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No description available.

The "Zákolanský potok" takes part in European nature program Special Area of Conservation because of the presence of stone crayfish (Austropotamobius torentium), which is listed as threatened species. The area around brook is intensively agriculturally cultivated. Water from wastewater treatments plants is drained to the local brooks. The aim of the work was to describe diversity of macrozoobenthos on the brook called "Zákolanský potok". Further aim was to evaluate the ecological condition of the watercourse using biotic indexes. The samples of macrobenthos were taken from three profiles in five sampling periods. Profile 1 was control, profile 2 was under the wastewater treatments plants and the third profile was placed down the stream. Diversity, biomass, saprobic index, BMWP, and ASTP scores were evaluated for the community of macrozoobenthos. The saprobic index was evaluated to the beta-mezosaprobity value (2.0-2.4) in the first profile, the saprobic index on the second profile showed a relatively wide range from worse oligosaprobity to worse beta-mesosaprobity (1.2-2.4). On the third profile, the saprobic index ranged from better beta-mesosaprobity to better alpha-mesosaprobity (1.6-2.6). The BMWP and ASPT scores in all profiles refer to medium to low quality aquatic environments. The diversity of the community gained the best values on the 3rd profile, here was found with one more taxon than on the 1st profile. With increasing organic load, diversity decreased on the 2nd profile, although a more sensitive species was found here.

O lagostim Norte-Americano Procambarus clarkii está dentre as espécies exóticas estabelecidas no Brasil, registrada no estado de São Paulo. Este crustáceo de água doce apresenta grande potencial de invasão (ampla plasticidade ecológica, elevada agressividade, enorme poder de dispersão). Além disso, é portador do oomiceto Aphanomyces astaci, ao qual as espécies de crustáceos nativas do Brasil podem não ser imunes. Inúmeros impactos já foram associados à presença de P. clarkii em várias partes do mundo, desde danos ao ecossistema até impactos sobre a biota nativa. A fim de contribuir com informações relevantes para o desenvolvimento de estratégias de manejo e mitigação de impacto desta espécie no Brasil, esta pesquisa (1) levantou informações sobre a dinâmica populacional e o efeito da sazonalidade na sua abundância, (2) aperfeiçoou e propôs um método padronizado, rápido e acessível para o monitoramento das populações invasoras, (3) testou uma abordagem para controle populacional, (4) verificou a ecologia alimentar e as variações sazonais e intrapopulacionais na dieta, relacionando estes aspectos com o potencial de impacto, (5) analisou a diversidade genética de 9 populações estabelecidas no estado de São Paulo através da utilização de marcadores mitocondriais, (6) sumarizou o panorama legal sobre espécies invasoras, e (7) propoe ações para o manejo de invasão de P. clarkii. Foi definida uma metodologia padronizada para o acompanhamento das populações invasoras de P. clarkii, baseada no método de Schumacher e Eschmeyer para populações fechadas. As análises de dinâmica populacional demonstraram que não há efeito sazonal na abundância da população estudada e que a mesma segue crescendo com taxas consideráveis. Após testar um método de controle populacional baseado na remoção periódica de indivíduos ao longo de um ano, percebeu-se que a abundância populacional aumentou drasticamente e que o controle populacional através de remoção intensiva de indivíduos deve ser mais eficiente que a remoção extensiva. O estudo da dieta evidenciou a voracidade destes lagostins, que se alimentam continuamente de itens diversificados, tanto de origem animal quanto vegetal. Sua alta plasticidade trófica contribui para o alto potencial de estabelecimento em novos ambientes, uma vez que pode utilizar diferentes recursos alimentares dependendo da sua disponibilidade. Esta alta diversidade alimentar também está relacionada com o elevado poder de impacto, uma vez que fontes de diferentes níveis tróficos são utilizadas como recurso alimentar, podendo gerar um desequilíbrio trófico multidirecional, além de ameaçar a abundância e diversidade das espécies consumidas. Nas análises moleculares, foram encontradas apenas 7 haplótipos compartilhados por indivíduos de populações diferentes. Nenhum haplótipo é compartilhado entre populações brasileiras e indivíduos de populações autóctones, embora 3 haplótipos sejam observados entre populações nativas e outros 4 sejam encontrados em algumas populações brasileiras. As diferentes abordagens analíticas aplicadas ao longo deste estudo indicam que P. clarkii está adequadamente adaptado às situações bióticas e abióticas encontradas no Brasil, não havendo nenhuma estação em que os indivíduos encontrem barreiras importantes que pudessem dificultar sua sobrevivência e