alexey-chernyak's Identifications

Sakhalin sturgeon of the 2015 generation at Konakovo sturgeon propagation facility (research and propagation base of the All-Russian Research Institute of Freshwater Fisheries (VNIIPRH) (town of Konakovo, Tver Region).

Videos of the observation:
https://www.youtube.com/watch?v=y5rTDgjVa_I

https://www.youtube.com/watch?v=Gq6r15Q7bNE

Sakhalin sturgeons of the 2015 generation were obtained during an expedition to the Tumnin River in 2015 (curator of research and propagation works - Viktor Khrisanfov (Moscow), field works manager - Konstantin Yafarkin (Vanino, Khabarovsk Region). During the expedition period one Sakhalin sturgeon female was caught. That female came to the Tumnin River for spawning. The expedition could not catch a male, and the female was temporarily sent to the Anyui sturgeon propagation facility of Amurrybvod - the local branch of The Russian Federal Agency for Fishery (Nanai Peoples District, Khabarovsk Region, Russia), where part of the Sakhalin sturgeons of the 2007 and 2008 generations were located. These two generations were obtained during expeditions to the Tumnin River in 2007 and 2008 from wild females and males of Sakhalin sturgeon that came to the Tumnin River for spawning: the fish were caught and kept temporarily in pools on the bank of Tumnin River, eggs and sperm were obtained from them in the field, the eggs were fertilized and incubated, the larvae were delivered to the Anyui sturgeon propagation facility (a certain number of larvae of the 2008 generation were also sent to Aleksin sturgeon propagation facility to the European part of Russia. The dilevery was facilitated by Alexey Chernyak - the curator of The Rarest Eurasian Sturgeon Species Conservation Programme of the Euro-Asian Regional Association of Zoos and Aquariums. By 2015, male Sakhalin sturgeons from the 2007 and 2008 generations had already matured in Anyui sturgeon propagation facility and were used to fertilize eggs obtained from the wild female that was temporarily brought to Anyui sturgeon propagation facility and later sent back and released to the Tumnin River.
Videos of the expedition to the Tumnin River in 2015 and work at Anyui sturgeon propagation facility:

https://www.youtube.com/watch?v=h5i8WWzQYao&t=1149s

https://www.youtube.com/watch?v=JFU3tX7xsPs

https://www.youtube.com/watch?v=yzFwW0Map9o

https://www.youtube.com/watch?v=TE6HmU7JEVs&t=2s

https://www.youtube.com/watch?v=zwAW0vPnI1I&t=2s

By the fall of 2015, the Sakhalin sturgeon larvae obtained in the spring of 2015 had grown to juveniles with an average weight of 4 g, and Viktor Khrisanfov brought 100 of these sturgeon juveniles from the Anyui sturgeon propagation facility (Khabarovsk Region) to Konakovo sturgeon propagation facility (Tver Region) in the European part of Russia:

https://www.youtube.com/watch?v=juoj5ihX0Z8&t=1s

During the November 22, 2023 examination and valuation of Sakhalin sturgeons of the 2015 generation at Konakovo sturgeon propagation facility 26 Sakhalin sturgeons with an average weight of 9 kg were counted, among which several mature males and one mature female were found and the female will presumably be ready for spawning in the spring of 2025. Ultrasound diagnostics of sex and degree of maturity was used for valuation.