National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
How to become a critically endangered species: a review of the distribution and status of the crucian carp (Carassius carassius)
Janda, Benedikt ; Choleva, Lukáš (advisor) ; Lojkásek, Bohumír (referee)
The Crucian carp (Carassius carassius) is the native species of fish in European standing and slowly flowing waters. Thanks to their high resistance to adverse abiotic conditions, they also inhabited dead arms of river, ponds and floodplains. Despite its resilience, this species has been declining or completely retreating from the most of natural habitats since the middle of the 20th century. The negative direct human interventions into the species populations were, intensive fishing and the elimination of suitable habitats as a result of landscape defragmentation, which was part of flood control measures. Secondly, the human-made introductions of non-native species, the Gibel carp (Carassius gibelio), capable of gynogenetic reproduction, strongly competes with the native species for resources. The extent to which the situation of the native Cruvian carp is critical and ow it has historically occured is revised in the formo f literaly search by this bachelor's Thesis. Keywords The Crucian carp, gynogenesis, molecular genetic methods, cytochrome b gene, taxonomy, hybridization, introduction, microsatellites
Changes in physico-chemical parameters of the Orlik reservoir selected tributaries
ZELENKOVÁ, Kamila
The topic of the thesis is determination of concentration of dissolved solids in water and seasonal changes in surface water chemistry for specific affluents of Orlík water reservoir. Water samples were collected on regular basis and analysed in a laboratory during one season (November 2014 - November 2015). The thesis is focused on monitoring of changes in phosphate and nitrate concentrations, in particular. The results of analysis indicate that measured concentrations of substances at monitored locations reflect generally measured data within the region. Concentrations of NO3-N peak in winter to early spring seasons, therefore seasonal changes do occur; differences between locations have not been proven statistically. As for the parameter PO4-P within locations downstream pond systems no significant statistic differences were identified. Values of PO4-P concentration are not primarily associated with agricultural activities but rather with local sources existing within the catch basin. It has been concluded from testing water quality upstream and downstream fish ponds that pond management had no impact on quality of water within the monitored locations in 2015; respectively no additional phosphor and nitrogen load was imposed on Orlík water reservoir

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