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Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960’s, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs. Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.

Trichomycterid catfishes have long been considered as absent in the Parnaíba River basin, Northeastern Brazil, in what constitutes their most conspicuous gap in geographic distribution. Herein we report on the first occurrence of the family in that basin. The new species is described from the riacho da Volta, right tributary to the upper rio Parnaíba, Piauí State. It is distinguished from its congeners by the combination of two or three pairs of ribs; 36–38 post Weberian vertebrae; a color pattern composed of round, similar-sized, non-coalescent spots; I,5 pectoral-fin rays; the first haemal arch on the 5th or 6th vertebrae; and the first completely fused (to the tip) haemal spine on the 15th vertebra. A putative autapomorphy is the partial (minimally 50% of their length) or total fusion between the anterior arms of the basipterygium. Preliminary evidence suggests that the new species can be related to northern South American forms, a pattern that fits the general Amazonian relationships of the fishes in the Parnaíba River drainage. Although the new species fills in an important qualitative gap in trichomycterid continental distribution, the taxon is apparently rare and extremely restricted in distribution, with the type series being its only record so far. The paucity of trichomycterids in the Parnaíba remains a puzzling biogeographical phenomenon. Resumo Os bagres tricomicterídeos têm estado surpreendentemente ausentes na bacia do rio Parnaíba, Nordeste do Brasil, no que constitui sua lacuna mais evidente na distribuição. Relatamos a primeira ocorrência da família na bacia. A espécie nova é descrita do riacho da Volta, tributário do lado direito do alto rio Parnaíba em Uruçuí, Piauí. Ela é distinguida de suas congêneres pela combinação de dois ou três pares de costelas; 36–38 vértebras pós weberianas; padrão de coloração composto de manchas arredondas, de tamanhos semelhantes e não coalescentes; I,5 raios nas nadadeiras peitorais; o primeiro arco haemal na 5° ou 6° vértebra, e o primeiro espinho haemal completamente fusionado (até a extremidade) na 15° vértebra. Uma possível autapomorfia é a fusão parcial (mínimo de 50% do seu comprimento) ou total entre os braços anteriores do basiopterígio. Evidências preliminares sugerem que a espécie nova pode estar relacionada com as formas do norte da América do Sul, padrão que se encaixa nas relações amazônicas dos peixes da drenagem do rio Parnaíba. Embora a espécie nova preencha uma importante lacuna na distribuição continental dos tricomicterídeos, o táxon é aparentemente raro e extremamente restrito em distribuição, sendo a série-tipo seu único registro até o momento.

Insufficient knowledge about ecology of weed macrophytes from a large-scale perspective narrows the necessary decision-making for biodiversity conservation. The present study aimed to assess the occurrence frequency of Egeria densa in lotic and lentic/semi-lotic environments from a Brazilian dammed river, as well as to quantify the attributed explanation (pure or combined) by limnological and spatial variables on species occurrence frequency. Between 2006 and 2010, we repeatedly visited sample points classified as lotic (45) or lentic/semi-lotic environments (23) to collect data on species occurrence and limnological variables. We also generated spatial variables derived from latitude and longitude of sample points. E. densa showed a recurrent occurrence in the sample points classified as lentic/semi-lotic. Both spatial variables (16) and limnological variables (total phosphorus, nitrate, nitrite, transparency and turbidity) significantly contributed to explaining the species occurrence frequency. Forty-nine percent of the occurrence frequency variation was accounted purely by spatial variables. However, less than five percent of occurrence frequency variation was accounted purely by limnological variables. The several dams placed along the river determined the lentic/semi-lotic environments formation and regulated the dispersion processes of individuals of E. densa, consequently causing a recurrent occurrence of this species in particular environmental classes.

