Germplasm degradation caused by inbred is an important problem that should be avoided during fish fry production in aquaculture.The inbred risk may be more severe in fry production of Amur sturgeon Asipenser schrenckii and Kaluga Huso dauricus because of their late maturation,rare mature fish resource and the ability to reproduce a large amount of eggs at one time.The present work examined the genetic diversity of 4 Amur sturgeon and 2 Kaluga reserved parent fish boodstocks from two hatcheries,using mitochondrial control region(D-loop)fragment sequence(Amur sturgeon 425 bp;Kaluga 434 bp(as the molecular marker.A total of 5 haplotypes were detected among 34 individuals from 4 Amur sturgeon stocks.There were 11 polymorphic sites,accounted for 2.6% of the total sites,no parsimonyinformative sites.There were 1-10 variable size among different haplotypes,accounted for 0.2%-2.4% of the total sites.Genetic distance among these haplotypes varied from 0.002-0.024.The haplotype divergence,average number of nucleotide differences and nucleotide divergence were 0.768,4.367 and 0.011,respectively.There was only one haplotype for each Kaluga stock from the two different hatcheries.Genetic difference between the two Kaluga haplotypes was 0.005,indicating a marked low genetic difference in Kaluga reserved parent fish broodstocks.These results show that much attention should be paid to avoid the inbred risk in sturgeon fry production,especially for Kaluga.