Projects

Methodology of predatory fish quantification in drinking-water reservoirs to optimize the management of aquatic ecosystems

Project No. QK1920011

Principal investigator: RNDr. Petr Blabolil, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Applied Research Program of the Ministry of Agriculture for the period 2017–2025

Duration: 2019–2021

The aim of the project is to develop a methodology for quantification of predatory fish to optimize the management of drinking-water reservoirs using data from the investigator s comprehensive database and practical field tests. This main output together with the other outputs (proven technologies to use environmental DNA from water, longlines to determine the populations of European catfish and universal antenna systems, and prototype fish picking equipment from a large fyke-net) are the key for the effective planning of the fisheries management aiming to influence the food chain by predation on planktivory fish. This will positively affect water quality.

 

Aquaculture of rheofilous fish

Project No. QK1920326

Principal investigator: Mgr. Peter Podhorec Ph.D., South Bohemian University, Faculty of Fisheries and Protection of Waters

Co-investigator: RNDr. Marek Šmejkal, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Applied Research Program of Ministry of Agriculture for the period 2017–2025

Duration: 2019–2021

The impacts of anthropogenic changes on the river environment lead to decrease of abundance and diversity in rheophilous fish communities. One of the possibilities to enhance native populations, especially where natural recruitment is not successful, is stocking of trained fish with high probability of their survival. Fish produced in aquaculture environment are formed by different selection pressure than fish in the natural environment. Although it seems impossible to maintain whole spectrum of natural behaviour in aquaculture while keeping the efficiency on the same level, it is at least possible to improve condition of stocked fish and escape reactions to predators. Production of rheophilous fish in conditions with enhanced emphasis on their condition and with acquired reaction to predation may potentially improve the stocking efficiency of rheophilous fish. Model fish species used in this study is the rheophilous asp (Leuciscus aspius). This species is produced as important community component of water drinking reservoirs, where it decreases the number of omnivorous fish species. Asp reared in artificial conditions will be divided in four groups and we will test the effect of condition (water speed during rearing) and presence/absence of alarm cues from predation on the survival rates of stocked fish in natural environment. We will assess relative survival rates three times a year (spring, summer and autumn) and the impact of improved conditions of rearing to survival will be evaluated.

 

Biomanipulation as a tool for the improvement of reservoir water quality

Project No.: CZ.02.1.01/0.0/0.0/16_025/0007417

Principal investigator: Prof. RNDr. Jan Kubečka, CSc., Mgr. Tomáš Jůza, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Ministry of Education, Youth and Sport of the Czech Republic administrate the support provided from EU funds

Duration: 2018–2022

Water is the most important of global resources and therefore strong emphasis is placed on sustaining its high quality. Due to climatic changes, water resources are exposed to various climatic extremes and only healthy ecosystems with good ecological potential are able to withstand these changes. Surveys have shown that most of the reservoirs in the Czech Republic are in an unsatisfactory state and amendments to improve this situation will have to be implemented in the near future. Evaluation of the ecological potential has clearly shown that the cause of this negative state is eutrophication, stemming from increased loads of phosphorus and nitrogen into water bodies. A successful biomanipulation, or the achievement of better water quality through targeted changes in the food chain, requires interventions in the watersheds which lead to decreased nutrient loading into reservoirs as well as development of bulk reduction fishing. The aim of the project is a unique wholelake experiment with the monitoring of all of the important parts of the reservoir food chain before, during, and after a targeted manipulation. The project will evaluate the effect of reducing the stock of undesirable fish species and the proliferation of predatory fish species on specific trophic levels, and, ultimately on the improvement of water column transparency and water quality in selected reservoirs. The majority of the biomass of planktivorous fish will be removed from three model reservoirs differing in nutrient load (trophy). At the same time, predatory fish will be introduced. Detailed monitoring of the entire reservoir ecosystem from fish, zooplankton, fytoplankton, macrophytes, and bacteria to nutrients and reservoir metabolism will help uncover the effects of such a vigorous manipulation. The economic rentability of these biomanipulations will also be evaluated, with the aim to put into numbers the difference between the costs and the savings due to the improvement of ecological potential (Water Framework Directive). Other savings can include easier treatment of raw water in waterworks processing or an increase in the recreation potential. According to the Water Framework Directive, all European Union member states are expected to reach at least good ecological state of water bodies by the year 2027. Biomanipulation represents one of the important tools to fulfill this ambitious goal.