Este trabalho teve como objetivo avaliar a influência do período (diurno e noturno) e da lua (nova e crescente) na riqueza de espécies de peixes da zona de arrebentação da Praia de Jaguaribe (Ilha de Itamaracá, PE); avaliar a variação interanual da riqueza dessas espécies e avaliar o desenho amostral utilizado para representar a riqueza das espécies de peixes em zonas de arrebentação. Para isto os peixes foram coletados mensalmente, ao longo de 36 meses, em quatro combinações de período do dia e fases da lua, sendo: diurno-nova, diurno-crescente, noturno-nova; noturno-crescente. Para as comparações entre estas situações e também entre os agrupamentos de dados para período diurno, período noturno, lua nova, lua crescente, ano 1, ano 2 e ano 3, foram calculadas as seguintes variáveis: riqueza total de espécies, número de espécies compartilhadas, número de espécies exclusivas, número de espécies raras e comuns em termos de abundância e freqüência de ocorrência. Foram também comparadas as curvas de riqueza acumulada para as diferentes combinações de dados. Pudemos observar que houve forte efeito do período do dia, da fase da lua e do ano sobre as assembléias, embora estes efeitos sejam mais claros sobre a composição de espécies do que sobre o número de espécies. Cada situação avaliada apresentou elevado número de espécies raras. Os valores de riqueza de espécies e de abundância de indivíduos foram maiores no período diurno do que no noturno, na lua nova do que na lua crescente, e no ano 1 do que nos demais anos. As assembléias de peixes da zona de arrebentação do Jaguaribe podem ser representadas adequadamente com 12 meses de coleta, desde que em cada mês sejam coletados os dois períodos do dia e as duas fases da lua.

This research aimed to understand how anthropic impacts generated by sugarcane plantations and urban development affect a Neotropical river in northeastern Brazil, through the evaluation of the relationships between the local ichthyofauna and environmental variables, and different patterns of land cover, in addition to seasonal variation. Monthly samples of environmental parameters and icthyofauna were taken from September 2013 to August 2014 in the lower course of the Capibaribe River (PE, Brazil). Environmental parameters varied significantly among land cover and seasons, grouping separately samples from the Anthropized and Forested areas. Highest values of phosphorus, chlorophyll-a, fecal coliform (E. coli) and ammoniacal nitrogen, together with the lowest dissolved oxygen concentrations, were recorded in the Anthropized areas. Species richness, evenness, and diversity of fishes were highest in the Forested areas, while abundance was highest in the Anthropized areas. Our results emphasize the importance of riparian forests, since the forested sites had best environmental conditions and ichthyofauna with higher diversity and evenness. Impacts caused by sugarcane plantations and urban development resulted in the simplification of the ichthyofauna and nutrient enrichment, which underpinned a process of eutrophication. Our results reinforce the need for the development of management plans that encourage rational land use practices, the protection of aquatic ecosystems, the recovery of riverside areas, and the conservation of local biodiversity.

This research evaluated the growth of Daphnia similis in wastewater from Nile tilapia (Oreochromis niloticus) farmed in a biofloc system (carbohydrate:nitrogen of 12:1). During 30 days, physical-chemical and growth variables were measured in the following treatments: DCWC—D. similis growth in clear water with the addition of C. vulgaris (autotrophic culture); DB—D. similis growth in biofloc wastewater from Nile tilapia farmed without the addition of C. vulgaris (mixotrophic culture); and DBC—D. similis growth in biofloc wastewater from Nile tilapia farmed with the addition of C. vulgaris (mixotrophic culture). The biofloc wastewater (DB and DBC) underwent significant changes in water quality (P 0.05) from DB in relation to MAD in the second cycle. Thus, wastewater from Nile tilapia cultivation in a biofloc system as a culture medium for raising D. similis, with the addition of C. vulgaris, proved to be a promising option for producing live food for aquaculture.

Knowledge about phytoplankton communities is important for aquaculture due to their influence on environmental variables. The goal of the study was to evaluate the ecological effect of seaweed Grac...

The objective of this study was to evaluate the effect of the addition of Navicula sp. on the growth and fatty acids profile of Litopenaeus vannamei postlarvae in a biofloc system (BFT). Four treatments were used: BFT; BFT 2.5N (addition of 2.5 × 10⁴ cells/ml of Navicula sp.); BFT 5N (addition of 5 × 10⁴ cells/ml of Navicula sp.) and BFT 10N (addition of 10 × 10⁴ cells/ml of Navicula sp.), all in triplicate. The shrimp (1 ± 0.01 mg) were stocked at a density of 3,000 postlarvae/m³ and fed with commercial feed. The diatom was added every 10 days, and at the end of 42 days, shrimp performance, water quality and proximal composition were evaluated. The BFT 5N and BFT 10N treatments had higher performance values, highlighting the values of productivity (2.30 and 2.42 kg/m³) and specific growth rate (15.92 and 16.08%/day), which were higher than the other treatments. In addition, the highest levels of fatty acids were observed in treatments with diatom (BFT 5N and BFT 10N), indicating the benefits of Navicula sp. on growth enhancement and fatty acid content of L. vannamei postlarvae grown in biofloc systems.

