Das Schicksal der großen Störarten in der Oberen Donau.

Denisia 33, zugleich Kataloge des oberösterreichischen Landesmuseums Neue Serie 163 (2014): 423-442.

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Zusammenfassung:

Durch Fischfang und Gewässerverbauung sind die Störartigen in der Donau inzwischen stark gefährdet und teilweise nahe der Ausrottung. In der österreichischen Donau kommt als kleinste autochthone Art nur noch der Sterlet vor. In der Oberen Donau sind die vier großen Störartigen durch Migrationshindernisse und Überfischung inzwischen ausgestorben. Die Analyse historischer Quellen belegt aber zumindest für manche Arten wie den Hausen in der Vergangenheit eine große wirtschaftliche Bedeutung dieser Tiere, vor allem im Raum Wien. Die hohe Anzahl gehandelter Tiere lässt dabei auf relativ hohe Bestandsdichten in früheren Zeiten schließen. Während für den Hausen eine relativ gute Datengrundlage vorliegt ist die Zuordnung anderer Störarten aus taxonomischer Sicht deutlich schwieriger, da eine große Anzahl von Fehlbestimmungen vorliegt. Die vorliegenden Daten lassen jedoch darauf schließen, dass zumindest der Waxdick und möglicherweise der Glattdick in der Oberen Donau regelmäßig anzutreffen waren, während es keinen dezidierten Nachweis des Sternhausens für diesen Abschnitt gibt. Der Europäische Stör war in seinem Vorkommen auf die Untere Donau beschränkt und spielte für die Störfischerei in der Oberen Donau keine Rolle.

Abstract:

The fate of the large sturgeon species in the Upper Danube. The Danube is home to six sturgeon species, all of which are highly endangered and in some cases already extinct. Through overfishing in the past centuries, four species went almost extinct in the Upper Danube; later the construction of power plants and dams made spawning migrations impossible and led to their doom in the Upper and Middle Danube. In the lower part of the Danube longer spawning runs of diadromous species have been made impossible with the construction of the hydropower plants at the Iron Gate. The sterlet ( Acipenser ruthenus), the last representative of this fish family in the Austrian Danube, is ‘Fish of the Year 2014’ in Austria, while the European sturgeon
(Acipenser sturio) is ‘Fish of the Year 2014’ in Germany. This article is a compilation of three articles (S CHMALL & F RIEDRICH
2014a, 2014b; F RIEDRICH et al. 2014) and deals only partly with autecological issues but rather examines the former range limits and economic importance of these fish, and further identifies the current situation of sturgeon species in the whole Danube basin and efforts to protect them. In terms of historical sources the focus lies on the catchment of the Austrian Danube.

schmall-biblio

Sturgeon farming in Western Europe: recent developments and perspectives.

Aquatic Living Resources 14(6), November 2001:367-374. DOI: https://doi.org/10.1016/S0990-7440(01)01136-6

Abstract:

Sturgeon production in Western Europe originating from aquaculture in 1999 was approximately 1300 t revealing an increasing trend. Three species represent 95 % of the annual production: white sturgeon (Acipenser transmontanus) 43 %, Siberian sturgeon (Acipenser baerii) 34 %, and Adriatic sturgeon (Acipenser naccarii) 18 %. The remainder is provided by various species including hybrids. The main countries in decreasing order of production are Italy, France, Spain, Germany and Poland. Fish are fed commercial formulated diet. The most significant changes in the sturgeon industry during recent years have been in the ownership of farms, in the emergence of the pond as a production system, and in the increasing caviar production from farmed sturgeon. In 1999, the production of farmed caviar from France and Italy, originating from Siberian and white sturgeon, respectively was close to 6 t. The number of active sturgeon farms in Western Europe is estimated to be approximately thirty, half of which are hatcheries. This paper presents different strategies and management approaches in sturgeon production and caviar processing. The potential caviar market and its dynamics are assessed and likely changes are discussed. Finally, some of the scientific investigations needed to improve and support this development are highlighted. Five different fields are distinguished: biological reserve, genetics, reproduction, farming, and quality of end products.

williot-biblio

Natural genetic polymorphism and phylogeography of Siberian sturgeon Acipenser baerii Brandt, 1869.

