Fish Stock Assessment Methods for Lakes and Reservoirs:

Towards the true picture of fish stock


September 11-15, 2007


Ceske Budejovice, Czech Republic


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Latest version of the Program (*.xls)




(max. 15 mins + 5 mins discussion)

Bronze Sponsors:




Publishing House of the Academy 

of Sciences of the Czech Republic



(max. 90 x 120cm - width by length)



Morning sessions with break


Afternoon sessions with break

10th Sept. (Monday)



Registration (12pm - 10pm), 

Welcome Party, 7.30 - 10.00 pm

11th Sept. (Tuesday)

Registration (8am-12pm) 

Opening ceremony (10-10.30am)


Gillnets, Gillnets & Acoustic

Gillnets (from 10.30am)

Shallow and Specific Water Acoustic

12th Sept. (Wednes.)

Lake Acoustics 


Lake Acoustics (+ workshop 1.)

Lake Acoustics

Visit of Budvar brewery (5pm), dinner (7pm)

13th Sept. (Thursday)

Sampling With Active Gear and Fry Sampling


Trip to the Rimov Reservoir and Cesky Krumlov town (2pm), Conference banquet (7pm)

Sampling With Active Gear and Fry Sampling 

(+ workshop 2.)

14th Sept. (Friday)

Several Methods, Intercalibration, Standardization 


Several Methods, Intercalibration, Standardization

Several Methods, Intercalibration, Standardization

Demographic and Statistical Approaches

15th Sept. (Saturday)

Use of Sport and Commercial Fishing Data


Electric Gear, Visual Observation 

Use of Sport and Commercial Fishing Data

Closing ceremony


In connection with CEN effort to standardize the methodology of fish sampling, two special workshops will be held during the conference:

1.  II. European workshop on Standardized Methods for Sampling Fish with Acoustics.

Following the first workshop organised in UK in March 2005, where a draft of European standards for sampling fish with acoustics was created, the announced workshop is intended to confront this document with wider audience and the most recent findings.


2 Initial workshop on seine netting methodology for quantitative sampling of fish.

The workshop is aimed to set-up a baseline for the European seining norm and bring together the people interested in preparation of the norm draft during future workshops.

Although the workshops are primarily aimed on setting European standards, the participation of scientists from other areas is most welcomed. The workshops will be held as separate sections during the conference program. They will consist of standard oral and poster presentations followed by more extended discussion.

Biosonic Workshop - Saturday 15 September, 3pm - 7pm, info to download

Pasgear2 Workshop - Friday 14 September, ca 6pm - 8pm, info to download

Didson Demo - Tuesday 11 September, 6pm - 8pm, info to download



Preliminary list of contributions, split into days and scientific sessions . The list is now alphabetical with no assignment to time within the sessions. Please check your record and inform us in case of errors. Thank you.

Tuesday 11 Sep.

Session: Gillnets, Gillnets and Acoustics

Keynote Lecture:

Pan-European standardised sampling by gill-nets: Exploring temporal and spatial variability of lake fish assemblages.  

Kerstin Holmgren and Thomas Mehner

Oral presentations:

Spatial and temporal scales of variation among populations of fish in coastal lakes: implications for research surveys. 

C. A. Gray, D. Rotherham, A.J. Underwood, M.G. Chapman

How to calculate the fish stock population in lakes - a comparison of different methods. 

Torben L. Lauridsen, Frank Landkildehus, Erik Jeppesen

Density dependent catchability may bias species composition in gill net catches. 

Arne Linlokken

Overestimation of percid fishes (Percidae) in gillnet sampling. 

Marie Prchalová, Jan Kubečka, Milan Říha, Radek Litvín, Martin Čech, Jaroslava Frouzová, Milan Hladík, Eva Hohausová, Jiří Peterka, Mojmír Vašek

Size selectivity of gillnets for roach Rutilus rutilus, perch Perca fluviatilis and rudd Scardinius erythrophthalmus. 

