The thesis deals with eutrophication of fishponds in the sixteen regions in the Czech Republic. Data about basic chemistry and nutrients (nitrogen and phosphorus) were evaluated in terms of temporal (during the years 1995 - 2003 and 2012) and spatial differences. ANOVA one-way and linear regression analysis, were used for detail description. Only regions (locality) Lednice, Brno, Ostrava and Řežabinec showed regular differences in most of the parameters. Between other regions individual differences were frequently found, mostly in conductivity and alkalinity, which are primarily reflect the different character of the catchments e.g. natural conditions. Less significant differences were observed in total N, and minimal differences were found in total P and chlorophyll. The high level of fishpond eutrophication has been also demonstrated by similarities in seasonal trends. Increasing the average value of the total P from 0, 23 mg/L to 0, 32 mg/L and increased chlorophyll concentration from 76 ?g/L to 218 ?g/L from spring to summer, are typical patterns for shallow fishponds heavily loaded with nutrients. The results allow to conclude, that fishpond eutrophication level is similar over the most of studied regions and remains unchanged during the last decades.

Realizou-se, no Centro de Pesquisa e Treinamento em Aquicultura - CEPTA/IBAMA, em Pirassununga/SP, entre 28 de junho e 12 de agosto de 1991, um experimento com o objetivo de avaliar a influência de juvenis de Pacu (Piaractus mesopotamicus, HOLMBERG, 1887) nas características limnológicas da água. Avaliou-se também o impacto do fluxo contínuo de água nas comunidades planctônicas e na qualidade de água do viveiro. O experimento foi conduzido em dois viveiros retangulares escavados, com área útil de 350 m2, 1% de declividade, com abastecimento de água individual feito através de canaletas de concreto a céu aberto. A água de abastecimento foi proveniente da represa Velha (área de 5ha.), alimentada pelo córrego da Barrinha. Os viveiros foram abastecidos com um volume de 277 m3 de água, atingindo uma profundidade máxima de 1,2 m. Esses viveiros foram tratados com 50 g/m2 de calcário dolomítico e 200 g/m2 de esterco fresco de bovino, sendo que um serviu como controle e o outro foi povoado com pacu. No viveiro com Pacu foi feito arraçoamento diário com 1050 g de ração comercial. As amostras de água dos viveiros foram coletadas no período de 28 de junho a 12 de agosto de 1991, em intervalos que variaram de 2 a 3 dias. Foram monitoradas as seguintes variáveis limnológicas: temperatura, pH, transparência da água, material em suspensão, alcalinidade, dureza, condutividade elétrica, oxigênio dissolvido, nitrito, nitrato, amônia, fosfato total, fosfato dissolvido, fósforo inorgânico, silicato reativo, fitoplâncton, produção primária do fitoplâncton, clorofila a, zooplâncton e conteúdo estomacal dos juvenis de Pacu. A presença do Pacu no viveiro afetou a qualidade da água, elevando as concentrações de nutrientes e contribuindo para a diminuição das concentrações de oxigênio dissolvido. Com isto, a produção primária bruta foi, em média, mais elevada no viveiro com Pacu do que no controle. O fluxo contínuo de entrada e saída de água também afetou a qualidade da água dos viveiros, principalmente em relação à concentração de oxigênio dissolvido. O sinergismo entre o fluxo de água e a presença do Pacu contribuiu para que houvesse uma pertubação nas comunidades planctônicas em desenvolvimento nos viveiros. A comunidade do fitoplâncton esteve dominada pelas clorofíceas, principalmente pelas desmidiáceas. A