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Caviar is a high cost delicacy consisting of salt-cured fish-eggs of the sturgeon family. Natural populations of sturgeon have declined during the past century through poaching for caviar, water pollution, and habitat degradation, making them currently the world’s most endangered group of species. It has led to the development of sturgeon culture, originally for reintroduction, but more recently for caviar production. “Besides pure species, less priced caviar is also produced by fertile sturgeon hybrids. Among those, bester (hybrid between beluga Huso huso female and sterlet Acipenser ruthenus male) is the most widely used.

Caviar from hybrids is almost impossible to identify from pure species caviar without reliable DNA-based technique. Similarly, identification of sturgeon species is very complicated and requires molecular genetic techniques” says Milos Havelka, who works on sturgeon research at Faculty of Fisheries and Protection of Waters, University of South Bohemia.
Researchers from University of South Bohemia in cooperation with Hokkaido University in Japan developed new method for identification of beluga sturgeon and its caviar. Beluga caviar is the most costly in the trade. Less valuable roe from other species or hybrids is sometimes fraudulently sold as beluga caviar. “Using modern methods of molecular genetics, we identified species-specific variants in genome of beluga and sterlet sturgeons. Taking advantage of these variants, we have developed simple method allowing identification of beluga, sterlet and their interspecific bester hybrid. Importantly, the tool works for caviar and requires only one roe for analyses” adds M. Havelka.    
Developed tool should contribute to better, more reliable, regulation and control of global trade of high value sturgeon products as well as to their management and conservation. The protocol is straightforward and thus can be easily implemented across laboratories.
Detailed info is available in original article: Havelka, M., Fujimoto, T., Hagihara, S., Adachi, S., Arai, K. 2017. Nuclear DNA markers for identification of Beluga and Sterlet sturgeons and their interspecific Bester hybrid. Scientific Reports. Doi: 10.1038/s41598-017-01768-3
Figure 1. Caviar sample ready to be analysed.
Figure 2. Schematic workflow of caviar sample analysis using developed method.