratory problems of the juveniles and deterioration of their overall condition. Rapid detection of pathogen particles under aquaculture conditions is crucial, therefore the principal aim of this study was to establish a molecular method for rapid and effective detection of the WSIV. This is the first study thoroughly comparing WSIV detection methods in sturgeons cultured in Poland, Germany, and Italy. Materials and methods. A total of 244 samples were collected from 82 sturgeons representing six species: beluga, Huso huso (Linnaeus, 1758); sterlet, Acipenser ruthenus Linnaeus, 1758; Siberian sturgeon, Acipenser baerii Brandt, 1869; Russian sturgeon, A. gueldenstaedtii; Atlantic sturgeon, Acipenser oxyrinchus Mitchill, 1815; and European sea sturgeon, Acipenser sturio Linnaeus, 1758, as well as five sturgeon hybrids: Siberian × Russian, Adriatic (Acipenser naccarii Bonaparte, 1836) × Siberian, Adriatic × beluga, Siberian × sterlet, and beluga × sterlet. The samples were screened for the WSIV using conventional PCR, real-time PCR, and in situ hybridization (ISH) methods. Results. In total, positive results were obtained in 231 (94.67%) out of 244 analysed samples, except for H. huso where DNA of WSIV was not identified. DNA of WSIV was most frequently detected in the kidney (97.92%), intestine (97.50%), skin (94.97%), and gills (93.29%). The most effective method for detecting DNA of WSIV in sturgeons was real-time PCR (92.62% of), PCR (90.98%), and ISH (49.24%). Conclusion. The host range of the WSIV seems to be wider than expected, however, further studies are necessary since no clinical symptoms were observed in sturgeons and their hybrids.

ON THE TECHNIQUE OF MODELING ONTOGENETIC CHANGES IN FISH AND INSECTS LIFECYCLE

The article discusses the approach to modeling of metamorphoses in the development of a number of species in the context of their influence on the success of long-term trends of population dynamics. Changes in survival during early ontogenesis, controlled by important factor – the rate of individual development in a competing group of individuals, can cause unexpected degradation of population with a small excess fishing impact. The theory of nonlinear efficiency of reproduction leads us to the hypothesis that two different nonlinear effects are controlled by similar mechanisms. For insects such fluctuations in survival during metamorphosis can start another process - the rapid outbreak of pests, where actual formalization of the impact of parasites on the first stage of development, depending on the initial concentration of clutches, but limited resources is taken into account at a finishing. The method has been for submission to decline of generations on the basis of dynamic overriding differential equations with discrete-continuous structure of time. To extend the previously proposed model for the formation of generations is formed computing structure for the account mortality depending on the level of competition, complete with trigger functional and a new scheme describing the changes the growth rate for the example of the Caspian Sea sturgeon in three ecological and physiological stages of development. The new model has a non-trivial possibilities parametrically modification of behavior regimes. The coexistence of alternative cycles is explained by the increase in adaptive interspecies differences.

Comparative Modeling of Two Especial Scenarios of Bioresources Collapses: Canadian Atlantic Cod and Caspian Sea Sturgeon

Comparative Modeling of Two Especial Scenarios of Bioresources Collapses: Canadian Atlantic Cod and Caspian Sea Sturgeon