 

Floating green islands, a perspective alternative for improvement of ecological potential and support of littoral habitats in water reservoirs

Project No.: TH02030633

Principal investigator: Prof. RNDr. Jan Kubečka, CSc., Doc. Ing. Josef Hejzlar, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: Technology Agency of the Czech Republic

Duration: 2017­–2020

The aim of this project is to develop floating islands technology for reservoirs application (construction design, substrate, composition of plants and field tests of mechanics and ecosystem benefits). The target of the project is the littoral habitat, which is normally the richest habitat of natural lakes. In most of our reservoirs it is eco-hydrologically degraded due to water level fluctuations. Aquatic macrophytes are destroyed here by drying and freezing or due to shading by low transparency. Project outputs will enhance the ecological potential of reservoirs by supporting species diversity of aquatic organisms, the structure of the fish stock, nesting of waterfowl, nutrient reduction, water quality and aesthetic value.

 

Development of technical measure for protection of natural riverine fish stock against masive migration of undesirable fish species from Lipno reservoir as encouragement of population of brown trout and freshwater pearl mussel Margaritifera margaritifera

Project No.: TH02030709

Principal investigator: Mgr. Milan Muška, Ph.D., Prof. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: Technology Agency of the Czech Republic

Duration: 2017–2020

The aim of the project is to select suitable location and develop mobile migration barrier above the Lipno reservoir. The barrier must not influence either the river flow or transport of debris, but have to effectively prevent reservoir fish from migrating into upper Vltava river catchment. Effectively operating barrier assures undisturbed development of indigenous salmonid assemblage in upper Vltava river improving hereby the essential requirements for reproduction of critically endangered Pearl mussel. Simultaneously, the location of the barrier should allow finding suitable spawning habitats for desirable fish species from the reservoir. Developed technology will be applicable to many similar places where regulation of fish migration is necessary and building weirs is not possible.

 

Strategy AV21 – Diversity of Life and Health of Ecosystem - Activity: Fish pheromone role in timing and synchronization of reproduction 

Project No. 580310/992200

Principal investigator: Mgr. Marek Šmejkal, Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Academy of Sciences

Duration: 2017

Many fish species inhabit turbid aquatic environment which ultimately disable precise visual communication among individuals and reliable identification of their mates. Chemical communication may provide crucial information about sex and sexual maturity of encountered individual. Hence, fish species that has such ability may lower the possibility of wasting milt and eggs with immature individual or different fish species. As a model organism, we investigate chemical communication in asp (Leuciscus aspius) inhabiting rivers and reservoirs of Central and Eastern Europe. This research combines field passive telemetry study with laboratory analysis of pheromone presence in varying gonadal development state of females as well as experimental tests of pheromone function on males. Fish pheromones are potentially important tool for regulation of invasive species, many of which are cyprinid species closely related to asp. This research is made in close corroboration with Centre Algatech – research group of RNDr. Pavel Hrouzek, Ph.D.

 

 

Co-creating a decision support framework to ensure sustainable fish production in Europe under climate change (ClimeFish)

Project no.: 677039

Principal coordinator: Prof. Michaela Aschan, University of Tromso, Norway

Principal investigator of freshwater sector: Prof. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: EU Horizon 2020

Duration: 2016–2020

Read more: http://climefish.eu/

Scientist from 16 countries join forces to help ensure that the increase in seafood production comes in areas and for species where there is a potential for sustainable growth, given the expected climate changes. In ClimeFish they will provide a support framework for decision makers, thus contributing to robust employment and sustainable development of rural and coastal communities. In Czech part of the project we intend to rationalize the angling use of fish production under changing environment.

Why: Climate changes are real, they are happening right now and they are threatening sustainable growth in aquaculture and fisheries worldwide. The world population is growing, and the demand for food is increasing. Forecasts indicate an overall decline in food production due to climate change. ClimeFish addresses the necessity of changes, both when it comes to utilizing opportunities and mitigating risks under climate change. ClimeFish will help ensure that the increase in seafood production comes in areas and for species where there is a potential for sustainable growth. IN Czech conditions the growth of production is complicated by the changes of nutrient concentrations and angling effort. All these factors will be considered.

