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Chinese sleeper is an invasive species from South Asia inhabiting Eastern and Central Europe. So far, no detailed analysis of the reproductive cycle of Chinese sleepers has been conducted. The aim of the study was to describe the reproductive cycle of Chinese sleepers in the Wilanówka River, Vistula tributary (Poland, Central Europe). Fish morphometric data, age, gonadal maturity, and absolute and relative fecundity of females were analysed. A standard paraffin technique and six-stage scales were used to assess the gonad development and maturation in both sexes. The age of the studied fish ranged from 0+ to 6+.The female-to-male ratio was 1:1. Females and males mature at age 1+.The smallest female and male reaching maturity were 3.8 and 3.7 cm long, respectively. An extended spawning season from the beginning of April to mid-September was determined based on gonadal maturity analysis. The mean absolute fecundity was 2,971 (180–19,656) oocytes. The male reproductive system comprises paired testis (spermatogenic region, blackish color) and paired testicular gland (secretory region, whitish color). In both regions, seasonal changes were observed. Male gonads during winter had completed spermatogenesis, and the lobules were filled with spermatozoa. Very fast spermatogenesis and overlapping of reproductive cycles have been observed in Chinese sleeper males. Almost all year round testis contains spermatozoa. In the new habitat examined, this species was characterized by earlier maturation and longer reproduction season, compared to the native habitat and other native species of the examined area. Moreover, high female fecundity, multiple spawning, and lower investment in the development of gonads in males allow maintaining vitality and protecting the nest, contribute to the species competitiveness and successful colonization of new areas.

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. Materials 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 type-specific 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.

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 barrier height, type and density, as well as biogeographical location. This work allows us to foresee what potential environmental gain or loss can be expected with planned barrier management actions in rivers, and to prioritize management actions., (© 2023. Springer Nature Limited.)

Background: Ventilator-associated pneumonia (VAP) occurs in approximately 10-20% of mechanically ventilated patients, and is associated with an extremely high mortality rate (up to 70%). The purpose of the study was to determine the susceptibility spectrum of Klebsiella, Pseudomonas and Acinetobacter strains isolated from VAP patients., Methods: We analysed 81 strains of microorganisms isolated from bronchoalveolar lavages (BAL) of VAP patients. The minimal inhibitory concentrations (MIC) of antibiotics recommended for empirical therapy were determined using an automated VITEK 2 system, and for the MIC of doripenem - the Etest assay. Results were analysed following the guidelines of the Clinical and Laboratory Standards Institute., Results: For infections caused by the group of bacteria under investigation, the most successful regimen was monotherapy with carbapenems (doripenem, meropenem and imipenem). Cephalosporins (cefepim and ceftazidim) were less effective in vitro. The worst results were obtained with the combination of piperacillin/tazobactam with aminoglycosides (amikacin or gentamicin) or fluoroquinolones (ciprofloxacin)., Conclusions: Antibiotic monotherapy proved to be more effective in VAP patients than combined therapy; the best results were achieved with carbapenems. Doripenem showed strong activity in vitro against P. aeruginosa and Klebsiella sp. and should be considered for empirical VAP therapy; however, carbapenems may be less effective against Acinetobacter baumannii. The wide range of bacteria, and their broad range of susceptibility to antibiotics, suggests the need for modification of current recommendations.