A short history of sturgeon caviar production in Turkey

Compared to other countries, caviar production in Turkey has a short history, which began principally in the early 1950s, peaked during the 1960s, and began to decline towards the end of the 1970s. Sturgeon fishery was practiced in the estuaries of the rivers Kızılırmak, Yeşilırmak, Sakarya and Çoruh. Thus, processed caviar originated from the districts of Carsamba, Bafra (Samsun City) and Karasu (Sakarya City) and appeared mainly in the markets of Istanbul. Techniques used to capture mature fish were nets set at sea and with hooks (‘karmak’ in Turkish) at the mouth of a river. Two processing techniques were commonly used: (i) malossol/mongol caviar (lightly/highly salted) and (ii) pressed caviar. Landings were mainly recorded in the Istanbul Kumkapı fish hall, reaching 300 tonnes per year in the late 1960s; however, catches declined drastically in the 1970s to only about 30 tonnes. In 1962, caviar production from Acipenser sturio was between 1200 and 1300 kg in the Yeşilırmak River; 1000 to 1200 kg in the Kızılırmak River; and 50 to 80 kg in the Sakarya River. For A. nudiventris, the respective data were 300–400 kg from Yeşilırmak River; 500–600 kg from Kızılırmak River; and 200–250 kg from Sakarya River. The rapid decline in Black Sea sturgeon stocks led to catch restrictions in Turkish coastal areas beginning in 1971. Following the construction of several hydrodams on the main sturgeon rivers in the 1970s, the few sturgeon spawning grounds that remained were drastically affected. Further deterioration of riverine environments was caused by increased pollution in the 1970s–1990s. Sturgeon catches dropped rapidly to less than 10 tonnes after 1975, whereby the fishery collapsed with only a few fish recorded sporadically after 2000. Over the past five years, aquaculture farms began to rear sturgeons for caviar production, with anticipation of initial marketing in 2014–2015. The forecast for 2020 is on the order of 6–8 tonnes of caviar per year.

Hope for the Rhone's Missing Sturgeon

Ancient DNA research may help give one species, the European sea sturgeon (Acipenser sturio), a new future, according to research presented at the Third International Symposium on Biomolecular Archaeology.

Caspian Sea sturgeon Conservation and Fisheries: Past present and Future

Caspian Sea sturgeon Conservation and Fisheries: Past present and Future

The aerobic bacterial flora of hatchery reared Caspian Sea sturgeon fingerlings

Journal of Applied IchthyologyVolume 22, Issue s1 p. 261-264 The aerobic bacterial flora of hatchery reared Caspian Sea sturgeon fingerlings Alireza Shenavar Masouleh, Alireza Shenavar MasoulehSearch for more papers by this authorIssa Sharifpour, Issa SharifpourSearch for more papers by this authorAbolfathe Shojaei Arani, Abolfathe Shojaei AraniSearch for more papers by this author Alireza Shenavar Masouleh, Alireza Shenavar MasoulehSearch for more papers by this authorIssa Sharifpour, Issa SharifpourSearch for more papers by this authorAbolfathe Shojaei Arani, Abolfathe Shojaei AraniSearch for more papers by this author First published: 10 July 2007 https://doi.org/10.1111/j.1439-0426.2007.00964.xCitations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume22, Issues1December 2006Pages 261-264 RelatedInformation

Atlantic sturgeons (Acipenser sturio, Acipenser oxyrinchus): American females successful in Europe

Recent molecular data on the maternally inherited mitochondrial (mt) DNA have challenged the traditional view that the now extinct Baltic sturgeon population belonged to the European sturgeon Acipenser sturio. Instead, there is evidence that American sea sturgeon Acipenser oxyrinchus historically immigrated into the Baltic Sea. In this study, we test the hypothesis that A. oxyrinchus introgressed into, rather than replaced, the A. sturio population in the Baltic. We established four single nucleotide polymorphisms (SNPs) in the nuclear MHC II antigen gene with a species-specific SNP pattern. Using an ancient DNA approach and two independent lines of molecular evidence (sequencing of allele-specific clones, SNaPshot), we detected both A. sturio and A. oxyrinchus alleles in the available museum material of the now extinct Baltic sturgeon population. The hybrid nature of the Baltic population was further confirmed by very high levels of heterozygosity. It had been previously postulated that the immigration of the cold-adapted A. oxyrinchus into the Baltic occurred during the Medieval Little Ice Age, when temperature likely dropped below the degree inducing spawning in A. sturio. Under this scenario, our new findings suggest that the genetic mosaic pattern in the Baltic sturgeon population (oxyrinchus mtDNA, sturio and oxyrinchus MHC alleles) is possibly caused by sex-biased introgression where spawning was largely restricted to immigrating American females, while fertilization was predominantly achieved by abundant local European males. The hybrid nature of the former Baltic sturgeon population should be taken into account in the current reintroduction measures.

When the American sea sturgeon swam east.

