Donnerstag, 06 August 2020 13:14

CSAR, D., SCHAUER, M. & GUMPINGER, C. (2012)

Long-term investigation on fish migration patterns between pre-alpine lakes and their major tributaries with special focus on protected species within SAC areas.

Conference Paper 9th ISE 2012, Vienna. (PDF)

Abstract:

In the designated SAC (Special Area of Conservation) site“Mond-und Attersee” (comprising two large pre-alpine lakes in Upper Austria and the mouths of their major tributaries) the spawning migration of the protected species pearlfish (Rutilus meidingeri) and Danube bleak (Alburnus mento) was investigated in the years 2004 and 2010. For this purpose, a dynamic fishweir with an integrated trap for catching upstream migrating fish was installed near the mouths of the respective rivers. The main factor correlating with the spawning migration turned out to be the water temperature of the rivers. Furthermore, differences between sexes were found concerning body length and weight as well as the main immigration period into the streams.

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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.

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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.

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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.

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Montag, 03 August 2020 10:29

CARPENTER, K.E. (ed., 2002)

The living marine resources of the Western Central Atlantic.

Volume 2: Bony fishes part 1 (Acipenseridae to Grammatidae).

FAO Species Identification Guide for Fishery Purposes and American Society of Ichthyologists and Herpetologists Special Publication No. 5.Rome, FAO. 2002. pp. 601-1374.

Summary:

This 3 volume field guide covers the species of interest to fisheries of the major marine resource groups exploited in the Western Central Atlantic. The area of coverage includes FAO Fishing Area 31. The marine resource groups included are the bivalves, gastropods, cephalopods, stomatopods, shrimps, lobsters, crabs, hagfishes, sharks, batoid fishes, chimaeras, bony  fishes, sea  turtles,  nd marine mammals. The introductory chapter outlines the environmental, ecological, and  biogeographical factors influencing the marine biota, and the basic components of the fisheries in the Western Central Atlantic. Within the field guide, the sections on the resource groups are arranged phylogenetically according to higher taxonomic levels such as class, order, and family. Each resource group is introduced by general remarks on the group, an illustrated section on technical terms and measurements, and a key or guide to orders or families. Each family generally has an account  summarizing family diagnostic characters, biological and fisheries information, notes on similar families occurring in the area, a key to species, a checklist of species and a short list of relevant literature. Families that are less important to fisheries include an abbreviated family account and no detailed species information. Species in the important families are treated in detail (arranged alphabetically by genus and species) and include the species name, frequent synonyms and names of similar species, an illustration, FAO common name(s), diagnostic characters, biology and fisheries information, notes on geographical distribution, and a distribution map. For less important spe-cies, abbreviated accounts are used. Generally, this includes the species name, FAOc ommon name(s), an illustration, a distribution map, and notes on biology, fisheries, anddistribution. The final volume concludes with an index of scientific and common names.

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Freitag, 31 Juli 2020 10:02

WOLFRAM, G. & MIKSCHI, E. (2007)

Rote Liste der Fische (Pisces) Österreichs.

In: Zulka, K. P. (Red.): Rote Liste gefährdeter Tiere Österreichs, Teil 2. Grüne Reihe des Lebensministeriums Band 14/2. Böhlau-Verlag, Wien, Köln, Weimar.

Zusammenfassung:

