New strategies for brood stock management of sturgeon in the Sea of Azov basin in response to changes in patterns of spawning migration

Abstract

The sturgeon stock in the Sea of Azov is presently maintained by artificial reproduction allowing for the harvest of sturgeons in this basin. Shortened spawning migrations in regulated rivers and long-term artificial selection of the ripest fish at the hatcheries have resulted in high functional maturity of sturgeon spawners in the sea near the river mouth. The traditional technology of artificial sturgeon reproduction is non-effective under modem ecological conditions. The use of ecological and hormonal methods to control seasonal propagation of stellate sturgeon, A.stellatus, Russian sturgeon, A.gueldenstaedti, beluga, Huso huso, and sterlef Aruthenus, make it possible to stagger the sexual cycle of breeders from the various biological groups for early ( 5 months) or later (6 months) spawning. Use of these methods preserves the natural heterogeneity of sturgeon populations maintained through stocking, and also allows for a considerable increase in the quantity of fry reared at the same production base.The use of the synthetic analogue of mammalian gonadotropin-releasing hormone (Gn-RHa) is better for inducing maturity of the ripest brood fishes, especially for stellate sturgeon, in comparison with the traditional pituitary injections. The schedule of injections was determined for the various species and seasons of spawning.Short-term rearing of larvae in ponds (no more than 15 days) and subsequent adaptation to sea water in brackish lagoons (1-5 %) allows for repeated use of nursery ponds in sturgeon hatcheries and a considerable increase in the quantity and survival of sturgeon juveniles in the sea.The restoration of the sturgeon population structure in the Sea of Azov is not possible without developing a genetic collection of the fish under a controlled culture regime. IntroductionThe most effective sturgeon culture in the Azov Sea basin is in the region of the Kuban River. From 1991-1996 five sturgeon hatcheries released 25-27 million juveniles of Russian and stellate sturgeons annually. Approximate yearly catches were 900 tons in

Application of synthetic hormone LHRH-A2 on the artificial propagation of Persian sturgeon Acipenser persicus

“…Dorafshan et al (2002) pointed out an insignificant difference between quantity of produced egg and survival of egg until eyedegg stage by using GnRH-a in comparison with pituitary gland in Oncorhynchus mykiss. Chebanov and Savelyeva (1999) believed that using GnRH-a gained more beneficiary than pituitary gland hormone for induction of Acipenser stellatus. Brzuska and Adamek (1999) recorded a considerable number of dead larvae in the last phase of incubation of eggs obtained from European catfish (Silurus glanis L.) females treated with Des-Gly 10 [D-Ala 6 ] LHRH Ethylamide.…”

Hatchery stock enhancement and conservation of sturgeon, with an emphasis on the Azov Sea populations

“…For example, transfer of the broodfish from cold water to spawning temperatures on methods II and III is determined by the duration of their exposure to low temperature, which is different for different ecotypes (Chebanov and Savelyeva, 1999). The water project and selective breeding of 'productive' females in hatcheries have already impacted these traits.…”

“…Three different methods, described in detail by Chebanov and Savelyeva (1999), were used for 'conditioning' females before spawning: I -conventional method (ambient water temperature, usually holding for a short time); II -short delay of spawning (exposure to low temperature for 10-25 days); III -long delay of spawning (exposure to low temperature up to 3 months). The less mature broodfish require additional holding in the hatchery to reach the stage of development responsive to hormonal treatment.…”

A guide to the embryonic development of the shovelnose sturgeon (Scaphirhynchus platorynchus), reared at a constant temperature

“…In addition to providing caviar production, aquaculture techniques can be used to aid conservationists. Conservation aquaculture has been used to enhance current stocks and reintroduce several species of sturgeon to their historic ranges (Chebanov and Savelyeva, 1999; Schramm et al., 1999; St Pierre, 1999; Chebanov et al., 2002; Ireland et al., 2002). Efforts are currently underway by the U. S. Fish and Wildlife to supplement and reintroduce shovelnose sturgeon populations in Ohio and West Virginia (G. Conover, U.S.…”