Epidemiological Studies on Leaf Blights of Maize Caused by Exerohilum turcicum (Pass.) Leonard and Suggs and Bipolaris maydis (Nisik. and Miyake)

The Field experiments conducted at Maize Research Station,Vagarai, Tamil Nadu, India during kharif 2019, 2020 & 2021 to study the disease development in relation to weather parameters, viz., temperature, relative humidity, rainfall with the leaf blights of maize. Observations on the spore load and disease grade were taken from 33rd standard week to 44th standard weeks at weekly interval. Increased spore load of 13 to 48 Nos. / Microscopic observations for TLB and 3 to 5 Nos./microscopic observations with the temperature ranges between 22-35?C, Humidity 48-72% and 19-24° Dew will lead to the TLB & MLB disease incidence with the grade of 1to 4 was observed. Based on the observations, the first appearance of leaf blight diseases were observed between 35th and 45th days after sowing with the grade of 1 (34th meteorological standard week). The disease grade increased from 1 to 4 as the age of the crop increases. There was a sudden increase in disease intensity because of increased scattered showers and increased relative Humidity (44th meteorological standard week). Temperature has not much influenced the disease development, since it was almost uniform throughout the cropping season in these three years. From the dataset, we would like to highlight that 34th and 44th meteorological standard weeks are highly critical for leaf blight disease development. Hence, spraying with mancozeb or zineb @ 2-4 g/l or propiconazole 25% EC @ 1ml/l during 34th and 44th meteorological standard week is recommended to manage the disease during kharif seasons in Tamil Nadu.

Seasonal Occurrence of Melon Fruit Flies (Zeugodacus cucurbitae Coq.) and Its Natural Enemies on Bitter Gourd

Aim: To study the seasonal occurrence of cucurbit melon fly and correlation study with weather parameters to know the impact of abiotic environmental factors on the activity of melon fruit fly concerning infesting the fruits of bitter gourd in crop ecosystem.Place and Duration of Study: College of Agriculture, VNMKV Parbhani, Maharashtra. Studies during two seasons Rainy and Summer 2021 and 2022 respectively.Methodology: The experimental plot was kept unsprayed throughout the crop season. The observation was recorded as soon as the incidence was noticed from five randomly selected plants at weekly intervals. The observations of fruit flies were recorded from the day of fruit formation to the last picking of the fruit. The damaged and healthy fruits were recorded at eachpicking to knowing the percentage fruit infestation by fruit flies.Results: Fruit fly was the major pest of bitter gourd in fruit damage. The fruit damage record range was 15.65 to 59.33 per cent in the rainy season whereas, 28.99 to 61.14 per cent in the summer season. The per cent fruit infestation shows a significant and positive correlation with no. of maggots per fruit (r = 0.857 and 0.905) during both seasons respectively. Weather parameters like morning relative humidity (MRH) and rainfall the during rainy season show significant and positive correlation (r = 0.87 and r = 0.71 respectively) whereas, during the summer season significant and positive correlation (r = 0.77) with MRH and significant and negatively correlated with (r = - 0.66) minimum temperature. The record of larval pupal parasitoid Psyttalia fletcheri (Silvestri) and it was discovered that 16% of the population was parasitized during the experimental periodConclusion: The infestation may vary from season to season, region to region and concerning variety also. Here the infestation range was higher during the summer season, which may be because of the coincidence with the fruit season of mango in that area.

Response of Molybdenum and Foliar Application of Zinc on Growth and Yield of Cowpea (Vigna unguiculata L.)

During the summer of 2022, the experiment was carried out at a crop research farm for agricultural research in the department of agronomy. Three different doses of molybdenum (800, 1000, and 1200 g/ha) were applied to the soil as treatments, coupled with zinc (5 kg/ha, 1% foliar spray, 2.5 kg/ha along with 0.5% foliar spray), as well as a control. Ten treatments were used in the experiment, which was designed as an RBD and triple replicated. The highest plant height, maximum number of branches, maximum number of root nodules, plant dry weight, CGR, RGR, and yield parameters, such as more pods per plant, seeds per pod, test weight, seed yield, and stover yield, were observed after the application of 1200g molybdenum with 2.5kg of zinc and 0.5% foliar spray.

Diversity of Basidiomycetous Macrofungi from Mpanga Forest in Mpigi District, Central Uganda

The present study was conducted at Mpanga Research Forest located in Mpigi District, Uganda, during the months of March, April, May and Jun 2020 (for the first rainy season) then in September, October, November, and December 2020 (for the second rainy season) to determine the diversity and distribution of macrofungi as well as their influence by seasonality, and physicochemical properties of the soil. An inventory was carried out through plot sampling and survey which consists of installing three permanent plots of 30 m x 30 m in each of the four selected sites, the soil was also measured in the sample plots. To measure distribution and diversity, abundance, species richness, density, and Simpson's and Shannon's indices were calculated. SPSS version 20 software was used for the significance tests of the diversity parameters between the two rainy seasons and for those of the correlation between the soil factors and the abundance of macrofungi species. A total of 120 species of basidiomycetous macrofungi distributed in 53 genera and 22 families were recorded. The dominant genus was Psathyrella followed by Marasmius belonging to the most dominant families (Coprinaceae and Marasmiaceae), and the most dominant orders (Agaricales and Tricholomatales). During the two rainy seasons, the majority of the species that have been collected belong to the group of saprophytes. Macrofungi species collected during the second rainy season were more abundant and diverse than those collected during the first rainy season. Among the physicochemical properties of the soil, pH, calcium, potassium, nitrogen, organic carbon, phosphorus, clay, sand and organic matter were significantly correlated with the abundance of macrofungal species. The results of this study provided basic information on the diversity of macrofungi in Mpanga forest, it can be a point of reference for further research to study the evolution of macrofungal biodiversity in this forest.

Morphogenetic and structural characteristics of gamba grass subjected to nitrogen fertilization and different defoliation intensities / Características morfogênicas e estruturais do capim-andropógon submetido à adubações nitrogenadas e intensidades de desfolha

This study aimed to evaluate the morphogenetic, structural, and productive characteristics of Andropogon gayanus cv. 'Planaltina' subjected to different nitrogen fertilization levels and defoliation intensities. The experiment was done in a completely randomized design with a factorial arrangement of six nitrogen doses (0, 100, 200, 300, 400, and 500 kg N ha-1) and two defoliation intensities (15 and 30 cm). The production and structure data were grouped into rainy and dry periods, while morphogenesis data were compared only among different fertilization and defoliation intensities. The total dry forage biomass (TDFB), dry mass of leaves (DML), dry mass of stems (DMS), and dead forage dry mass (DFDM) were then determined. In addition to these variables, the morphogenetic characteristics of the plants and the numbers of tillers alive and dead were evaluated. There was no interaction (P>0.05) between the effects of nitrogen fertilization doses and the intensity of defoliation on TDFB, DML, DMS, and DFDM in both of the evaluated phases (rainy and dry). It was also observed that the rates of leaf elongation, leaf appearance, and leaf blade elongation increased with nitrogen fertilization. On the other hand, the culm elongation rate and phyllochron decreased as the dose applied increased. The defoliation intensity did not influence (P>0.05) the morphogenetic characteristics examined, nor did it affect the senescence rate of nitrogen in leaves and number of live leaves per tiller. The number of dead tillers increased linearly during the rainy period. Based on these results, to improve the efficiency of production of gamba grass it is recommended that it be managed with a defoliation intensity of 30 cm and nitrogen fertilization of 286.52 kg N ha-1 year-1.

Objetivou-se avaliar as características morfogênicas, produtivas e estruturais do Andropogon gayanus cv. Planaltina submetido a níveis de adubação nitrogenada e intensidades de desfolha. O delineamento experimental foi o inteiramente casualizado com arranjo fatorial 6x2, doses de nitrogênio (0, 100, 200, 300, 400 e 500 kg de nitrogênio ha-1) e intensidades de desfolhas (15 e 30 cm). Os dados de produção e estrutura foram agrupados em períodos chuvoso e seco e os de morfogênese analisados somente em função da adubação e intensidade de desfolha. Foi determinada a produção de biomassa de forragem seca total (BFST), massa seca de folhas (MSF), massa seca de colmos (MSC) e massa seca de forragem morta (MSFM). Além dessas variáveis foram avaliadas as características morfogênicas e de perfilhos vivos e mortos. Houve interação (P<0,05) entre as doses e intensidade de desfolhas para a MSFT, MSF, MSC e MSFM em ambas as fases de avaliação. Observou-se que as taxas de alongamento foliar, aparecimento foliar e comprimento da lâmina foliar aumentaram com a adubação nitrogenada. Por outro lado, a taxa de alongamento do colmo e Filocrono diminuíram com a aplicação das doses crescentes. As intensidades de desfolha não influenciaram (P>0,05) nas características morfogênicas, assim como a adubação na taxa de senescência foliar e número de folhas vivas por perfilho. O número de perfilhos mortos aumentou de forma linear durante o período chuvoso. Recomenda-se manejar o capim-andropógon com intensidade de desfolha de 30 cm e adubação nitrogenada de 286,52 kg de N ha-1 ano-1, visando a maior produção.

Infección por Angiostrongylus cantonensis (Nematoda: Metastrongylidae) en Rattus rattus (Rodentia: Muridae) en una localidad de La Habana, Cuba / Infection by Angiostrongylus cantonensis (Nematoda: Metastrongylidae) in Rattus rattus (Rodentia: Muridae) in a locality of Havana, Cuba

Introducción: La meningoencefalitis eosinofílica producida por Angiostrongylus cantonensis (Chen, 1935), es una zoonosis emergente presente en Cuba. En el país existen escasos estudios de prevalencia de infección en los hospederos definitivos, que puedan determinar sitios de riesgo para el establecimiento de medidas efectivas en la prevención de la enfermedad. Objetivo: Determinar la prevalencia de infección por A. cantonensis en una población natural de R. rattus, su relación con la estructura poblacional y la época del año en una finca que pertenece al Programa de la Agricultura Urbana y Suburbana de Cuba. Material y Métodos: Se realizó un estudio descriptivo en el municipio La Lisa, La Habana. Se hicieron capturas de roedores mensuales durante los períodos lluvioso y poco lluvioso. Se examinaron las arterias pulmonares de los roedores capturados en búsqueda de parásitos adultos. El índice parasitológico de prevalencia fue calculado y comparadas las frecuencias entre los períodos del año y la edad ecológica. Resultados: Se capturaron 63 roedores identificados como Rattus rattus, de ellos 46,03 por ciento estuvo infectado con A. cantonensis, con un incremento de la infección en los individuos adultos (59,46 por ciento) y en el período lluvioso (55,88 por ciento). Conclusiones: Se demuestra por primera vez en Cuba la infección de A. cantonensis en R. rattus. La presencia de individuos adultos, la alta abundancia de roedores y la temporada lluviosa son los factores que incidieron en una mayor infección de A. cantonensis, y que aumentan la probabilidad de transmisión a los hospederos intermediarios y, por ende, el riesgo de transmisión al humano(AU)

Introduction: Eosinophilic meningitis caused by Angiostrongylus cantonensis (Chen, 1935) is an emergent zoonosis present in Cuba. In the country, few studies about the prevalence of infection in definitive hosts, which can determine risk sites for the establishment of effective measures to prevent the disease, have not been carried out so far. Objective: To determine the prevalence of infection with Angiostrongylus cantonensis in a natural population of Rattus rattus, its relationship with the population structure, and the season of the year in an urban farm field belonging to the Programme of Urban and Suburban Agriculture of Cuba. Material and Methods: A descriptive study was conducted in La Lisa Municipality, Havana, Cuba. The rats were collected monthly during the rainy and dry seasons. The pulmonary arteries of the captured rodents were examined for adult worms. The prevalence of parasitological indices was calculated. The frequencies of infection were compared between the seasons of the year and ecological ages. Results: A total of 63 rodents identified as Rattus rattus were captured. Of the total of individuals captured, 46.03 percent were infected with A. cantonensis, with an increase of infection in adult individuals (59.46 percent) and during the rainy season (55.88 percent). Conclusions: The infection of A. cantonensis in its definitive host R. rattus, and its circulation in the study area in the analyzed period was demonstrated for the first time in Cuba. The presence of adult rats, the high quantity of rodents and the rainy season were the factors that contributed to a greater infection of A. cantonensis, which increase the probability of transmission to intermediate hosts, and consequently, the risk of transmission to humans(AU)

Fish population responses to hydrological variation in a seasonal wetland in southeast México

Hydrological variation differently affects fish species. In the present study, the response of local populations of 13 fish local species to hydrological variation in a tropical wetland was evaluated. The objectives were to analyze the abundance response of fish species with distinct life history strategies and to assess the role of hydrological variation on fish population patterns. We found that opportunistic strategists were favored by high hydrological variation in drought periods, the equilibrium strategists were related to stable habitats, and periodic strategists were regulated by floods and temperature. However, the life history strategies identified for some species in this study do not correspond to the classification reported in other studies. Our results highlight the importance to study the abundance responses of species at local and regional scales to identify variations in life-history strategies, which can reflect local adaptations of species to hydrological changes, this is useful in order to understand and predict the responses of fish populations to the local environment.(AU)

La variación hidrológica afecta de manera diferencial a las especies de peces. En el presente estudio, se evaluó la respuesta de las poblaciones locales de 13 especies de peces considerando la variación hídrica en un humedal tropical. Los objetivos fueron analizar la respuesta de las abundancias de las especies de peces con diferentes estrategias de historia de vida e identificar la importancia de la variación hídrica en los patrones de las poblaciones de peces. Se encontró que los estrategas oportunistas fueron favorecidos por la alta variación hídrica en los periodos de sequía, los estrategas de equilibrio se relacionaron con hábitats estables, y que los estrategas periódicos son regulados por las inundaciones y la temperatura. Sin embargo, para algunas especies las estrategias de historias de vida identificadas en este estudio no corresponden a la clasificación reportada en otros estudios. Nuestros resultados resaltan la importancia de estudiar las respuestas de la abundancia de las especies a escalas locales y regionales para identificar las variaciones en las estrategias de historia de vida, las cuales pueden reflejar adaptaciones locales de las especies a cambios hídricos, esto es útil para entender y predecir las repuestas de las poblaciones de peces a los ambientes locales.(AU)

Balance de nitrógeno, fósforo y potasio en vacas Holstein pastando praderas de kikuyo (Cenchrus clandestinus) en el norte de Antioquia / Balance de nitrógeno, fósforo y potasio en vacas Holstein pastando praderas de kikuyo (Cenchrus clandestinus) en el norte de Antioquia / Balanço de nitrogênio, fósforo e potássio em vacas holandesas pastejando capim-quicuio (Cenchrus clandestinus) no Norte de Antioquia

Abstract To aim to estimate the balance of nitrogen (N), phosphorus (P) and potassium (K) in Holstein cows in northern Antioquia in the three thirds of lactation and in two seasons (high and low precipitation) grazing kikuyo grass (Cenchrus clandestinus), nine cows (three by lactation third) of five herds to which they estimated forage intake, consumption of food supplements and mineralized salt, were selected and were estimated excretion of feces, urine and milk secretion during last three days of an experimental period of 14 days in every season. Food samples, feces, urine and milk were taken in which the content of N, P and K were determined and digestibility, balance and efficiency of each nutrient in milk production were calculated. Data were analyzed under a completely randomized design in a factorial arrangement 3x2. With the advancement of lactation the efficiency of N, P and K decreased (p0.89) nor forage intake (p>0.24) were affected by reduced precipitation. It was conclude that the season can affect the balance and efficiency of nutrients in lactating cows mainly because management guidelines in the food supplement.

Con la finalidad de estimar el balance de nitrógeno (N), fósforo (P) y potasio (K) en vacas Holstein del norte de Antioquia en los tres tercios de la lactancia y en dos épocas del año (alta y baja precipitación) pastando praderas de kikuyo (Cenchrus clandestinus), se seleccionaron nueve vacas (tres de cada tercio) de cinco hatos a las que se les estimó el consumo de forraje, de los suplementos alimenticios y de sal mineralizada y se les estimó la excreción de heces, orina y la secreción láctea durante los últimos tres días de los 14 días que duraba el periodo experimental en cada época. Se tomaron muestras de los alimentos, heces, orina y leche en los que se determinó el contenido de N, P y K y se calculó la digestibilidad aparente, el balance y la eficiencia en el uso de cada nutriente en la producción de leche. Los datos se analizaron bajo un diseño completamente al azar en un arreglo factorial 3 x 2. Con el avance de la lactancia se redujo la eficiencia en el uso del N, P y K (p0,89) ni el consumo de la pradera (p>0,24) se vieran afectados. Se concluye que la época del año puede afectar el balance y eficiencia en el uso de los nutrientes en vacas lactantes debido principalmente a pautas de manejo en el suplemento alimenticio.

Resumo Com a finalidade de estimar o balanço de nitrogênio (N), fósforo (P) e potássio (K) em vacas holandesas do norte de Antioquia no terceiro tercio de lactação e em dois épocas do ano (alta e baixa precipitação) pastejando capim-quicuio (Cenchrus clandestinus), selecionaram-se nove vacas (três de cada tercio) de cinco rebanhos nas quais estimou-se o consumo de forragem, dos suplementos alimentícios e de sal mineralizada e além, estimou-se a excreção de fezes, urina e a secreção láctea durante os últimos três dias dos 14 que durava o período experimental em cada época. Tomaram-se amostras dos alimentos, fezes, urina e leite nos que se determinaram o conteúdo de N, P, e K e calcularam-se a digestibilidade aparente, o balanço e a eficiência no uso de cada nutrimento na produção de leite. Os dados analisaram-se sob um desenho completamente ao acaso num desenho fatorial 3 X 2. Com o avanço da lactação se reduz a eficiência no uso de N, P e K (p0,89), nem o consumo do capim (p>0,24), foram afetados. Conclui-se que a época do ano pode afetar o balanço e a eficiência no uso dos nutrientes para vacas em lactação devido principalmente as pautas de manejo no suplemento alimentício.

Using satellite data to study the relationship between rainfall and diarrheal diseases in a Southwestern Amazon basin / O uso de dados de satélite para estudar a relação entre chuva e doenças diarreicas em uma bacia na Amazônia Sul-Ocidental

Abstract The North region is the second region in Brazil with the highest incidence rate of diarrheal diseases in children under 5 years old. The aim of this study was to investigate the relationship between rainfall and water level during the rainy season principally with the incidence rate of this disease in a southwestern Amazon basin. Rainfall estimates and the water level were correlated and both of them were correlated with the diarrheal incidence rate. For the Alto Acre region, 2 to 3 days’ time-lag is the best interval to observe the impact of the rainfall in the water level (R = 0.35). In the Lower Acre region this time-lag increased (4 days) with a reduction in the correlation value was found. The correlation between rainfall and diarrheal disease was better in the Lower Acre region (Acrelândia, R = 0.7) and rainfall upstream of the city. Between water level and diarrheal disease, the best results were found for the Brasiléia gauging station (Brasiléia, R = 0.3; Epitaciolândia, R = 0.5). This study’s results may support planning and financial resources allocation to prioritize actions for local Civil Defense and health care services before, during and after the rainy season.

Resumo A região Norte é a segunda no Brasil com a maior taxa de incidência de doenças diarreicas em crianças menores de 5 anos. O objetivo deste estudo foi investigar a relação entre chuva e nível do rio, principalmente durante a estação chuvosa, com a taxa de incidência da referida doença em uma bacia no sudoeste da Amazônia. Estimativas de chuva e nível do rio foram correlacionadas e ambos correlacionados com a taxa de incidência da diarreia. Para a região do Alto Acre, 2 a 3 dias de defasagem é o melhor intervalo para observar o impacto da chuva no nível do rio (R = 0.35). Na região do Baixo Acre essa defasagem aumentou (4 dias) com redução na correlação. A correlação entre chuva e doenças diarreicas foi melhor na região do Baixo Acre (Acrelândia, R = 0.7) e a chuva rio acima da cidade. Entre o nível do rio e as doenças diarreicas, os melhores resultados foram encontrados para a estação de Brasiléia (casos em Brasiléia, R = 0.3 e Epitaciolândia, R = 0.5). Os resultados deste estudo podem dar apoio ao planejamento e alocação de recursos financeiros para priorizar ações para Defesa Civil e serviços de saúde antes, durante e depois da estação chuvosa.

<b>A Case of Extremity Pain Onset During Rainy Season Successfully Treated Using B</b><b>yakujutsubushito</b> / 日本東洋医学雑誌

The patient was a 45-year-old woman who began suffering from pain in her extremities 1 year and 6 months previously, and who received Oketsu-reducing Kampo. Her pain disappeared in a year. Six months after her treatment ended, she visited our hospital again complaining of the same symptom. Due to strong signs of Oketsu, we prescribed her a Kampo that reduces Oketsu, but her pain largely persisted. On re-examination, we noticed that her condition had occurred during the rainy season on both instances and speculated that high humidity and strong ‘wind' may be the reason. Therefore, Byakujutsubushito was prescribed for her, and her pain disappeared in 2 weeks. However, in the following rainy season, she visited us again complaining of the same pain, and Byakujutsubushito was again administered, and that relieved her from pain in 11 days. Although it is stated that Byakujutsubushito is useful for the treatment of pain resulting from dampness and ‘wind', there are very a few reports on this in the <i>Kinkiyoryaku </i>text. Nowadays, we live in air-conditioned spaces, and high humidity results in ‘cool wind’ and exterior dampness. Frequent movement in and out of such spaces worsens extremity pain, and we believe that the incidence of this condition is increasing. And we believe that Byakujutsubushito is one of the most useful formulations for the treatment of this condition that occurs during rainy season.

Histomorfometria testicular do morcego Phyllostomus discolor (Chiroptera: Phyllostomidae) em áreas de Mata Atlântica de Pernambuco / Histomorphometry Testis the bat Phyllostomus discolor (Chiroptera: Phyllostomidae) in areas of Atlantic Forest of Pernambuco

Este estudo analisou a condição reprodutiva, por meio da histomorfometria, de P. discolor coletados em fragmentos de Mata Atlântica do litoral sul de Pernambuco, durante as estações seca e chuvosa. Os animais são de coleção e foram classificados de acordo com a posição testicular (descendentes e não descendentes). Para as análises histomorfométricas, foram selecionados aleatoriamente 18 espécimes durante as estações seca e chuvosa, dos quais (n = 11) com testículos descendentes e (n = 7) com testículos não descendentes. Os resultados demonstraram que as maiores médias da área de ocupação dos túbulos seminíferos foram na estação chuvosa, independente dos espécimes apresentarem os testículos descendentes ou não. Isso pode estar relacionado a um maior investimento em produção espermática, já que na estação chuvosa, existe uma maior disponibilidade de alimentos devido às precipitações pluviométricas.

This study analyzed the reproductive condition, by histomorphometry, of P. discolor collected in forest fragments of the South Coast of Pernambuco during the dry and rainy seasons. The animals are Collection and were classified according to the position testicular (descendants and not descendants). For histomorphometric analysis, 18 were randomly selected specimens during the rainy and dry seasons, being (n = 11) with descendant testicles and (n = 7) with testicles no descendant. The results showed that the highest area average occupancy of the seminiferous tubules were in the rainy season, regardless of the present specimens the testes descendant or not. This may be related to a greater investment in sperm production, since the rainy season, there is a greater availability of food due to rainfall.

Fish farm and water quality management / Piscicultura e manejo da qualidade da água

Fish farms' water quality management is analyzed with regard to the management employed and the different trophic states are compared within the system during the dry and rainy seasons. Six sites were marked two in the water supply (P1 and P2), and four within the fish farm (P3 to P6). Whereas sites P1 and P2 (water supply) were characterized as oligotrophic, the others were mesotrophic and eutrotrophic sites. Environmental variables, mainly nutrients, conductivity, COD, BOD5 and TSS tended to increase as from P3 due to management and fertilization. Greater impact has been registered in the fish farm under analysis for variables COD, ammonia, total phosphorus and TSS during the discharge and pond emptying period. Frequent monitoring of water quality should be undertaken in fish breeding and plankton production ponds, especially in those close to P3 and P4. Removal of sediment in decantation lake or P5 is also recommended to decrease nutrient concentrations, especially phosphorus, accumulated on the bottom soil.

Este estudo objetivou avaliar a qualidade da água em uma piscicultura em função do manejo adotado e comparar os diferentes graus de trofia dentro deste sistema nas estações de seca e chuva. Seis pontos foram delimitados sendo dois na água de abastecimento (P1 e P2) e quatro dentro da piscicultura (P3 ao P6). Os pontos P1 e P2 foram caracterizados como oligotróficos e os demais como mesotróficos e eutróficos. Houve tendência das variáveis ambientais principalmente, nutrientes, condutividade, DQO, DBO5 e STS aumentarem a partir do P3 em função do efeito do manejo e fertilização. As variáveis DQO, amônia, fósforo e STS foram de grande impacto dentro da piscicultura estudada, principalmente, no período de descarga e esvaziamento dos viveiros e tanques. Frequente monitoramento da qualidade da água deve ser realizado nos viveiros de criação de peixes e nos tanques de produção de plâncton, especialmente naqueles próximos aos pontos P3 e P4. Outra recomendação a ser adotada é a remoção do sedimento na lagoa de decantação (P5) devido ao grande acúmulo de fósforo neste local.

Spatial patterns of zooplanktivore Chirostoma species (Atherinopsidae) during water-level fluctuation in the shallow tropical Lake Chapala, Mexico: seasonal and interannual analysis

This study addresses the influence of water-level fluctuations on fish distribution at two temporal scales: seasonal (dry and rainy) and interannual (low and high volume conditions). The analysis of abundance relationships among three zooplanktivore Chirostoma species at fifteen sites in Lake Chapala, Mexico, revealed the significant influence of contrasting conditions (P=0.0002). Seasonally, segregation was more related to species dominance in the dry season and exclusively related to environmental characteristics in the rainy season. Interanually, biotic influence occurred in the shallowest and the deepest episodes of the lake. Environmental characteristics influenced species distribution when the lake reached 25 percent of its volume. Site, depth, temperature, and salinity were the leading factors influencing fish distribution. These results emphasize the necessity to implement different management strategies according to lake volume, particularly when a critical threshold is reached.

El presente estudio describe la influencia que tiene la fluctuación del nivel del agua en la distribución de los peces a dos diferentes escalas: estacional (estiaje y lluvias) e interanual (condiciones de bajo y alto volumen). El análisis de las relaciones de abundancia entre tres especies zooplanctófagas de Chirostoma en quince sitios del Lago de Chapala, México, reveló una influencia estadísticamente significativa en las condiciones contrastantes (P=0.0002). Estacionalmente, la segregación estuvo más relacionada a la dominancia de las especies en la época de estiaje y exclusivamente relacionada a las características ambientales en la época de lluvias. Interanualmente, la influencia biótica se presenta en los episodios más someros y más profundos del lago. Las características ambientales influenciaron la distribución de las especies cuando el lago alcanzó el 25 por ciento de su volumen. El sitio geográfico, profundidad, temperatura y salinidad fueron los principales factores que influenciaron la distribución de los peces. Estos resultados enfatizan la necesidad de implementar diferentes estrategias de manejo de acuerdo al volumen del lago, particularmente cuando se alcanza un umbral crítico.

Spatial variations in the zooplankton community from the Corumbá Reservoir, Goiás State, in distinct hydrological periods - DOI: 10.4025/actascibiolsci.v31i3.4132 / Spatial variations in the zooplankton community from the Corumbá Reservoir, Goiás State, in distinct hydrological periods - DOI: 10.4025/actascibiolsci.v31i3.4132

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll-a concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll- concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

Características ambientais de cinco Igarapés de terra-firme em reservas florestais no estado do Amazonas e sua relação com Batrachospermum cayennense (Batrachospermaceae, Rhodophyta)

Five sandy soil terra-firme streams in five forest reserves near BR-174 Road (Manaus-Boa Vista) in Amazonas State (02o19'-02°27'S, 59º45'-60º05'W) were investigated. The streams were visited from July/1996 to September/1997, and each one was searched through for two times, one in the "dry" period and other in the "rainy" one. The environmental variables analysed were: water temperature, dissolved oxygen concentration, dissolved oxygen saturation, current velocity, canopy cover, stream width, stream depth, pH, specific conductance and turbidity. B. cayennense specimes were found just at the "dry" period in one of the streams, and in both of them in the others. The results for physics and chemical parameters were in agreement with that previosly recorded for this region.

Foram investigados cinco igarapés de terra-firme com substrato arenoso localizados em área de reserva florestal nas proximidades da Rodovia BR-174 (Manaus - Boa Vista), Estado do Amazonas (02° 19-02°27'S, 59°45'-60°05'W). Os igarapés foram visitados entre julho de 1996 e setembro de 1997, e cada um foi percorrido em duas ocasiões, uma no período de menor precipitação ("seco") e outra no de maior precipitação ("chuvoso"). As variáveis ambientais analisadas foram: temperatura da água, concentração de oxigênio dissolvido, saturação de oxigênio, velocidade superficial da correnteza, cobertura do dossel, largura do igarapé, profundidade do igarapé, pH, condutividade elétrica e turbidez. Espécimes de B. cayennense foram encontrados apenas no período "seco" em um dos igarapés e em ambos os períodos nos demais. Os resultados obtidos para os parâmetros físicos e químicos foram, em linhas gerais, condizentes com aqueles registrados anteriormente para a região.