Papers by Jacek Szlakowski
This publication is a Technical report by the Joint Research Centre (JRC), the European Commissio... more This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.
Nature Communications
European rivers are disconnected by more than one million man-made barriers that physically limit... more European rivers are disconnected by more than one million man-made barriers that physically limit aquatic species migration and contribute to modification of freshwater habitats. Here, a Conceptual Habitat Alteration Model for Ponding is developed to aid in evaluating the effects of impoundments on fish habitats. Fish communities present in rivers with low human impact and their broad environmental settings enable classification of European rivers into 15 macrohabitat types. These classifications, together with the estimated fish sensitivity to alteration of their habitat are used for assessing the impacts of six main barrier types (dams, weirs, sluices, culverts, fords, and ramps). Our results indicate that over 200,000 km or 10% of previously free-flowing river habitat has been altered due to impoundments. Although they appear less frequently, dams, weirs and sluices cause much more habitat alteration than the other types. Their impact is regionally diverse, which is a function of...
HAL (Le Centre pour la Communication Scientifique Directe), 2017
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
La composition du regime alimentaire et l'intensite de l'alimentation du poisson des glac... more La composition du regime alimentaire et l'intensite de l'alimentation du poisson des glaces (Champsocephalus gunnari) autour de la Georgie du Sud en janvier/fevrier 1991 ont ete analysees pour 3 877 estomacs recueillis a 44 stations. La proportion du krill (Euphausia superba) dans les estomacs et l'intensite alimentaire relevees etaient particulierement faibles en une periode ou des aliments de haute valeur energetique sont necessaires pour la maturation finale des gonades.
We estimate over 200,000 km or 10% of previously free-flowing river habitat length has been lost ... more We estimate over 200,000 km or 10% of previously free-flowing river habitat length has been lost due to impoundments, an amount equivalent to the entire length of rivers in Italy. This loss strongly depends on the biogeographical location and a type of impounding barrier. European rivers are disconnected by more than one million man-made barriers that physically limit or completely block aquatic species migration and contribute to the loss of freshwater habitats8. One of the pervasive effects of barriers is the one caused by impoundment, which directly modifies lotic (flowing) stretches of river into lentic (lake-like) habitats5. Depending on structure and composition of fish communities expected at the barrier location the biological consequences may vary. EU-wide analysis of fish communities observed at river sections with low human induced alteration resulted in a macrohabitat classification of European rivers into 15 river types with expected fish community structure. This set a...
![Research paper thumbnail of Rozwoj ogolnoeuropejskiej metody oceny stanu ekologicznego rzek na podstawie ichtiofauny - Europejski Wskaznik Ichtiologiczny [EFI plus]](https://attachments.academia-assets.com/98775703/thumbnails/1.jpg)
Streszczenie. Ramowa Dyrektywa Wodna określa ramy działania mające służyć poprawie jakości ekolog... more Streszczenie. Ramowa Dyrektywa Wodna określa ramy działania mające służyć poprawie jakości ekologicznej wód powierzchniowych Wspólnoty. Istotną rolę w ocenie stanu ekologicznego wód odgrywać mają elementy biologiczne, takie jak: fitoplankton, fitobentos, makrofity, bezkręgowce denne i ryby. W 2004 r. opracowano Europejski Wskaźnik Ichtiologiczny (European Fish Index, EFI), który w zamierzeniu miał zapewnić standardowe narzędzie wspomagające realizację Ramowej Dyrektywy Wodnej. Do sporządzenia i testowania wskaźnika EFI wykorzystano archiwalne dane z elektropołowów prowadzonych w rzekach kilkunastu krajów, przeważnie z Europy Zachodniej i Południowej. Możliwość zastosowania tak opracowanego wskaźnika EFI okazała się ograniczona do typów rzek przeważających w bazie danych stanowiących podstawę jego opracowania. Testowanie przydatności wskaźnika do oceny rzek nizinnych, przeważających w północno-wschodnich regionach UE (np. w centralnej i północnej Polsce, północnych Niemczech i Finlan...
