The characteristics of the Warta River and its tributaries ichthyo fauna with in the boundaries of Załęcze Nature Park Area (Central Poland)

The ichthyofauna of the Warta River and its changes brought about by anthropogenetic factor shave been investigated for more than fourty years. The investigations have proved that the slightly altered ichthyofauna, which is characteristic for a barbel region, has survived only with in the boundaries of Załęcze Nature Park area. The fragment of the Warta River with in the boundaries is populated by barbus, nase, chub, zarthe and 15 other species of fish as well as by brook lamprey. In order to preserve the above-mentioned reophilous species and to protect their spawning-grounds the author proposes to establish a strict fauna - preserve (Fig. 1) (for summary see page 375-376).Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

Comments on the Taxonomy of the Three-Spined Stickleback, Gasterosteus Aculeatus Linnaeus

Author Institution: Department of Taxonomic Zoology, University of Lodz, PolandOn the basis of 5491 specimens from 61 habitats in all parts of Poland, the author infers that the present accepted division of the three-spined stickleback into trachura, homozygote living in salt waters and coastal waters, and leiura, homozygote living in fresh continental waters, with semiarmata separated off as the hybrid of both adaptive types living in the borderline between both homozygotes, has not found confirmation in the analysed material. Members of trachura in Poland have their habitats in the whole area of this species. The semiarmata and leiura types appear in small numbers either together with, or independently of, the members of trachura, and are confined to the coastal waters of the Baltic Sea east of the mouth of the Vistula, and to the Odra and Vistula rivers not farther south than 51 degrees north latitude

Verification of the dualism ordering method by the canonical correspondence analysis: fish community samples

AbstractTwo ordination techniques (Romaniszyn diagram, RD, and Canonical correspondence analysis, CCA) were applied to the same data set (fish assemblage composition along two Paraná river tributaries and associated environmental variables), to identify spatial community patterns and further to evaluate the performance of RD. The major patterns in these Brazilian streams were successfully revealed by both methods (i.e. clear separation of both tributaries on the basis of fish assemblage composition and environmental factors), but more complex situations may limit the application of RD in comparison with CCA

Does the use of various population parameters affect fish assemblage structures?

While studying the fish populations in small streamlets and their responses to climate change and anthropogenic stress, the following parameters are used: present/absent species, relative number, and relative biomass recently. Although the image/structure of the population differ from these parameters, this problem has not been investigated by researchers in this topic. It is now known that the potential energy accumulated in animal tissues is the best indicator of his strength and importance in nature, but I have not encountered work assessing the image of population structure according to these population parameters. Consequently, most reliable parameter − the relative calorific value of biomass (in the wet weight), was used. Relative biomass is the parameter of the population, which was found to be the closest to the calorific value of the biomass, as demonstrated by the SOM (self-organizing map) artificial neural network algorithm used in this study. For this reason, attempts have been made to convince authors of future work that relative biomass studies are used in the studies of fish assemblages, as research has already been undertaken, and this paper provides evidence that this choice is justified.Regularly published works devoted to fish assemblage structures are constructed from three population parameters: species number, relative number or relative biomass. The last one is the most similar to the estimated by the relative caloric content of biomass (wet weight), i.e. the best indicator of the strength and importance of a population in nature

Evaluation of electrofishing efficiency in a stream under natural and regulated conditions

Sampling efficiency (p), estimated from the Zippin depletion model and the percentage of fish obtained during first runs (single-pass electrofishing), which is also named relative abundance (C1), calculated as the ratio of C1 to estimated density for a site (Ce), were analysed in five contiguous sites in a small lowland stream in Poland over 23 years. The sampled reach was unregulated during the first decade of the study period, but regulated by weirs and sluices in the latter 13 years. The sites were populated with 17 fish species during this period. Sampling efficiency p calculated for all species did not differ significantly between the five sites in any given year, between benthic and non-benthic species, or between the natural and regulated periods. Differences in p were only observed between some species. C1 differed significantly between large and small species and, except for roach, was not dependent on the number of runs. Results indicate a high stability of both sampling indices in this small stream, despite changes in channel morphology after regulation: information which could be useful for future sampling research in streams

Species richness estimators applied to fish in a small tropical river sampled by conventional methods and rotenone

A number of analytical tools were applied to estimate fish species richness in a small tropical stream (Brazil) that had been sampled by conventional methods (double stick net, electrofishing) and rotenone. Three sites were compared in two seasons each and a total of 34 species were captured. The sampling efficiency of electrofishing was much better than that of the double stick net and little worse than of rotenone. No estimator was thoroughly consistent and accurate in predicting species richness on the basis of electrofishing, but the Homogenous Model, which assumes that all species have the same detection probabilities, was best. The rarefaction technique should be used with caution as it may produce misleading results in species richness predictions