The two species of Atlantic sea sturgeon on either shore of the North Atlantic, Acipenser sturio in Europe and A. oxyrinchus in North America, probably diverged with the closure of the Tethys Sea and the onset of the North Atlantic Gyre 15-20 million years ago, and contact between them was then presumably precluded by geographic distance. Here we present genetic, morphological and archaeological evidence indicating that the North American sturgeon colonized the Baltic during the Middle Ages and replaced the native sturgeon there, before recently becoming extinct itself in Europe as a result of human activities. In addition to representing a unique transatlantic colonization event by a fish that swims upriver to spawn, our findings have important implications for projects aimed at restocking Baltic waters with the European sturgeon.

Threatened Fishes of the World: Acipenser oxyrinchus Mitchill, 1815 (Acipenseridae)

Common names:Atlantic sturgeon,common sturgeon,sea sturgeon (E),esturgeon noire (F).Conservationstatus: Currentlyreceives federal pro-tection with U.S.fishery closed for40 years. Listed asthreatened in Canada (Birstein et al. 1997).Identification: D 38–46, A 26–28 rays, dorsal scutes 7–16, lateral scutes 24–35 and ventral scutes 6–9. Body elongated and spindle shape in cross section. Rostrum long forAcipenseridae. Juveniles have distinct black contour band running along dorsal surface of rostrum which disappears with age. Juveniles lack the oval-shaped black rostral patchof adults on the ventral surface of the snout. Two pairs of barbels, usually originating closer to the tip of snout than mouth. Upper lip indented in the middle and lower lipinterrupted. Rows of rhombic plates present between rows of scutes on the laterodorsal and lateroventral surface. Scutes do not undergo absorption and hook-like appendagepresent on all except in very large individuals. Preanal and postdorsal plates paired. Rhombic plates on either side of the anal fin larger than those co vering rest of body. Atlanticsturgeon may reach a size of 4m and weigh 350kg but nowadays most adults are much smaller. Weight for migrating mature males is 30–45kg and for females 50–110kg.Color variable throughout life. Juveniles have dark brown dorsum with dark scutes. Central portion of all dorsal scutes lighter. Central portion on head plates also light. Ventralsurface white. Adults usually dark brown on dorsum but sometimes peanut brown or even coppery in appearance. Ventral surface white or slightly yellowish. Illustration of aHudson River 110cm long juvenile by Paul Vecsei. Distribution: Occurs along the eastern coast of North America, from southern Labrador to northern Florida. In Canadararely seen in Hamilton Inlet of Labrador but a large stock (consisting mostly of immature individuals) is present in the Gulf of St. Lawrence and lower St. Lawrence River(Caron & Tremblay 1999). Recently, a few migrating adults were reported as far upstream as Sorel, Quebec (Bergeron personal communication). Large population presentin the Bay of Fundy, heavily exploited during the upstream migration in the St. John River. Atlantic sturgeon occur sporadically along the United States coast from Maineto the St. Johns River of eastern Florida (Bain 1997). Only the Hudson River has significant numbers of juveniles in the estuary with a few dozen adults re turning to spawnin the reaches of Haverstraw (Bain personal communication). A subspecies referred to as Gulf sturgeon, A. desotoi, inhabits the Gulf of Mexico and spawns in rivers alongthe northern coast of the Gulf from the Mississippi Delta to the Suwannee River (Wirgin et al. 1997). Abundance: Severely depleted throughout most of its range. In UnitedStates waters, the once enormous Hudson River population is now reduced, with very few adult migrants returning to spawn. With the closure of the commercial fishery, thispopulation is thought likely to recover since juveniles are present in large numbers in the lower estuary. Canadian populations occur principally in the Gulf of St. Lawrence,comprising mostly of juveniles. The whereabouts of the adults of this population is still unknown (Caron & Tremblay 1999). The St. John River has a healthy annual run ofadult spawners but is under severe exploitation. Licenses are being retired and with no new ones being issued, the Bay of Fundy/Saint John population may return to almostpre-exploitation abundance.Habitat and ecology: Atlantic sturgeon are thought to occur in coastal waters where food items abound. Since they feed on various invertebrates(principally mollusks) and fish species such as capelin, Mallotus villosus, they presumably rarely venture into deep waters. Life at sea is little understood for this species butjuveniles are known to remain in their river of origin until the age of 7 before migrating to sea. Reproduction: Atlantic sturgeon are anadromous and begin entering rivers inspring and early summer depending on the distance required to travel to their spawning grounds. Spawning takes place over rock-gravel substrate at a water temperature of 18