expansão, de forma que é indiferente a época do ano em que se fará maiores investimentos em manejo das populações invasoras. / Amongst the non-native species currently stablished in Brazil, the North-American freshwater crayfish Procambarus clarkii, is highlighted. This species has notable economic importance worldwide due to its value to aquaculture among aquarists. The occurrence of this species in Brazil seems to be restricted to the State of São Paulo. Procambarus clarkii shows a remarkable potential of invasion as a result of its wide ecological plasticity, elevated aggressiveness and high dispersion capacity. Additionally, it hosts the oomycete Aphanomyces astaci, which might infect and threat native crustaceans. Many impacts were associated to the establishment of this crayfish around the world, from ecosystem disturbances to the harm of native biota. In order to provide relevant information to the development of impact mitigation actions and management strategies related to P. clarkii’s invasion in Brazil, this research (1) evaluated the population dynamics and the effect of seasonality on abundance of one invasive population, (2) adapted and proposed a standardized method to monitor invasive populations which is easily executed and of low budget, (3) tested an approach for population control, (4) verified the trophic ecology of this freshwater crayfish, considering seasonal and intrapopulational variations, relating this aspect to invasive capacity and potential impact, (5) analyzed the genetic variability of 9 populations established in the State of São Paulo through molecular mitochondrial markers, (6) summarized the legal panorama about invasive species, and (7) proposes management actions to deal with P. clarkii invasion. After testing some traditional methods for abundance estimation, in search for the most easily replicated and performed, we defined a standardized methodology to monitor invasive populations of P. clarkii, based in the estimation method of Schumacher and Eschmeyer for closed populations. The population dynamic analysis demonstrated that seasonality does not play a role in abundance and that the population is in continuous growth. The test of population control, based on periodical removal of individuals for a year did not result in a decrease on abundance as we expected. Thus, we believe that intensive animal removal might be more promising than extensive removal. The diet evaluation evidenced the remarkable voracity of this crayfish, which continuously feeds on a variety of items as macrophytes, algae, insects, crustaceans, mollusks, fishes and amphibians. We also found a notable trophic plasticity that must contribute for the great establishment and potential impact offered by this species. The molecular analysis showed 7 haplotypes that are shared among individuals from different populations. No haplotype is shared between native and Brazilian populations however, some native populations share 3 haplotypes and some Brazilian share 4 haplotypes. The variable approaches used in this thesis indicate that P. clarkii is adequately adapted to biotic and abiotic conditions in Brazil and it seems that there is no season in which individuals are under important ecological pressure related to population abundance or food resources, which would difficult their survivorship or range expansion. Thus, according to our data, there is no specific season in which population are subjected to any notable pressure that could be favored for management.

The purpose of this work was to describe the current status of benthic communities on the main stream of Elbe River and Ohře River and their tributaries affected and non-affected by biological invasions - especially by round goby (Neogobius melanostomus) and spiny - cheek crayfish (Faxonius limosus). Sampling for this research took place from April 2018 to August 2018, while morphiologic survey of waterbodies was done in November 2017. Two tributaries of the Elbe River (Milešovský brook and Ploučnice River) and one tributary of the Ohře River (Čepel) were selected for this research. Two 100 m long sections (lower stretch potentially affected by invaders and upper stretch as referential) were monitored at each tributary. At the same time a 100 m long main flow section was monitored near the mouth of the tributaries. The following parameters were monitored: morphology of the stream and basic physical and chemical parameters of water, zoobenthos community, crayfish occurrence, and fish community. The benthic communities of the upper streams were less affected by biological invasions. The biodiversity of the benthic communities in the upper sections was richer compared to the lower sections. The occurrence of the round goby seemed to be factor affecting benthic and fish communities at the sites concerned. It was an eudominant species in the Elbe section in Děčín and becoming dominant in the lower section of Ploučnice River.

