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Kalinowska K.,Inland Fisheries Institute in Olsztyn | Grabowska M.,University of Bialystok
Hydrobiologia | Year: 2016

Ice cover can considerably influence the food web structure and dynamics of lake ecosystems during winter. The aim of this study was to test the hypothesis that, due to unfavourable conditions, abundances of planktonic organisms are low under ice. The components of the microbial loop (nanoflagellates, ciliates) and the classical food web (algae, rotifers, crustaceans) were investigated in a eutrophic lake from January to April, at 7-day intervals. The phytoplankton was dominated by the mixotrophic chrysophyte Synura uvella, which formed an intense phytoplankton bloom. Nanoflagellates (mostly heterotrophic forms) and ciliates (oligotrichs, prostomatids) were present in relatively high numbers. Rotifers were represented by the algivorous taxa (Notholca squamula, Polyarthra dolichoptera) and reached surprisingly high abundances. There were no significant correlations between physical parameters and protists, but correlations were apparent between the thickness of the ice and the numbers of cyanobacteria, diatoms (negative) and chrysophytes (positive). The absence of crustaceans and relationships between rotifers and both algae and nanoflagellates indicate that these groups were probably a crucial factor determining the abundance and composition of the rotifer community. These results suggest that the microbial loop had a central role in the functioning of the ecosystem under ice in this eutrophic lake. © 2016 Springer International Publishing Switzerland

This paper presents preliminary results of a comparison of the seasonal activity of lake minnows, Eupallasella percnurus (Pall.), and crucian carp, Carassius carassius (L.), in a few small water bodies. Field studies were conducted based on catches made with baited traps in periods without ice cover from April to December 2006. E. percnurus became active earlier than did C. carassius and their period of intense activity was longer. The first E. percnurus appeared in the traps in early April when the ice was still melting, and these fish were caught at a temperature range of 3.5-29.2°C. C. carassius were caught most abundantly in the beginning of May at temperatures from 15°C; this species was usually noted in traps at a narrower, but higher, temperature range in comparison with the E. percnurus. Additionally, the activity of both these species was similar with regard to weather conditions; both species were less active on cloudy days and when atmospheric pressure was increasing.

Sikorska J.,Inland Fisheries Institute in Olsztyn | Wolnicki J.,Inland Fisheries Institute in Olsztyn
Archives of Polish Fisheries | Year: 2011

The present paper summarizes all available scientific data on the historical and current occurrence of the endangered cyprinid fish species lake minnow, Eupallasella percnurus (Pall.), in Wielkopolskie Voivodeship in Poland. In the twentieth century, only three or four sites were identified in this part of the country. Today, there is only one site in the voivodeship situated in the vicinity of Wolsztyn, which is classified as highly threatened and is subject to protection under the European Ecological Natura 2000 Network as PLH300028 "Barłożnia Wolsztyńska". Although some findings of unknown sites of E. percnurus in Wielkopolska remain feasible, the prerequisite for the preservation of this species in this region is the urgent implementation of active protection measures. These should include an assessment of the present condition of the existing population, a partial deepening of the water bodies inhabited by this species, and searches for other water bodies nearby that are suitable for future introductions of wild or cultivated individuals in order to increase the number of existing populations.

Zebek E.,University of Warmia and Mazury | Napiorkowska-Krzebietke A.,Inland Fisheries Institute in Olsztyn
Environmental Monitoring and Assessment | Year: 2016

Lake Jeziorak Mały is a shallow urban lake where storm water pretreatment separators and a fountain-based water aeration system were installed as protective-restoration measures to enhance water quality. We investigated the effect of these procedures on phytoplankton dynamics and physicochemical properties in the littoral and pelagial zones in 1996–2003, 2005, and 2013. A decrease in cyanobacteria proportion, abundance, and biomass has been noticed, and other phytoplankton groups increased after these procedures. Significantly elevated species diversity was recorded in the littoral zone with the exchange of cyanobacteria and diatom dominant species typically induced by alteration from hypertrophic to eutrophic status. For example, the polytrophic Limnothrix redekei was replaced by eutrophic Planktolyngbya brevicellularis. This stemmed from greater oxygenation, water visibility and diminished pH, conductivity, and orthophosphates. Our results showed that introducing these restoration measures influence on the long-term succession of phytoplankton and induced the change from a polytrophic to eutrophic state, and that such measures are vitally important in future considerations of shallow urban lake management. © 2016, The Author(s).