densidade do fitoplâncton foi mais elevada no viveiro com Pacu. Durante todo o experimento, os cladóceros foram bem sucedidos em ambos os viveiros, o que não aconteceu com os rotíferos e nem com os copépodos. A alta densidade populacional dos cladóceros provavelmente deve ter influenciado na densidade de rotíferos no viveiro com Pacu, pois as duas populações mostraram relação inversa. Os copépodos contribuíram com uma espécie filtradora, sendo que as demais eram capturadoras. Os Cyclopoida foram mais abundantes no viveiro com Pacu. Na análise do conteúdo estomacal foram encontrados os seguintes itens alimentares: ração, sementes, gramas, plâncton, animais bentônicos e detritos. Os itens do plâncton mais freqüentes foram: zooplâncton (ovos de copépodos, ovos de rotíferos, larvas de chironomideo e restos de zooplâncton parcialmente digeridos) e fitoplâncton (Eunotia hexasghliphis e Scenedesmus quadricauda). / An experiment to evaluate the influence of young forms of Pacu (Piaractus mesopotamicus HOLMBERG, 1887) on limnological characteristics of water was conducted at Centro de Pesquisa e Treinamento em Aquicultura - CEPTA/IBAMA, located in Pirassununga, SP, Southeastern Brazil, from 06/28 until 08/12/1991. The impact of continuous water flow on the planktonic communities and water quality was also evaluated. The experiment was performed in two fishponds with 350 m2, 1.2 m of depth and 1% of declivity. Water supply came from open channels from Represa Velha (50.000 m2), that was supplied from Barrinha stream. The fishponds received 277 m3 of water, 50 g/m2 of dolomitic calcareous and 200 g/m2 of fresh manure. One fishpond was kept as a control and the other received young forms of Pacu that were fed daily with 1050 g of commercial feed. Samplings were carrired out from June, 28 to August, 12 at two or three days of intervals. Temperature, pH, water transparency, suspended materials, alkalinity, hardness, electrical conductivity, dissolved oxygen, nitrites, nitrates, ammonia, total phosphate, dissolved phosphate, inorganic phosphorus, reactive silicate, phytoplankton, primary production of phytoplankton, chlorophyll a, zooplankton and stomach contents analysis of young forms of Pacu were obtained as limnological variables. The presence of Pacu in the fishponds affected water quality by increasing nutrients concentration and contributing to the decrease of dissolved oxygen. Thus the primary production was higher in this system than in the control. The continuous incoming and outcoming water flow affected water quality on fishponds, mainly in relation to concentration of dissolved oxygen. Synergistic effect between water flow and presence of Pacu contributed to changes in the developing planktonic communities in the fishponds. The planktonic communities were dominated by Chlorophyta, mainly desmids. The phytoplankton density differed between the two fishponds, being higher in the one with Pacu. During the experiment, the Cladocera was successful in both fishponds, but this did not occur with Rotifera and Copepoda. The success of Cladocera probably controlled the density of Rotifera in the water. One of Copepoda was a filtering specie and the others were predators. The Cyclopoida was more abundant in the fishpond with Pacu than in the control. Stomachal content analysis showed: ration, seeds, grass, plankton, bentonic animals and detritus. The most frequent items of plankton were zooplankton (eggs of Copepoda, eggs of Rotifera, Chironomideo larvae and zooplankton partially digested) and phytoplankton (Eunotia hexaghliphis and Scenedesmus quadricauda).

