Genetic Structure and Diversity of Native Tench (Tinca tinca L. 1758) Populations in Hungary—Establishment of Basic Knowledge Base for a Breeding Program

Abstract

Tench is a cyprinid fish that has undergone human-induced translocations. The natural populations of the species are on the decline due to habitat loss and spawning grounds degradation. The genetic diversity of seven natural populations was investigated to establish the genetic knowledge base for successful conservation efforts and for selective breeding. Twelve microsatellite markers, the sequencing of a 615 bp section of mtDNA (Cytb) and PCR-RFLP analysis of two nuclear markers (Act) and (RpS7) were used to analyze the genetic variation and structure among 175 individuals. All microsatellite loci were found to have moderate levels of polymorphism. The pairwise Fst values between population pairings were moderate; the populations were aligned to four clusters. The Cytb gene showed 20 haplotypes; 67.1% of individuals were categorized as Eastern, while 32.9% to the Western haplogroup. Analysis of the Act and RpS7 genes showed that the level of hybridization among the two haplogroups is high within the sampled populations. Hungarian Tench populations are genetically less diverse compared to natural populations in Western-Europe, but they still represent valuable genetic resources and Lake Fertő, Lake Kolon and Csörnöc-Herpenyő populations can be optimal candidates for future selective breeding programs.

The Direct Effects of Climate Change on Tench (Tinca tinca) Sperm Quality under a Real Heatwave Event Scenario

“…The sperm motility of tench males exposed to a 16-day thermal stress model was reduced in terms of progressive and total motility along the first minute post-activation, confirming the negative effect previously reported in rainbow trout (Oncorhynchus mykiss), where sperm motility and concentration were reduced in male specimens who were exposed early on to a 90-day thermal stress model during the parr stage [51]. Considering the fact that rainbow trout is a temperate stenotherm [52] and that tench is an eurytherm species [50], the present results further highlight how currently occurring extreme events like heatwaves may result in reduced reproductive performance in male fish.…”

“…Tench ( Tinca tinca ) fish are an interesting model for exploring the effects of naturally occurring heatwaves, as they are currently reared in natural ponds (under restricted conditions that do not allow them to escape from changes in abiotic conditions such as high environmental temperatures and/or low dissolved oxygen). However, they also show several interesting physiological and biochemical features for studies, such as clear sexual dimorphism (in males, the pelvic rays are more robust and longer and extend beyond the anus) and tolerance to low dissolved oxygen values and to a wide range of environmental temperatures (up to 37 °C; [ 50 ]). Here, we demonstrated a deleterious effect on sperm quality from tench males exposed to a heatwave model mimicking the natural and registered thermal conditions during summer in inland Spanish lagoons, where they are reared [ 27 , 50 ].…”

“…However, they also show several interesting physiological and biochemical features for studies, such as clear sexual dimorphism (in males, the pelvic rays are more robust and longer and extend beyond the anus) and tolerance to low dissolved oxygen values and to a wide range of environmental temperatures (up to 37 °C; [ 50 ]). Here, we demonstrated a deleterious effect on sperm quality from tench males exposed to a heatwave model mimicking the natural and registered thermal conditions during summer in inland Spanish lagoons, where they are reared [ 27 , 50 ]. The sperm motility of tench males exposed to a 16-day thermal stress model was reduced in terms of progressive and total motility along the first minute post-activation, confirming the negative effect previously reported in rainbow trout ( Oncorhynchus mykiss ), where sperm motility and concentration were reduced in male specimens who were exposed early on to a 90-day thermal stress model during the parr stage [ 51 ].…”

Trends of Eurasian Perch (Perca fluviatilis) mtDNA ATP6 Region Genetic Diversity within the Hydro-Systems of the Eastern Part of the Baltic Sea in the Anthropocene

“…In addition, many freshwater fish species are either commercially exploited [23,27] or keystone species [28]. Even though a large body of data concerning the distribution, abundance, and ecology of many fish species, both in freshwater and brackish environments [29,30], has been collected, the findings on their intraspecific genetic variability [22,[31][32][33], phylogeographic relationships [34][35][36], and postglacial history [24,37,38] remain fragmented. Furthermore, such data are quite limited even for extensively studied fish species [20,39].…”