Acta Ichthyologica et Piscatoria, 2017
Background. Fish-based indices for evaluation of river ecosystem quality have been used since the... more Background. Fish-based indices for evaluation of river ecosystem quality have been used since the 1980s, when the Index of Biotic Integrity (IBI) was first introduced. Assessment of the ecological status of rivers, based on fish assemblages is required by the Water Framework Directive. During last 15 years a number of national assessment methods based on fish fauna were developed. The recently designed tool for fish-based assessment of ecological status (EFI+IBI_PL) applied in river monitoring in Poland is presented in this paper. Material and methods. The new European Fish Index EFI+ is a multimetric tool consisting of two specific indices, each with two metrics developed separately for salmonid-and cyprinid-river zones. Those metrics were used in the European intercalibration process to validate national methods. However, the original EFI+ method is not adequate to some lowland river types (physical-factor classification), so it was complemented by a typespecific modification of the Index of Biotic Integrity (IBI_PL). The method was tested on fish data from 493 sites located in 431 surface water bodies sampled in 2011-2012 according to the CEN standard 14011. Results. The EFI+ index was adapted to the specificity of Polish rivers by eliminating some inconsistences of the ecoregion division and problems related to the lack of the Dniester River in the EFI+ software and presented in this paper as EFI+PL. The index of diadromous fish occurrence (D) was also adapted from an original EFI+ method and used as a supplementary assessment tool. Specific IBI metrics were developed for large lowland rivers (with sandy or gravel bottom substrate), organic rivers (flowing through peat areas), and rivers connecting lakes (with the presence or lack of salmonid fish species). A software tool for indices calculation was also developed. The method combination (EFI+IBI_PL) was than tested on a set of 493 monitoring sites sampled in 2011-2012. Both indices classified the highest percentage of sites into moderate ecological state/potential class, but for IBI_ PL this percentage was much higher than for EFI+. Percentage of sites classified to good ecological status or high ecological potential by IBI_PL index were lower than for EFI+. The analysis indicates the consistence of classification for 77% of sites to high/good and below good ecological status by the EFI+PL/IBI_PL method and pressure index. Conclusion. The results of a two-years monitoring program show that the combination of modified EFI+ and IBI methods can be applied as a tool for river ecological status assessment in Poland, however some further method modifications are needed.
Acta Ichthyologica et Piscatoria, 1992
The fish Wedi!!!! mi. tire South Georgl.a shelf were sampled m .:he 19116/87-19811/89 fishing smo... more The fish Wedi!!!! mi. tire South Georgl.a shelf were sampled m .:he 19116/87-19811/89 fishing smom, during three RV "Profmor Siedlecki '" erwm. The biologic&! mucture of fish st� the A�h-fgrequeney and qe /distributions-during the period of ffl!dy .ue desm'bed. The biol!W$ of fish stocks WW! mlmatoo by the "Swept Area Method "'. INTRODUCTUON Large scale commercial. exploitation of fish stocks m-1.nm� Sooth Georgia (F AO statistical subarea 48.3) began at the end of the 1960s. In the 1969/70 fishing season (split year, with the fishing season running from July through to the end of following June) it started with catches of nearly 400 OOO tonnes of Notothenia rossii marmorata and just over 10. 0.000 tonnes l.n 1970/71. In the following fishing seasons catches of this species were decreasing and in 1988 the stock .size was estimated to be less tlum 5% of its pristine level (Kock and K5ster 1989). The rapid depletion of the N. rossii mar•' morata stock was a serious sign that the Antarctic fish resources were limited and wl• ne:rable to heavy exploitation. The overfishing of N. rossii marmoratu stock c�used the fishery shiftslto other species, Champsocephalusgurmari. Since 1980/81 ithu beco111e the target species in the fishery around South Georgia, although the annual catches have exhibited large fluctu.atiom,, mostly due to variations in year class strength (Mucha and Slbsarczyk 1988, Kock and KOster 1989); To stop the decline and overfishing of fish stocks, the Commission for the Conserva• tion of Antarctic Marine Living Resources (CCAMLR), adopted several conservation 78 Jozef Sosinski, Jacek Szlakowski measures and introduced a catch report:ng system. In 1984 commercial fishing was prohibited within 12 nautical. miles of South Georgia and mesh regulation was intro duced with a minimum mesh size 120 mm for N. rossii and Dissostichus eleginoides, and 80 mm for other species. In 1985 direct fishing on N. rossii marmorata around South Georgia was prohibited, and in 1987 the total catch. of C. gunnari around South
Acta Ichthyologica et Piscatoria, 1990
Growth in length and weight of Psetta maxima in consecutive years of life was determined basing o... more Growth in length and weight of Psetta maxima in consecutive years of life was determined basing on back calculation of age from the otoliths. Von Bertalanffy's equation and Szypul'a!s polynomials were also used.
