Volume 40 (2011): Issue 1 (March 2011)

The present analysis is based on 140 quantitative samples collected from depths of 20 to 500 m in the central basin of Admiralty Bay and its inner shallow area, Ezcurra Inlet. One hundred and twenty species were identified, of which 47 species were new for Admiralty Bay. Mean density of crustaceans decreased with depth. Highest species richness was observed at depths of 50–100 m. Historical data and present investigations revealed distinct differences in the amphipod assemblages at different depths. In the subtidal zone, Gondogeneia antarctica was the dominant species; in the shallow sublittoral (down to ca 50 m) Prostebbingia gracilis and Hippomedon kergueleni played an important role. Below 50 m, the importance of phoxocephalid species increased.

The aim of the research was to evaluate crustacean forage resources for fish in five shallow lakes varied in respect to species richness and coverage of submerged macrophytes, and thus representing different alternative stable states. The results revealed that lakes with a high or moderate abundance of macrophytes and moderate visibility (macrophyte-dominated Lake Rotcze, phytoplankton-macrophyte dominated lakes Sumin and Głębokie) displayed reach crustacean forage base for fish. Poor feeding conditions were found in two extremely different lakes: turbid phytoplankton-dominated Lake Syczyńskie devoid of macrophytes, and heavily vegetated, clear-water macrophyte-dominated Lake Kleszczów. Possible reasons for these differences are discussed.

The effect of cyanobacterial blooms on the phytoplankton structure in the lowland Narew River (north-eastern Poland) was examined. The studies were carried out at stations situated at different distances from the eutrophic Siemianówka Dam Reservoir. In 2008, the investigated lowland reservoir and the outflowing river were characterized by the dominance of toxic cyanobacteria (from July to October). At a station situated 130 km below the dam, species composition in the river was very similar to that in the shallow reservoir. Planktothrix agardhii was the main and permanent dominant, both in limnoplankton and potamoplankton. The current study indicates that the eutrophic Siemianówka Dam Reservoir is the main and rich source of phytoplankton for the outflowing Narew River. Cyanobacteria were dominant in the river phytoplankton at all sampling stations, but their share in phytoplankton biomass gradually decreased with the distance from the dam. Chemical analysis revealed the presence of microcystins (MCs) in water samples collected from June to October. The toxins, mainly demethylated MC analogues, were detected at a long distance down the river, even 100 km from the dam. Maximum concentration of MCs (14.3 μg l−1) was measured on 13 October, 9.1 km below the dam.

Regardless of origin, all water bodies situated inside forests form a unique habitat for many freshwater animals due to the allochthonous detritus covering the bottom, composed mostly of leaves from waterside trees. For many years these woodland ponds have been considered to be advantageous to regional biodiversity. Investigations were carried out in eight anthropogenic woodland ponds, formed as a consequence of coal mining activities, situated in forest complexes in Upper Silesia (Southern Poland), to evaluate the impact of allochthonic and autochthonic plant detritus on the formation of zoobenthic communities, together with insolation intensity. In sites covered by a layer of allochthonic plant matter, zoobenthos were more abundant compared to places covered by autochthonic detritus. The density of zoobenthos in sun-exposed sites was two to three times greater than in shaded sites.

A total of 379 individuals of Eriocheir sinensis (198 males and 181 females) were captured in the Odra estuary (Poland). The crabs were thawed and their carapace length (CL), the maximum carapace width (CW) and the maximum height (CH) were measured. Measurements were also taken on each claw, the claw length (CHL1, the right claw; CHL2, the left claw), the width (CHW1 and CHW2 for the right and the left claw, respectively), and the height (CHH1 and CHH2 for the right and the left claw). For each crab, the wet weight was measured for each of the following body components: the whole crab (CrWe), the carapace (CaWe), the right claw (WRC) and the left claw (WLC). For females, the relationship between CL and CW, CH and CW were isometric, and for all linear measures, the relationship with CW was positively allometric. For males only this first relationship was isometric, but others were positively allometric. The differences between relative growth parameters for males and females were statistically significant.

