Current Affairs and Information

In this section you will find information on the newest research projects at our institute, new co-operations with other institutions and various other important news

A new IfB-Newsletter (# 1, 2026) is available here !

(unfortunately, still only in German language)

Publications resulting from a project carried out by the IfB in the north-eastern Himalayan region of India

On behalf of the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, our institute supported the development of knowledge and practical skills among local and regional authorities and universities as part of a two-year project on the protection and sustainable management of aquatic resources in the north-eastern Himalayan region of India. As part of this, a series of educational, training and capacity-building events were held with our partners, during which various materials were jointly produced, including an illustrative analysis to assess the vulnerability of selected fish species to climate change, a handbook setting out principles for monitoring fish stocks in the region (link) and a handbook on the management and performance monitoring of fish sanctuaries (Link). All these resources are available for download by following the links provided or by searching our publications page.

Titlepage of the handbook on scientific methods for freshwater fish sampling, Northeast India (image: © GIZ)

Title photo of the handbook on fish sanctuaries, Northeast India (image: © GIZ)

Title page of the GIZ-report on climate vulnerability of freshwater fish, Northeast India (image: © GIZ)

Title page of the Leopoldina Report on Freshwater Aquaculture

Study: Sustainable Circular Aquaculture – Policy Report

In times of dwindling resources and increasing food insecurity, modern, cycle-oriented freshwater aquaculture can make a valuable contribution to the sustainable production of animal protein. A recently published joint report by the German National Academy of Sciences Leopoldina and the Brazilian Academy of Sciences (Academia Brasileira de Ciências, ABC) demonstrates this for Germany and Brazil.
The report contains concrete, practical recommendations aimed at decision-makers in politics and administration as well as researchers with the aim of transferring scientific results into practice across countries and further developing aquaculture in a sustainable manner.
The largely untapped potential for freshwater aquaculture in Germany and Brazil could enable increased domestic production of nutritious freshwater fish products, which is currently well below the global average in both countries. The team of authors has identified three key areas for action to better exploit this potential. These relate to regulations and approval procedures, which should be made clearer and simpler, appropriate training and further education for specialist personnel, and improved technology transfer from research to practice, which should be geared as closely as possible to local conditions, fish species, production systems and emissions management.
The full document, entitled ‘Advancing sustainability and circularity in aquaculture to build a resilient global food system’, is available on the Leopoldina website.

Newly created shallow water zone in a quarry pond (photo with permission: © F. Möllers/AVN)

Study on contributions to preservation of fish populations was awarded a globally acknowledged sustainability prize

In a six-year study of 20 quarry ponds, Prof. Arlinghaus's research group at the IGB Berlin was able to demonstrate that structural enhancement measures contribute to supporting fish populations, whereas traditional and repeated fish stocking does not. This is the first study of its kind to examine the management and protection of fish populations directly in practice using such a large sample and such a methodologically sound approach. The results of the project have been published in numerous articles, including in the renowned journal Science (https://www.science.org/doi/abs/10.1126/science.adf0895). Anglers from local clubs and waters were involved in the planning and implementation of the measures in order to build trust between the stakeholders. This combination also impressed the international jury of sustainability researchers. They awarded Prof. Arlinghaus and his team the Frontiers Planet Prize, a globally significant research prize for sustainability (https://www.igb-berlin.de/news/robert-arlinghaus-ist-national-champion-des-frontiers-planet-prize). We congratulate Prof. Arlinghaus and the entire project team on this recognition and appreciation for applied fisheries research and are delighted to now have Dr. Sven Matern, one of the scientific authors of the study and co-first author of the publication in Science, among our own ranks.

Recently launched:

Brand new English-language diary for the KoMoDo-Project. Just use the link below and you'll be right there, to find exciting information (and viusual impressions) on the day-to-day workings of this important research project.

Come and have a look!

The Project OderAngeln is launching its next round of activities!

We need you!!!

Please visit our "OderAngeln" webpage for further information

The European Eel (Anguilla anguilla) is Fish of the Year 2025

In Germany, a ‘Fish of the Year’ is chosen each year to raise awareness of endangered fish species and their habitats. In a public online vote, the European eel (Anguilla anguilla) was chosen for 2025.