UAB ,,Raseinių žuvininkystės“ tvenkiniai suformuoti 1967-1979 m. Jie išsidėstę trijose vietose: šalia Gabšių gyvenvietės – Raseinių tvenkinių kompleksas, maitinamas Prabaudos upės vandeniu; Upės upelio slėnyje įrengtas Paupio tvenkinių kompleksas aukščiau apie 1 km nuo Paupio gyvenvietės ir tarp Šešuvio ir jo intako Alsos esančioje teritorijoje. Bendras tvenkinių plotas 1042 ha. Tvenkininė žuvininkystė vis labiau pradeda įsitvirtinti tarp kaimo verslų, nors sovietmečiu pastatytuose žuvininkystės tvenkiniuose su mechaniniu vandens kėlimu vandens apykaitai tvenkiniuose palaikyti reikalingos didelės lėšos energetinėms išlaidoms apmokėti, tačiau šis kaimo verslas sukuria nemažai darbo vietų kaime, o žuvininkystės produkcija turi paklausą ne tik Lietuvoje, bet ir užsienyje. Žuvininkystės sukuriama produkcija gerokai sumažėjo lyginant ją su 1990 m., tada buvo išauginta ir sugauta 5800 tonų žuvies, 1998 m. žuvų sugavimas sudarė 1511 tonų, 2001 m. – 2001 tonų ir 2006 – 2225 tonų. Norint sėkmingai plėtoti žuvininkystės verslą, reikalinga ieškoti būdų atnaujinti žuvininkystės įmonių tvenkinių siurblinių energetinę įrangą, remontuoti žuvininkystės tvenkinių hidrotechnikos statinius.Šio darbo tikslas - atlikti UAB ,,Raseinių žuvininkystės“ įmonės tvenkinių HTS techninės būklės tyrimą ir įvertinimą, siekiant gauti ir panaudoti Europos Sąjungos struktūrinių fondų lėšas numatomai renovacijai ir modernizavimui. / The fishponds of the closed joint-stock company “Raseiniai žuvininkystė” were arranged during 1967-1979 years. They are located in the three following places: near the settlement of Gabšiai - the complex of Raseiniai ponds is feeded by the waters of the Prabauda river; in the stream Upe valley the Paupys pond complex is arranged about 1 km upstream the settlement of Paupys and in the territory between the Šešuvis river and its tributary Alsa there is Alsa fishponds . The total fishponds area is 1042 ha. In order to successfully plan the activity of fishery enterprises the evaluation and forward planning of the technical condition of the present ponds’ hydraulic structures is necessary for the reconstruction. The aim of this work was to carry out the investigation and evaluation of the technical state of the hydraulic structures built on the ponds of the closed joint-stock company “Raseiniai žuvininkystė” in order to use the means from the European Union structural funds for the planned renovation and modernization. The object of investigation - the closed joint-stock company “Raseiniai žuvininkystė” situated in the territory of Raseiniai district as well as the evaluation of its economical activity and the state of hydraulic structures built on the ponds. Field investigations of the hydraulic structures built in the complex of Alsa and Paupys ponds were evaluated according to the requirements of the modified Building technical regulations STR 1.12.03:2006 considering the... [to full text]

UAB „Daugų žuvis" tvenkiniai įrengti 1968-1969 m., jų bendras plotas 594 ha, apie 99 ha tvenkinių ploto intensyviai žuvininkystei nenaudojami. Tvenkiniams vanduo imamas iš Dusmenos ir Varėnės upių, vandeniui tiekti įrengtos dvi siurblinės. Nuo siurblinių pastatymo yra praėję apie 40 metų, todėl siurbliai, jų varikliai ir pagalbiniai įrengimai yra susidėvėję fiziškai, technologiškai bei morališkai pasenę. Žuvininkystės įmonės vadovai norėdami išlaikyti įmonę konkurencinėje rinkoje, turėtų atsižvelgti į kylančias problemas energetikos sektoriuje, ir ieškoti galimybių sumažinti siurblinių eksploatacijos išlaidas minimaliai rekonstruojant siurblines ir atnaujinant reikalingą siurblinių įranga. Baigiamajame darbe yra nustatomi siurblinių hidrauliniai parametrai. Daugiakriterinės analizės pagalba, naudojant tarptautinės atominės energijos agentūros laisvai platinamą programinę įrangą – DAM, palyginami keli siurblių pakeitimo variantai ir iš jų sąlyginai išrinkti optimaliausi variantai. Daugų žuvininkystės įmonės tvenkinių hidrotechnikos statinius sudaro tvenkinių dambos, vandens įleistuvai, išleistuvai, vandens atitekėjimo, nutekėjimo vamzdynai ir kanalai, skydų/šandorų kėlimo mechanizmai, žuvų išgaudymo duobės ir pan. Kadangi nuo tvenkinių įrengimo laiko jau praėję apie 40 metų, tai betoniniai/gelžbetoniniai tvenkinių hidrotechnikos statiniai (įleistuvai, išleistuvai, vamzdynai, žuvų išgaudymo duobės) yra gerokai susidėvėję. Įvertinant HTS techninę būklę buvo naudota STR 1.12.0... [toliau žr. visą tekstą] / The