Skora M.E.,Inland Fisheries Institute in Olsztyn
Archives of Polish Fisheries | Year: 2012

The Siberian sturgeon, Acipenser baerii Brandt, is reported in the Reda River, which flows into the Puck Bay, for the first time. In total, 12 specimens of A. baerii were caught during monthly surveys in June and July 2006. The fish were captured during downstream movement between 18:00 and 06:00. The specimens collected in Reda River ranged from 10.3 to 15.5 cm standard length (SL). It is hypothesized that the fish originated from one of the hatcheries located on the banks of the Reda River. This is also the first report of Siberian sturgeon in Polish Pomeranian rivers.

Mickiewicz M.,Inland Fisheries Institute in Olsztyn
Archives of Polish Fisheries | Year: 2012

The current report was written using data from the 1973-2004 period regarding fisheries catches and stocking. These data come from management logs for 300 lakes with a total surface area of 116,736 ha. In the 1973-1982 period, the mean annual value of catches for all species of fish was 226.33 PLN ha-1, and this was twice as high as that in the 1995-2004 period (113.77 PLN ha-1). Of stocked species, eel, Anguilla anguilla (L.) (46%), and vendace, Coregonus albula (L.) (17%), dominated the value structure of catches in the first decade, while eel (35%), vendace (15%), pike, Esox lucius L., (11%), and pikeperch, Sander lucioperca (L.) (9%) dominated in the second decade. The mean annual value of stocking material of all species in the 1973-1982 period, which was 385.91 PLN ha-1, was more than 7.5 times higher than that in the 1995-2004 period (50.40 PLN ha-1). This difference was determined by the value of eel stocking. With a share of more than 95%, the value of eel stocking dominated decisively in the first decade. In the second decade analyzed, the value of stocked eel (57%), vendace (15%), and pike (14%) dominated. After eliminating the value of eel catches and stocking, the value of stocking in comparison with the value of catches in the first decade analyzed was barely 15%, while in the second decade analyzed it was almost twice as high at 29%.

Chybowski L.,Inland Fisheries Institute in Olsztyn
Archives of Polish Fisheries | Year: 2014

The subject of the study was four populations of signal crayfish from Naryjska Struga River and lakes Pobłędzie, Mauda, and Staw Płociczno. The morphometric differentiation of female and male signal crayfish was studied with discriminant analysis. It was confirmed that both females and males from the Naryjska Struga River differ from the crayfish from the three lakes. The characters that best discriminated females were those associated with the cephalothorax and cheliped width, while in males they were those associated with the chelipeds and the abdomen. © Inland Fisheries Institute in Olsztyn, Poland.

Ocalewicz K.,University of Warmia and Mazury | Dobosz S.,Inland Fisheries Institute in Olsztyn | Kuzminski H.,Inland Fisheries Institute in Olsztyn
Cytogenetic and Genome Research | Year: 2012

Cytogenetic screening of the androgenetic brook trout (Salvelinus fontinalis, Mitchill 1814) offspring hatched from eggs exposed to 420 Gy of X-radiation before insemination exhibited residues of the irradiated maternal nuclear genome in the form of small chromosome fragments. Remnants of the irradiated chromosomes had different sizes, and their number varied intraindividually from 1 to 15. To efficiently pass through the series of the cell divisions, such chromosome fragments must have had functional kinetochores. Distribution patterns of the telomeric hybridization signals on the chromosome fragments enabled us to distinguish their 3 groups: (i) telomere-less ring chromosomes with fused broken chromosome arms, (ii) rings formed in the course of fusion of the radiation-broken chromosome arm with the opposite telomeric region and exhibiting interstitial telomeric signals at the fusion point, and (iii) chromosome fragments with fused unprotected sister chromatids of 1 broken arm and intact telomeres from the other arm. Disturbances during segregation of such fragments, mainly breakages during anaphase, may partially explain intraindividual variation in the number and size of the chromosome fragments observed in the androgenetic brook trout. Copyright © 2012 S. Karger AG, Basel.