What: ClimeFish will provide guidelines for how to make climate-enabled management plans to prepare and adapt to climate change while minimizing economic losses and social consequences. Thus, based on the expected climatic challenges, ClimeFish will contribute to robust employment and sustainable development of rural and coastal communities. The output of the project will be the ClimeFish Decision Support Framework (DSF), which contains guidelines, databases and the ClimeFish Decision Support System (DSS). The results of the project will be used for optimization of fishery in Lipno reservoir and other waterbodies.

How: ClimeFish will develop forecasts for production scenarios that will serve as input to socio-economic analysis and identify risks and opportunities regarding climate changes. Strategies to mitigate risk and utilize opportunities will be identified in co-creation with stakeholders, and will serve to strengthen the scientific advice and to improve long term production planning and policymaking. The project addresses three production sectors: marine aquaculture, marine fisheries and lake and pond production in a total of 16 case studies, involving more than 25 species. For Czech fisheries, the main target species are wells, Silurus glanis, pikeperch, Sander lucioperca and carp, Cyprinus carpio.

 

Changes in fish isotopic signals: linking land use and reservoir food webs

Project No. 15-01625S

Principal investigator: Mgr. Mojmír Vašek, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2015-2017

This project aims to evaluate the impacts of anthropogenic nutrient subsidies on food web structure and functioning in reservoir ecosystems. Carbon and nitrogen isotope signals of key fish species will be measured in a representative sample of Czech reservoirs. The isotopic compositions of top consumers, combined with environmental monitoring data, will allow us to explore how the intensity of catchment land use affects food web dynamics, trophic interactions and energy flows in recipient reservoirs. Specifically, in this project a unique set of archived fish scales will be analysed for isotopic composition and the obtained results will be used to track historical changes in reservoir productivity and nutrient loading. We expect that changes in anthropogenic nutrient inputs can affect carbon cycling at the base of reservoir food webs and, consequently, these changes in carbon cycling are transferred to the top of food webs and reflected in isotope values of fish scales. Further, we intend to use a broad set of contemporary spatial data to examine whether reservoir fish community structure and fish scale isotope values reflect the intensity of catchment land use. We will compare reservoir catchments contrastingly influenced by human activities and we expect that the extent of human activities in catchments should significantly affect both community structure and isotopic composition of reservoir fishes. Finally, using both stable isotopes and traditional gut content analyses, we want to explore how trophic position and resource utilisation in reservoir fishes are influenced by anthropogenic nutrient subsidies and reservoir morphology. We expect that both anthropogenic nutrient inputs and reservoir morphology may have strong impacts on trophic niche differentiation in reservoir fishes. The project will provide novel results that improve our knowledge of functional links between aquatic ecosystems and surrounding landscapes, and can also help to formulate sound protection and management plans for freshwater catchments.

 

Long-term effect of fish reduction on Daphnia in a large reservoir and confounding effect of changes of carbon and phosphorus load from the watershed

Project No. 15-24309S

Principal investigator: RNDr. Jaromír Seďa, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2015–2017

Socio-economic changes in Europe in 90-ties caused changes in nutrient cycling in managed coutryside.  Project goal is to explain the changes in the structure of reservoir trophic cascade nutrients-phytoplankton-zooplankton under long-term trends of decreasing phosphorus loads and in parallel increasing loads of terrestrial dissolved organic carbon.

 

Strategy AV21 – Diversity of Life and Health of Ecosystem - Activity: Monitoring of cryptic species having indicative value using harmless sampling methods

Project No. 580300/991100

Principal investigator: Mgr. Petr Blabolil, Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Academy of Sciences

Duration: 2015-2016

Monitoring changes of biota composition and abundances is important to evaluate changes in the environment. These environmetal shifts on scales from local catchment management to global changes are especially evident in water ecosystems. One of the most sensitive elements are fish integrating all lower parts of the trophic food-web. However, most of the current research is dedicated to dominant fish species, that can be easily captured using common sampling equipment. Cryptic species, sensitive to environmental changes, are often neglected. The aim of the project is to develop and verify new monitoring scheme using harmless sampling methods (electrofishing, fyke-nets, SCUBA diving) in reservoirs.  Model species are burbot (Lota lota) and stone loach (Cobitis elongatoides). Both endangered species and good ecological quality elements. 