Die vorliegende Arbeit folgt den Richtlinien zur Fortschreibung der Roten Liste gefährdeter Tiere Österreichs (Zulka et al. 2001). Die aktuelle Checkliste der Fische Österreichs umfasst 84 Taxa. Im Vergleich zur letzten Roten Liste (Spindler et al. 1997) wurden einige Taxa aufgrund aktueller nomenklatorischer und taxonomischer Entwicklungen, auf die gesondert eingegangen wird, neu aufgenommen. Zwei Taxa werden als weltweit ausgestorben (Kategorie EX; Extinct) beurteilt, fünf Taxa sind regional ausgestorben (Kategorie RE; Regionally Extinct). In der Gefährdungs-kategorie „Critically Endangered“ (CR, vom Aussterben bedroht) finden sich sechs Ar-ten, 18 in der Kategorie „Endangered“ (EN; stark gefährdet) und 15 in der Kategorie „Vulnerable“ (VU; gefährdet). Neun Arten stehen auf der Vorwarnliste (Kategorie NT; Near Threatened), 17 weitere Arten, also rund ein Fünftel der aufgenommenen Taxa, sind in Österreich der Kategorie „Least Concern“ (LC; nicht gefährdet) zugeordnet. Für drei Taxa mit äußerst unsicherer taxonomischer Situation reicht die Datenlage für eine Einstufung nicht aus (Kategorie DD; Data Deficient). Bei weiteren neun in die Checkliste aufgenommenen Arten handelt es sich um überregional verbreitete und reproduzierende Neozoen, die explizit nicht in die Beurteilung im Rahmen der Roten Liste einbezogen werden (Kategorie NE; Not Evaluated). Aufgrund geänderter Definitionen der Gefährdungskategorien ist die vorliegende Arbeit mit der Roten Liste von Spindler et al. (1997) nur bedingt vergleichbar. Die meisten Unterschiede der Gefährdungseinstufung sind auf methodische Änderungen oder eine geänderte Datenlage zurückzuführen.


Volltext: http://www.dws-hydro-oekologie.at/wp-content/uploads/wolfram_mikschi_2007_rotelistefische.pdf

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Dienstag, 05 November 2019 10:24

GEIGER, C. (2007)

Die „Hellabrunner Mischung“ im Vergleich mit MS 222 als Tauchbadnarkose bei verschiedenen Fischen.

Vet. med. Dissertation

v + 112 Seiten

Tierpark Hellabrunn, München
Betreuer: Prof. Dr. H. Wiesner
Klinik für Fische und Reptilien der Tierärztlichen Fakultät der LMU München
Vorstand: Prof. Dr. R. Hoffmann

Voller Text

Zusammenfassung:

In der vorliegenden Studie wurde eine Kombination aus Ketamin- und Xylazinhydrochlorid („Hellabrunner Mischung“ - HM; 1ml enthält etwa 100mg Ketamin und 125mg Xylazin) auf ihre Eignung zur Anwendung als Tauchbadnarkose bei Fischen untersucht. Beide Grundsubstanzen sind in Deutschland zur Anwendung bei Lebensmittel liefernden Tieren zugelassen. Die Wirksamkeit der HM wurde bei Koikarpfen (Cyprinus carpio), Regenbogenforellen (Oncorhynchus mykiss) und Kaiserbuntbarschen (Aulonocara stuartgrantii) überprüft und anschließend mit dem bei Fischen üblicherweise verwendeten Narkosemittel MS 222 (Tricain) verglichen.

Zur Ermittlung einer geeigneten Dosierung der HM wurden in Vorversuchen bei allen drei Fischarten die Parameter Anflutungszeit, Aufwachzeit, erreichte Narkosetiefe und die Häufigkeit von Exzitationen in der Anflutungs- und Aufwachphase bei verschiedenen Konzentrationen der HM im Narkosebad herangezogen. Die so für die Fischarten getrennt als optimal erkannte Dosis wurde in den Hauptversuchen bei 26 - 28 Tieren pro Fischart im Vergleich mit einer Standarddosis von MS 222 eingesetzt. Dabei wurde die eine Hälfte der Fische zunächst mit HM betäubt, die andere mit MS 222. Nach einer zweiwöchigen Ruhepause wurden die Untergruppen mit dem jeweils anderen Narkosemittel behandelt, sodass alle Fische je einmal mit der HM und einmal mit MS 222 untersucht werden konnten. Die Temperatur des Narkosebads war dabei den jeweiligen Haltungsansprüchen der Fischarten angepasst und daher unterschiedlich für Koikarpfen (20°C), Regenbogenforellen (10°C) und Kaiserbuntbarsche (25°C). Als ideale Dosis der HM für Forellen wurden 0,6 ml/l Wasser beurteilt, bei den Koikarpfen und Kaiserbuntbarschen jeweils 0,8 ml/l.