Napiorkowska-Krzebietke A.,Inland Fisheries Institute in Olsztyn | Hutorowicz A.,Inland Fisheries Institute in Olsztyn
Archives of Polish Fisheries | Year: 2014

The aim of the study was to perform an ecological status assessment based on the phytoplankton in the vendace-type Lake Dejguny in accordance with the requirements of the Water Framework Directive. The phytoplankton analyses were conducted during three growth seasons in 2006, 2007, and 2008. The phytoplankton multimetric Phytoplankton Metric for Polish Lakes (PMPL) was used to assess the lake's ecological status. The average total biomass of phytoplankton ranged from 1.6 to 3.9 mg dm-3, while the average biomass of Cyanoprokaryota ranged from 0.4 to 1.4 mg dm-3, with the minimum noted in 2008. The phytoplankton assemblages were dominated mainly by filamentous Cyanoprokaryota and pennate Bacillariophyceae in 2006 and 2008, or exclusively by pennate Bacillariophyceae in 2007. The relatively low total biomass and Cyanoprokaryota biomass, as well as seasonal phytoplankton dynamics with the dominant taxa of Tabellaria flocculosa, Dinobryon sociale, and D. divergens confirmed the lake's mesotrophic state and some of the features of reference conditions in this lake, whereas the predominance of filamentous species Planktothrix agardhii and Planktolyngbya limnetica was characteristic of eutrophic conditions. However, a clear tendency towards progressive eutrophication stemming from the significant domination of filamentous Cyanoprokaryota was observed, and according to the PMPL the assessment indicated that Lake Dejguny had a good ecological status in 2006 and 2007 and even a high one in 2008.

Jankowska B.,University of Warmia and Mazury | Zakes Z.,Inland Fisheries Institute in Olsztyn | Zmijewski T.,University of Warmia and Mazury | Szczepkowski M.,Inland Fisheries Institute in Olsztyn
Food Chemistry | Year: 2010

This study addressed determinations of the fatty acid profile of muscle, liver and mesenteric fat in European perch originating from natural aquifers and from intensive rearing in a closed circuit on an artificial feed mixture. The qualitative composition of fatty acids was identical in both groups of perch, except for 16:4 acid identified exclusively in the reared perch. The study demonstrated equal concentrations of saturated (SFA) and unsaturated (UFA) fatty acids in muscles, liver and mesenteric fat of both groups of perch. The wild fish, however, were characterised by lower concentrations of monoenoic (MUFA) and higher concentrations of polyenoic (PUFA) fatty acids. Analyses also demonstrated similar contents of n - 3 PUFA in muscles and their diversified concentrations in liver and mesenteric fat (higher in the wild fish), as well as a higher content of n - 6 PUFA in all samples. The lower content of MUFA in the wild perch was mainly due to lower concentrations of cis18:1 n - 9 and 20:1 n - 9, whereas the higher content of n - 3 PUFA was due to a higher concentration of DHA, and the higher content of n - 6 PUFA was due to a higher concentration of arachidonic acid (AA). The biggest differences between wild and reared perch were detected for AA. The wild and reared perch were also found to differ in the n - 3/n - 6 ratio (higher in the reared fish) and to have similar values for atherogenic index (AI) (except for liver and mesenteric fat) and thrombogenicity index (TI). A comparative analysis of the fatty acid profile of diets and fish demonstrated that the contents of docosahexaenoic (DHA) and n - 3 PUFA in the wild and reared fish were higher than those determined in natural feed and artificial feed mixture, whereas concentrations of AA and n - 6 PUFA were consistent with those assayed in both diets. It suggests that perch displayed a capability for bioconversion of long-chain highly unsaturated fatty acids, especially of DHA, from their dietary precursors. © 2009 Elsevier Ltd. All rights reserved.

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