Russ. J. Genet. 53: 358–368. https://doi.org/10.1134/S1022795417030024

Abstract:

Five populations of Siberian sturgeon Acipenser baerii collected throughout the species distribution range (Lake Baikal, Lena, Yenisei, Kolyma, and Irtysh rivers) were examined for genetic polymorphism using five tetraploid microsatellite loci and the mitochondrial DNA control region. It was demonstrated that Siberian sturgeon was represented by genetically well-differentiated groups that corresponded to hydrographic basins, Ob–Irtysh, Baikal–Yenisei, Lena, and Kolyma. Population assignment of the Siberian sturgeon broodstock should be considered in the restocking programs.

barmintseva-biblio

Störarten in der Donau.

Auenmagazin 20: 42-45.

Zusammenfassung:

Störe sind ein wesentliches Faunenelement der Donau und stellten in der Vergangenheit durch ihre Migration eine Verbindung zwischen dem alpinen Donauraum und dem Schwarzen Meer her. Heute sind zwei von sechs Donaustören bereits ausgestorben und die verbliebenen Arten sind durch Wilderei, Beifang, Migrationsbarrieren und Habitatverlust vom Aussterben bedroht. Eine Vielzahl von Projekten forciert Bemühungen zum Schutz und zur Wiederansiedelung, welche jedoch nur koordiniert und in internationaler Kooperation Aussicht auf Erfolg haben.

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neuburg-biblio

Il recupero dello storione cobice in Italia - ACTION PLAN -Progetto Life 04NAT/IT/000126 "Conservation and Breeding of Italian Cobice Endemic Sturgeon".

160 Seiten. DOI: 10.13140/2.1.1085.7286.

Abstract:

