نتایج جستجو برای: squalius cephalus
تعداد نتایج: 779 فیلتر نتایج به سال:
The FishProtector, an Electric Flexible Fish Fence is investigated in ethohydraulic experiments. protection potential tested using outdoor, experimental channel. To find optimum parameter settings, cable clearance, approach flow angle, and the size of electric field vary within predefined limits. Due to combination both, physical barrier (tensioned steel cables) behavioral (pulsed low voltage r...
ساختار سنی و الگوی رشد ماهی سفید رودخانه‌ای در سر شاخه توجی رودخانه تالار استان مازندران از مرداد 1387 تا مرداد 1388 بررسی شد. 298 عدد ماهی با دستگاه الکتروشوکر و تور ترال صید و در فرمالین 5 درصد تثبیت شدند. وزن و طول ماهیان اندازه‌گیری و سن آنها از روی فلس تعیین گردید. طبق نتایج ماهیان در محدوده سنی+0 تا +4 بودند. ضریب رگرسیون الگوی رشد با روش کاربردی پائولی نشان داد که نرها و ماده‌ها و ماهیان...
The main objective of this study was to collect new data on the occurrence, levels of priority and emerging organic compounds in freshwater fish sampled in the Rhone River. The 34 studied contaminants included alkylphenols, bisphenol A, polybromodiphenylethers (PBDE), perfluorinated compounds, hexabromocyclododecanes (HBCD), hexachlorobenzene and hexachlorobutadiene (HCBD). About 50 fish sample...
The Rhine catchment in Switzerland has been transformed by a chain of hydroelectric power stations. We addressed the impact of fragmentation on the genetic structure of fish populations by focusing on the European chub (Squalius cephalus). This fish species is not stocked and copes well with altered habitats, enabling an assessment of the effects of fragmentation per se. Using microsatellites, ...
Squalius janae, sp. nov., is described from the upper Dragonja River system in the Adriatic Sea basin in Slovenia. The new species is distinguished from other members of the S. cephalus species group by a combination of the following characters: a long head, head length, 29−32% SL, always markedly exceeding body depth; a pointed conical snout; a slightly subterminal mouth, with a clearly projec...
Population structure can significantly affect genetic-based demographic inferences, generating spurious bottleneck-like signals. Previous studies have typically assumed island or stepping-stone models, which are characterized by symmetric gene flow. However, many organisms are characterized by asymmetric gene flow. Here, we combined simulated and empirical data to test whether asymmetric gene f...
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