Yellow Eel ("Gelbaal"; photo: J. Simon IfB)

The European eel (Anguilla anguilla) is a wanderer between two worlds. Sexually mature, so-called ‘Blankaale’ (naked eels) migrate from the inland and coastal waters of Europe and cross the Atlantic to reach their spawning grounds. These are located between the West Indies and Bermuda in an area of the sea known as the Sargassosee (Sargasso Sea). The parent eels die there after mating and spawning. After hatching, the eel larvae are carried by the Gulf Stream to the European continental shelf. During their further migration towards the coast, the eel larvae transform into transparent juvenile eels, which are on average 7 cm long and weigh 0.33 g. Some of these fish, now known as ‘Glasaale’ (glass eels), remain in the coastal area, while others migrate upstream the estuaries and colonise rivers and lakes. There they spend their main growth phase as so-called ‘Gelbaale’ (yellow eels) or ‘Fressaale’ (feeding eels; photo left) until they reach sexual maturity.

While many other native fish species reach sexual maturity after four to five years, eels in our inland waters take 10–20 years to do so. Another peculiarity of this fish species is that the males, with a maximum body length of 50 cm and a weight of 200 g each, remain significantly smaller than the females, which can grow to over a metre in length and weigh several kilograms. Once the eels have built up sufficient fat reserves, their skin takes on a silvery colour and their eyes and pectoral fins grow larger – they have transformed into silver eels (photo right) and are ready to begin their return journey to the Sargasso Sea.

Head of a male "Blankaal" (naked eel) with large eye (photo: © IfB)

For more than three decades, eel stocks have been in sharp decline throughout Europe. The current quantity of glass eels along the Atlantic coast of Western Europe is estimated to be only about one to ten per cent of the level in the comparable period of 1960 to 1979. The complex life cycle of the eel makes it particularly sensitive to changes in its environment. There are many possible causes for the decline in the eel population, and their significance is often insufficiently understood. These causes range from oceanic factors to numerous negative influences in our inland waters, such as channelisation, diseases, and pollution, to fishing by anglers and the often fatal passage of power plant turbines. The International Council for the Exploration of the Sea (ICES) is, therefore, critical of the population trend and recommends a precautionary halt to all human impacts on the population, as well as the restoration of the quality and connectivity of eel habitats.

The eel is the only native fish species with its own European Union regulation. This obliges the member states to draw up management plans for all eel catchment areas in order to replenish the stocks in our inland waters and thus increase the number of parent eels for the next eel generation. This should be done primarily by improving the protection of eels in lakes, rivers and on the coasts. In addition, it is currently necessary to stock our river basins with young eels, as only a few glass eels (photo below) currently arrive in the estuaries of our rivers and are unable to continue their journey upstream from there due to the many man-made obstacles such as weirs or reinforced banks.

Glass eel - size comparison with a matchstick (photo: © IfB)

Our institute has been dealing with eel stock development and measures to support the stock for over 20 years. One focus of our work is also the scientific monitoring of the stocking measures in several federal states. We want to contribute to the stocked eels being vital and healthy and to have optimal growth and development conditions. In this way, we want to ensure that the stocked eels are vital and healthy and have optimal conditions for growth and development. In addition, we collect data on important stock parameters such as natural immigration of young eels, growth, survival rates and the quantity of migrating silver eels. This data is used to model stock development in the Elbe catchment area and, in particular, to estimate the effect of eel stocking measures. Our results show that eel stocks in our inland waters have increased significantly in recent years. Every three years, we report on the status of the implementation of the German Eel Management Plans in accordance with the EU Eel Regulation, including in the Elbe and Oder river basins.

Links to further information: German Eel Management (German language only), the necessity of eel stocking measures, and the actual procedure of eel stocking (German language only).