The issue of sustainability has greatest significance in the midst of unilateral bio-socioeconomic degradation resulting from intense and increasing societal pressures placed on the unified global ecology. In such an environment, sustainable development seeks to manage natural resources within a free market economy, aiming to meet the needs of today's population, and to protect and enhance current resource quality and abundance. In this light, techniques of integrated sustainable primary production and wastewater management are the subject matters of this applied research. There are many researchable issues which could be addressed within the subject matter. The first focus in the research scope was driven by the most severe sustainability issue facing Central Queensland (Australia) in 2000: the depletion and degradation of freshwater supplies. Central Queensland (CQ) is an arid sub-tropical region that has suffered from a marked reduction in rainfall and increase in temperature over the last 100 years, {Miles, 2004 #172}, and by the year 2000, conditions had been exacerbated by eight years of severe drought and warmer than average temperatures and resulted in widespread animal and crop failures due to freshwater shortages. Such a problem required a multi-faceted ecological, social, and economic approach. Hence, research centred on investigating the science of integrating regional water-related industries and agribusiness, and biodiverse ecosystems to achieve water and wastewater reuse applications, and associated eco-socioeconomic benefits. Specifically, this research investigates the integration of (a) electrical power station wastewater (b) barramundi culture, (c) red claw culture, (d) constructed wetlands (for water quality management and habitat creation), and (e) hydroponic flower culture. This research produced outcomes of integrated water and wastewater reuse and recycling, marketable agriproducts production (fish, crayfish, and flowers), water and wastewater reuse and conservation, wetland primary production, carbon dioxide sequestration, aquatic pollution control, and biodiversity creation and support. Successful design and management, experimental trialing and evaluation of system components and subjects, and the development of a knowledge base including static and dynamic system models, represent advances in respective research areas, and underpin the emerging discipline of integrated systems approaches to eco-socioeconomic development. Additionally, several gaps in the current body of knowledge regarding integrated systems were filled, and interactive management tools were developed. Apart from this study, the integration of technologies (as described above) has not, to this author's knowledge, been accomplished.

Dur At Talah sedimentary sequence, located at the southern side of the Sirt Basin in central Libya, is composed of 150 m thick of mainly siliciclastic rocks. The importance of this sequence is linked to the importance of the Sirt Basin as one of large hydrocarbon reservoirs in Libya. The sequence is also an excellent site for vertebrate fossils of Late Eocene, the age of the sequence. Previous studies, though very limited compared to the importance of this area, are focused on its paleontological content. Sedimentology received only scant attention before this project. This thesis is an outcrop based study in which the focus is given to the sedimentary and biogenic (trace fossils) structures, aiming at defining and interpreting depositional facies which building up the sequence. The study is mainly based on field data which are analyzed on the light of related published literature and on the comparison with modern sedimentary environments. Results of facies analysis have led to splitting the entire sequence into three genetically related intervals. The oldest, we called the New Idam Unit (around 80m), is composed of very fine sandstones to mudstones. New Idam Unit is unconformably overlain by the Sarir Unit (around 50m), composed of medium grained cross bedded sandstones (the lower 25-30 m) changes up to very coarse and microconglomeratic sandstone (the upper 20-30 m). Thus, the Sarir Unit is split into the lower Sarir Subunit and upper Sarir subunit. The New Idam Unit presents both classical and unusual sedimentary and biogenic indicators that attribute this unit to estuarine depositional environment. It starts with outer estuarine (the lower 35 m) and ends up with inner estuarine (the upper 45 m). Maximum flooding surface is located in between. Above this surface the fluvial indicators increase and tidal indicators decrease, thus providing clue for basinward (North) migration of the shoreline. The lower Sarir subunit which was previously interpreted as fluvial deposits, preserves multi-scale sedimentary structures that undoubtedly belong to tidal processes. This is especially evidenced at the lower part of the lower Sarir Subunit (LLS). Fluvial indications over dominates the tidal ones in the upper part of the lower Sarir (ULS). Due to this configuration the whole lower Sarir subunit is interpreted as shallow marine, deltaic, depositional system, occurred during sea level ¨normal¨ regression. This time, maximum flooding surface is located between the LLS and ULS. The lower Sarir subunit is terminated by subaerial unconformity, with evidences of subaerial exposure preserved at the top of the ULS. These are intruded by the upper Sarir subunit which presents clear evidences of strictly fluvial environment of deposition. The deposits of the upper Sarir subunit record the low stand system tract part of the Dur At Talah sequence. In addition to the outlined results, the sequential pattern of the depositional events is suggested for the entire sequence of Dur At Talah. This study provides a valuable information regarding the depositional and sequential aspects of the Sirt Basin during the late Eocene, it also provide an unique case study for the better understanding of the shallow marine tidal deposits.

