Young European sturgeon (Acipenser sturio)
Reintroduction of the European and Atlantic sturgeon
The purpose of the sturgeon reintroduction project is to help conserve one of Germany’s historically most important migrating fish. The aim is to reestablish self-reproducing populations of the two species (see below) historically found in the North Sea and Baltic Sea catchment areas. The reintroduction projects additionally aim to improve conditions for the fish in the ecosystems they inhabit, for example with integrated catchment area management to restore river regimes and improve structural diversity. Given the variety of habitats it frequents, this also means the sturgeon will prepare the way for other species with similar habitat needs, such as salmon, sea trout, houting, twait and allis shad, and other characteristic river fauna.
Release site on the Odra river.
Release site on the Oste river.
Posters and flag.
Establishment of a parental population
Just as resident species adapt to habitats naturally over time, introduced species must suit the habitats they are released into. Historically there were several geographically separate populations of European sturgeon (Acipenser sturio), and genetic analysis and description of these populations based on museum samples have formed an important part of the project. This work showed the surviving A. sturio in the Gironde to be virtually identical with sturgeon historically found in the North Sea and the rivers flowing into it. Restocking with A. sturio from the Gironde (European Atlantic sturgeon, known as European sturgeon for short) is therefore the obvious choice for reintroduction of the species to the North Sea.
The sturgeon formerly found in the Baltic Sea, on the other hand, were descendants of Acipenser oxyrinchus – North American Atlantic sturgeon, known for short as Atlantic sturgeon – a species that entered the Baltic Sea about 1,000 years ago. This means fish suitable for replenishing the Baltic Sea population can be obtained from the St. Lawrence River and the St. John River in Canada.
A self-reproducing population requires a stock of parent fish. Parent populations are currently being established for reproduction and restocking purposes in line with the recent genetic findings on the origins of North Sea and Baltic Sea sturgeon. To build stocks of A. sturio , captively bred fish have been brought to the Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin under a partnership with the CEMAGREF research institute in France. Captive breeding first succeeded in France in 2007 and 2008. These fish will be used to build up a parent population in Germany and for initial restocking trials.
Potential habitats for early development stages
An important precondition for the successful reestablishment of sturgeon is the availability of intact spawning areas along, or in tributaries of, the three rivers being considered for release sites – the Odra, the Elbe and the Rhine. In work carried out to date, spawning sites known historically from the literature have been investigated along the Odra and its tributaries. The findings so far show several stretches of water in the Odra catchment area to be basically suitable as spawning sites. Some of them first need to be returned to a more natural state. The main negative factor affecting the quality of such sites is the high level of nutrient pollution in Polish tributaries to the Odra. Gravel banks that may provide a suitable substrate for spawning have also been identified in the middle Elbe.
Development of alternative fishing techniques
Modified gillnets are currently being tried out in coastal fisheries to minimise by-catch of sturgeon in commercial fishing. While preventing by-catch, the trials aim to maintain the efficiency of the fishing gear for catching target species (zander and perch). These trials of the efficiency and selectivity of modified fishing gear are being carried out in the German part of Szczecin Lagoon. The trials involve testing various net types and mesh sizes and are taking place in cooperation with LFA MV, the Mecklenburg-Western Pomerania state research institute for agriculture and fisheries.
Initial restocking
trials with Atlantic sturgeon
(A. oxyrinchus)
May 2007 saw the first release of young sturgeon into the Odra River. The fish were all tagged and some had transmitters attached. The restocking trials were continued in 2008, and some 35,000 fish have now been released into the Odra and its tributaries. This forms part of research into sturgeon migratory behaviour and habitat utilisation in the Odra region to assess the river system’s suitability for reestablishment of a sturgeon population. A monitoring programme identifies and quantifies risk factors for survival of the young fish. The research outcomes will provide the basis for management of a possible large-scale reintroduction to follow.
Initial restocking
trials with European sturgeon
(A. sturio)
The first tagged sturgeon, some with transmitters attached, were released into the Elbe river in September 2008. A further restocking trial was launched in the Oste River in April 2009. The research on sturgeon migration and habitat use patterns in the Elbe region aims to identify the needs of the species and determine the river system’s suitability for reestablishment of a sturgeon population.
Further information:
Dipl. Biol. Dr. J. Geßner
Gesellschaft zur Rettung des Störs e.V. (Save the Sturgeon Society)
sturgeon@igb-berlin.de
Phone: +49 (0)30 64181626
Broschüre:
Nationaler Aktionsplan zum Schutz und zur Erhaltung des Europäischen Störs (Acipenser sturio)
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Viele weitere Informationen über dieses Projekt finden Sie in unserer neuen Broschüre :
Nationaler Aktionsplan zum Schutz und zur Erhaltung des Europäischen Störs (Acipenser sturio)
Diese Broschüre herunterladen
oder beim BMU bestellen:
www.bmu.de
The sturgeon
a living fossil
The sturgeon’s prehistoric traces go back 200 million years to the age of the dinosaurs. Of the 27 species worldwide, all are vulnerable or endangered. Through to the late nineteenth century, the European sturgeon was an important member of ecological communities in the rivers of northern Germany. Sturgeon habitats were largely destroyed following the industrial revolution as a result of widespread pollution and river engineering. By the early years of the twentieth century, drastic overfishing had sealed the sturgeon’s fate. Germany’s last colony survived in the river Eider until 1969. As far as western German rivers are concerned, the species has since been classified as extinct in the wild. The world’s sole remaining known population of European sturgeon is restricted to the Gironde river in France.
An exciting media event: The first release of sturgeon into the wild.
Small sturgeon with a big future.
European Atlantic sturgeon (Acipenser oxyrinchus) with marking.