 

 

Structuring effect of submerged macrophytes on trophic relationships and distribution of fish in deep lakes (MacFish)

Project No. 7F14316

Principal investigator: RNDr. Jiří Peterka, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Co-investigator: Karl Oysten Gjelland, Ph.D., Norwegian Institute for Nature Research

Financial support: Czech-Norwegian Research Programme

Duration: 2014-2017

Predation by fish is the primary top-down structuring force in aquatic ecosystems, and a change in predator-prey interactions involving fish may cause a change in the strength of trophic cascades and finally result in ecosystem shifts. Submerged macrophytes play an important role beyond that of primary production, as they provide increased structural complexity and niche potentials for fish. However, most of the scientific attention on habitat use in fish and the influence of macrophytes have been given to small and shallow lakes, where the vegetated areas are well-developed and the availability of a large deep water refugium is absent or limited. Our goal is to gain a detailed understanding of the structuring effect the submerged macrophytes have on fish communities in deep lakes. In order to achieve this, we will contrast two newly formed deep lakes of similar size and colonization history, but one with and the other without submerged macrophytes. We will use the latest developments in high-resolution positioning telemetry to assess individual habitat use and activity patterns in the different species of the multispecies assemblages in the two lakes. This will be combined with other sampling techniques, such as echosounding, acoustic cameras, video cameras, electrofishing, trawling and gillnetting, with an emphasis on the non-lethal methods and covering all ontogenetic stages from fish larvae to mature adults. Individual trophic position will be assessed by diet studies and stable isotope analyses. We will use the resulting data to study intra- and interspecific overlap in habitat and trophic niche use, as well as activity patterns with high spatiotemporal resolution. Combined with consumption estimates in piscivorous predator fishes and life-history characteristics such as growth and age at maturation in prey fish, a comprehensive and detailed insight into the effect of submerged macrophytes on the fish community structures and dynamics will be reached. The project will provide novel basic research results that will have important relevance for the management and restoration of water bodies, and it will strengthen the cooperation and knowledge transfer between Czech and Norwegian aquatic ecosystem research.

 

Hydroacoustical distinguishing between fish and bubbles, and quantification of methane bubble ebullition in freshwater reservoirs of temperate zone

Project no: P504/12/1186

Principal investigator: Ing. Jaroslava Frouzová, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Co-investigator: Ing. Petr Stanovský,  Ph.D., Department of Multiphase Reactors, Institute of Chemical Process Fundamentals of the ASCR, v. v. i.

Financial support: Czech Science Foundation

Duration: 2012-2015

The acoustic parameters of rising methane bubbles will be measured by echosounders at different frequencies at man-made bubbles. The special algorithms using multi-frequency record will be developed to distinguish the bubble echoes from the fish echoes having the same acoustic size. The obtained method will be used to estimate of fish abundance and biomass more accurately. Further, the model describing the bubble rise and dissolution in will be modified for freshwater lakes. The relation between bubble volume and acoustic echoes from experiments with m an-made bubbles will be used to gain more exact data about the amount of the methane bubbles ebullated from the chosen reservoirs in temperate zone. The spatiotemporal changes in their productions will be monitored also. At the end, the research should enlighten the correlation of the quantity and quality of ebullated methane bubbles with the environmental conditions.

 

Centre for Ecological Potential of Fish Communities in Reservoirs and Lakes (CEKOPOT)

Project No. CZ.1.07/2.3.00/20.0204

Principal investigator: Doc. Josef Matěna, Ph.D., Prof. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: Ministry of Education, Youth and Sport of the Czech Republic administrate the support provided from EU funds

Duration: 2012–2015

Fish communities in reservoirs and lakes are highly valuable from genetic, ecological and economical point of view. They have also substantial influence on the water quality in these ecosystems. The project enables support of a top quality team for the synthesis of functions mentioned above and for the definition of ecological potential of fish communities. We assume improvement and widening of methods presently used and investigation of fish stock of the most important and interesting reservoirs in the Czech Republic. At the same time, the Czech activities will be interconnected with European initiatives in order to publicize the huge effort of the Czech limnological school for explaining the true picture of the fish communities and their role in the ecosystem. The complex specification of the ecological potential (faunistic, fish-productive and biomanipulative value, equilibrium of the population dynamics a trophic interactions) will be possible by enhancement of inland human resources, support of external stays on top institutions, integration into European structures and close cooperation with an external expert. The engagement of a top expert in the field of hydroacoustics As./Prof. Helge Balk from Norway enables the improvement of methods especially the data collection in shallow water layers (0-5 m).

A new methodological approach have been planned – the analysis of stable isotopes in fish which should help us to clarify the role of particular species and its ontogentical stage in the food webs of ecosystems studied.

