Distribution of the non-indigenous fish species, Lepomis Gibbosus (Linnaeus, 1758), in Albania

Pumpkin seed, Lepomis gibbosus L., is a native fish species to the eastern North America and is introduced to Europe freshwaters during the late nineteenth century and now appears to be wide spread in numerous countries. During the last two decades, the species spread rapidly into the Albanian inland water bodies. The distribution and abundance of invasive fish species Lepomis gibbosus L. inhabiting different water ecosystems, natural or man-made, standing or running ones was investigated. The study was carried out during a period of 10 years mostly during active breeding period for pumpkinseeds. The investigated water bodies are located along different water basins of Albania. Habitat quality was assessed after fish sampling. The following biological and physical habitat variables were considered: dissolved oxygen (mg l-1), pH, and water temperature (oC) measured with multi-parametric probes; electro conductivity (μS/cm) was measured with portable conduct meter. Substrate composition was visually estimated in a 1-m-wide band centered across each assessed area

Which factors influence spatio–temporal changes in the distribution of invasive and native species of genus Carassius?

Within the genus Carassius Jarocki, 1822 , the crucian carp (C. carassius L., 1758) occurs naturally in the northern part of Middle Danube Basin (Austria, Morava, Slovakia). This species has the least concern status in this region, but observations in the last decades suggest that it is very close to extinction here. The distribution of crucian carp is limited to a small number of vanishing lentic habitats (oxbow lakes, marshlands). These biotopes are in the last stage of succession due to the drying up of the landscape and a reduction in the creation of new natural alluvial habitats. The non-native cyprinid, C. gibelio (Bloch, 1782), known as gibel carp and Prussian carp, has gradually become eudominant in a wide spectrum of habitats/biotopes since the 1960s Several biological adaptations of non-native species are generally considered the strong basis for the mass spreading in the invaded area. The other side of the expansion of non-native C. gibelio is affected by anthropic activities associated with fish farming, translocation and stocking the fish in open water ecosystems. In this study, we analysed historical scientific data on the distribution of Carassius spp. published from the 19th century to the present from the mentioned areas. The results suggest that the number of records of invasive C. gibelio has gradually increase in rivers, regulated channels and creeks, which could be considered as natural pathways of spreading. However, the presence of invasive C. gibelio in artificial biotopes (fishponds, reservoirs) is continuous from the 1960s. In the area mentioned, the artificial biotopes are managed by national fisheries associations and relate to the historical way of farming in Central and Eastern European countries. To show the current state of the fishing grounds of the Slovak Angling Association, we a created the distribution map based on the Carassius spp. catches recorded in last two decades

Diel changeover of fish assemblages in shallow sandy habitats of lowland rivers of different sizes

Diel dynamics of species richness and fish abundance were studied in three lowland rivers that differed significantly in size (discharge) in to the upper Vistula River drainage system (Poland). Shallow sandy habitats at point bars were repeatedly sampled with beach seining over 24-h periods. Species richness peaked at dusk and then decreased throughout the 24-h period in all the rivers. Overall fish abundance changed similarly in the smallest and the largest river, whereas in the mid-sized river it increased in the late afternoon hours. Some species (three gudgeon species, golden loach, and chub) were persistently nocturnal, whereas others (dace, bleak, and roach) shifted to diurnal activity in the mid-sized and large rivers. These differences in diel changes in the abundance of certain species might be explained in the context of variation in availability (i.e., proximity) of other, more heterogeneous habitats

The “True Colours” of Golden Loaches (Teleostei: Cobitidae)

Loaches of the genus Sabanejewia are model organisms for many ichthyologic studies focusing on morphological and colour variation. The bright lateral spots—a part of the mimicry of this fish—cause a taxonomic puzzle. Common practice is that morphometric and molecular studies lack habitat assessments of species originating from different environments. In this study, we analysed body shape and colour variation within two species of Sabanejewia in order to reveal whether they are more affected by phylogeny or environmental conditions. The environmental parameters were obtained using satellite mapping tools, body shape using geometric morphometry, and the molecular identification of specimens using an analysis of mitochondrial DNA (sequence of the cytochrome b gene). Generalized linear mixed models were used for the analysis of lateral spot numbers, and principal components analysis to describe the changes in landmark position defined by the permutation tests. Results show a significant impact of the locality elevation and specimen’s sex on the change of the body shape. We identified significant differences in the number of lateral spots, which are considered mimicry variation across an elevation gradient. Morphological differences of Sabanejewia spp. vary with ecological factors along the river continuum