On the subject:

River Landscape of the Years 2024/25 is the River Stepenitz (Elbe)

there is a new clip on the YouTube channel of the Landesanglerverband Brandenburg e.V. (LAVB). You can find the video here, and detailed information and links on the subject right below:

River Landscape of the Years 2024/25 is the River Stepenitz (Elbe)

In the context of the "Elblachs 2000" programme launched in the 1990s, the Brandenburg State Angling Association (LAVB) and the IfB started the reintroduction project for salmon and sea trout in the Stepenitz catchment area (Prignitz) in 1998, because this river is not only home to a large number of species that have disappeared in many other places, but is also characterised by a high level of preserved unspoiled nature and water quality.
In order to secure the successes of this project to date, to focus more strongly on the existing threats to one of our last intact watercourse systems, and to contribute to the further improvement of water conditions the German Angling Federation (DAFV), together with the German Naturefriends Association (NFD), selected the Stepenitz as the "River Landscape of the Years 2024/25" on 13 December 2023.

The Brandenburg Angling Association LAVB (Landesanglerverband Brandenburg) wants to engage the public and put the spotlight on these issues. Thus they have released three new videos on the YouTube channel to highlight and explain the reintroduction project for salmon and sea trout:

Video 1

Video 2

Video 3
You can find further information about this topic on the websites of the LAVB and the German Angling Association DAFV (Deutscher Angefischerverband e.V.) - in German language only

Photo (copyright Fario e.V.): Eggs of the returning salmon are harvested and fertilised at the breeding station of the association "Fario e.V."; in the following spring the Stepenitz is restocked with the juveniles.

IfB enters into co-operation with two Indian universities

In March 2024, our institute signed Memorandi of Understanding with the Universities of Don Bosco in Assam and Manipur in Manipur. More information on the event and future activities can be found in the section About Us - Cooperations, Partners and Networks - Co-operations with India

Titel page of the new Volume 65 of the IfB-publication series in polish language

Volume 65 of the IfB publication series: Development, utilisation and protection of the fish fauna in the Brandenburg Oder now available in Polish language

Thanks to the financial support of the MLUK (Ministry of Agriculture, Environment and Climate Protection of the State of Brandenburg), this important report could be translated and thus made available to our Polish colleagues. The report summarises historical and current fish data on the Oder against the backdrop of planned and ongoing development measures. Therefore it provides documentation on the ecological value of the river landscape as well as a basis for assessing the environmental impact of the Odra river development.

The report is available for download. You can find it in our publication database.

If you require a printed copy, please contact the IfB by email.

Article on Eels in peer-reviewed journal:

Does it make sense to restock glass eels in Winter?

The population of the European eel is at an all-time low. This is to be counteracted throughout Europe by various measures. One of them is stocking. This involves catching glass eels after their arrival on the European coasts and transferring them to inland waters which they can no longer reach due to the blocking of rivers with weirs, locks, etc. Because of the critical state of the eel stock, this stocking must be carried out carefully and expertly. Traditionally, this is done in spring to provide the young eels with good starting conditions in inland waters. Due to warmer winters and better availability of glass eels in January and February, more glass eels have been restocked in Germany in the winter in recent years. However, it is not known whether lower temperatures and food availability at this time affect the survival of glass eels. A recent study by the IfB has now investigated this question. The results show that the survival rate (19-45 %) and growth performance of glass eels restocked in winter are comparable to those of glass eels restocked in spring. This makes stocking glass eels in winter a suitable alternative to traditional spring stocking.

Aussetzen von Glasaalen Find a link to the original article here

The Common River Mussel (or brook mussel, Unio crassus) Project, Brandenburg

Common River Mussels (image: M. Zauft, with permission)

In the last week of March 2023 the starting signal was given:

Minister Vogel started a project funded by the EU-Life-Programme, which will take care of the conservation of the Common River Mussel (or brook mussel) populations in Brandenburg over a period of 10 years!

The IfB is involved as a co-operation partner doing various studies and activities; the project is managed by the Brandenburg Nature Conservation Fund Foundation, with the Stuttgart Natural History Museum an additional co-operation partner.

We are very pleased about this success of our team in the Fish and Aquatic Ecology Department, which prepared and obtained the participation in this large project.

Here is the link to the official press release of the Brandenburg Ministry of Agriculture, Environment and Climate Protection.

In May 2023, the new Brandenburg Common River Mussel project actually started and the first work was carried out by IfB staff: more than 300 minnows were released in the Barolder Mühlenfließ. As native host fish species, minnows play a very important role in the life cycle of the endangered brook mussel.
The project-managing foundation NaturSchutzFonds Brandenburg has issued a press release on this activity (in German language, only).

