Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Native fish species before extinction - invasive species on the increase

01.10.2018

The majority of Bavaria's watercourses are in poor ecological condition. A team from the Technical University of Munich (TUM) has now conducted the first systematic analysis of long-term data on fish stocks in the Upper Danube, Elbe and Main rivers. The team concluded that native fish species are on the verge of extinction, while the populations of some invasive species are increasing.

On behalf of the Bavarian State Office for the Environment and financed by the Bavarian Ministry of the Environment, the scientists analyzed all available fish data sets for the Bavarian catchment areas of the Danube, Elbe and Main rivers over a period of more than 30 years. They compared the current status with the historically derived reference status of the originally occurring species at the respective locations.


Kessler gobies and other goby species from the Black Sea originally came to Bavaria via the ballast water of the ships and are today strongly represented in the Danube and Main rivers.

J. Geist/ TUM

The study, published in the October issue of the journal "Biological Conservation," shows that native character species such as grayling, after which a river region was named, have suffered massive losses in terms of both area and numbers compared to their historical reference status.

A similar picture emerges for other specialized fish species whose habitats are severely affected by siltation, higher water temperatures and dammed water bodies. Many of the particularly endangered species have complex lifecycles and are dependent on special conditions during different life phases.

"If these special conditions no longer exist, or if the animals cannot migrate between sub-habitats, then they will have problems," says Dr. Melanie Müller from the Department of Aquatic Systems Biology at the Technical University of Munich and author of the study.

Formerly widespread species are strongly declining today.

A new result of the study is also that species such as the “common dace”, which were previously regarded as widespread, are also declining compared to the historical reference status. In contrast, those species known as generalists, which demand very little from their habitat, are now propagating even more.

Notable among these species are many non-native fish which were either deliberately imported to Central Europe, such as the rainbow trout or the topmouth gudgeon, or which arrived unintentionally via the ballast water of ships, such as the Pontocaspian goby species.

"In the future, we will have to be prepared to encounter increasing numbers of water bodies with new biological communities consisting of a mixture of species that would never naturally meet," says Prof. Jürgen Geist, professor at the Department of Aquatic Systems Biology and head of the study.

For this reason, systematic long-term analyses of the distribution and abundance of aquatic species are important: "The conservation of species and biodiversity must not stop at the water surface and should be based on scientific results," says Prof. Geist.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Jürgen Geist
Technical University of Munich (TUM)
Chair of Aquatic Systems Biology
Tel: +49 (8161) 71 – 3767
E-Mail: geist@wzw.tum.de

Originalpublikation:

Mueller, M., Pander, J., Geist, J.: Comprehensive analysis of > 30 years of data on stream fish population trends and conservation status in Bavaria, Biological Conservation 226; 311–320, 2018. DOI: https://doi.org/10.1016/j.biocon.2018.08.006

Weitere Informationen:

https://www.tum.de/nc/en/about-tum/news/press-releases/detail/article/34972/

Dr. Ulrich Marsch | Technische Universität München

More articles from Life Sciences:

nachricht To proliferate or not to proliferate
21.03.2019 | Max-Planck-Institut für molekulare Zellbiologie und Genetik

nachricht Discovery of a Primordial Metabolism in Microbes
21.03.2019 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

To proliferate or not to proliferate

21.03.2019 | Life Sciences

Magnetic micro-boats

21.03.2019 | Physics and Astronomy

Motorless pumps and self-regulating valves made from ultrathin film

21.03.2019 | HANNOVER MESSE

VideoLinks
Science & Research
Overview of more VideoLinks >>>