Marie Prchalová, Jan Kubečka, Milan Říha, Tomáš Jůza, Jiří Peterka, Mojmír Vašek, Vladislav Draštík, Michal Kratochvíl, Josef Křížek

Biased performance of the CEN standard gillnet in productive shallow lake habitats

A. Specziár, Tátrai I., Erõs T. and Bíró P.

Sampling with pelagic gillnets in a deep eutrophic reservoir: diel fluctuation and depth stratification of fish catches. 

Vašek M., Kubečka J., Čech M., Draštík V., Matěna J., Peterka J. and Prchalová M.

Investigations on the Structure of Fish Stocks in Ataturk Dam Lake By Using Acoustical Approaches. 

Ekin Akoglu and Ali Cemal Gucu   

Session: Shallow and specific water acoustic


Keynote Lecture:

Recent advances in solving signal-to-noise problem in fisheries acoustics. 

Helge Balk, Torfinn Lindem, Frank R. Knudsen, Jan Kubecka

Oral presentations:

Winter fish distribution in the Gornoslinkinskaya Riverbed Depression in the Irtysh. 

Degtev E. A

Improved in-situ target strength measurements of fish in horizontal hydroacoustic applications. 

Georg Rakowitz, Hubert Keckeis, Helge Balk, Wolfgang Herold, Jan Kubecka

Dual frequency identification sonar (DIDSON): Application of a high definition imaging sonar for studies of fish behavior and qualitative assessment of fish distribution

Patrick Schneider

Poster session

Wednesd. 12 Sep.

Session: Lake Acoustics


Keynote Lecture:

Small-scale trawling: the state-of-art, successes and failures  

Petri Suuronen

Oral presentations:

Hydroacoustical estimates of fish abundance in lakes – what does matter? 

Doroszczyk L, Godlewska M, Długoszewski B.

Better fish stock estimates in reservoirs: day or night acoustic surveys? 

Vladislav Draštík, Jan Kubečka, Martin Čech, Jaroslava Frouzová, Michal Tušer, Oldřich Jarolím

Target strength estimation of Lates niloticus and Oreochromis niloticus using in-situ acoustic data and backscattering model. 

Inigo Everson, Robert Kayanda, Taabu Munyaho

Hydroacoustical measurements at two frequencies: 70 and 120 kHz - consequences on fish stock estimation. 

Godlewska M., Guillard J., Colon M.          

Within-year spatio-temporal variation in pelagic lake fish abundance: consequences for echosounding sampling strategies 

Thrond O. Haugen, Frank R. Knudsen

Acoustic separation of fish and a larval insect (Chaoborus flavicans) in a lake using a two frequency echosounder. 

Frank Reier Knudsen and Petter Larsson

Fish orientation along the longitudinal profile of the Rimov reservoir. 

Michal Tuser, Jan Kubecka, Jaroslava Frouzova, Oldrich Jarolim

Assessment of juvenile whitefish densities (Coregonus lavaretus L.) in a deep prealpine lake using trawling and hydroacoustics. 

Wanzenböck, Josef & Finster, Martin

Quantitative assessment of fish populations in still waters using hydroacoustics and survey gill netting: experiences with Arctic charr (Salvelinus alpinus) in the U.K. 

Winfield, I. J., Fletcher, J. M., James, J. B. & Bean, C. W.       

Seasonal Abundance of Pelagic Forage Fish and Spawning-Size Cisco in the Western Arm of Lake Superior. 

Daniel L. Yule, Jason D. Stockwell   

The study of fishes’ spatial distribution and quantity estimation in under the ice period with using of scanning sonar.            

Borisenko E. S., Mochek A. D., Degtev E. A.

Thursday 13 Sep.

Session: Sampling with active gear and Fry Sampling


Keynote Lecture:

Towards standard operating procedures for acoustic surveys in the Great Lakes: progress and remaining issues  

Lars Rudstam, Patrick Sullivan, Sandra Parker Stetter, Dave Warner, Donald Einhouse, Ted Schaner, Bernie Pientka and Dan Yule

Oral presentations:

The use of system approach for bream Abramis brama (L.) stock assessment in shallow Lake Lacha. 

Gerasimov Yu.V., Lapshin O.M., Stolbunov I.A., Bazarov M.I., Pavlov D.D., Malin M.I.

