"The present study focused on different types of hybridization and their impacts on compare reproductive features (fertilization rate and hatching rate) and, fitness-related traits such as growth rate, cumulative survival rate, critical swimming speeds and specific growth rate in different sturgeon species, as well as level of heterozygosity among sturgeon hybrids and purebreds using set of microsatellite loci. Production of intraspecific hybrids between different populations is one of the effective strategy in aquaculture in order to obtain better offspring. Additionally, it is pivotal to monitor the genetic condition of the stocks before producing hybrids. The population genetic analysis of Danube and Volga population of sterlet showed that both the populations are genetically divergent. Additionally it revealed the gene diversity and level of heterozygosity was high in Danube population compared to Volga population. The intraspecific hybrids produced between Danube and Volga sterlet were subjected to performance tests. The significant effects of hybrid vigor were recorded in terms of average weight and cumulative survival of produced hybrids as well as reproductive features like fertilization rate and hatching rate. The results from critical swimming speed in changing temperatures assessments revealed no significant differences among the purebred and hybrid crosses which indicated no effect of intraspecific hybridization on critical swimming speed in juvenile stage. The mean number of alleles and level of heterozygosity was significantly higher in one of the reciprocal hybrid. This suggests us that it is not just production of hybrids but it is always necessary to take the position of the individual population in a hybridization matrix. Detailed investigation of fitness-related traits (growth rate and cumulative survival) in purebreds of Russian sturgeon and Siberian sturgeon and their interspecific hybrids were undertaken. Russian sturgeon and Siberian sturgeon belongs to same ploidy level (Recent tetraploids). Our results revealed both the hybrids (reciprocal) performed better than both the parent species in one of the fitness-related traits examined. One of the hybrid (Russian sturgeon × Siberian sturgeon) recorded best growth rate and its reciprocal hybrid recorded the best survival rate (Siberian sturgeon × Russian sturgeon). Although no significant difference was observed in the heterozygosity levels among the purebred and hybrid crosses, the mean number of alleles was significantly higher in Siberian sturgeon × Russian sturgeon hybrid. Experimental interbreeding of sturgeon species (sterlet and Siberian sturgeon) bearing different ploidy levels and chromosome numbers, followed by molecular investigation of obtained progeny and examination of fitness-related traits revealed one of the hybrid performed better than purebreds. Additionally the heterozygosity levels were significantly high in one of the hybrid. The general rule of the negative interaction which could occur between the parental genes with different ploidy and its apparent impact on the intergeneric hybrid genome was not supported in our study. Therefore, given the evidences and observations provided by this study in controlled conditions, the above mentioned intraspecific and interspecific hybrids could be suggested for intensive aquaculture and might be also suitable for polyculture stocks. With respect to the growth properties of the monitored hybrids, these hybrids may present a significant competitive risk for wild populations of pure sturgeon species, in the event of their release into wild. Added to that, due to the easy hybridization of sturgeons in aquaculture conditions, as well as in natural waters, presents a considerable potential for this issue for further scientific research aimed at using different types of hybrids in aquaculture, as well as their impact on pure species in natural waters." In SHIVARAMU, Sahana. Hybridization of sturgeons =: Hybridizace jeseterů. Vodňany: Fakulta rybářství a ochrany vod, Jihočeská univerzita v Českých Budějovicích, 2019. 106 stran. ISBN 978-80-7514-095-1. Zdroj anotace: OKCZ - ANOTACE Z WEBU