<abstract xmlns="http://www.w3.org/1999/xhtml"><p>There has been the assessment of current occurrence and situation of non-native fish species in two hydrological regions – the Upper Odra and Morava river basins. The river basin of Upper Odra is situated in the area of River Odra springs featuring mostly minor streams which are not currently accessible for the migration of fishes from the lower river parts and from the Baltic Sea because of the existence of tens of migration barriers in the area of Poland. There has been actually proved the occurrence of eight non-native fish species the presence of which is, with the exclusions of <italic>Carassius gibelio</italic> and <italic>Pseudorasbora parva,</italic> the result of the planned introduction related to the fish management activities. The River Morava basin consists of two parts – the system of the River Morava itself and the entire River Dyje basin. Currently, there are 16 non-native fish species. Apart from the eight species existing also in the Odra river basin, there are also eight other species the existence of which relates to the migration accessibility from the confluence of these two rivers for fishes from the River Danube through the lower part of the River Morava. The species <italic>Lepomis gibbosus, Neogobius melanostomus</italic> and <italic>Proterorhinchus semilunaris</italic> were the last ones which have arrived there by themselves. <italic>Coregonus maraena</italic> and <italic>Coregonus peled</italic> are bred in fishponds.</p><p>The basic part of the non-native fishes’ spectrum existing in free waters of the two basins consists of the species which are bred in aquaculture and fishponds (<italic>Oncorhyncus mykiss, Salvelinus fontinalis, Ctenopharyngodon idella</italic>, <italic>Hypophthalmichthys molitrix,</italic> and <italic>Hypophthalmichthys nobilis</italic>). These species, with the exception of <italic>Hypophthalmichthys molitrix</italic> and <italic>Hypophthalmichthys nobilis,</italic> introduced also into the fishing grounds and especially <italic>Oncorhynchus mykiss</italic> and <italic>Ctenopharyngodon idella</italic> make the important fishes for anglers. Their presence in the waters of the Czech Republic might be considered as beneficial from the economic point of view. From the ecological point of view, the im- portant fact is that they have become very well acclimatised in the local conditions and their natural breeding does not take place and their distribution in water ecosystems, as well as their numbers are fully determined by the management of the Czech Anglers Union. However, <italic>Carassius gibelio</italic>, <italic>Pseudorasbora parva</italic> and also <italic>Lepomis gibbosus</italic> in the River Morava basin have been assessed as distinctly invasive species having more negative impacts on the original ichthyocenosis and biodiversity. <italic>Neogobius melanostomus</italic> is also potentially dangerous in this basin. In the case of spread of <italic>Lepomis gibosus</italic> into the River Odra basin, it might become also potentially highly dangerous.</p></abstract>

There has been the assessment of current occurrence and situation of non-native fish species in two hydrological regions – the Upper Odra and Morava river basins. The river basin of Upper Odra is situated in the area of River Odra springs featuring mostly minor streams which are not currently accessible for the migration of fishes from the lower river parts and from the Baltic Sea because of the existence of tens of migration barriers in the area of Poland. There has been actually proved the occurrence of eight non-native fish species the presence of which is, with the exclusions of Carassius gibelio and Pseudorasbora parva, the result of the planned introduction related to the fish management activities. The River Morava basin consists of two parts – the system of the River Morava itself and the entire River Dyje basin. Currently, there are 16 non-native fish species. Apart from the eight species existing also in the Odra river basin, there are also eight other species the existence of which relates to the migration accessibility from the confluence of these two rivers for fishes from the River Danube through the lower part of the River Morava. The species Lepomis gibbosus, Neogobius melanostomus and Proterorhinchus semilunaris were the last ones which have arrived there by themselves. Coregonus maraena and Coregonus peled are bred in fishponds.The basic part of the non-native fishes’ spectrum existing in free waters of the two basins consists of the species which are bred in aquaculture and fishponds (Oncorhyncus mykiss, Salvelinus fontinalis, Ctenopharyngodon idella, Hypophthalmichthys molitrix, and Hypophthalmichthys nobilis). These species, with the exception of Hypophthalmichthys molitrix and Hypophthalmichthys nobilis, introduced also into the fishing grounds and especially Oncorhynchus mykiss and Ctenopharyngodon idella make the important fishes for anglers. Their presence in the waters of the Czech Republic might be considered as beneficial from the economic point of view. From the ecological point of view, the im- portant fact is that they have become very well acclimatised in the local conditions and their natural breeding does not take place and their distribution in water ecosystems, as well as their numbers are fully determined by the management of the Czech Anglers Union. However, Carassius gibelio, Pseudorasbora parva and also Lepomis gibbosus in the River Morava basin have been assessed as distinctly invasive species having more negative impacts on the original ichthyocenosis and biodiversity. Neogobius melanostomus is also potentially dangerous in this basin. In the case of spread of Lepomis gibosus into the River Odra basin, it might become also potentially highly dangerous.

Non-native fish species in River Odra and Morava basins in the Czech Republic

Acta Musei Silesiae, Scientiae Naturales

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

{"article-title":"Non-native fish species in River Odra and Morava basins in the Czech Republic"}

There has been the assessment of current occurrence and situation of non-native fish species in two hydrological regions – the Upper Odra and Morava river...

Non-native fish species in River Odra and Morava basins in the Czech Republic

Published Online: Sep 19, 2018

Page range: 81 - 96

DOI: https://doi.org/10.2478/cszma-2018-0007

Keywords
alien fish species, impact, native fish species, River Odra and Morava basins

© 2018 Bohumír Lojkásek et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Non-native fish species in River Odra and Morava basins in the Czech Republic

Published Online: Sep 19, 2018

Page range: 81 - 96

DOI: https://doi.org/10.2478/cszma-2018-0007

Keywordsalien fish species, impact, native fish species, River Odra and Morava basins

© 2018 Bohumír Lojkásek et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
alien fish species, impact, native fish species, River Odra and Morava basins