Bottom trawl biomass estimates of Lates niloticus in the kenyan waters of Lake Victoria, East Africa

Albert Getabu

The efficiency of three fry trawls for sampling the freshwater pelagic fry community. 

Tomáš Jůza, Jan Kubečka

Performance of two active sampling gears to follow density dynamics of 0+ European whitefish (Coregonus sp. L., 1758). 

Martin Finster & Josef Wanzenböck

Quantitative assessment of young of the year fish: is there correspondence between larval densities and late summer year class strength?

Stephan Hülsmann, Thomas Mehner, Annekatrin Wagner, Hendrik Dörner, Uwe Kahl, Gregor Thomas, Sven Volkmann

How to assess the development of a 0+ perch population: is one sampling method enough? 

Werner Scharf, Lisa Heermann, Jost Borcherding      

Estimation of population size of vendace and whitefish larvae: effect of variability of lake-specific vertical distributions. 

Olli Urpanen, Timo J. Marjomäki, Markku Viljanen, Hannu Huuskonen & Juha Karjalainen

Efficiency of beach seine nets. 

Říha Milan, Kubečka Jan, Čech Martin, Draštík Vladislav, Frouzová Jaroslava, Hladík Milan, Hohausová Eva, Jarolím Oldřich, Jůza Tomáš, Kratochvíl Michal, Peterka Jiří, Prchalová Marie, Tušer Michal, Vašek Mojmír

Friday 14 Sep.

Session: Several methods, intercalibration, standardisation


Keynote Lecture:

Standard Sampling Methods for North American Inland Fish: A Multi-Agency Project Coordinated by the American Fisheries Society.  

Scott A. Bonar, Wayne A. Hubert, and David W. Willis 

Keynote Lecture:

Accuracy of various methods of fish stock assessment in large Russian lakes and reservoirs. 

Vladimir G. Tereschenko

Oral presentations:

 The inland fisheries data collection in Republic of Latvia. 

Janis Birzaks, Eriks Aleksejevs, Kaspars Abersons

Sinusoidal foraging – species specific response to limited foraging opportunities in the epipelagic zone of reservoirs.

Čech Martin, Peterka Jiří, Vašek Mojmír, Kubečka Jan, Matěna Josef

Assessment of bream (Abramis brama) and roach (Rutilus rutilus) stock in the Upper Volga taking into consideration their intrapopulation spatial differentiation. 

Gerasimov Yu.V., Stolbunov I.A.

Toward a Standardised European Method for Sampling Fish with Acoustics. 

Jon Hateley, Ian Winfield

Behavioral considerations in the assessment of brook trout (Salvelinus fontinalis) populations of Sierra Nevada tarns (California, U.S.A.). 

Thomas M. Jenkins, Curtis Milliron

Gillnet catch in estimating the abundance and structure of fish stock – comparison of gillnet and trawl samples in a eutrophic lake. 

M. Olin, T. Malinen & J. Ruuhijärvi

Fish occurrence in the open water habitat of the eutrophic canyon shaped Římov Reservoir (Southern Bohemia): comparing indirect and direct methods of investigation.

Peterka Jiří, Čech Martin, Vašek Mojmír, Jůza Tomáš, Draštík Vladislav, Prchalová Marie, Kubečka Jan, Matěna Josef

Gillnet and trawl catches in estimating habitat selection, diurnal activity and structure of fish stock – predicting the catches of biomanipulation. 

J. Ruuhijärvi, M. Olin & T. Malinen

Fish assemblage in a large short-term regulated river reservoir. 

Teppo Vehanen, Juha Jurvelius and Markku Lahti

The joined use of hydroacoustic and CEN standard multi-mesh gill nets to assess the lake fish communities

C. Verges and J. Guillard

Comparison of fish catch efficiency and selectivity of four different types of gears in a shallow macrophytic Yangtze lake (Niushan Lake), China. 

Shaowen Ye, Zhongjie Li, Sovan Lek, and Sithan Lek-Ang

Session: Demographic and Statistical Approach


Oral presentations:

Stock assessment of roach (Rutilus rutilus, L.) of the Kakhovka reservoir (Dnieper River, Ukraine) using recreational fishing data. 

Didenko A.V., Buzevich I.Y., Spesivy T.V.     