Restoration of sturgeons: lessons from the Caspian Sea Sturgeon Ranching Programme

Depletion of sturgeon stocks world‐wide has increased interest in aquaculture‐based restoration programmes. The Caspian Sea Sturgeon Ranching Programme (SRP) of the former Soviet Union represents a unique opportunity to evaluate expense, benefits and potential ecological and genetic effects of such restoration programmes. The SRP was initiated in the 1950s to compensate for lost spawning habitat in the Volga River and elsewhere. After its completion in 1962, the Volgograd Dam reduced spawning grounds in the Volga River system, the principal spawning tributary of the Caspian Sea, by ∼80%. For two of the three commercial sturgeon species (Russian sturgeon, Acipenser güldenstädti, and stellate sturgeon, A. stellatus), yields improved after the imposition of the 1962 moratorium on sturgeon harvests in the Caspian Sea. Volga River fisheries were managed for spawning escapement. Although imprecisely known, the contribution of the millions of stocked Russian and stellate juveniles during 1962–91 was most likely important to sustaining fisheries, although less so (contributing to <30% of the adult stock) than natural recruitment. Apparently, reduced spawning grounds, supplemented with artificial spawning reefs were sufficient to support reproduction and large fishery yields of Russian and stellate sturgeons. For beluga sturgeon, Huso huso, harvests in the Volga River were nearly all dependent upon hatchery stocking. Beluga sturgeon spawning grounds were mostly eliminated with the construction of the Volgograd Dam. Without the hatchery programme, beluga sturgeon in the Volga River and Caspian Sea would in all likelihood have been extirpated. Currently, sturgeons are severely depleted in the Volga River and Caspian Sea due to poaching and lack of co‐operation between countries exploiting the species. Aquaculture‐based restoration in Russia is now viewed a chief means of rebuilding stocks of Caspian Sea sturgeons.

Restoration of sturgeons: lessons from the Caspian Sea Sturgeon Ranching Programme

Restoration of sturgeons: lessons from the Caspian Sea Sturgeon Ranching Programme

Sturgeon abundance and distribution in the Caspian Sea.

The number of sturgeons and their distribution on feeding grounds in the Caspian Sea were assessed. Data were collected between 1991 and 1996 on environmental factors, species composition, and population sizes in the Northern, Middle and Southern Caspian Sea except for Iranian waters. The results show a drastic decline of the sturgeon populations on the feeding grounds at sea. In order to preserve the Caspian Sea sturgeon populations, efforts of all States surrounding the Caspian Sea must be increased and harmonised to serve a single system of fishery management, stock conservation and enhancement measures based on natural reproduction and artificial propagation.

Amino-acid sequence homology in the muscle aldolases from sturgeons of different species.

STUDIES on the primary structure of aldolases isolated from ox, pig and rabbit muscle show that the amino-acid sequence of fructose 1,6-diphosphate aldolase [EC 4.1.2.13] has been highly conserved throughout mammalian evolution1. But comparison of the primary structure of the enzyme from these species with that from the muscle of a single North Sea sturgeon, presumably Acipenser sturio, indicated that although the proteins were homologous, a number of amino-acid replacements occurred between sturgeon aldolase and the aldolases of the phylogenetically distant mammalian species1. As a knowledge of the nature and number of amino-acid replacements between homologous proteins caft provide information both about the functional role of individual residues and about evolution, further comparative studies of rabbit and sturgeon aldolases were undertaken and an account of the sequence homology around the active-site-lysine residue of aldolases from rabbit muscle, rabbit liver and the muscle of the river sturgeon of Eastern Canada, Acipenser fulvescens, has been given2,3.

A Comparison of Atlantic Sea Sturgeon with a New Subspecies from the Gulf of Mexico (Acipenser oxyrhynchus de sotoi)

The sea sturgeon, Acipenser oxyrhynchus Mitchill, occurs in the western north Atlantic Ocean from Canadian waters south to the Gulf of Mexico. Specimens taken from eastern Florida to Quebec are assigned to the typical subspecies oxyrhynchus, while 2 specimens from off Mississippi are here described as the new subspecies de sotoi. The latter differs in having a longer head, longer pectoral fins, strongly developed scutes of distinctive shape and an unusually long spleen.