purpose of this work is to evaluate technical state of Dusmena and Varene pumping stations hydro-technical and energetic equipment, the usability and expediency of this equipment in the conditions of market economics. The purpose of this work is also to choose the most suitable variants of replacement of pumping stations main units and auxiliary mechanisms by new ones. Technical state of fishponds hydraulic structures (inlet, outflow, fish catch hole elements) and overgrow of fishpond areas with aquatic plants are analyzed in the paper too. The Dusmena pumping station was built in 1969 and there are three vertical axial 02-42 type pumps. The pumping station on Varene River was built in a same year and reconstructed in 1983. There are two duplex inflowing horizontal centrifugal D 1250/14 type pumps. Daugai Fishery enterprise pumping stations were built more than 40 years ago, so the pumps, their engines and auxiliary mechanisms of these pumping stations are shabby, physically and technologically old. The pumping stations are very important element of fishponds, because the cost of fishery productions belongs on pumping station rational work. The reconstruction of the pumping station in Varene is necessary in the case of the use of Intersigma or Flygt pumps, because these pumps have negative suction head, as existing pumps are with positive suction head in Varene pumping station. If Intersigma or Flygt pumps would be installed, vacuum pumps were not necessary in this... [to full text]

Community of phytophilous macrozoobenthos (PM) represents an important component of fishponds ecosystems concerning biomass as well as essential part of food webs. There are evident linkages between PM and water macrophytes. Their influence on PM is the main topic of many scientific papers which state three main water macrophyte characters with the strongest impact on PM - coverage, biomass and morphological complexity. The main aim of this diploma theses was to analyse linkages between four different water macrophyte species and PM in eight different fishponds devided into two groups according their localisation- třeboňské a rakouské. Water macrophyte species have any influence on PM abundance in both fishpond groups. Water macrophyte species have significant influence on biomass of PM in třeboňské and rakouské fishponds analysed together and also in both fishpond groups analysed separately. PM biomass was significantly higher in Glyceria maxima during first sampling period in both fishpond groups. Water macrophyte species have significant influence on PM diversity in třeboňské and rakouské fishponds analysed together and in rakouské fishponds group analysed separately. Just one variable, water macrophyte species, was analysed in my diploma thesis, but some others abiotic and biotic variables influence phytophilous macrozoobenthos community in fishponds littoral zones as well. That´s why conclusions of this thesis should be interpreted circumspectly.

Realizou-se, no Centro de Pesquisa e Treinamento em Aquicultura - CEPTA/IBAMA, em Pirassununga/SP, entre 28 de junho e 12 de agosto de 1991, um experimento com o objetivo de avaliar a influência de juvenis de Pacu (Piaractus mesopotamicus, HOLMBERG, 1887) nas características limnológicas da água. Avaliou-se também o impacto do fluxo contínuo de água nas comunidades planctônicas e na qualidade de água do viveiro. O experimento foi conduzido em dois viveiros retangulares escavados, com área útil de 350 m2, 1% de declividade, com abastecimento de água individual feito através de canaletas de concreto a céu aberto. A água de abastecimento foi proveniente da represa Velha (área de 5ha.), alimentada pelo córrego da Barrinha. Os viveiros foram abastecidos com um volume de 277 m3 de água, atingindo uma profundidade máxima de 1,2 m. Esses viveiros foram tratados com 50 g/m2 de calcário dolomítico e 200 g/m2 de esterco fresco de bovino, sendo que um serviu como controle e o outro foi povoado com pacu. No viveiro com Pacu foi feito arraçoamento diário com 1050 g de ração comercial. As amostras de água dos viveiros foram coletadas no período de 28 de junho a 12 de agosto de 1991, em intervalos que variaram de 2 a 3 dias. Foram monitoradas as seguintes variáveis limnológicas: temperatura, pH, transparência da água, material em suspensão, alcalinidade, dureza, condutividade elétrica, oxigênio dissolvido, nitrito, nitrato, amônia, fosfato total, fosfato dissolvido, fósforo