In den Hauptversuchen ließ sich mit diesen Konzentrationen bei allen drei Fischarten eine Induktion in weniger als 10 Minuten erreichen (6-9 Minuten), die Aufwachzeit dauerte einheitlich etwa 20 bis 24 Minuten. Außer bei den Forellen konnten auch tiefe Narkosestadien provoziert werden. Während der Anflutungsphase traten bei Kaiserbuntbarschen und Koikarpfen selten Erregungszustände, meist nur in Form von spuckenden Maulbewegungen, auf. Bei diesen beiden Fischarten verlief die Aufwachphase überwiegend ruhig. Die Forellen waren in der Einleitungsphase zu 92,3% verhaltensauffällig und in der Aufwachphase zu 57,7%. Die Narkosen mit MS 222 verliefen bei den Fischarten verschieden. Mit der als mittlerer Standard geltenden Dosis von 70 mg/l Wasser war bei den Kaiserbuntbarschen keine eindeutige Wirkung zu erreichen. Bei ihnen wurde deshalb die Dosis auf 116mg MS 222 /l erhöht. Die Induktion verlief mit 70mg MS 222 /l bei den Koikarpfen etwa gleichlang, bei den Forellen signifikant kürzer und bei den Buntbarschen mit 116mg MS 222 /l wesentlich länger als mit der HM. Alle drei Fischarten waren nach MS 222 schneller wach als nach der HM, die Buntbarsche hatten jedoch zuvor trotz der erhöhten Dosis in keinem Fall eine OPToleranz erreicht. Die Häufigkeit von Exzitationen war unter MS 222 insgesamt deutlich höher mit Ausnahme der Aufwachphase der Forellen.

Bei den Forellen war der Einsatz der HM zwar möglich, mit MS 222 in der Dosis 70 mg/l ließ sich eine Narkose bei dieser Fischart allerdings besser einschätzen und verlief wesentlich schneller. Bei den Koikarpfen und Kaiserbuntbarschen hingegen erwies sich die HM als sicher anzuwendendes Anästhetikum. Bei diesen beiden Spezies fiel die Beurteilung des erreichten Narkosestadiums mit der HM sogar leichter als unter MS 222. Bei den Kaiserbuntbarschen war die Wirkung des MS 222 völlig unzulänglich. Mit der HM dagegen konnten tiefe Narkosen, aus denen alle Tiere komplikationslos erwachten, erzielt werden. Speziesabhängig stellt die „Hellabrunner Mischung“ eine effektive und sichere Alternative zu herkömmlichen Tauchbadanästhetika dar.

Summary:

Hellabrunn mixture in comparison with MS 222 as immersion bath anaesthesia in different fish In this study a combination of ketamine- and xylazinehydrochloride (Hellabrunn mixture - HM; 1ml contains approximately 100mg ketamine and 125mg xylazine) was examined to find out if it is suitable to be applied in immersion bath anaesthesia. Both substances are registered for use in food animals in Europe. The effectiveness of this combination was tested on koicarp (Cyprinus carpio), rainbow trout (Oncorhynchus mykiss) and flavescent peacock (Aulonocara stuartgrantii) and afterwards compared with the commonly applied anaesthetic MS 222 (active substance: tricaine methane sulphonate).

To establish a suitable dose of HM the parameters induction time, recovery time, the achieved stage of anaesthesia, and the frequency of exzitative behaviour were measured during previous trials. The dose that was found to be working best in a fish species was then used with 26 to 28 animals in the main trials and afterwards compared with a standard dose of MS 222. This was done by first anesthetizing half of the group of each species with HM and the other half with MS 222. After a recovery period of 14 days both parts of the group were vice versa treated with the corresponding anaesthetic agent. This meant that each fish of all the three species was finally treated with both anaesthetics, HM and MS 222 and that there was a total number of anaesthetic protocols of 26 to 28 for each anaesthetic agent. The temperature of the immersion bath was always adapted to the physiological habitat of the fish, so that the temperature was different with koicarp (20°C), rainbow trout (10°C) and flavescent peacock (25°C). For rainbow trout a dose of 0.6 ml HM per litre proved to be ideally suited for this species as well as a dose of 0.8 ml HM/l for both koicarp and flavescent peacock. With these doses it was possible during the main trials to induce anaesthesia in less than 10 minutes (6-9 minutes) while recovery took 20 to 24 minutes. Excluding rainbow trout even deeper stages of anaesthesia could be provoked. During the induction period exzitative behaviour was almost never seen in koicarp and flavescent peacock unless some subtle changes of respiratory movements and ventilation rate. In both species recovery took place uneventfully. 92,3% of the rainbow trout showed abnormal behaviour during induction and so did 57,7% of them during recovery.