In the framework of the project a field course and one world conference dealing with the function of fish in the reservoir ecosystem will be organized.

The outputs of the project will be as follows: i) final establishment and stabilization of the working group FISHECU, ii) involvement of the Czech Republic into the European intercalibration net (JRC-EEWAI intercalibration forum, Lake-Fish Intercalibration Group LFIG), iii) production of scientific papers, iv) external stays of our scientists and students oriented on hydroacoustics and methods of stable isotopes studies.

 

Get out! she signalized: sex segregation of freshwater fish

Project No. P505/12/P647

Principal investigator: RNDr. Marie Prchalová, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2012-2014

Sex segregation is widespread in animal kingdom. But it has not been investigated much in freshwater fishes. The guppy is the only aquatic vertebrate for which hypotheses of sex segregation were verified. In this project we will study sex segregation of the five most common fish species of lentic freshwaters of Europe. Using gillnet sampling and segregation coefficient we will be able to say whether fishes are sexually segregated and how (habitat vs. location segregation). Three potential reasons for segregation will be tested (predation pressure, water temperature, food availability). Sex dimorphism will be studied in detail as well. Parameters as life expectancy, growth, condition, length-weight relationship and morphology of branchial sieve will be compared between sexes. Females of the target species can be more active and have better condition, which could bias the representativeness of gillnet sampling. Thus we plan an easy experiment when we will perform gillnet sampling in a rented pond stocked with a completely known fish community in terms of sex ratio and condition.

 

Freshwater sport fish management and enhancement

Project No. 2010-001577

Principal investigator: J. Wesley Neal, Robert Kroger, Craig G. Lilyestrom

Financial support: Puerto Rico department of Natural and Environmental Resource

Duration: 2009-2014

Subcontract: Threadfin shad prey production in tropical reservoirs

Subcontract number: 080300-341539-01

Subcontractor: RNDr. Marie Prchalová, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Subcontract duration: 2009-2011

Much of the research and management decisions for largemouth bass Micropterus salmoides in Puerto Rico have been based on the assumption that prey availability is not limiting, yet conclusive data to this end are not available. Threadfin shad are the primary prey species for sport fish in Puerto Rico reservoirs, yet directed research has never effectively quantified threadfin shad abundance or annual production. Threadfin shad appear to reproduce year-round, but the extent of reproduction in not known. Whereas effective largemouth bass management requires consideration of both predator and prey, improved understanding of prey population dynamics is required for reservoirs in Puerto Rico. The subcontract comprises two jobs - comparison of active versus passive gears for sampling threadfin shad in Puerto Rican reservoirs and population dynamics of threadfin shad in Puerto Rico.

 

Predator avoidance strategies in early life stages of percid fishes

Project No. 206/09/P266

Principal investigator: RNDr. Martin Čech, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2009-2011

The project is focused on predator avoidance strategies of early life stages of percid fishes – European perch Perca fluviatilis L., zander Sander lucioperca (L.), ruffe Gymnocephalus cernuus (L.) - in stratified canyon-shaped reservoir, non-stratified shallow reservoir and opencast mine lake. It follows up the recent finding that percid fry are able to create sympatric ecological groups with different behaviour (Čech et al. 2005). This is supposed to be an excellent strategy of the species to avoid predation pressure, which would be of different level in different main habitats and in different water bodies. A special attention will be paid to the newly discovered community of bathypelagic percid fry in stratified canyon-shaped reservoir (Čech et al. 2005, Čech & Kubečka 2006, Čech et al. 2007a, b, Kratochvíl et al. 2008), which most probably changes to bottom-dwelling community in case of non-stratified shallow reservoir and to dense deep water vegetation-dwelling community in opencast mine lake. The effectiveness of individual strategies will be evaluated using various new approaches including scientific sonars (SIMRAD), acoustic (DIDSON) and underwater camera for monitoring of behaviour of both prey and predator and SCUBA divers for quantitative fry sampling in dense vegetation.

 

Calibration of sampling methods for Spanish fish populations in reservoirs

Project No.

