How to become a critically endangered species: a review of the distribution and status of the crucian carp (Carassius carassius)

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, microsatellite