نتایج جستجو برای: sturgeons

تعداد نتایج: 248  

Journal: :E3S web of conferences 2023

Poaching of aquatic biological resources is one the most common environmental crimes, causing direct and indirect harm to entire amount fish stocks. It necessary have a clear understanding composition quality poacher’s catches in order properly manage This paper examines poaching lower reaches Irtysh River, based on data forensic ichthyologic examinations over past 9 years. The study showed tha...

Journal: :Biodiversity and Conservation 2022

Abstract Sturgeon populations are declining worldwide and the target of extensive conservation efforts. Addressed in several pieces legislation, sturgeons have received considerable attention as flagship or umbrella species. Despite need for a better understanding distribution population status, use traditional sampling methods failed past, thereby hampering reliable assessments, prerequisite c...

D. Kor H. Ghadirnejad M. Tavakoli M.R. Behrooz Khoshghalb

The sturgeon stock assessment was performed to aim at estimation of absolute and relative abundance and determination of species composition at lower 10 m depths using the Si-Sara2 RV vessel in the Iranian coasts of the Caspian Sea in Guilan, Mazandaran and Golestan provinces during 6-30 September 2011-2012. In this study, 40 stations were selected on the basis of stratified random sampling des...

ژورنال: علمی شیلات ایران 2012
توکلی, محمود, جوشیده, هاشم, خوشقلب, بهروز, فدایی, بهروز, مرادی, یزدان, پرافکنده حقیقی, فرخ,

This study was carried out in Turkmen fishing station to examine suitable mesh size of gill nets for Persian sturgeon, Acipenser persicus, to decrease possibility of catching immature specimens and increase catch likelihood for larger fish. The Holt model was used to determine suitable length for catch and selection of mature Persian sturgeon females. Following preliminary studies some 920 expe...

A. Veshkini A.R. Vajhi M. Masoudi Fard M. Moghim,

Knowledge of both sex and maturity stage without killing fish is important from many aspects. The establishment of accurate sex and maturity determination without external sexual dimorphism or when external characters are not developed has usually involved the use of either hormone radioimmunoassay or biopsy techniques. These methods are time and labor consuming as well as harmful to fish. Ther...

A. Veshkini, A.R. Vajhi, M. Moghim, M. Masoudi Fard,

Knowledge of both sex and maturity stage without killing fish is important from many aspects. The establishment of accurate sex and maturity determination without external sexual dimorphism or when external characters are not developed has usually involved the use of either hormone radioimmunoassay or biopsy techniques. These methods are time and labor consuming as well as harmful to fish. Ther...

Over the last century the reproduction of sturgeon has been intensively studied par Russian scientists who established a technology for the ranching of alevins which included artificial fertilization of gametes taken from wild broodfish and larvae rearing. More recently, since 1970, major contributions originated from teams in the USA, the EU, Japan and Iran. A rather good knowledge of the repr...

Over the last century the reproduction of sturgeon has been intensively studied par Russian scientists who established a technology for the ranching of alevins which included artificial fertilization of gametes taken from wild broodfish and larvae rearing. More recently, since 1970, major contributions originated from teams in the USA, the EU, Japan and Iran. A rather good knowledge of the repr...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی و علوم دریایی 1386

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