inorgânico, silicato reativo, fitoplâncton, produção primária do fitoplâncton, clorofila a, zooplâncton e conteúdo estomacal dos juvenis de Pacu. A presença do Pacu no viveiro afetou a qualidade da água, elevando as concentrações de nutrientes e contribuindo para a diminuição das concentrações de oxigênio dissolvido. Com isto, a produção primária bruta foi, em média, mais elevada no viveiro com Pacu do que no controle. O fluxo contínuo de entrada e saída de água também afetou a qualidade da água dos viveiros, principalmente em relação à concentração de oxigênio dissolvido. O sinergismo entre o fluxo de água e a presença do Pacu contribuiu para que houvesse uma pertubação nas comunidades planctônicas em desenvolvimento nos viveiros. A comunidade do fitoplâncton esteve dominada pelas clorofíceas, principalmente pelas desmidiáceas. A densidade do fitoplâncton foi mais elevada no viveiro com Pacu. Durante todo o experimento, os cladóceros foram bem sucedidos em ambos os viveiros, o que não aconteceu com os rotíferos e nem com os copépodos. A alta densidade populacional dos cladóceros provavelmente deve ter influenciado na densidade de rotíferos no viveiro com Pacu, pois as duas populações mostraram relação inversa. Os copépodos contribuíram com uma espécie filtradora, sendo que as demais eram capturadoras. Os Cyclopoida foram mais abundantes no viveiro com Pacu. Na análise do conteúdo estomacal foram encontrados os seguintes itens alimentares: ração, sementes, gramas, plâncton, animais bentônicos e detritos. Os itens do plâncton mais freqüentes foram: zooplâncton (ovos de copépodos, ovos de rotíferos, larvas de chironomideo e restos de zooplâncton parcialmente digeridos) e fitoplâncton (Eunotia hexasghliphis e Scenedesmus quadricauda). / An experiment to evaluate the influence of young forms of Pacu (Piaractus mesopotamicus HOLMBERG, 1887) on limnological characteristics of water was conducted at Centro de Pesquisa e Treinamento em Aquicultura - CEPTA/IBAMA, located in Pirassununga, SP, Southeastern Brazil, from 06/28 until 08/12/1991. The impact of continuous water flow on the planktonic communities and water quality was also evaluated. The experiment was performed in two fishponds with 350 m2, 1.2 m of depth and 1% of declivity. Water supply came from open channels from Represa Velha (50.000 m2), that was supplied from Barrinha stream. The fishponds received 277 m3 of water, 50 g/m2 of dolomitic calcareous and 200 g/m2 of fresh manure. One fishpond was kept as a control and the other received young forms of Pacu that were fed daily with 1050 g of commercial feed. Samplings were carrired out from June, 28 to August, 12 at two or three days of intervals. Temperature, pH, water transparency, suspended materials, alkalinity, hardness, electrical conductivity, dissolved oxygen, nitrites, nitrates, ammonia, total phosphate, dissolved phosphate, inorganic phosphorus, reactive silicate, phytoplankton, primary production of phytoplankton, chlorophyll a, zooplankton and stomach contents analysis of young forms of Pacu were obtained as limnological variables. The presence of Pacu in the fishponds affected water quality by increasing nutrients concentration and contributing to the decrease of dissolved oxygen. Thus the primary production was higher in this system than in the control. The continuous incoming and outcoming water flow affected water quality on fishponds, mainly in relation to concentration of dissolved oxygen. Synergistic effect between water flow and presence of Pacu contributed to changes in the developing planktonic communities in the fishponds. The planktonic communities were dominated by Chlorophyta, mainly desmids. The phytoplankton density differed between the two fishponds, being higher in the one with Pacu. During the experiment, the Cladocera was successful in both fishponds, but this did not occur with Rotifera and Copepoda. The success of Cladocera probably controlled the density of Rotifera in the water. One of Copepoda was a filtering specie and the others were predators. The Cyclopoida was more abundant in the fishpond with Pacu than in the control. Stomachal content analysis showed: ration, seeds, grass, plankton, bentonic animals and detritus. The most frequent items of plankton were zooplankton (eggs of Copepoda, eggs of Rotifera, Chironomideo larvae and zooplankton partially digested) and phytoplankton (Eunotia hexaghliphis and Scenedesmus quadricauda).