To date, no characterization of spawning habitats on scientific basis was made for the eastern Baltic salmonid populations. The aim of the present study was to characterize spawning habitat preferences and redd gravel structure of sea trout in lowland streams of western Lithuania. The redd position at the habitat-unit scale, microhabitat hydrological characteristics and the redd gravel structure have been analyzed. The spawning site selection by sea trout was related to the in-stream characteristics, but not to the riparian features. Redds were positioned mainly in the transitional pool-riffle zones, associated with close proximity to potential cover for spawners. At the microhabitat scale, sites with relatively consistent hydrological parameters (mode of water depth 0.25–0.40 m, flow velocity 0.4–0.7 m s−1 and Froude number 0.2–0.4) were selected from a wide range of available sites. Egg incubation conditions, in terms of the redd gravel structure in the spring, were of intermediate quality, while varied widely within particular reaches. According to the results of the present study, it is apparent that sea trout have particular preferences for spawning sites, which should be considered in emerging river-restoration projects.

This is the first comprehensive review to examine the role of the central European invasion corridor on fish introductions into Belarusian and Polish inland waters (Dnieper-Bug-Vistula-Oder-Elbe-Spree-Havel). Historical and recent data were assessed, including the results of a 2003–2008 survey along the Belarusian and Polish sections of the corridor. Since the eighteenth century, at least six fish species of Ponto-Caspian origin have spread via the corridor and migrated westwards to the Baltic basin, with five species found in recent surveys, namely the monkey goby Neogobius fluviatilis, round goby N. melanostomus, racer goby N. gymnotrachelus, tubenose goby Proterorhinus marmoratus and the white eye-bream Abramis sapa. Four other non-native species were also found within the corridor — the Amur sleeper Perccottus glenii, gibel carp Carassius gibelio, brown bullhead Ameiurus nebulosus and the topmouth gudgeon Pseudorasbora parva. Their presence is related to numerous accidental introductions to many localities in Belarus and Poland, rather than from using the corridor as an invasion route. One species, the ninespine stickleback, Pungitius pungitius, has migrated from the Baltic basin to the Black Sea drainage systems.

The aim of this study was to reconstruct paleoenvironmental changes of the SW part of the Gulf of Gdańsk. Three subbottom sedimentary cores were analyzed with respect to diatom flora. Post-Littorina Sea assemblages were noticed in the lower parts of the cores, whilst the present-day eutrophication of the gulf was evidenced in their superficial sediments, with high abundance of so-called ‘anthropogenic assemblage’ taxa. Shifts in the species composition might have been caused by intensified nutrient load, increasing organic matter concentrations and possible silica limitation.

Physicochemical and benthos data were collected from 12 marine monitoring stations in Daya Bay, during 2001-2004. 12 stations in Daya Bay could be grouped into three clusters: cluster I consisted of stations in the southern part of Daya Bay (stations S1, S2 and S6); cluster II consisted of stations in the cage culture areas (stations S3, S4, S5 and S8); cluster III consisted of stations in the southwest, the middle and the northeast of the Bay (stations S7, S9, S10, S11 and S12). Calculation with bivariate correlations between benthos and major physicochemical factors showed that the density of benthos in all stations correlated positively with temperature, DO, pH, NH4-N, SiO3-Si, SiO3-Si /PO4-P and chlorophyll a and was negatively correlated with salinity, Secchi, COD, NO3-N, NO2-N, TIN, PO4-P, TIN/PO4-P and BOD5. Factor analysis showed that there were high positive loading salinity, Secchi and NH4-N of three clusters. Results revealed that temperature, DO, pH, SiO3-Si and SiO3-Si/PO4-P and chlorophyll a could also play an important role in determining the biomass of benthos in Daya Bay, especially near the Nuclear Power Plants, in the southern part and in the cage culture areas.

Eriocheir sinensis is a habitat for invertebrates living externally and internally. It may transport native and non-native species to new habitats. Present studies on the Chinese mitten crab from Lake Dąbie add four new taxonomic units to the number of pathogens: Ichthyophonus hoferi, Epistylis sp., Branchiobdella sp. and Digenea gen. sp., which until now have not been found in this host.