Anaesthesia with MS 222 was different in the course with the three species. Flavescent peacock did not show any response to the standard dose of 70mg MS 222/l. For this reason the dose was increased with this species to 116mg MS 222/l. With 70mg MS 222/l in koicarp induction time was the same as with HM. It was significantly shorter in rainbow trout and with 116 mg/l much longer in flavescent peacock in comparison to HM. All the three species did awake more rapidly after anaesthesia with MS 222 than with HM with the flavescent peacock never having reached any anaesthetic stage. Exzitative behaviour was observed more frequently under MS 222 excluding the induction period of rainbow trout. Application of HM in rainbow trout is possible, but with 70mg MS 222/l anaesthesia in this species is easier to control and more rapidly in its course.

In koicarp and flavescent peacock HM proved to be an anaesthetic easy to apply and safe. In both species the monitoring of the achieved anaesthetic stages was even easier with HM than with MS 222. In the flavescent peacock MS 222 was completely ineffective. In contrast using HM it was possible to induce even deeper stages of anaesthesia from which they recovered without any complications. Depending on the species HM is an effective and safe alternative to conventional immersion bath anaesthetics.

 

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International Transport of Live Fish in the Ornamental Aquatic Industry.

126 Seiten, mit zahlreichen Farbfotos, Tabelle und Grafiken.

Ornamental Fish International, Maarssen NL. ISBN: 978-90-75352-70-2. Mittlerweile ist eine 2, erweiterte Auflage verfügbar.

Contents:

All aspects of transporting ornamental fishes are discussed, including the supply chain, the preparation for shipment, fish packaging and treatment on arrival, the volume of trade, the legislation on import and export, as well as facts on mortalities due to transport.

 

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Donnerstag, 12 April 2018 21:15

DÖNNI, W. & FREYHOF, J. (2002)

Einwanderung von Fischarten in die Schweiz - Rheineinzugsgebiet.

Mitteilungen zur Fischerei 72: 1-89.
Herausgeber: Bundesamt für Umwelt, Wald und Landschaft (BUWAL)

Zusammenfassung:

Die Fischartengemeinschaft der Schweiz war durch das Aussterben und die Neu- oder Wiedereinwanderung seit jeher Veränderungen unterworfen. Neben natürlichen Ursachen wie z. B. Klimaschwankungen ist seit einigen hundert Jahren der Mensch zunehmend verantwortlich für Verschiebungen im Artengefüge. Seit Ende des 19. Jahrhunderts ist die Beeinflussung durch den Menschen derart gross, dass in der Schweiz 8 Fischarten als Folge der Gewässerverschmutzung, der Überfischung, vor allem aber der Flussverbauungen ausgestorben sind.

Gleichzeitig mit dem Verschwinden dieser Arten wurde eine beträchtliche Anzahl nicht einheimischer (allochthoner) Fischarten (Fisch-Neozoen) vorwiegend aus fischereilichen Überlegungen in unsere Gewässer eingesetzt. Heute umfasst die Fischfauna der  Schweiz mindestens 16 fremde Fischarten, die zumeist etablierte Bestände  bilden konnten. 13 Arten gelangten durch gezielten Besatz oder das Einschleppen via Besatzmaterial, 2 Arten über die Zierfischhaltung und 1 Art aus unbekannten Gründen in die  Gewässer. Heute ist das Einsetzen allochthoner Fischarten in der Schweiz auf gesetzlicher Ebene befriedigend geregelt.