Photosynthesis and primary production were estimated in fishpond phytoplankton during period 2008-2010 in Třeboň fishpond region, Czech Republic. Photosynthesis was measured by the oxygen method in computer-assisted light pipetting system Illuminova. Altogether 64 samples of fishpond phytoplankton and 11 cyanobacterial cultures were analysed. Cyanobacteria and chlorococcal algae formed the most important part of phytoplankton biomass and their photosynthesis-irradiance (P-I) curves showed shade-adapted type of P-I curves with the high photosynthetic efficiency. No significant differences in the main parameters of P-I curves were obtained between different types of phytoplankton (chlorococcal-dominated, cyanobacteria- dominated). The results are consistent with the high turbid conditions in eutrophic or hypetrophic fishponds. On the contrary photosynthesis in cyanobacterial cultures differs from "wild" phytoplankton and therefore they can not be taken in primary production models. Primary production was estimated according Talling's model (1957), based on daily measurement of radiation, extinction coefficient of water and seasonal courses of chlorophyll concentration. Photosynthetic capacity and onset of light saturation determined in P-I curves were used as physiological parameters of Talling's model. The...

Realizou-se, no Centro de Pesquisa de Peixes Tropicais (CEPTA/IBAMA), em Pirassununga-SP, um experimento com o objetivo de avaliar a influência da densidade de estocagem de peixes e do fluxo diferenciado de entrada e saída de água em viveiros de piscicultura nas características físicas e químicas da água; na estrutura (composição e densidade), biomassa, sucessão e diversidade de espécies da comunidade do fitoplâncton e na composição e densidade da comunidade do zooplâncton (considerando-se apenas grupo), procurando-se avaliar o balanço de entrada e saída de materiais em viveiros, enfatizando a concentração de nutrientes, comunidade planctônica, concentração de material em suspensão e clorofila a. Além disso, procurou-se quantificar os impactos da atividade da piscicultura nos recursos hídricos, demonstrando suas interações positivas e negativas com o ambiente. Os estudos foram desenvolvidos durante 60 dias, com coletas diárias inicialmente e a cada dois dias após o peixamento, analisando-se a temperatura, pH, condutividade elétrica da água, oxigênio dissolvido, material em suspensão, nutrientes, alcalinidade, dureza, cálcio, clorofila a, comunidade zooplanctônica e fitoplanctônica. Os resultados obtidos demonstraram o efeito do fluxo de água e da densidade de estocagem de peixes sobre as características físicas e químicas da água, observando-se a redução acentuada na concentração de oxigênio dissolvido na água (valores abaixo de 2 mg/l), aumento nas concentrações de fósforo e nitrogênio, material sem suspensão e clorofila a. Em conseqüência do aumento da concentração de nutrientes, principalmente de fósforo, ocorreu um aumento na biomassa e na densidade do fitoplâncton e na densidade do zooplâncton. A redução de oxigênio dissolvido na água, associado à outras variáveis, promoveu uma mortandade de peixes no tratamento T2. A divisão Chlorophyta foi dominante no fitoplâncton nos diferentes tratamentos e o padrão de sucessão observado foi Desmidiaceae&#8594Chlorococcales&#8594Cyanophyta. Em relação ao zooplâncton, Rotifera foi dominante na fase de enchimento, sendo posteriormente substituído por Cladocera e Copepoda. Nos diferentes tratamentos foi possível observar a interação indireta do efeito cascata. O sistema de piscicultura gerou cargas potencialmente poluidoras, sendo que a ração foi a responsável pelo incremento de nutrientes na água do efluente. Em média as concentrações de fósforo foram 36 vezes maior que o permitido por lei, enquadrando o efluente dos tratamentos como impróprio para serem lançados em rio de Classe 2. Considerando-se