Документы

Информирование о состоянии окружающей среды на территории Республики Казахстан и оценка эффективности мероприятий в области охраны окружающей среды

информирование о состоянии окружающей среды на территории Республики Казахстан и оценка эффективности мероприятий в области охраны окружающей среды 

информирование о состоянии окружающей среды на территории Республики Казахстан и оценка эффективности мероприятий в области охраны окружающей среды 

Baku 2017

The Ural sturgeon yield-to-fishery relative to river discharge was the highest in the Caspian Sea till recently. The environmental conditions to secure natural reproduction are still satisfactory for successful sturgeon reproduction. However, nowadays the catch in all regional sturgeon species is negligible. The Ural sturgeon population dynamics are analyzed along with some anthropogenic and natural factors affecting them. It is argued that legal overfishing (including all legal means of fish removal), based upon (a) faulty estimations of sturgeon stock and catch limits and (b) inappropriate fishery policies are the principal reasons for the stock decline in the Ural. The maintenance of the natural reproduction in the Ural is considered to be the primary strategy for the stock replenishment. If used at all, artificial propagation should be used only as an additional secondary option exclusively at the historical sturgeon habitats upstream the Ural river and not in the river delta, where the hatcheries are located now. Transboundary cooperation of basin countries with active inter- national involvement is essential to prevent further deterioration of the situation. ***The attached copy is furnished to the author for non-commercial research and education use, including for instruction at the author’s institution, sharing with colleagues and providing to institution administration. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the chapter (e.g. in Word or TEX form) to their personal website or institutional repository.***