Broodstock Formation and Sterlet (Acipenser ruthenus) Reproduction in the West-Kazakhstan Region

Abstract

A dramatic decline of sturgeons’ stocks including the sterlet (Acipenser ruthenus) in the Caspian Sea including creates the need to establish aquaculture broodstock. Broodstock management can allow conserving the gene pool of the sterlet and the creation of captive broodstock further serve as a source of sterlet fry aimed at restoring natural populations of the sterlet in the Caspian Sea. In this regard, the study aims to develop the technology of sterlet broodstock formation in the pond-based sturgeon hatchery and recirculatory aquaculture systems in the West-Kazakhstan region. Captive sterlet broodstock formation was carried out by two methods-domestication and from the egg. Both methods were effective in sterlet broodstock management. It was the first sterlet brood stock program carried out in the sturgeon hatchery in Kazakhstan in which brood fish were taken from the natural populations of sterlet in the Kazakhstan parts of the Caspian Sea. The sterlet broodstock was genotyped using mitochondrial DNA markers. Sequencing of the control region of mitochondrial DNA in the studied individuals, for the purpose of species identification and detection of maternally inherited variability, reveals that captured broodstock from natural populations belongs to Acipenser ruthenus. As a result of artificial breeding in the hatchery 3.6 kg of fertilized eggs was obtained from 34 females and 20 males. Genetic analysis was carried out to create a genetic passport of sterlet for the Kazakhstan populations. It also revealed that at least 20 pairs of brood stock are required to avoid inbreeding and conserve the genetic diversity of the sterlet in the hatchery system. For this purpose, the structure of the recirculatory aquaculture system should provide the possibility for industrial breeding of sterlet in the region.