Acta Ichthyologica et Piscatoria, 1990
Fish biology SUMMER FOOD OF JUVENILE TURBOT, PSEIT A MAXIMA (L) AND FLOUNDER., PLATICHTHYS FLESUS... more Fish biology SUMMER FOOD OF JUVENILE TURBOT, PSEIT A MAXIMA (L) AND FLOUNDER., PLATICHTHYS FLESUS (L.), At S�TOUSC, POMER.ANIAN BAY LETNI POKARM NARYBKU, PSEITA MAXWA (L.) I STORM. PLATICHTHYS FLESUS (L.
Fragmenta Faunistica, 2012
A b stra c t: In 1999-2003, investigations o f the fish fauna were carried out in selected rivers... more A b stra c t: In 1999-2003, investigations o f the fish fauna were carried out in selected rivers o f the M azovian Lowland. Electrofishing was used to investigate species diversity and abundance at 35 sam pling sites. In total, 8618 fish representing 29 species were caught, w eighing in total 77.9 kg. 13 to 22 species o f fish and lam prey were registered. The highest num ber o f species was identified in the Świder R iver (22), dom inated in abundance by roach (35.1%) and stone loach (34.9%), and in the Rządza River (20), dominated by gudgeon (33.4) and roach (24.9%). Ten-spined stickleback dom inated in the D ługa River (45.5%), roach in the Klusów ka river (27.0%), and gudgeon (48.4%) and sunbleak (30.0%) in the U trata River. 9 reophilic species were identified in particular rivers, accounting for 8.6% to 61.0% o f total abundance. The abundance o f pike, the m ajor predator o f small lowland rivers accounted for 0.1% in the U trata River to 1.3% in the R ządza River. The highest abundance o f fish in term s o f numbers and the biom ass per 1 km o f river course w ere found in the K lusów ka River and the Długa River. K ey w o rd s: lowland rivers, dom inant species, fish communities, stability o f occurrence I n t r o d u c t i o n So far, studies of the fish fauna of the Mazovian river have been carried out in the Jeziorka River, which flows into the Vistula River near Wilanów and the Czarna Struga River, the tributary of the Dluga River in the Narew River basin (Rembiszewski 1964), the Bzura River and its right tributary the Utrata River, the Wkra River, which flows into the Narew River below the Dębe dam, left tributaries of the Narew River, some of which are located in the Mazovian region, as well as the Pilica basin (
Journal of Water and Land Development, 2010
In the Malta Reservoir a total of 16 fish species belonging to six families were recorded in 2008... more In the Malta Reservoir a total of 16 fish species belonging to six families were recorded in 2008. In the Nordic multi-mesh gillnets 4528 fish belonging to 11 species, with the total weight of 149.5 kg, were caught. The total beach seine catch was 34348.9 kg, which in terms of the reservoir area of 64 ha amounted to biomass density 536.7 kg•ha-1. Of 11 species caught with the beach seine roach (Rutilus rutilus) was the most abundant species (485031 fish, 7578 individuals•ha-1) with the highest share in biomass (24283.4 kg, 70.7%). The average electric catch at two sampling sites in the Cybina River running in the reservoir bowl was 105 kg (which gave estimate of 2.6 ton in all), with a marked dominance of the roach, which constituted 65.4% of fish catch in weight and 93% in numbers. Taking under consideration the results of electrofishing the estimated fish density in the Malta Reservoir in 2008 could reach as much as 577.7 kg•ha-1. The proportion of predatory fish in the fish assemblage biomass was 20.1%.
Fisheries Research, 2012
In shallow waters horizontally aimed transducers are used to maximize usable survey volume due to... more In shallow waters horizontally aimed transducers are used to maximize usable survey volume due to the physical limitations of the environment. However, horizontal acoustic measurements of fish lengths are problematic because in mobile applications there is no way to determine the orientation of the fish relative to the axis of the acoustic beam. The draining of Malta Reservoir in Poland (average depth 3 m) provided an unique opportunity to check the accuracy of acoustic estimates of fish biomass. Before draining, detailed investigations of the fish population were performed using standard gillnetting and horizontal echosounding (split beam Simrad EY500, 120 kHz). During the draining of the reservoir fish were collected and weighted. Three different methods were used to convert the horizontal measurements of acoustic energy into fish total length and the biomass estimates were compared with the results of the fish census that was performed during the draining of the reservoir. The best agreement between the acoustic estimates and the fish census of 565 kg ha −1 and 576 kg ha −1 , respectively, was obtained with Method 1, which uses deconvolution to remove the effect of an assumed random distribution of fish aspect angle and a TS-TL relationship derived from a mixed population of European freshwater species (Frouzova et al., 2005). Deconvolution assumes random distribution of fish orientation, which means this assumption is likely to be valid, at least for Malta Reservoir.
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Papers by Jacek Szlakowski