Allochthone Fischarten können in vielerlei Hinsicht negative ökologische Auswirkungen haben. So sind beispielsweise ein Konkurrenz- oder Prädationsdruck auf einheimische (autochthone) Arten möglich. Auch eine Hybridisierung mit nah verwandten Vertretern der lokalen Fauna oder das Einschleppen von Krankheiten und Parasiten kann zu Beeinträchtigungen führen. Neozoen müssen aber nicht immer Probleme verursachen. Sie können sich auch unauffällig in die lokale Artengemeinschaft einfügen.

Das  Wissen  über  die  Rolle,  die  die  allochthonen  Fischarten  innerhalb  der  autochthonen  Artengemeinschaft spielen, weist fast durchwegs grosse Lücken auf. Unerwünschte Interaktionen mit den einheimischen Arten können daher unbemerkt ablaufen. Bei unerklärlichen Bestandesrückgängen autochthoner Fischarten sollte daher auch der Einfluss von Neozoen in Betracht gezogen  werden. Dieser könnte in den nächsten Jahren an Bedeutung gewinnen, da eine ganze Anzahl neuer Fischarten quasi vor der Tür
in  die  Schweiz steht. Nachdem der Rapfen (Aspius aspius) und der Blaubandbärbling (Pseudorasbora parva) in den letzten Jahren  via Hochrhein den Weg in die Schweiz gefunden  haben, ist zu erwarten, dass kurzfristig 6, mittel- und langfristig 9 zusätzliche  allochthone Fischarten auf diesem Weg in die Schweizer Gewässer gelangen könnten. Bei 6 dieser potenziellen Neozoen ist mit beträchtlichen negativen Auswirkungen auf die autochthone Fischgemeinschaft (Konkurrenz, Prädation) zu rechnen; es handelt sich um die Dickkopf-Elritze (Pimephales promelas), die Amurgrundel (Perccottus glehni), die Flussgrundel (Neogobius fluviatilis), die Nackthals-Grundel (N. gymnotrachelus), die Kessler-Grundel (N. kessleri) und die Schwarzmund-Grundel (N. melanostomus).
.
Neben einer Einwanderung allochthoner ist auch die Immigration ausgestorbener, autochthoner Fischarten in den nächsten Jahren zu erwarten. Dies gilt vor allem für das Flussneunauge (Lampetra fluviatilis), den Lachs (Salmo salar) und die Meerforelle (Salmo trutta).

Der  vorliegende  Bericht  liefert  eine  Übersicht  über  die  Neozoen  der  Schweizer  Fischfauna. Neben den bereits vorkommenden Arten befasst er sich mit möglichen Neueinwanderern, aber auch mit den heute ausgestorbenen, dereinst hoffentlich  wieder einwandernden Arten. Die  Situation im  Einzugsgebiet des Rheins steht dabei im Zentrum der Betrachtung. 37 Arten (bzw. Taxa) werden im Detail beschrieben.

Volltext (PDF)

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Donnerstag, 12 April 2018 20:58

DÜMPELMANN (C. & KORTE, e. (2013)

Rote Liste der Fische und Rundmäuler Hessens (Pisces & Cyclostomata).

4. Fassung (Stand: September 2013)
34 Seiten
Erstellt im Auftrag des Hessischen Ministeriums für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz (HMUKLV).
ISBN 978-3-89274-366-8.

Die der vorliegenden Roten Liste der Fische und Rundmäuler Hessens zu Grunde liegenden Daten wurden im Rahmen der Erstellung  des Hessischen Fischartenatlas erhoben und zusammengeführt. Der Gesamtdatensatz setzt sich aus den  Einträgen der landesweiten  Artendatenbank bei Hessen-Forst im Servicezentrum Forsteinrichtung und Naturschutz (FENA) sowie aus Literaturangaben,
Gutachten, belegten Hinweisen von Bearbeitern zum Hessischen Fischartenatlas und Sammlungsbelegen zusammen.

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