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The potential use of PIT telemetry for identifying and tracking Spinycheek crayfish in their natural environment.
VÍCH, Petr
Main purpose of this diploma work was to find out possibility using PIT telemetry in monitoring strange crayfish species Spinycheek crayfish Orconectes Limosus. Research of the theme consisted of three steps: two laboratory researches and one research in the natural environment. The first laboratory study concerned tagging passive integrated transponder (PIT) to various part of crayfish body. PIT tags were internally implanted to cephalothorax, abdomen and claw. The highest mortality was in tagging to claw. The second laboratory research consisted of comparing different tagging methods to PIT telemetry. Crayfish were tagging by PIT telemetry, soldering, visible implant elastomers and visible implant Alpha tags. Among tagging groups there were not to find out different in mortality. In the third research the crayfish were tagging in their natural environment. There were using three methods: PIT telemetry, soldering and VI Alpha tags. This experiment wasn´t successful. During recapturing crayfish there were not to find any tagging crayfish.
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Activity of noble crayfish (Astacus astacus) and spiny-cheek crayfish (Orconectes limosus) under the laboratory coditions
MUSIL, Martin
Activity of noble crayfish (Astacus astacus) and spiny-cheek crayfish (Orconectes limosus) under the laboratory coditions University of South Bohemia České Budějovice - Faculty of Agriculture, Department of Fisheries Author: Martin Musil Contact: mue.@seznam.cz Abstract: Some authors point out, that the American species are more activated than European during the day. Noble crayfish (Astacus astacus L.) is the night animal. Spiny-cheek crayfish (Orconectes limosus Raf.) is the most agresive species with more activity during the day, whose is of itself ecologic and reproductions characteristic typical r{--}strategist. And over than above it is a vector of crayfish plague. Objective of this study was the observe the daily and noctural of both species, the influence of fish predators and murmurs of agresivity. The bulk of this work was in ethologic laboratory with using videotechnic in control conditions and directed lightregimen. The findings see the big diference between species, that the spiny-cheek crayfish is more activated that the noble crayfish (51,4%{$\pm$}4,33 of the 24 hour activity) with slight diference between the day and night. Someones of the subjects don´t look for the cover during the experiment, it were mainly the females, whose activity were better than the male. Noble crayfish embodied low aktivity (15,1%{$\pm$}8,22 of the 24 hour activity) with more highly diference between the day and night and with slight diference between the sex. The inherence of the fish predator have had slight influence on the both species, rather sometimes take on the crayfish attention. The agresivity of the both is at least comparable, so it isn´t clear, that the spiny-cheek crayfish would be more successful in proximate competetion without the infection of crayfish plague.
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Impact of american mink on stone crayfish populations
PAVLUVČÍK, Petr
1. Impact of introduced American mink (Mustela vison) predation on endangered stone crayfish (Austropotamobius torrentium) was examined in western Bohemian middle-sized streams for two years. Mink diet selectivity and its impact on its prey abundance were been investigating as the main target of this study. 2. The mink diet was described from excrements which were found on the target areas. The importance of different types of prey was specified by their relative numeric contribution to diet. The number of hunted crayfish was elicited from the number of crayfish remains which were collected during two years. The crayfish abundance was determined by capture {--} recapture method. 3. The crayfish was most frequently observed component of mink diet. The rate of mink predation on crayfish was dependent on density of crayfish population. This observed rate was lower during winters than during summers. The mink preferred significantly longer crayfish than was the mean of this value in population. 4. Although the crayfish was important part of mink diet the trend of impact of mink on crayfish is still inexplicit. It would be important to continue in this research to determine correlation between these two species.
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Comparison of Postembryonic Development of Native and Non-native Crayfish
KANTA, Jan
The diploma thesis observed the indicators of growth in individual developmental stages of our native crayfish (Astacus astacus, Austropotamobius torrentium, Astacus leptodactylus) and non-native crayfish (Pacifastacus leniusculus, Orconectes limosus) under experimental conditions. The next aim of work was to describe the time of hatching of these species, the moulting interval, the frequency of moulting and increase after individual moulting during the first vegetation season in two different temperatures (15{$\rm^o$}C a 21{$\rm^o$}C).
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Production of sac-fry of perch by means of hormonally induced semiartificial and/or artificial propagation
Kouřil, J. ; Hamáčková, J. ; Lepič, P. ; Lepičová, A. ; Mareš, J. ; Barth, Tomislav
[D-Ala.sup.6./sup., ProNHEt.sub.9./sub., desGlyNH.sub.2./sub..sup.10./sup.] mGnRH and [D-Tle.sup.6./sup., ProNHEt.sup.9./sup., desGlyNH.sub.2./sub..sup.10./sup.] mGnRH were compared in their abilities to induce the ovulation of perch females after the intramuscular administration.
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Community ecology of parasites of chub fry (Leuciscus cephalus L.)
Dávidová, M. ; Jurajda, Pavel ; Gelnar, M.
The formation and development of metazoan parasite community of chub fry (Leuciscus cephalus L.) was followed in the period from July 2000 to May 2001. Chub fry (N=190) were sampled monthly from the River Morava. Altogether 27 parasite species have been recorded. The most common parasites in the investigated locality were representatives of the class Monogenea, especially viviparous gyrodactylids. First, juvenile fish 29 mm in size were found to be infected with ectoparasites and metacercariae. On the opposite, host fish larger then 50 mm were colonised with intestinal parasites.
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The effect of posthodiplostomosis on the cyprinid fish fry
Ondračková, Markéta ; Dyková, Iva ; Gelnar, M. ; Jurajda, Pavel
Posthodiplostomosis, called also black-spot disease, is caused by metacercariae of Posthodiplostomum cuticola (Trematoda, Diplostomatidae). These parasites were studied on the cyprinid fish in floodplain area of the River Dyje in South Moravia. Twelve species from 16 totally explored Cyprinids were infected by metacercariae of P. cuticola during 1998, 1999 and 2001. Roach (Rutilus rutilus), rudd (S. erythrophthalmus), silver bream (B. bjoerkna), common bream (A. brama), bitterling (R. sericeus) and Prussian carp (C. auratus gibelio) were infected in all followed seasons. These species were histologicaly examined. During the cyst development the progressive maturation of connective tissue in outer layer of the cyst and infiltration of pigment cells were observed. Production of black pigment around the parasite cyst was chacteristic host reaction. Mainly melanocytes and in a small measure iridocytes took part in the pigmentation. The metacercariae of P. cuticola caused in the juvenile fish spine and body deformation. By high invasion the tissue dystrophy was observed.
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