Comparison of different yield predictive models to estimate fish yield in Shahpur dam reservoir, Pakistan. 

Muhammad Yamin Janjua and Daniel Gerdeaux

The state, trends and threats of the Lake Victoria fisheries and environment. 

Kolding, J., van Zwieten, P.A.M., Hecky, R.E., Silsbe, G. M. and Mkumbo, O. C.

Per-recruit simulation for a Prussian carp Carassius gibelio fishery in the Siemianówka Reservoir, Poland. 

Jacek Szlakowski

The new approach of fish stock monitoring: Method of the retrospective analysis and forecast the state of fish assemblage in lakes and reservoirs.

Vladimir G Tereshchenko

Poster session

Saturday 15 Sep.

Session: Use of sport and commercial fishing data


Keynote Lecture:

Unravelling the facts and figures about the status of the fish stocks in Lake Victoria.

Ian G Cowx

Oral presentations:

Are the stocks of cyprinids fish in lowland dam reservoirs underexploited? 

Paweł Buras

Contribution of daily fisheries statistics (obligatory and voluntary) to the knowledge of fish population in Lake Annecy (France).

Daniel Gerdeaux, Yamin Janjua

Long-term trends in sport fishery yield from different reservoirs and large rivers in the Labe watershed (Czech Republic) between 1958-2006.

Martin Jankovský

A robust method to account for influence of selectivity in multi-mesh gillnet fishing units on length-based stock assessment: A case study of Sri Lankan reservoirs. 

R.P. Prabath K. Jayasinghe and Upali S. Amarasinghe

Assessment of anglers' catches in dam reservoirs on the example of Zegrze Dam Reservoir.

Wiesław Wiśniewolski, Arkadiusz Wołos, Irena Borzęcka

Fish stock assessment in dam reservoirs in upper Vistula River basin, based on the results of the registration of anglers' catches.

Arkadiusz Wołos, Maciej Mickiewicz

Session: Electric Gear and Visual Observations


Oral presentations:

Boat electrofishing catch relative to electrode arrangement.

Kratochvíl M. & Miranda L. E.        

Visual counting of pike in a large reservoir.

Torsten Schulze, Matthias Pitsch, Stephan Hülsmann 

POSTERS                           Preliminary list of posters. Please check your record and inform us in case of errors. Thank you.


Feasibility of LeCren Method for population Estimation of Freshwater fish in Iran.

Asghar Abdoli, Rahman Patimar, Hossein Mostafavi, Bahram H. Kiabi and Pooneh Rasooli   

Range dependent bias in target strength of a calibration sphere and fish due to non spherical sound spreading in a shallow environment.

Axenrot, T., Ogonowski, M., and Knudsen, F.R.

Basic methods used for of the Russian lakes and reservoirs fish stock assessment.

Brazhnik Svetlana           

Assessment of stocks of introduced fish in the Kakhovka reservoir (Dnieper River, Ukraine).

Buzevich I.Y., Didenko A.V.

Hydroacoustic monitoring of the bathypelagic layer of European perch (Perca fluviatilis L.) fry in reservoirs: from raw ecological characteristics to particular features of fish behaviour.

Martin Cech, Jan Kubecka, Vladislav Drastik, Jaroslava Frouzova, Michal Kratochvil, Josef Matena, Jiri Jarosik, Josef Hejzlar    

Distribution of egg strands of European perch (Perca fluviatilis, L.) with respect to depth and spawning substrate

Martin Čech, Jiří Peterka, Milan Říha, Tomáš Jůza and Jan Kubečka

The management of the drinking water-supply reservoirs under the WFD.

Duras Jindrich, Hladik Milan    

Distribution of common carp in a Spanish reservoir in relation to thermal loading from a nuclear power plant.

Encina, L.; Rodríguez-Ruiz, A. and Granado-Lorencio, C.

Assessing fish assemblages in reed habitats of a large shallow lake – a comparison between gillnet sampling and electrofishing.

Tibor Erõs, Specziár A. & Bíró P

Indices of fish size from acoustic surveys on Lake Victoria.

Inigo Everson, Albert Getabu, Robert Kayanada, Anthony Munyaho, Rhoda Tumwebaze

Detailed patterns of scattering from lateral aspects of freshwater fish.