Principal investigator: Doc. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Project partners: ECOHYDROS, S.L., Spain, Department of Ecology of the Universidad de Sevilla, Spain

Duration: 2009-2010

The project is aimed at improvement of ecological potential of Spanish reservoirs and enhancement of fisheries management by improving the methods of assessment of qualitative and quantitative composition of the fish stock. The project includes introduction of active methods of monitoring, namely new hydroacoustic and trawling approaches. Active methods should mitigate the main weaknesses of the current monitoring based predominantly on passive methods. Managing of the use of active trawling gear for fish capture would represent the revolution both in monitoring and the management of reservoirs. The project follows the philosophy of the EC water framework directive 2000/60/EC and promises to create new fish monitoring methodology and to bring new crucial knowledge to the methods of fish capture in general.

 

Estimation of fish yield potential in lakes, fish assessment in Lake Werbellinsee

Project No.

Principal investigator: Doc. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Project partner: Institut für Binnenfischerei e.V. Potsdam-Sacrow

Duration: 2009-2010

The investigations were be carried out on Lake Werbellinsee in September 2009 by using the following methods:

1) Hydroacoustic survey by scientific echosounder (two day and night surveys)

2) Survey of the open water fish by fry trawls (approximately 20 trawlings by 3x3 m trawl)

The emphasis of the survey work was on the population assessment (abundance, spatial and vertical distribution, species and size composition) of vendace (Coregonus albula) and smelt (Osmerus eperlanus).

 

Monitoring the environment of man-made lakes: what can fisheries data and models tell us?

Project No. A/CZ0046/2/0029

Principal investigator: MSc. David Boukal, Ph.D., Doc. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: EEA Grant/Norway

Duration: 2009-2010

Research and development of a comprehensive database on fish population dynamics and history of exploitation in selected man-made reservoirs in the Czech Republic. Development of mathematical models to identify exploitation strategies that take into account stakeholder interests along with the ecological and evolutionary consequences of the exploitation, with the aim to identify the 'best' strategies and identify data/parameters/processes whose measurement can greatly improve the quality of the monitoring of the status of fish stocks in Czech man-made reservoirs. Communication of the main scientific findings to the key stakeholders identified during this study.

 

Optimalisation of the biomanipulative effect of predatory fish in ecosystems of water reservoirs

Project No. QH81046

Principal investigator: Doc. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: National Agency for Agriculture Research

Duration: 2008-2012

Účelem navrhovaného projektu je zvýšení efektivnosti managementu rybích obsádek vodních, prioritně vodárenských nádrží. Jedná se o jeden z ekotechnických způsobů, jak omezit projevy eutrofizace, včetně rozvoje sinic. Projekt je zaměřen hlavně na bolena dravého a též na candáta, tedy na dva velmi perspektivní druhy ryb pro biomanipulace pelagických ekosystémů, kterými údolní nádrže jsou. Pro oba druhy také není dosud vyjasněn jejich vzájemný vztah, což brání efektivnímu využívání jejich biomanipulačního potenciálu. Pozornost je soustředěna na odchov, potravní chování, vysazování a na přežívání vysazených ryb ve vodárenských nádržích. Zároveň dojde k využití a zachování původního genetického zdroje bolena dravého.

 

Monitoring of the fish stock of Czech reservoirs

Project No. CZ0091

Principal investigator: Doc. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: EEA Grant/Norway

Duration: 2008-2010

The project is aimed at improvement of ecological potential of Czech reservoirs and enhancement of fisheries management by improving the methods of assessment of qualitative and quantitative composition of the fish stock. The project includes introduction of active methods of monitoring, namely new hydroacoustic and trawling approaches. Active methods should mitigate the main weaknesses of the current monitoring based predominantly on passive methods. Managing of the use of active trawling gear for fish capture would represent the revolution both in monitoring and the management of reservoirs. The project follows the philosophy of the EC water framework directive 2000/60/EC and promises to create new fish monitoring methodology and to bring new crucial knowledge to the methods of fish capture in general.

 

Effect of food quantity and quality on the reverse in competitive success between 0+ perch and roach

Project No. KJB600960810

Principal investigator: RNDr. Jiří Peterka, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Grant Agency of the Academy of Sciences of the Czech Republic

Duration: 2008-2010

Young-of-the-year perch and roach dominate the 0+ fish communities of meso- to eutrophic temperate water bodies across Europe. General succession from dominance of perch to roach with increasing ecosystem productivity has been documented for lakes of different trophic status and when comparing fish community structure within reservoirs with pronounced longitudinal gradients. Better competitive abilities of juvenile roach for crustaceoplankton have been suggested as responsible for these changes. But recently, the higher efficiency of roach for copepod or cladoceran prey was doubted. This project aims to clarify the effect of intra- and interspecific foraging competition of juvenile roach on perch in manipulative enclosure experiments with larvae and juveniles of both species, and particularly, focuses on the effect of food quantity and quality (prey taxa, prey size, timing of diet shifts etc.) on the changes in competitive success (evaluated as realized growth) between both species.