Gravel infill on the Rhin - part of the LIFE Bachmuschel project plan (image: M. Zauft, with permission)NaturSchutzFonds Brandenburg)

"Fischforum am Jägerhof" 2024 - Training event at the Institute

A detailed report ("Nachlese") about the institute's training event in February 2024 has been released and also published in the January 2025 issue of the trade journal "Märkischer Angler" (German language only). The event was well received and topics vividly discussed. Day 1 was all about the various marketing strategies for fisheries and whether the sektor analyses done by the IfB in the current years were able to provide supporting insights for improving such strategies. On Day 2 waterbodies and fishstocks were discussed, and options for their development and management.

New articles in peer-reviewed journals authored by IfB-scientists

In the article: Effects of mining activities on fish communities and food web dynamics in a lowland river, co-authored by D. Hühn, the macrozoobenthos and fish communities in the Spree above and below a dam, where significantly different iron concentrations occur in the water, were compared. The main fish species in the highly iron-loaded water above the dam tended to feed on terrestrial food animals (insects) more than the species in the less iron-loaded water below the dam. While the communities above and below the dams did not differ in their composition, their growth was significantly different due to the energetically different food.

In the article: Optimising the mass marking of fish with alizarin red S: an example with glass eels by Janek Simon, published in the Journal of Fish Biology, deals with the optimised marking of eels with alizarin red S. The marking of fish is an important tool for fisheries management, especially for evaluating the stocking success of endangered fish species such as eels. In order to improve the tagging of glass eels with Alizarin Red S (ARS) and to reduce tagging costs, the study conducted laboratory experiments under different conditions (e.g. temperature, ARS concentration, immersion time, fish density) and with ARS from different suppliers. Among other things, two options for reducing labelling costs were identified. This creates the conditions for organising larger marking campaigns in a cost-efficient manner.

You can also download the article from our website in the publications section.

In the article: Sodium chloride (NaCl) as a treatment against trichodiniasis for pike perch (Sander lucioperca) in recirculating aquaculture systems by C. Naas et.al., published in Aquaculture International, deals with the treatment of ectoparasites in the aquaculture of pike perch. In the experiment presented, pikeperch from the Sacrower See net pen were transferred to recirculating aquaculture systems (KLA) with different NaCl concentrations. During the 21-day period, it was tested whether the ectoparasites naturally found on the pikeperch could be reduced or even eliminated using NaCl (0, 3, 6 g l-1). The use of 3 g NaCl l-1 proved to be insufficient despite the significant reduction in ectoparasites. Under conditions of closed KLA, however, the ectoparasite density of a representative of the Trichodidinae family could be completely eliminated with the aid of continuous exposure to 6 g NaCl l-1.

EFRE building project successfully completed

"Fischforum am Jägerhof" 2023 - Training event at the Institute

The face-to-face event was very well attended and focused intensively on carp pond management and its current challenges on the event's first day, 15 February 2023. Presentations by IfB staff and guests were very informative and were lively discussed by the carp pond farmers and trout producers present. The second day, on 22 February 2023, was similarly structured, dealing with the topic of eel and pike-perch and their management in inland waters. This topic was primarily aimed at commercial and angling fisheries as well as fisheries authorities.

Please read the detailed (German language) report on the Fischforum 2023, which was also published in the trade journal "Märkischer Angler", issue 02/2023.

Event review on the twin anniversary celebrations in September 2023: 100 years of Inland Fisheries Research at the "Jägerhof" site and 30 years since the founding of the IfB

On 23/09/2022, Brandenburg's Minister of Agriculture Axel Vogel and Saxony-Anhalt's Minister of Agriculture Sven Schulze congratulated on a twin anniversary at the Jägerhof on Lake Sacrow together with representatives of the state governments of Thuringia and Schleswig-Holstein as well as associations, companies and authorities: Research into fish stocks and their use began here 100 years ago. And for 30 years, the Potsdam Institute of Inland Fisheries (IfB) has existed as an independent research institution on the basis of funding agreements with several federal states.