os resultados obtidos, recomenda-se o tratamento do efluente antes do lançamento no Rio Mogi-Guassu, corpo receptor e enquadrado como rio de Classe 2. / An experiment was conducted at the Tropical Fish Research Center (CEPTA, Pirassununga, SP, Brazil) to analyze the influence of the density of fish stocks and the differentiated water inflow and outflow in fishponds on the limnological characteristics of the water, its structure (composition and density), biomass fluctuations, succession and diversity of the phytoplankton and the composition and density of the zooplankton (considered only by group), in order to evaluate the balance of the entry and exit of biomass in fishponds, with emphasis on the concentration of nutrients, planktonic biomass (chlorophyll) and suspended matter. The experiment also aimed to quantify the impact of fishculture on hydric resources, demonstrating its positive and negative effects on the environment. The study was carried out for 60 days, with daily samples taken initially, and at two days\' interval after the introduction of the fish. The characteristics analyzed were water temperature, water load, dissolved oxygen, pH, conductivity, nutrients, suspended matter, chlorophyll a composition, density, diversity, abundance of phytoplankton, density and abundance of zooplankton. The results obtained demonstrated the effect of the water flow and the density of fish stocks on the physical and chemical characteristics of the water. An accentuated reduction was observed in dissolved oxygen concentrations (under 2 mg/l) and in increased phosphorous, nitrogen, organic matter and chlorophyll concentrations. The increased concentration of nutrients, mainly phosphorous, caused increased levels of phytoplankton and zooplankton biomass and density. The depletion of dissolved oxygen in the water, coupled to other variables, led to fish mortality under the T2 treatment. The Chlorophyta division predominated in the phytoplankton under the different treatments and the succession observed was a Desmidiaceae&#8594Chlorococcales&#8594Cyanophyta pattern. As for zooplancton, Rotifera predominated in the inflow phase and was later substituted by Cladocera and Copepoda. The indirect interaction of the cascade effect was observed during the different treatments. The fish culture system generated potentially polluting loads, with fish feed found to be responsible for the increased nutrient waste in the effluent. Phosphorus concentrations were, on average, 36 times higher than allowed by law, characterizing the effluent from the treatments as unsuitable to be cast into class 2 rivers. Based on the findings of this study and on environmental management strategies, it is recommended that the effluent be treated before the water is allowed to flow into the Class 2 recipient, the Mogi-Guassu river.

The aim of this methodically oriented thesis was to find spatial distribution of water bugs in fishpond by parallelly used two different sampling methods - classic method (netting) and light traps as well as to find, if sampling method can influence a result of ecological study by substantial way. Study was realized in the one locality - fishpond Polepšil (region: Vysočina: Moravskobudějovicko) in years 2007 and 2008. Spaces {--} transects for sampling were difined. Efficiency of water bug sampling by nett is conspicuously less than sampling by light traps. More species and individuals (in total sum of samples and in samples from individual transects too) were sampled by light traps under comparable conditions. Chemical yelow-green light of light traps was more attractive for water bugs than the pink one. Spatial preferences of some corixid species and their developmental stages were noted by application of light trap method of sampling. Light trap method of samplings brings more complete and valuable data for ecological studies of water bug communities.