In the Italian waters there were historicaly three species of sturgeon: Huso huso (Beluga sturgeon), Acipenser sturio (common sturgeon) and Acipenser naccarii (Cobice sturgeon). The first two species are considered as locally extinct, while the Cobice sturgeon is still signalled, even if seldom. There is moreover a population of this species banished to the fresh waters of the Tessin river, an affluent of the Po river, due to the building of the barrage of Serafini Island on the Po river. The main reason that brought the Cobice sturgeon to the danger of extinction is the eccessive fishing pression. Just in recent times legislation protected all three species, completely forbidding their fishing. Different factors contributed to the decline of population, among them the interruption of the fluvial continuity which, preventing the going back up of some intervals of rivers reduced the number of reproductive sites. The biological cycle of the Cobice sturgeon is very long, male specimens reach sexual maturity at 7-11 years of age, with a total length of at least 80 cm, and female specimens at 12-14 years of age, with a length of at least 1 m. The Cobice sturgeon has been object of numerous studies and projects, both of research and conservative. During the years, single Administrations on the whole territory, in particular in Lombardy, Veneto and Emilia-Romagna, have been engaged in local conservation interventions, even with repopulation programs. The population restricted to fresh waters of Tessin has then been object of a specific conservation program guided by the Lombardy Park of the Tessin Valley and co-financed by the European Community through the project LIFE03NAT/IT/000113. Only with the project LIFE04NAT/IT/000126 a common and coordinated commitment on a big area has been started, almost the areale of distribution of the species. This project that lasted three years involved Lombardy, Veneto and Emilia-Romagna. The involvement of regional Bodies, Parks and Province Authorities of three regions has represented a successful prerequisite, as the Cobice sturgeon moves and migrates on a big area, not belongig to a unique jurisdition. The project realization was possible thanks to three solid fundamentals: the experience of the Public Authorities, the availability of a stock of Cobice sturgeon, the gained and consolidated technology for its reproduction and breeding. The stock specimens were captured in the 1970s in the same project area and since then maintained in captivity. This stock and its descendants built the only and fundamental tank for the species rescue. All specimens now kept ex-situ, both by public authorities and private citizens, come from that original centre, whose specimens, still living, are bred and belong to the Azienda VIP of Orzinuovi in Lombardy, breeding site with CITES authorization. The technology for the reproduction and breeding in all life stages of the Cobice sturgeon was worked out in the same facility that was the first to realize the bloodless reproduction of A. naccarii in the 1980s. Afterwards, thanks to the LIFE project, artificial reproduction was carried out also at the public centre of Quinto di Treviso, in Veneto. Thanks to the project LIFE04NAT/IT/000126 the genetic characterization of a part of the specimens kept ex-situ has been carried out and a crioconservation technique of the seed of the Cobice sturgeon has been worked out realizing the germoplasm bank. Thanks to the reproductions of the two breeding centres, an important repopulation effort has been performed. Seeding of 66,038 Cobice sturgeon specimens has been carried out: 17,038 of them had an average length of 50 cm and an average weight of 900 gram, the remaining 49,000 specimens were put at the post-larva stage. The post-larva seeding has been performed according to a successful reproduction of the two centres, so that it goes beyond the plant potentiality to wean a so high number of alevins. For this reason the choice was to release the specimens at this life stage. Before carrying out the repopulation program, the watercourses have been studied in detail, showing important features of the habitat for the Cobice sturgeon, as for example substratum granulometry, stream velocity and bathymetry. Particular attention has been drawn to the presence of holes. In the three regions involved in the project, following rivers have been studied: Po, Adda, Oglio, Mincio, Adige, Bacchiglione, Brenta, Sile, Piave, Livenza, Lemene, Tagliamento. For the evaluation of the repopulation program both campaigns of direct sampling with nets and electrofishing and monitoring campaigns through a national networtk that have involved fishermen for leisure, professional fishermen, volunteers and the staff of the security service of the different Bodies have been carried out. The monitoring network was previously organised, with informative meetings and distribution of materials. Thanks to this organisation, in case a sturgeon was accidentally captured, it was possible to signal it calling the nearest referring centre. As soon as the nearest surveyor received the call, he immediately went to the capture place to verify, with an adequate reader, the presence of microchip and to survey the biometric measures. If no microchip was present, a fin fragment of around 1 cm2 was taken for genetic tagging. The genetic tagging, thanks to the results of the genetic characterization analysis, made it possible to recognise the specimens analysed as descendants of the stocks kept in captivity (F0), deriving then from previous repopulation programs, or as wild. Out of 38 analysed animals, 23 have resulted not assignable to the F0. The organization of the monitoring network had also the aim of awakening the fishermen, but dissemination of the project was spread also among schools, carrying out a specific program of environmental education in which around 500 school groups corresponding to the total involvement of around 10,000 students have been met. The results of the repopulation and of the monitorings carried out both directly and through the survey network have been organized in a Geographical Information system (GIS). The GIS was developed on a geo-database with a geographical reference of the seeding points and the points of capture, to which following information has been added: information of the single specimens sown or captured, as the microchip number, length, weight, genetics of origin, date and place of seeding/capture, etc. These tables were linked with the points with a geographical reference and among them, in order to access all available information through GIS for each of the thousands of specimens having a microchip. This Action Plan for the Cobice sturgeon is the result of the same project but it also considered the Action Plan produced by the Tessin Park for the repopulation at the moment banished to the fresh waters of that river. The action plan was performed on the model of the management Plan and is therefore structured in four sections: knowledge framework; evaluation of the ecologic needs; aims; management strategy. Thanks to this structure one clear general goal was set: the conservation of the A. Naccarii in a satisfying state, as defined by the Habitat Directive. To this follow 14 detailed aims that are functional to the general aim: giving the Sile river the fluvial continuity back; monitoring on some rivers of the dangerous structures for the species; facilitation to the overcoming of barrages; conservation of the habitats where the Cobice sturgeon lives; reduction of the competition with the silurus; reduction of the poaching; awakening of the population to the topic of the conservation; awakening of the authorities; progressive increase of the natural population; ex-situ stock conservation; increase of the genetic diversity of the natural population; increase of the knowledge about the bio-ecology; promotion of a regional, provincial and sector planning and programming system; conservation of the species in the Ticino River. The management stategy analysed moreover the value of the Action Plan, integrating it in the regulations, as the areale of the Cobice sturgeon covers three different regions and it is not restricted to the sites of Rete Natura 2000. Periodical deadlines for the review of the Action Plan have been furthermore set, having the aim of adjusting it to the development of the conservation status of the natural population. Depending on such periodical reviews, some detailed aims have been selected: they cannot be faced in the first deadline, but it will be certainly necessary to consider them in the following reviews. In order to clearly identify how to reach those goals, the management activities were outlined and organized according to the types selected in the “Manual for the management of the Nature Sites 2000” of the Italian Ministry for the Environment: active intervention (IA); regulations (RE); monitoring and/or research programs (MR); didactic programs (PD). Each goal goes back to a structured table with the following items: Goal; Activity description; Implementation timetable; Indicators and parameters; Priorities; Expected results; Costs estimate; Potential programmatic references and financial funds; Person in charge of the implementation.

caramori-biblio

Managing Polyploidy in Ex Situ Conservation Genetics: The Case of the Critically Endangered Adriatic Sturgeon (Acipenser naccarii).

