نتایج جستجو برای: rutilus caspicus
تعداد نتایج: 1051 فیلتر نتایج به سال:
Quantifying the effects of human activity on the natural environment is dependent on credible estimates of reference conditions to define the state of the environment before the onset of adverse human impacts. In Europe, emission controls that aimed at restoring ecological status were based on hindcasts from process-based models or paleolimnological reconstructions. For instance, 1860 is used i...
Migration has evolved as a strategy to maximise individual fitness in response to seasonally changing ecological and environmental conditions. However, migration can also incur costs, and quantifying these costs can provide important clues to the ultimate ecological forces that underpin migratory behaviour. A key emerging model to explain migration in many systems posits that migration is drive...
این تحقیق با هدف بررسی قرابت خویشاوندی ماهیان جنس Rutilus در سواحل جنوبی دریای خزر انجام گردید. برای این تحقیق در مجموع تعداد 30 قطعه ماهی از سه جمعیت ماهی کلمه (بندرترکمن، رودخانه شلمانرود و رود ارس) به عنوان درونگروه و 10 قطعه ماهی سفید از صیدگاه بندرترکمن بهعنوان برونگروه تهیه شد. تمامی نمونهها بر اساس دستورالعمل استاندارد شفافسازی شده و اجزاء اسکلتی آنها مورد بررسی و تجزیه و تحلیل ...
By conveying information of disease resistance, sexual signals may be used as cues for adaptive mate choice. Here we report observations on survival of laboratory-maintained, wild-collected, sexually mature, ready-to-spawn cyprinid fish, Rutilus rutilus (roach), under accidental epidemic attributed to Flavobacterium psychrophilum, diagnosed using species-specific PCR. The fish were maintained i...
Aquatic prey show behavioral modifications in the presence of predation-risk cues that alleviate their risk from predation. Aedes albopictus (Skuse), Aedes japonicus (Theobald), and Culex pipiens L. are invasive mosquitoes in North America, and their larvae are prey for the native mosquito predator, Toxorhynchites rutilus (Coquillett). Ae. albopictus and Ae. japonicus are recent invaders, where...
Multiple predator species can interact as well as strongly affect lower trophic levels, resulting in complex, nonadditive effects on prey populations and community structure. Studies of aquatic systems have shown that interactive effects of predators on prey are not necessarily predictable from the direct effects of each species alone. To test for complex interactions, the individual and combin...
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