Aquaculture represents a sustainable alternative to natural fisheries for provision of high quality, animal protein. Crustaceans make a significant contribution to global aquaculture production, of which decapods are the most economically important group. Among freshwater crayfish, the genus Cherax includes several species that have emerged as important culture species. A suite of favourable biological attributes, including fast growth and an omnivorous feeding habit, have contributed to establishment of successful culture of Cherax quadricarinatus (redclaw) in many countries. Aspects of redclaw production, however, remain relatively undeveloped, in particular feed formulation. To better understand the digestive processes and nutritional requirements of redclaw, this study examined the relationship between diet composition and digestive enzyme activity, growth performance and diet digestibility coefficients. The extent to which redclaw can efficiently utilise complex polysaccharides, such as cellulose, has been speculated on by authors who reported endogenous cellulase activity in this species. I evaluated the use of insoluble α-cellulose by redclaw, demonstrated that high dietary levels (30%) can significantly reduce the specific activity of selected digestive enzymes (amylase and cellulase), while also lowering apparent digestibility coefficients. Inclusion of α-cellulose above 12% also significantly reduced survival rate, specific growth rate and feeding efficiency in this organism which corresponds with low tolerance for insoluble fibre by other decapods. Even though redclaw possess endogenous cellulases, they appear to have only a limited capacity to utilise insoluble fibre in their diets. Further, I assessed the impact of different nutrient profiles on digestive enzyme activity, growth and tail muscle composition in redclaw. Purified diets containing varying levels of dietary protein significantly affected activity of digestive enzymes (protease, amylase and cellulase) and the composition of the tail muscle tissue. Redclaw have a relatively low protein requirement, which was reflected here, as little significant difference was observed in growth rates and the feed conversion ratio was only significantly affected by the lowest protein diet. Manipulation of the non-protein energy component in purified diets (protein to lipid ratio) had no effect on growth performance indices in redclaw. Digestive enzyme activity (protease) was however, strongly influenced by both the amount of protein and lipid in the diet and a significant correlation was observed between protease activity and growth performance indices. The findings here, provide preliminary data for consideration of digestive enzymes such as proteases as potential growth indicators for freshwater crayfish. These enzymes are already recognised as reliable biological indicators for comparison of digestive efficiency and potential growth rate in fish. The relationship between diet composition and digestive enzyme expression observed here, stress the need for further empirical evaluation of specific ingredients in artificial diets for redclaw. A range of single cell, plant and animal-based, agricultural products were assessed for their potential use in diets formulated for redclaw. Analysis of dietary supplements revealed that apparent digestibility of crude protein was generally higher for diets containing plant-based ingredients. A similar outcome was observed for digestibility coefficients of test ingredients. Ingredient type also had a significant effect on digestive enzyme activity. Importantly, a significant correlation was observed for enzyme activity and apparent digestibility coefficients. It appears that redclaw have the capacity to utilise nutrients from a broad range of dietary ingredients successfully including animal, single cell and in particular, plant matter in their diet. Taken together, the results presented here demonstrate that digestive enzyme activities in redclaw are significantly influenced by diet composition. I show clearly that the ability of redclaw to utilise various nutrients (measured as digestibility coefficients) is highly correlated with digestive enzyme activity. Finally, protease activity demonstrated a potential for use as an indicator of redclaw growth performance. The data presented here will contribute to development of better and cheaper feed formulations for use in redclaw aquaculture and have broader applications to freshwater crustacean culture. In particular, the potential for use of plant-based ingredients in aqua-feeds for redclaw will contribute to a more economically and environmentally sustainable redclaw culture.