 

Horizontal acoustic surveys and fish behaviour in the open water

Project No. 206/07/1392

Principal investigator: Doc. RNDr. Jan Kubečka, CSc., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2007-2010

Most fish of the open water of large reservoirs of Czech Republic (also applies to many lakes and reservoirs worldwide) inhabit surface layers where they can be studied quantitatively preferably by horizotal acoustic surveys. The aim is to solve main persistent problems of horizontal surveying like undefined behaviour of ultrasonic field, uncertainty of fish size estimates, microdistribution, discrimination between small fish and bubbles, influences of swimming behaviour and diurnal changes of behaviour. The emphasis is on improvement of quality of mobile surveys with large spatial coverage. The problems will be solved by the combination of (i) klassical split-beam echosounder, (ii) newest commercially available high frequency multibeam sonar Didson, which has theoretically a number of advantages (iii) direct fishing and optical approaches. Project should significantly improve horizontal detection of fish, interpretation of records and elucidate a number of patterns of pelagic behavoir of fish which is insufficiently known in fresh waters.

 

Patterns and reasons of different pelagic behaviour of perch fry: novel insight into the declared ecological plasticity of a species

Project No. 206/06/1371

Principal investigator: RNDr. Martin Čech, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2006-2008

The project follows up the recent finding that juvenile perch Perca spp. are able to create sympatric ecological groups with different behaviour. The epipelagic fry (EPF) spent the whole 24 hours in the epilimnion whereas the bathypelagic fry (BPF) performed diel vertical migrations (DVMs), being in the epilimnion during the night and migrating into the cold hypolimnion during the day. The project aims on better definition of newly discovered groups, temporal and spatial patterns of their separation, reasons of sympatric existence of EPF and BPF, profitability and fate of individual strategies, cues of DVMs, predation pressure on pelagic perch fry, gradients in perch fry abundance, age and size distribution as well as perch egg strands deposition on the longitudinal profile of the reservoir. New approaches including more quantitative and extensive acoustic and net sampling, SCUBA diving, molecular genetics, histology and parasitology will be used. Grouping behaviour of juveniles of close relative, zander, Sander and ruffe, Gymnocephalus will be also investigated and the project is likely to bring new understanding into early behaviour of perciform fish.

 

Seasonal dynamics of food consumption, growth and production of 0+ fish and their impact on zooplankton in a reservoir with trophic gradient

Project No. 206/06/P418

Principal investigator: MSc. Mojmír Vašek, Ph.D., Biology Centre CAS, Institute of Hydrobiology

Financial support: Czech Science Foundation

Duration: 2006-2008

Deep-valley reservoirs are unique aquatic ecosystems characterized by a high degree of spatial and temporal variability. This project aimed to analyze how variable environmental conditions within a model reservoir influence seasonal dynamics of age-0 fish abundance, food consumption, growth and production. Dynamics of age-0 fish was studied in the Římov Reservoir during two subsequent years, 2006 and 2007, that differed markedly in hydrological and weather regimes. A few generalist species from two families, Percidae and Cyprinidae, dominated age-0 fish assemblages. At the start of growing season, percids were abundant in pelagic habitat, but later on they shifted to littoral zone. An opposite trend in habitat use was recorded for age-0 cyprinids. Flooded shoreline vegetation enhanced survival of age-0 fish in 2006, while increased spring temperatures in 2007 accelerated ontogenetic development of age-0 fish. Underyearling fish in the Římov Reservoir were largely planktivorous throughout the whole growing season of both years. In the pelagic zone of the reservoir, impact of age-0 fish on zooplankton of the genus Daphnia was quantified using bioenergetics modelling. The estimated consumption rates of age-0 fish assemblages were found too low to be responsible for the midsummer decline of Daphnia population. In summary, extensive data on abundance, distribution, growth, production and food consumption of age-0 fish were collated during this project. The data provided valuable information on the structure and functioning of a reservoir ecosystem and, in practice, they can be beneficial for management of fisheries and water resources.

CONTACT

Biology Centre CAS
Institute of Hydrobiology
Na Sádkách 702/7
370 05 České Budějovice

Staff search