On 24/09/2022 the gates and doors of the Jägerhof were opened wide for the public to take a look behind the scenes of the work at the Institute. And the interest in the IfB's open day was great - more than 300 visitors found their way to us. Be it at demonstrations on small organisms in our waters, or at the various stations on fishery sampling devices, on inland fisheries, on aquaculture in climate change, on fish farming in recirculation systems, or even on the professional cutting and filleting of fish for cooking - lively discussions between visitors and Institute staff ensued everywhere.

At the Sacrow fish pull at the end of the open day, the handling of a pull net was demonstrated. The visitors could convince themselves of the delicious taste of freshly smoked Brandenburg fish at the stall by the lakeside.

Some impressions of the events can be gained here.

Information on research projects with current relevance

(ongoing or completed)

Development of the German Eel population model GEM IIIb

In connection with the development of the eel management plans for the German eel river basins (EMUs) and the preparation of the related implementation reports, the German Eel Model (GEM) was developed in cooperation with the Thünen Institute for Baltic Sea Fisheries in the period 2008-2017. This is an Excel-based, modular stock model that estimates the migrating silver eel quantity based on the stock input variables (natural increase, stocking), taking into account various mortality factors (natural mortality, commercial and recreational fishing, cormorant, hydropower plants). The GEM can be used to calculate both the reference value, the current silver eel outmigration and the future outmigration (forecast).

In order to enable the use of the German Eel Stock Model (version GEM IIIb) for further river basins, fish species and questions, a German-language version (Aalmodell GEM III_B-Version_Elbe_deutsch.xlsx) and an English-language version (Eelmodel GEM III_B-Version_Elbe_english.xlsx) can be downloaded free of charge. Furthermore, a German-language guide (Kurzbeschreibung_AalmodellGEM III_B-Version.pdf) is available on the structure of the model, how to use it and on the basic possibilities of use and results.

For the adaptation of the model to other river basins, but also for changes/precisions of basic model input variables, various model adaptations are necessary. For this purpose, an overview of all necessary model adaptations has been prepared and special Excel-based calculation tools have been developed, which you can view and download individually (see list below). Each of these tools contain corresponding calculation tables as well as a data sheet "ReadMe", in which the methodical procedure, the necessary input data, the calculations as well as the results are explained.

For further information and questions, please contact our staff member, Dipl.-Fischereiing. Erik Fladung, directly via .

Spreadsheets for model adaptation(in German language)

Animal Welfare Index - an analysis tool to assess animal welfare in pikeperch farming

In the joint project "IBETA", funded by the Federal Ministry of Agriculture (BMEL) and supervised by the Federal Agency for Agriculture and Food (BLE), an analysis tool for assessing animal welfare during pikeperch fattening in recirculation systems was prepared by the IfB. The aim was to develop a simple tool for fish farmers to objectively, methodically and uniformly check and communicate their animal welfare approaches and results without certification costs to consumers, fisheries and veterinary authorities.

The analysis tool is based on an Excel spreadsheet. It is quite easy to use, however, the tool covers a complex subject matter.

In the BLE press release on the project, a presentation on the topic is linked, which allows an introduction.

Following many years of experience with pike-perch rearing, we have developed and tested the approach on this species as a model. However, it can also be adapted for other aquaculture candidates, husbandry forms and husbandry stages. This was successfully demonstrated by our partners at the Landwirtschaftliches Zentrum Baden-Württemberg, Fischereiforschungsstelle (FFS) Langenargen, who were able to use rainbow trout as an example,

The analysis tool developed for the pikeperch, including operating instructions, can be downloaded, as can the final report on the IBETA project.

Fish Species Distribution Database - we would welcome your particpation!

Climate Change and Aquaculture

The "Forellenhof" , an aquaculture farm in Themar, Thuringia, is a cooperation partner for an IfB pilot project where the IfB is testing various methods of pathogen reduction in aquaculture facilities. Climate change is responsible for the warming of surface water used in aquaculture facilities. Warmer water often also carries higher concentrations of pathogens. In the project, ozone, UV and peracetic acid are being tested as pathogen-reducing measures to ensure the welfare of fish in aquaculture. A programme by the MDR radio station dealt with the project and also conducted an interview with the IfB's project leader, Dr Christopher Naas,which can be viewed here.

If you are interested in more detailed information on our ongoing or completed projects, please also visit our Publications page, where you can find and download themed issues (on individual topics) and annual reports (on current projects) based on the IfB publication series.

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