Frouzova J., Kubecka J., Mrkvicka T.

The target strength of Nile Perch, Lates niloticus based on cage experiments in Lake Victoria.

Getabu Albert                                                

A framework for developing appropriate sampling tools for designing large-scale and long-term research surveys.

C. A. Gray, D. Rotherham, A.J. Underwood, M.G. Chapman

The relationships among algae, zooplankton and fish stock levels in a small lowland reservoir.

István Grigorszky, György Dévai, Adrienn Tóth, Csaba Schnitchen, Viktória Béres, Alex Sándor Nagy

Comparative hydroacoustic and gillnet surveys of fish communities in a shallow, eutrophic lake.

Ágnes I. György, István Tátrai, Péter Bíró

Results of an attempt to quantify the reaction of zooplankton to the impact of fish.

J. Hrbáček, Z. Brandl and M. Seďa

Small but not easy – evaluation of sampling methods in small floodplain lakes.

Jurajda P., Janáč M., Kalous L., White S., Valová Z. & Ondračková M.

Atmospheric precipitation, evaporation, temperature and their influence on the fish productivity of aquatic ecosystems in different natural zones.

Kitaev S.P., Ilmast N.V

Results of use of rotenone and others ichthyocides in fish biomass definition of lakes in Europe and Western America

Kitaev S.P., Ilmast N.V.

Monitoring the Littoral Young-of-the-Year Fish Assemblages in Five Water Supply Reservoirs in the Czech Republic.

Josef Křízek, Martin Dušek

Harmonizing of acoustic and netting surveys in a multispecies reservoir system.

Jan Kubecka, Jaroslava Frouzová, Milan Hladík, Martin Cech, Eva Hohausová, Henk A.M. Ketelaars, Radek Litvín, Jirí Peterka, Mojmír Vašek, Marie Prchalová, Vladislav Draštík and Arco J. Wagenvoort


Aging Arctic charr (Salvelinus umbla) with fin-rays – a non-lethal aging method.

Kuhn, M., Gassner, H., Achleitner, D. & R. A. Patzner

The possibility of joint assertion of angling, fishing and nature conservation priorities in a reservoir (Lake Tisza, Hungary).

Alex Sándor Nagy, István Grigorszky, Csaba Schnitchen, Adrienn Tóth, György Dévai

Reproduction, growth, mortality and yield of Tilapia guineensis (Bleeker in Günther, 1862) Cichlidae) of a tropic

Charles Niyonkuru, Philippe Laleye & Jacques Moreau

Immersion mass marking of pikeperch (Sander lucioperca L.) larvae in oxytetracycline hydrochloride: marking persistence and ease of detection using fluorescence microscopy.

Peterka Jiří, Frouzová Jaroslava, Kubečka Jan, Matěna Josef     

Reduced recruitment changes trout stock structure.

D. K. Rowe

A first approach to assess reactions of vendace (Coregonus albula L.) shoals and single fish in the mouth of a pelagic trawl gear by stationary split-beam echosounding in a reservoir.

Marc Bodo Schmidt

Experience of fish number assessment in the Arkhangelsk oblast (Russia) lakes with the gill nets use.

Igor Studenov, Alexey Kozmin and Sergey Kulida  

Estimation of fish stocks using hydroacoustics and gillnet CPUE in a large shallow lake.

Tátrai I., Specziár A., Bíró P. & György Á.

Dynamic phase portrait method and the analysis of resistance of the fish assemblages.

Tereschenko V.G., Sokolovsky V.R., Strelnikov A.S., Timirhanov S.P.

Tie of variability of fish catches magnitude and structure with dimensions of lakes and reservoirs.

Tereshchenko V.G., Tereshchenko L.I.

Zooplankton (as fish nourishment) community structure in different vegetation types.

Adrienn Tóth, Katalin Zsuga, Sándor Nagy Alex

Stock status and assessment of pikeperch in Lake Peipsi-Pihkva.

Väino Vaino, Toomas Saat, Sergey Severin, Aimar Rakko


Commercial fishing: a reliable tool for fish monitoring in Italy?

Pietro Volta, C. Romano