Comparison of the Genetic Structure of Invasive Bigheaded Carp (Hypophthalmichthys spp.) Populations in Central-European Lacustrine and Riverine Habitats

Abstract

Bigheaded carps (bighead carp, Hypophthalmichthys molitrix, and silver carp, Hypophthalmichthys nobilis) and their hybrids play an important ecological and economic role in their original habitat, while their introduced stocks may pose serious ecological risks. To address questions about the persistence and invasiveness of these fish, we need to better understand their population structures. The genetic structures of bigheaded carp populations inhabiting Lake Balaton and the Tisza River were examined with ten microsatellite markers and a mitochondrial DNA marker (COI). The Lake Balaton stock showed higher genetic diversity compared with the Tisza River stock. Based on hierarchical clustering, the Tisza population was characterized only by only silver carps, while the Balaton stock included hybrid and silver carp individuals. All COI haplotypes originated from the Yangtze River. Based on the high genomic and mitochondrial diversity, along with the significant deviation from H–W equilibrium and the lack of evidence of bottleneck effect, it can be assumed that bigheaded carps do not reproduce in Lake Balaton. The present stock in Balaton may have originated from repeated introductions and escapes from the surrounding fishponds. The Tisza stock consists solely of silver carp individuals. This stock appears to have significant reproductive potential and may become invasive if environmental factors change due to climate change.

Microsatellites as Molecular Markers with Applications in Exploitation and Conservation of Aquatic Animal Populations

“…Population genetics of invasive species have been examined by studies of microsatellites in many species, including the evolution of brown trout populations originating from Poland and introduced to virgin rivers systems of the subantarctic Kerguelen Islands [ 222 ], smallmouth bass, Micropterus dolomieu , introduced to the range of Guadalupe bass, M. treculii in central Texas and its introgressive hybridization in a few rivers [ 223 ], Asian black carp, M. piceus , imported to U.S. aquaculture farms in the 1980 and present in the Mississippi River basin since the early 1990s [ 224 ], bighead carp, Hypophthalmichthys molitrix , and silver carp, H. nobilis , in Hungary, imported from China [ 225 ], and signal crayfish, Pacifastacus leniusculus , introduced to Europe from North American lakes for hatchery purposes [ 226 ].…”

Assessing Prospects of Integrating Asian Carp Polyculture in Europe: A Nature-Based Solution under Climate Change?

“…Although Asian carps have significant invasive potential, they also constitute a potential source of food. The intentional introduction of Asian carps in many European countries has led to cases of self-reproduction in the wild, such as in the Danube and Tisza River basins, an irrigation canal network in Northern Italy [17][18][19][20][21][22].…”

Silver Carp (Hypophthalmichthys molitrix) (Asian Silver Carp) Presence in Danube Delta and Romania—A Review with Data on Natural Reproduction

“…As a planktivorous fish species, Hypophthalmichthys spp. has biological traits that make it both ideal an aquaculture species and effective invaders (traits such as quick growth and reproduction, wide environmental tolerance, and general eating preferences); thus, in many of the territories where they have been introduced, Asian carp are now regarded as invasive species in areas outside their native range, especially in the USA [ 10 ].…”