PLoS One. 2011; 6(3): e18249. Published online 2011 Mar 29. doi: 10.1371/journal.pone.0018249

Abstract:

While the current expansion of conservation genetics enables to address more efficiently the management of threatened species, alternative methods for genetic relatedness data analysis in polyploid species are necessary. Within this framework, we present a standardized and simple protocol specifically designed for polyploid species that can facilitate management of genetic diversity, as exemplified by the ex situ conservation program for the tetraploid Adriatic sturgeon Acipenser naccarii. A critically endangered endemic species of the Adriatic Sea tributaries, its persistence is strictly linked to the ex situ conservation of a single captive broodstock currently decimated to about 25 individuals, which represents the last remaining population of Adriatic sturgeon of certain wild origin. The genetic variability of three F1 broodstocks available as future breeders was estimated based on mitochondrial and microsatellite information and compared with the variability of the parental generation. Genetic data showed that the F1 stocks have only retained part of the genetic variation present in the original stock due to the few parent pairs used as founders. This prompts for the urgent improvement of the current F1 stocks by incorporating new founders that better represent the genetic diversity available. Following parental allocation based on band sharing values, we set up a user-friendly tool for selection of candidate breeders according to relatedness between all possible parent-pairs that secures the use of non-related individuals. The approach developed here could also be applied to other endangered tetraploid sturgeon species overexploited for caviar production, particularly in regions lacking proper infrastructure and/or expertise.

congiu-biblio

Paddlefish (Polyodon spathula) in Europe: An aquaculture species and a potential invader.

Journal of Applied Ichthyology 35 (1): 267-274. https://doi.org/10.1111/jai.13672

Summary:

The paddlefish (Polyodon spathula) was first introduced to Europe in 1974, mainly due to its potential for rearing in natural polyculture ponds and large temperate reservoirs. The information on the history of paddlefish aquaculture efforts in Europe is scarce, as well as data on current paddlefish aquaculture status and trends. In addition, there is a lack of data on its presence and potential establishment in the wild, while its invasive potential and associated risks and impacts are largely unknown. In order to evaluate its current status in Europe, we conducted a survey among scientists, aquaculture producers and other stakeholders, and reviewed literature and data on the Internet. Based on the results obtained, we discuss the potential and the challenges in European paddlefish aquaculture development, and analyze paddlefish invasive potential and risks associated with its naturalization. Paddlefish aquaculture is well established only regionally in Europe, but offers relatively high potential for further development in pond farms. Nevertheless, future development will require careful planning, especially regarding market development and improved marketing strategies. While paddlefish likely represents a low‐risk invader, improved control and reporting on trade and intentional and unintentional releases will be required. Given the lack of knowledge on potential impacts following its introduction, due caution seems highly advisable.

jaric-biblio

Tracing the first steps of American sturgeon pioneers in Europe.

BMC Evolutionary Biology 8:221. https://doi.org/10.1186/1471-2148-8-221.

Abstract:

Background: A Baltic population of Atlantic sturgeon was founded ~1,200 years ago by migrants from North America, but after centuries of persistence, the population was extirpated in the 1960s, mainly as a result of over-harvest and habitat alterations. As there are four genetically distinct groups of Atlantic sturgeon inhabiting North American rivers today, we investigated the genetic provenance of the historic Baltic population by ancient DNA analyses using mitochondrial and nuclear markers.

Results: The phylogeographic signal obtained from multilocus microsatellite DNA genotypes and mitochondrial DNA control region haplotypes, when compared to existing baseline datasets from extant populations, allowed for the identification of the region-of-origin of the North American Atlantic sturgeon founders. Moreover, statistical and simulation analyses of the multilocus genotypes allowed for the calculation of the effective number of individuals that originally founded the European population of Atlantic sturgeon. Our findings suggest that the Baltic population of A. oxyrinchus descended from a relatively small number of founders originating from the northern extent of the species' range in North America.

Conclusion: These results demonstrate that the most northerly distributed North American A. oxyrinchus colonized the Baltic Sea ~1,200 years ago, suggesting that Canadian specimens should be the primary source of broodstock used for restoration in Baltic rivers. This study illustrates the great potential of patterns obtained from ancient DNA to identify population-of-origin to investigate historic genotype structure of extinct populations.