نتایج جستجو برای: esox lucius
تعداد نتایج: 570 فیلتر نتایج به سال:
One thousand three hundred seventy three fish specimens of eight different species from the vicinity of Kyiv, Ukraine, were examined for the presence of trypanosomes and 921 individuals were found to be infected. The prevalence of infection ranged from 24% in freshwater bream, Abramis brama (Linnaeus), to 100% in spined loach, Cobitis 'taenia' Linnaeus. The level of parasitaemia also varied sig...
The present study reports the results of virological survey in fish with an emphasis on the diseases included in the Czech National Legislation. Monitoring of fish both without symptoms and with a manifested disease was performed within this virological surveillance. Between January 1999 and December 2006, viral haemorrhagic septicaemia virus (VHSV), infectious haematopoetic necrosis virus (IHN...
Coastal development has severely affected habitats and biodiversity during the last century, but quantitative estimates of the impacts are usually lacking. We utilize predictive habitat modeling and mapping of human pressures to estimate the cumulative long-term effects of coastal development in relation to fish habitats. Based on aerial photographs since the 1960s, shoreline development rates ...
Selective harvest of large individuals should alter natural adaptive landscapes and drive evolution toward reduced somatic growth and increased reproductive investment. However, few studies have simultaneously considered the relative importance of artificial and natural selection in driving trait changes in wild populations. Using 50 years of individual-based data on Windermere pike (Esox luciu...
The mechanisms behind speciation have been subject of debate for centuries. The presence of resource polymorphism has been discovered to play a significant part in this process, and has been proven to induce phenotypic and genetic divergence. Although resource polymorphism has been intensely studied during the last few decades, there is a gap of information as to why this can be observed in som...
Traditional fisheries management theory supports aggressive exploitation of old and large fish to maximize a stock’s biomass production and yield. Here we present an age-structured fish population model with multidimensional density-dependence to test the hypotheses that protection of large, fecund individuals is beneficial for the population and selected fisheries variables and that effects of...
The ideal free distribution (IFD) theory is one of the most influential theories in evolutionary ecology. It predicts how animals ought to distribute themselves within a heterogeneous habitat in order to maximize lifetime fitness. We test the population level consequence of the IFD theory using 40-year worth data on pike (Esox lucius) living in a natural lake divided into two basins. We do so b...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید