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Eutrophication is recognized as the main water quality problem worldwide, mainly due to the prevalence of harmful cyanobacterial blooms. Submerged macrophytes can control cyanobacterial biomass by removing nutrients from the water column or producing allelopathic compounds. As a result, they are highlighted as a potential strategy for restoring eutrophic waters. However, studies in semi-arid tropical ecosystems have shown inconsistent results regarding the effects of submerged macrophytes on cyanobacterial communities and cyanotoxin production. The aim of this study was to assess the effect of submerged macrophytes on cyanobacterial community structure and microcystin production in a tropical semi-arid reservoir subject to intense periods of water level drawdown. Submerged macrophyte cover, surface water physical and chemical variables, cyanobacterial community biovolume and microcystin concentration were measured monthly between October 2014 and July 2015 at the entrance of the river (Zone I) and dam zones (Zone II) of a reservoir. Although both zones were dominated by the submerged macrophyte Egeria densa, there were significant differences in macrophyte cover: Zone I had greater submerged macrophyte cover and Zone II had lower submerged macrophyte cover. Higher total cyanobacterial biovolume, potential microcystin producer biovolume and microcystin concentrations were observed in the zone with the greater submerged macrophyte cover. Moreover, our results showed that nutrient concentrations (total phosphorous, total nitrogen and ammonium) and physical variables (water temperature and turbidity) were also associated with the zone with greater submerged macrophyte cover. This study highlights that the water level drawdown of the reservoir appears to have favored an increase in nutrient concentration, especially in the zones with dense vegetation, which may have contributed to the coexistence of the high cyanobacteria biomass, high submerged macrophyte coverage and high microcystin concentration. Thus, developing strategies for the management of submerged macrophyte cover during water level drawdown events is essential for improving water quality and reducing the risk of harmful cyanobacterial blooms at the ecosystem level in tropical semi-arid aquatic ecosystems.

We provide the first record of Xiphophorus maculatus (Günther, 1866) in a river basin in the northeastern Brazil. Specimens were collected in the Jaguaribe River basin, João Pessoa, Paraíba state, Brazil. Two hundred eighty-one specimens, corresponding to 143 males and 138 females of X. maculatus, were collected at nine sites along the basin, from 2017 to 2019. Specimens total length ranged from 17.5 to 26.6 mm in males and from 11.7 to 32.7 mm in females. Introduction of non-native species greatly threatens the biological diversity worldwide. When introduced into a new habitat, X. maculatus usually decreases microcrustacean, macroinvertebrate and native fish populations.

A new species of Parotocinclus is described from the Rio Mamanguape basin, in the State of Paraiba, north-eastern Brazil. The new species can be distinguished from all of its congeners, except for P. bahiensis, P. cesarpintoi, P. jumbo, P. nandae and P. spilosoma, by the presence of an abdomen covered by a few small and dispersed platelets (vs. an abdomen entirely covered by large plates in adult individuals or the absence of plates in that region). The new species differs from those mentioned above with respect to several features, such as an exposed pectoral girdle and supporting odontodes medially and laterally, the number of premaxillary and dentary teeth, odontodes covering only the lateral portion of the cleithrum and the absence of irregular golden lines on the head and body (colour in vivo). The new species was collected only in the upper and middle portions of the Rio Mamanguape basin, suggesting a geographic distribution restricted to the Caatinga biome.

Predictions of more frequent and intense toxic cyanobacterial blooms in the future arise due to the synergistic effects of eutrophication combined with climate change. Thus, the intensification of dry conditions in arid and semiarid areas promotes a reduction in the water level of aquatic ecosystems and favors the growth of cyanobacteria. Among these conditions, there is a lack of consensus on the role of nitrogen (N) or phosphorus (P) limitation, particularly when cyanobacterial communities are dominated by N-fixing taxa. The present study evaluated the effects of water volume reduction on cyanobacterial abundance and heterocyst production in semiarid tropical reservoirs during a period of prolonged drought. Physicochemical variables and the phytoplankton community were analyzed, and a structural equation model was built to identify the variables that explain the heterocystous cyanobacteria and heterocysts. The reduction in water volume increased the cyanobacterial biomass due to the increase in the biomass of heterocystous filamentous cyanobacteria associated with higher production of heterocysts. Heterocysts were correlated with an increase in the trophic status, low light availability and high salinity maintained under the lower volume conditions. In addition, contrary to expectations, heterocysts were not correlated with the N:P ratio, which suggests that in the tropics, N fixation does not necessarily occur when the N:P ratio is low, and N is limiting. These results indicate the potential for dominance of heterocystous filamentous cyanobacteria in future climate change scenarios, and therefore, we recommend that bloom mitigation strategies prioritize the reduction of N and P associated with the control of variables that favor heterocystous filamentous (i.e., light and salinity). We also recommend including cyanotoxin analysis in the relationship with lowering the water level to determine whether cell-bound toxin production and the associated risk to aquatic biota and humans are increased in the dry period.

Parotocinclus haroldoi is separated from most of its congeners by having an abdomen covered by relatively large plates (vs. naked abdomen or with small plates). This species occurs in Parnaíba River basin with two other congeners, P. cabessadecuia and P. cearensis. Parotocinclus haroldoi is distinguished from P. cabessadecuia for having developed adipose fin (vs. rudimentary or absent adipose fin) and P. cearensis, for having abdomen covered by entirely plates (vs. almost naked abdomen with small sparse plates). Parotocinclus haroldoi is known from the Parnaíba river basin in the state of Piauí, Maranhão-Piauí.

The functional diversity of phytoplankton communities was studied in two tropical estuaries subjected to anthropogenic pressure, despite one being environmentally protected. We applied functional diversity indices, analysed the dominant morphology traits and explored morphology-based functional groups. The less disturbed estuary showed slightly higher diversity and functional redundancy, during a wet season (on average 1.3 higher). Functional groups including nuisance species were more abundant in the heavily disturbed estuary. During a dry season, results for both systems were similar. Overall, abundance and functional diversity were higher in the upstream areas, associated with the river runoff containing freshwater species and essential nutrients for algae development. In both systems, diatoms were dominant (>75% of the community), however, the group included small and larger individuals, and freshwater to cosmopolitan species. This dominance and the change in traits were associated with sufficient nutrient supply, low light conditions, ressuspension and salinity changes, also associated with river runoff. Overall, the different functional diversity approaches enabled us to improve our understanding of the changes occurring in both systems.

Cyanobacteria harmful algal blooms (CyanoHABs) have become increasingly frequent and intense in public supply reservoirs as a result of eutrophication and global climate change. The semi-arid region of Brazil has a well documented history of CyanoHABs but the underlying factors that control the excessive proliferation of these organisms and the production of their bioactive secondary metabolites are not comprehensively understood. This study aimed to identify the environmental factors that explain the spatial and temporal variations in the abundance of cyanobacteria and the concentration of cyanotoxins (microcystins, saxitoxins, and cylindrospermopsin) in semi-arid reservoirs. The following hypotheses were tested: (a) the largest biovolumes of potential toxin producing cyanobacteria occur when cyanotoxin concentrations are highest; and (b) the environmental factors that explain variations in biovolume of cyanobacteria also explain changes in cyanotoxins concentrations. Samples were taken from four reservoirs located in the Northeast region of Brazil, over a three-month period (October 2016 and February and June 2017). Of the 24 species of cyanobacteria identified, 13 were potentially toxin-producing. Physicochemical variables such as water volume of the reservoir, water transparency, soluble reactive phosphorus, and total phosphorus explained the abundance of cyanobacteria and the levels of cyanotoxins. These results corroborate the hypothesis that similar physicochemical conditions influence the abundance and diversity of cyanobacteria and cyanotoxins. Cyanobacterial blooms composed of more than one potential toxin producing species were observed in the studied reservoirs, where potential microcystin-producing species were the most common. Microcystins and saxitoxins were detected in all the reservoirs studied, while cylindrospermopsin and the cyanobacterium Cylindrospermopsis raciborskii were simultaneously recorded in only one reservoir (Camalaú Reservoir). Cylindrospermopsin was only detected in a reservoir for the first time in the State of Paraíba. Canonical redundancy analysis showed that the cyanotoxins were related to potential toxin producing species. These results corroborate the proposed hypothesis that there is a correlation between cyanotoxins and the biomass of potential producers. Also, there were situations where cyanotoxins were detected without the presence of potential producers. These results demonstrate the need for reassessment of potential toxin producing species of cyanobacteria in semi-arid reservoirs. This may lead to the identification and characterization of novel producers of these bioactive secondary metabolites.

Geoengineering techniques have been used to control phosphorus and cyanobacteria in lakes promising greater and quicker chemical and ecological recovery. Techniques that use coagulants and clays to remove particulates and dissolved phosphorus from the water column have received great. In this study, bench-scale "flock & sink" assays were carried out to evaluate the efficiency of the coagulants aluminium sulphate (SUL), polyaluminium chloride (PAC) and chitosan (CHI), alone and combined with natural bentonite clays (BEN) and lanthanum-modified bentonite (LMB), to remove of phosphorus from a eutrophic reservoir in a semi-arid region of Brazil. In addition, the study seeks to assess the effects on the cyanobacteria density and the intra- and extracellular concentrations of cyanotoxins after the application of these geoengineering materials. The SUL and PAC coagulants effectively reduced the total phosphorus (TP), reactive soluble phosphorus (SRP), turbidity, chlorophyll-a, cyanobacteria density and intracellular microcystin, whereas CHI showed a low removal efficiency. Lanthanum-modified bentonite proved to be more effective than BEN; however, the application of the coagulants only was sufficient to successfully remove phosphorus and cyanobacteria from the water column. In addition, the efficiency of the "flock & sink" technique in cell removal varied among the cyanobacteria species. Small colonial species such as Aphanocapsa delicatissima, Merismopedia glauca and Merismopedia tenuissima were removed regardless of the treatment used, including those with CHI and BEN. As for the filamentous cyanobacteria, Cylindrospermopsis raciborskii, Geitlerinema amphibium, Planktothrix agardhii and Pseudanabaena catenata, removal was achieved only using PAC, SUL and LMB alone or when combined. The intracellular concentrations of saxitoxin and cylindrospermopsin and the extracellular fraction of these cyanotoxins and of microcystin were not influenced by the application of coagulants and clays. This indicates that cell lysis did not occur with the addition of the geoengineering materials. These results demonstrate that the "flock & sink" technique could be used for restoration of eutrophic waters.

Fatty acids are the main components of lipids and are necessary for the production and permeability of cell membranes, playing an essential role in the physiological responses of organisms. The biochemical composition of zooplankton might be used as bio-indicators of the trophic status of aquatic ecosystems. Aiming to fill the gap of knowledge in tropical estuaries, the main aim of this study was to test if the fatty acid profiles can reveal spatial and temporal shifts in the diet of copepods and therefore can be used as indicators of the trophic status of estuarine systems. We investigated the fatty acids composition of copepod species and their possible food sources along the salinity gradient of two tropical estuaries (Paraiba do Norte and Mamanguape estuaries, northeastern Brazil), during the rainy and dry seasons. We found clear seasonal differences regarding fatty acids composition and concentration in copepods, with maximal concentrations and diversity of total fatty acids during the rainy season. The copepods species were mainly carnivorous in the dry season and omnivorous in the rainy season and, in both estuaries, the diet of most copepods was dependent on food availability. The fatty acid profiles suggest that, in general, feeding patterns of zooplankton change spatially and temporally, reflecting the shifts in their food sources abundance (i.e., dominance among diatoms and flagellates, terrestrial detritus and small animals). We observed a residual proportion of terrestrial detritus and green algae in the diets and these items were only present in the dry season. Furthermore, the food sources in the Paraiba do Norte estuary, a system with high levels of anthropogenic disturbance, showed lower feeding quality, with lower essential fatty acids concentrations. Our study showed that fatty acid profiles can be used as ecological indicator to assess seasonal and spatial shifts in the trophic ecology of copepods in tropical estuaries and to distinguish systems with different levels of human impact in a fast and accurate way.

The scale of impact that the São Francisco River transposition project will have on the drainage basins ichthyofauna is still unclear, however, changes in the fish community diversity and abundance is probable. Surveys and registries of the fish fauna within key systems of the catchment basins are priority actions for the conservation of the aquatic diversity. This study conducted a taxonomic survey of the Epitácio Pessoa (Boqueirão municipality) and Argemiro de Figueiredo (Itatuba municipality), reservoirs ichthyofauna, both belonging to the Paraíba do Norte River basin, important socioeconomic and environmental systems for the transposition project. Monthly sampling was carried out between October/2014 to September/2015 in the upstream and downstream zones of the reservoirs. The specimens were collected using dip nets, drag nets, and sieves, and placed on ice in the field. Later in the laboratory, they were transferred to 10% formaldehyde and then preserved in 70% alcohol. A total of 2,328 specimens were collected representing five orders, 14 families, and 31 species in both systems. At the upstream zones 2057 specimens were collected representing 17 species, and at the downstream zones 271 specimens were collected representing 24 species. Of the 31 species recorded, 13 species are endemic to watersheds that drain rivers from the Brazilian semi-arid region, and seven species (Apareiodon davisi, Characidium bimaculatum, Hypostomus pusarum, Parotocinclus jumbo, P. spilosoma, Pimelodella enochi, and Prochilodus brevis) are endemic to the Mid-Northeastern Caatinga Ecoregion (MNCE). Among the latter, Parotocinclus spilosoma and Pimelodella enochi are endemic to the Paraíba do Norte River. Apareiodon davisi is classified as Endangered according to the current published Brazil’s official list of endangered species of fish and aquatic invertebrates. This pre-transposition ichthyofaunistic survey will serve as a basis for future post-transposition analyzes, considering this action will change the scope of the ecosystems diversity.

The hydrological periods drive the structure and organization of aquatic communities in semiarid regions. We hypothesize that a decrease of the precipitation during the dry period will favor the development of the periphytic algal community, leading to higher richness and density in this period. To test this hypothesis, we investigated the changes in the periphytic algal community structure in three shallow and eutrophic ecosystems of the Brazilian semiarid. The sampling was performed between 2007 and 2010 at two-mensal intervals. The sampling of periphytic algal was performed in aquatic macrophytes and rocks. The abiotic variables were analyzed simultaneously. Dominance in diatoms, cyanobacteria and chlorophytes, respectively, was observed in two periods. In the dry period, waters were alkaline and had high concentrations of nitrate and total phosphorus associated with the highest densities of Bacillariophyceae. In the rainy period the water was warmer, oxygenated and high concentrations of ammonia and soluble reactive phosphorus with diatoms remained dominant but with reduced density, while cyanobacteria and chlorophytes increased. Overall, periphytic algal community composition no responded to changes in the hydrological periods. However, the hydrological periods altered the dynamics of periphytic algal community, supported by the alternation of the most representative classes (diatoms and cyanobacteria) between the hydrologic periods. Our data suggest that the morphometric and chemical and physical characteristics of lentic aquatic ecosystems studied were more important in the dynamics of periphytic algal community than the hydrological periods and types of substrates. Resumo Os períodos hidrológicos impulsionam a estrutura e organização das comunidades aquáticas em regiões semiáridas. Nós hipotetizamos que uma diminuição da precipitação durante o período seco irá favorecer o desenvolvimento da comunidade de algas perifíticas, levando a uma maior riqueza e densidade nesse período. Para testar esta hipótese, nós investigamos as mudanças na estrutura da comunidade de algas perifíticas em três ecossistemas rasos e eutróficos do semiárido brasileiro. As amostragens foram realizadas entre 2007 e 2010 em intervalos de bimensais. A amostragem das algas perifíticas foi realizada em macrófitas aquáticas e rochas. As variáveis abióticas foram analisadas simultaneamente. A dominância de diatomáceas, cianobactérias e clorófitas, respectivamente, foi observada em todos os períodos. No período seco, as águas foram alcalinas com altas concentrações de nitrato e fósforo total associado às maiores densidades de Bacillariophyceae. Durante o período chuvoso as águas apresentaram-se mais quentes, oxigenadas e com altas concentrações de amônia e fósforo reativo solúvel. As diatomáceas permaneceram dominantes, mas com densidade reduzida, enquanto as cianobactérias e clorofíceas aumentaram. No geral, a composição da comunidade de algas perifíticas não respondeu as mudanças nos períodos hidrológicos. No entanto, os períodos hidrológicos alteraram a dinâmica da comunidade de algas perifíticas, apoiados pela alternância das classes mais representativas (diatomáceas e cianobactérias) entre os períodos hidrológicos. Nossos dados sugerem que as características morfométricas, químicas e físicas dos ecossistemas aquáticos lênticos estudados foram mais importantes na dinâmica da comunidade de algas perifíticas do que os períodos hidrológicos e tipos de substratos.

The introduction of exotic mollusk species has resulted in loss of biodiversity in semi-arid neotropical aquatic ecosystems. This study aims to relate the presence and density of Corbicula largillierti species to human disturbance, providing data for the conservation and management of aquatic ecosystems. Specimens were collected at Epitácio Pessoa reservoir in December 2011 and June 2012, presenting densities of 20.96 and 62.89 individuals per square meter, respectively. Anthropic disturbance metrics were calculated considering the presence, type and intensity of disturbance in littoral, riparian and flood zones. The occurrence of C. largillierti was mainly associated to the variables total phosphorus (261.05 ± 342.22 µg/L) and total nitrogen (440.79 ± 103.77 µg/L), near to tributaries. The occurrence of exotic mollusk species is evidence of the need for freshwater ecosystem conservation and management, particularly in reservoirs used for water supply. A introdução de espécies exóticas de moluscos resulta em perda de biodiversidade em ecossistemas aquáticos semiáridos neotropicais. Este estudo tem o objetivo de relacionar a presença e densidade da espécie Corbicula largillierti ao distúrbio humano, fornecendo dados para a conservação e manejo de ecossistemas aquáticos. Os espécimes foram coletados no reservatório Epitácio Pessoa em dezembro de 2011 e junho de 2012, com densidades de 20,96 e 62,89 indivíduos por metro quadrado, respectivamente. Métricas de perturbação antrópica foram calculadas considerando a presença, tipo e intensidade de perturbação nas zonas litorânea, ribeirinha e de inundação. A ocorrência de C. largillerti esteve associada ès variáveis fósforo total (261,05 ± 342,22 μg/L) e nitrogênio total (440,79 ± 103,77 μg/L), em locais próximos aos afluentes. A ocorrência de espécies exóticas de moluscos evidencia a necessidade de conservação e manejo de ecossistemas de água doce, principalmente em reservatórios utilizados para abastecimento de água.

Many species of bromeliads create an aquatic microcosm among their leaves. Besides their native aquatic fauna, these microcosms can be used by larvae of invasive mosquitoes like Aedes aegypti. We compared the mortality among A. aegypti larvae placed inside tanks of Aechmea fasciata bromeliads with larvae placed inside artificial microcosms and with microcosms with low pH (5.4), which simulate the acidic conditions found inside bromeliad tanks. A. aegypti larvae suffered a significantly higher mortality inside bromeliad tanks compared to larvae in control microcosms, but the mortality inside bromeliads did not differ statistically from that found in artificial microcosms simulating bromeliad acidic conditions. We concluded that bromeliad tanks tend to be a less suitable environment for the development of A. aegypti larvae than artificial containers due to the acidification generated by bromeliad physiology.

O zooplâncton do reservatório de Mundaú, Pernambuco, nordeste do Brasil foi estudado quanto a variabilidade temporal (entre os horários e períodos seco chuvoso) e espacial (nas regiões pelágica e litorânea em diferentes profundidades) correlacionando-as com as variáveis ambientais e com o fitoplâncton. Vinte e três táxons infragenéricos e cinco subgenéricos de zooplâncton foram encontrados. De forma geral, Rotifera foi o grupo dominante em todo o estudo. O fitoplâncton foi dominado pelas cianobactérias. No período seco, as variáveis físicas certamente controlaram o desenvolvimento do zooplâncton, favorecendo o estabelecimento de elevadas densidades algais. No período chuvoso, a correlação do zooplâncton com os níveis de nutrientes do sistema na região pelágica provavelmente conduziu a uma competição de recursos entre o fitoplâncton e o zooplâncton, controlando as densidades algais. Zooplankton from Mundaú reservoir, State of Pernambuco, northeast Brazil was studied concerning temporal (hours and seasonal period) and spatial (pelagic and coastal regions in different depths) variabilities, correlating them to the environmental variables and the phytoplankton. Twenty-three infrageneric and five subgeneric zooplankton taxa were observed. On the whole, Rotifera was the dominant group during this study, especially influenced by the oxygen concentrations. Phytoplankton was dominated by Cyanobacteria. On the dry period, physical variables certainly controlled the zooplankton's development, allowing elevated algal densities. On the rainy period, zooplankton correlation with the system's nutrients levels on pelagic region probably conduced to a resources competition between phytoplankton and zooplankton, controlling algal densities.

ObjectiveThe objective of this study is to evaluate whether the distribution of structural attributes of rotifers in reservoirs in the semiarid region is more strongly influenced by abiotic or biotic environmental factors (density of cyanobacteria).MethodSampling occurred in two reservoirs in the Paraíba Basin, northeastern Brazil (Poções and Camalaú) during April and June 2012. Eight sampling points were distributed at two stations in each reservoir: the region near the entrance of the main tributary and region of the dam and collections were made in the limnetic and littoral zone in every season. To assess the abiotic influence and density of cyanobacteria in the distribution of the structural attributes of rotifers, environmental variables bivariate correlation was conducted in series.ResultsIn Poções reservoir, the distribution of rotifer biomass was negatively related to the density of cyanobacteria; among the environmental variables, chlorophyll-a and total nitrogen were negatively related to all of the tested structural attributes, while the concentrations of total phosphorus were strongly related to the abundance of rotifers. In the Camalaú reservoir, the biomass was a structural attribute with a stronger correlation to the density of cyanobacteria; between the environmental variables and Egeria densa, nitrate was negatively related to all of the attributes tested, while transparency was moderately related to the abundance, biomass and richness as well as Chara sp. with abundance.ConclusionsAssemblages of rotifers are more clearly related to environmental conditions, especially those indicative of trophic conditions, despite the density of cyanobacteria having been a factor that was positively related to the structural characteristics of rotifers and thus indicative of such structural assemblies. This can be used for analysis of local environmental condition factors. ObjetivoO objetivo deste trabalho é avaliar se a distribuição dos atributos estruturais de rotíferos em reservatórios no semiárido é mais fortemente influenciada por determinantes ambientais abióticos ou bióticos (densidade de cianobactérias).MétodoAs amostragens ocorreram em dois reservatórios na Bacia do Rio Paraíba, nordeste do Brasil (Poções e Camalaú) durante abril e junho de 2012. Oito pontos de amostragem foram distribuídos em duas estações em cada reservatório: região próxima a entrada do principal tributário e região de barragem e em cada estação foram realizadas coletas na zona litorânea e limnética. Para avaliação da influência das variáveis ambientais abióticas e da densidade de cianobactérias na distribuição dos atributos estruturais de rotíferos foi realizada análise de série bivariada de correlação.ResultadosNo reservatório Poções, a distribuição da biomassa de rotíferos esteve negativamente relacionada com a densidade de cianobactérias e entre as variáveis ambientais a clorofila-a e nitrogênio total foram negativamente relacionadas com todos os atributos estruturais testados enquanto que as concentrações de fósforo total estiveram fortemente relacionadas com a abundância dos rotíferos. No reservatório Camalaú, a biomassa foi o atributo estrutural com maior fator de correlação com a densidade de cianobactérias e dentre as variáveis ambientais, Egeria densa e nitrato foram relacionadas negativamente com todos os atributos testados, enquanto que a transparência esteve moderadamente relacionada com a abundância, biomassa e riqueza, assim como Chara sp. esteve com a abundância.ConclusõesAs assembleias de rotíferos é mais claramente relacionada a condições ambientais, especialmente as indicativas de condições tróficas, apesar da densidade de cianobactéria ter sido um fator que esteve positivamente relacionado com os atributos estruturais dos rotíferos e desta forma os indicativos estruturais dessas assembleias podem ser utilizados até mesmo como fatores de análise das condições ambientais locais.

Corbicula largillierti is a native mollusk from China. In Brazil, this species was first recorded in the Pantanal of Mato Grosso. This short communication reports the occurrence of C. largillierti for the first time in the Paraíba river basin (Brazilian semi-arid), and also considers the risk of introduction of other molluscs invaders in this basin due to the diversion of water from the São Francisco River. Densities of individuals ranged from 33 to 65 ind.m-2 (maximum values of 484 ind.m-2) in coarse sediment (gravel, 2-4 mm). The diversion of waters from the São Francisco river can lead to the introduction of new species, enhancing ecological problems in the Paraiba river basin. Corbicula largillierti é um molusco nativo da China. No Brasil esta espécie foi registrada primeiramente no Pantanal do Mato Grosso. Esta nota registra a primeira ocorrência de C. largillierti na bacia do Rio Paraíba (semiárido brasileiro). Considera também os riscos potenciais de introdução de outros moluscos invasores nesta bacia devido è transposição das águas do Rio São Francisco. As densidades do molusco variaram de 33 a 65 ind.m-2 (atingindo valor máximo de 484 ind.m-2) em sedimentos grossos (cascalho, 2-4 mm). A transposição das águas do Rio São Francisco pode ocasionar a introdução de novas espécies exóticas potencializando problemas ecológicos na bacia do Rio Paraíba.

The present study evaluated the predation effects of the gastropod Melanoides tuberculatus on the taxa richness and density of the periphyton community. A laboratory experiment was conducted with two treatments: control (without M. tuberculatus) and with M. tuberculatus, each treatment being replicated four times. For periphyton colonization, glass slides were placed in 3.5 L of water from the environment of the gastropods. The analysis of species richness and density of the periphyton community on these artificial substrates showed significant differences (p

The present work presents an inventory of the traditional medicinal uses of animals in the municipality of Bom Sucesso in Paraíba State (PB) in the semiarid northeastern region of Brazil. Information was obtained through the use of semi-structured interviews with 50 people who use zootherapeutic products. A total of 25 animal species used for medicinal purposes were identified (18 vertebrates and seven invertebrates) distributed among five taxonomic categories; the groups with the largest numbers of citations were: mammals (8 citations), insects (7), and reptiles (5). The most cited animal species were: Tubinambis merianae “teju” lizards (44 citations); Apis mellifera Italian honeybees (318 citations); Gallus gallus chickens (31 citations); Ovis aries sheep (31 citations); Crotalus durissus rattlesnakes (14 citations); Boa constrictor (12 citations); and Bos taurus cattle (12 citations). A significant number of illnesses and conditions treated with animal-based medicines were cited, and the category with the greatest number of citations was “problems affecting the respiratory system”. Our results suggest that the use of zootherapeutics in the region is persistent, and that knowledge about these curative practices is an integral part of the regional culture. As such, studies concerning the uses of zootherapeutics are important windows to understanding human/environmental/cultural interactions and a pathway to conciliating regional cultures with efforts to conserve the native fauna.

This study presents the first record of Chantransia macrospora in the state of Rio Grande do Norte, in the semi-arid region of northeastern Brazil. Analyses of periphytic algae revealed C. macrospora individuals associated in particular with shells of Melanoides tuberculatus, a non-native species, suggesting that C. macrospora have been introduced into systems associated with the gastropods. In this context, new records of C. macrospora are still expected for the Brazilian semi-arid region in the next years. Este trabalho apresenta o primeiro registro de Chantransia macrospora do estado do Rio Grande do Norte na região do semiárido no nordeste do Brasil. Análises das algas perifíticas revelaram indivíduos de C. macrospora associados especialmente com conchas de Melanoides tuberculatus, uma espécie exótica, sugerindo que C. macrospora tenha sido introduzida nestes sistemas associados com o gastrópode. Neste contexto, novos registros de C. macrospora ainda são esperados para a região semiárida do Brasil nos próximos anos.

This study investigated the bioaccumulation of microcystin and its potential mutagenic effects in cage-reared fish. For six months, three reservoirs (Acauã, Cordeiro and Camalau) in arid regions of Brazil were monitored. After five months, 10 fish (Oreochromis niloticus) were collected from each tank, and the amounts of microcystin in their muscles and viscera were analysed. Mutagenic effects were also evaluated. Species of cyanobacteria were present during all months of our study. The highest biovolume of cyanobacteria and microcystin in water occurred in the Acauã Reservoir; this was followed by Cordeiro and Camalau. All fish sampled contained microcystin, ranging from 16.01 to 37.09ngg−1 in muscle and 228.2–804.0μgg−1 in liver. We observed significant differences between the micronucleus count in experimental and control fish (p