Realizou-se, no Centro de Pesquisa de Peixes Tropicais (CEPTA/IBAMA), em Pirassununga-SP, um experimento com o objetivo de avaliar a influência da densidade de estocagem de peixes e do fluxo diferenciado de entrada e saída de água em viveiros de piscicultura nas características físicas e químicas da água; na estrutura (composição e densidade), biomassa, sucessão e diversidade de espécies da comunidade do fitoplâncton e na composição e densidade da comunidade do zooplâncton (considerando-se apenas grupo), procurando-se avaliar o balanço de entrada e saída de materiais em viveiros, enfatizando a concentração de nutrientes, comunidade planctônica, concentração de material em suspensão e clorofila a. Além disso, procurou-se quantificar os impactos da atividade da piscicultura nos recursos hídricos, demonstrando suas interações positivas e negativas com o ambiente. Os estudos foram desenvolvidos durante 60 dias, com coletas diárias inicialmente e a cada dois dias após o peixamento, analisando-se a temperatura, pH, condutividade elétrica da água, oxigênio dissolvido, material em suspensão, nutrientes, alcalinidade, dureza, cálcio, clorofila a, comunidade zooplanctônica e fitoplanctônica. Os resultados obtidos demonstraram o efeito do fluxo de água e da densidade de estocagem de peixes sobre as características físicas e químicas da água, observando-se a redução acentuada na concentração de oxigênio dissolvido na água (valores abaixo de 2 mg/l), aumento nas concentrações de fósforo e nitrogênio, material sem suspensão e clorofila a. Em conseqüência do aumento da concentração de nutrientes, principalmente de fósforo, ocorreu um aumento na biomassa e na densidade do fitoplâncton e na densidade do zooplâncton. A redução de oxigênio dissolvido na água, associado à outras variáveis, promoveu uma mortandade de peixes no tratamento T2. A divisão Chlorophyta foi dominante no fitoplâncton nos diferentes tratamentos e o padrão de sucessão observado foi Desmidiaceae&#8594Chlorococcales&#8594Cyanophyta. Em relação ao zooplâncton, Rotifera foi dominante na fase de enchimento, sendo posteriormente substituído por Cladocera e Copepoda. Nos diferentes tratamentos foi possível observar a interação indireta do efeito cascata. O sistema de piscicultura gerou cargas potencialmente poluidoras, sendo que a ração foi a responsável pelo incremento de nutrientes na água do efluente. Em média as concentrações de fósforo foram 36 vezes maior que o permitido por lei, enquadrando o efluente dos tratamentos como impróprio para serem lançados em rio de Classe 2. Considerando-se os resultados obtidos, recomenda-se o tratamento do efluente antes do lançamento no Rio Mogi-Guassu, corpo receptor e enquadrado como rio de Classe 2. / An experiment was conducted at the Tropical Fish Research Center (CEPTA, Pirassununga, SP, Brazil) to analyze the influence of the density of fish stocks and the differentiated water inflow and outflow in fishponds on the limnological characteristics of the water, its structure (composition and density), biomass fluctuations, succession and diversity of the phytoplankton and the composition and density of the zooplankton (considered only by group), in order to evaluate the balance of the entry and exit of biomass in fishponds, with emphasis on the concentration of nutrients, planktonic biomass (chlorophyll) and suspended matter. The experiment also aimed to quantify the impact of fishculture on hydric resources, demonstrating its positive and negative effects on the environment. The study was carried out for 60 days, with daily samples taken initially, and at two days\' interval after the introduction of the fish. The characteristics analyzed were water temperature, water load, dissolved oxygen, pH, conductivity, nutrients, suspended matter, chlorophyll a composition, density, diversity, abundance of phytoplankton, density and abundance of zooplankton. The results obtained demonstrated the effect of the water flow and the density of fish stocks on the physical and chemical characteristics of the water. An accentuated reduction was observed in dissolved oxygen concentrations (under 2 mg/l) and in increased phosphorous, nitrogen, organic matter and chlorophyll concentrations. The increased concentration of nutrients, mainly phosphorous, caused increased levels of phytoplankton and zooplankton biomass and density. The depletion of dissolved oxygen in the water, coupled to other variables, led to fish mortality under the T2 treatment. The Chlorophyta division predominated in the phytoplankton under the different treatments and the succession observed was a Desmidiaceae&#8594Chlorococcales&#8594Cyanophyta pattern. As for zooplancton, Rotifera predominated in the inflow phase and was later substituted by Cladocera and Copepoda. The indirect interaction of the cascade effect was observed during the different treatments. The fish culture system generated potentially polluting loads, with fish feed found to be responsible for the increased nutrient waste in the effluent. Phosphorus concentrations were, on average, 36 times higher than allowed by law, characterizing the effluent from the treatments as unsuitable to be cast into class 2 rivers. Based on the findings of this study and on environmental management strategies, it is recommended that the effluent be treated before the water is allowed to flow into the Class 2 recipient, the Mogi-Guassu river.