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Vliv hustoty obsádek sumečka afrického (Clarias gariepinus) na efektivitu jeho intenzivního chovu v recirkulačním akvakulturním systému
TRNKA, Kamil
This study is a dressing the breeding process of the african catfish kept in RAS recycling waste heat from the biogas plant. The weight, SGR, FCR, FC, survival rate and were evaluated. During the first test different breeding densities were established (30, 60, 90, 120 kg.m-3) and fishes were kept in the tanks without lowering the the density to the original. Into the tanks with the same quality of the water, we introduced juveniles of the african catfish. Results of the first test showed that the best growth of the african catfish is achieved in the breeding density up to 230 kg.m-3. In the second experiment, the different breeding densities were established (90, 120, 150 a 180 kg.m-3). These densities were periodically lowered to the starting density each Month. In this test we achieved higher SGR and lower FCR. There were no significant differences among the density's groups. Third test was based on the presence of the sorting of the fish in tanks. While not sorting negative influence has appeared. In the non-sorted group, we found couple of marked-sized fish and couple of bellow average fish. Also, the growth parameters showed better results in the sorted group. All experiments showed that the best breeding density is from 180 up to 230 kg.m-3.
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Latitudinal and altitudinal trends in sperm morphology and estimated levels of promiscuity in passerine birds
Krejčířová, Zuzana ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee)
Sexual promiscuity, whereby females copulate with more than one male, is a quite common phenomenon in socially monogamous birds, and especially in songbirds. This behavior is assumed to influence the evolution of various anatomical traits associated with male ability to outcompete other males in the process of sperm competition. High promiscuity is, in a multi- species comparison, associated with higher relative testis mass, but may also affect sperm phenotypes and other male phenotypes. Sperm morphology is clearly differentiated across avian species and some studies suggest that stabilizing post-copulatory selection on sperm length is responsible for a clear association of between male variation in sperm length and levels of promiscuity. However, the association between other phenotypic traits and promiscuity remains less clear. In this study, I focus on sperm characteristics in relation to the estimated levels of promiscuity in songbirds of tropical and temperate zone climates, and across an altitudinal gradient in the tropics. I found that the coefficient of variation in sperm length, both between males (CVbm) and within males (CVwm), was indeed a good index of promiscuity. I also reveal the size of cloacal protuberance as an anatomical trait intimately associated with the level of sperm...
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Habitatové preference skorce vodního (\kur{Cinclus cinclus}) na tocích okresu Tachov.
LIŠKA, Martin
In the first part of the thesis, the number of breeding pairs of the White-throated Dipper on the watercourses of Tachov district in western Bohemia was monitored and their distribution was examined. In the second part, characteristics (chemical, physical, geographical, quantity and quality of prey) of occupied territories and reference plots were examined and the preferences of the Dipper were examined. In the third part, correlations between body characteristics of birds and quantity of prey in the territory were examined.
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