Interactions between non-native yabbies (Cherax albidus) and indigenous marron (Cherax tenuimanus) in the south-west of Western Australia are not well understood. While there is abundant evidence to suggest that invasive freshwater crayfish are detrimental to native species, the nature and degree of impact on marron populations by exotic yabbies remains unclear. Researchers have hypothesized that invasive species make faster and more appropriate use of information about their environment than native species. This greater behavioural plasticity can result in displacement of indigenous species, successful colonisation by invaders, and subsequent disturbance to natural ecosystems and representative biodiversity. / The research presented in this thesis examines the behavioural responses of an indigenous crayfish (C. tenuimanus) and an invasive crayfish (C. albidus) to waterborne odours derived from food, alarm sources and finfish predators. This study was undertaken to assist in the understanding of predatory and competitive interactions between indigenous and non-indigenous crayfish and fish predators, with particular relevance to Western Australia. Predation and competition are major forces influencing community structure in ecosystems; therefore knowledge of competitive and predatory interactions will be of benefit when considering future translocation policies. / Behavioural trials were conducted in two culture systems (54 L aquaria and a 70,000 L mesocosm), where marron and yabbies were exposed to a range of water-borne odours from finfish predators (silver perch and Murray cod), with and without competition from conspecific and heterospecific crayfish. A number of variables likely to influence crayfish behaviour were investigated: strength of chemical odour; crayfish size, gender, diurnal and nocturnal activity patterns; predator size; prior-residence; suitable habitat/shelter; and feed availability. / A key innovation in this research was the high replication in the aquarium-based observation trials using a Latin Cube design, which resulted in greater statistical strength and lower variability. More importantly, this research deviated from the tradition of exclusively using the ‘individual crayfish’ approach for odour-detection experiments and tested these results in a 70,000 L communal observation tank. This was an important development in crayfish behavioural experimentation, particularly as several key findings from the individual crayfish approach were confirmed in a multi-species environment. / Results from this study supported the hypothesis that invasive crayfish species make more appropriate use of a wider range of information about their environment than native crayfish species. Yabbies were found to possess behavioural characteristics not present in marron, such as clearer behavioural modifications to food and heterospecific odour, and cautionary behaviour in the presence of odour from a finfish predator. During simulated daylight conditions, marron displayed behaviours conducive to predation that were not present in yabbies, including less time spent in shelter and more time spent in locomotory activity. However, during specialised night-time observational studies developed during this research, these differences were not evident. This would not seem to be an unusual result, given that crayfish naturally forage at night and become more active; however, it may have important implications for future behavioural studies of crayfish, indicating a bias associated with day-time approaches. Crayfish size also played a role in behavioural modifications to water-borne odours. Larger marron displayed clearer changes in behaviour and were more responsive to heterospecific alarm odour than juveniles. Furthermore, juveniles of both species were more active than adults and sub-adults. / The expansion of the yabby population into Western Australian habitats occupied by marron has been facilitated through translocation for aquaculture, and biological characteristics of the species, some of which are typical of other invasive crayfish species including: tolerance of a variety of conditions; rapid growth; early sexual maturity; burrowing to escape drought and predation; capable of multiple spawns in a growth season; and aggressiveness. Another characteristic of invasive crayfish species also shared by yabbies, as supported by the results of this study, is high behavioural plasticity. / Although marron do not share the same level of behavioural plasticity found in yabbies, their larger body size increases their success in competitive interactions. The comparatively smaller body size of yabbies may be the major factor limiting their population expansion in the presence of marron, especially in water-bodies where shelter is a limited resource. / Marron are an important endemic species in Western Australia, but their conservation is threatened by competition and predation from exotic species. The research presented in this thesis indicates that invasive yabbies are more receptive to chemical stimuli and better equipped to respond to predation risk than marron. This information will be of benefit when considering future translocation policy in Western Australia and highlights the need for a cautious approach to species introductions.

The theoretical part of diploma thesis is aimed at breeding, growth and molting events in crayfish. Thesis is also aimed at life cycle and reproduction of three indigenous crayfish species (Astacus astacus, Austropotamobius torrentium, Pontastacus leptodactylus) and two introduced crayfish species (Faxonius limosus, Pacifastacus leniusculus). The results show apparent linear dependence between female size (POCL), abdomen surface (1M: y = -1061,2 + 65,4*x; r2 = 0,9829; p10-5; 2M: y = -1160,4 + 68,7*x; r2 = 0,8732; p < 10-5) and fertility (1M: y = -194,4 + 12,8*x; r2 = 0,4104 p = 0,0042; y = -330.9 + 15,9*x; r2 = 0.4372; p < 10-4) in once (1M) and twice (2M) molted females. As the length of carapax increase, the area of the abdomen increase and fertility increase in both groups of females. Furthermore, the differences in fertility, carapax length, abdomen surface, and weights in once and twice molted females of signal crayfish. In group of once molted females fertility (t-test, t = -3.12, p = 0.003), carapax length (t-test, t = -3.17, p = 0.003) = -3.24; p = 0.002) and the weight (t-test, t = -3.35; p = 0.002) was higher than in twice molted group of female. Consequentially evaluation of egg size of females. The size of the eggs did not differ between groups of females (1M and 2M) (t-test, t = -0.975, p = 0.335). The mean egg size for both groups of females was 2.71 ? 0.18 mm. Evaluation of post-ovulation conditions of the ovary, including visible signs of females that resorbed unovulated oocytes. Evaluating how much unovulated oocytes were found in the ovaries. Only in 46.4% of the total number of females were ovaries completely empty. In once and twice molted females were found in average 2.2 ? 3.8 and 1.9 ? 2.6. unovulated oocytes, respectively. In once molted, three females didn't lay eggs, two females lost the clutch of eggs. In twice molted females, six females did not lay the eggs and four females lost the clutch.