The aim of this study was to evaluate the bioremediation of effluents in the biofloc culture of shrimp juveniles using clams, seaweed and fish. Four treatments were considered: CLT – without biorem...

Dams have altered the physiography and ecology of large rivers, causing severe environmental changes at a global scale. Assuming that series of reservoirs induce physical, chemical, and biological longitudinal changes in rivers, we tested the hypotheses that (i) the structure of biological communities in reservoir cascades is not only affected by changes in water quality, but also by cumulative hydrological alteration and impacts on river connectivity; and (ii) fish are more affected by cumulative effects of reservoirs when compared to other aquatic assemblages. Samplings of three assemblages (phytoplankton, benthic macroinvertebrates, and fish) were conducted in the reservoir cascade of Sao Francisco River, Brazil. We estimated the relative role of environmental and spatial predictors through variation partitioning analyses. Environmental variables, cumulative reservoir volume, longitudinal position, and distances from nearest reservoirs were used as explanatory variables. Environmental variables were the most important for the phytoplankton community. No significant effects of the predictors used were found for benthic macroinvertebrates, whereas spatial variables and cumulative reservoir volume were the most important predictors for fish. Therefore, our results provide evidence of impacts along reservoir cascades, and suggest that their effects mainly influence fish assemblages.

We assessed the relationships among native and introduced fish species richness and a set of explanatory variables, including area, altitude, reservoir age, temperature, human influence index and fish abundance. We expected to find different relationships based on species origin (i.e., native or introduced). Based on compiled data from Brazilian reservoirs, we modeled the variation in the number of native and introduced fish species by generalized linear mixed models with different spatial autocorrelation structures. Reservoirs located in warmer regions and with higher fish abundance showed higher species richness of both native and introduced fish. Reservoir age tended to be negatively correlated with native species richness. Our results suggest that reservoir communities in warmer regions may be more resistant to local extinctions caused by impoundments, but they are more susceptible to species introductions. Our results also highlight that an extinction debt can be expected for native species because older reservoirs showed lower native species richness.

Dam construction alters flow regimes and can change the composition of aquatic communities. Using data from three Brazilian hydrographic basins, we tested the hypothesis that reservoir cascades act as environmental filters for fish traits. This dataset included information on different environmental variables and fish traits (diet, migration, fecundation, parental care, position in the water column, and body size), and we used multivariate analysis (partial RLQ) to quantify the relationships between environmental variables, species abundance and traits. We found that the abundance of migratory species declined towards downstream reservoirs, which tend to be smaller and less turbid with a shorter water residence time than upstream reservoirs. We also found evidence of an association between reservoir age and the domination of fish communities by small-sized species with parental care, external fecundation, and benthic habits. Our findings suggest that particular fish traits are selected for across reservoir cascades.

The freshwater fish curimba (Prochilodus argenteus) is an endemic species of the Sao Francisco River basin, with great aquaculture potential. The construction of several hydroelectric power dams along the river, and the pulsed releases of water from these dams altered and degraded the native fish habitats, which led to the development of a hatchery-reared fingerling restocking program. A comprehensive genetic baseline evaluation of the indigenous populations of curimba and of a hatchery stock was done using microsatellite markers. Pairwise F ST values, Bayesian analysis and the number of migrants per generation were used to illustrate the genetic structure of the curimba populations along almost 3000 km of the river, suggesting the existence of three units of conservation: one in the Upper, a second in the Middle and a third including part of the Middle, Submiddle and Lower stretches. We have analyzed the genetic contribution of hatchery stock releases in two stretches of the river using individual admixture coefficients; and the results showed that admixture makes a negligible contribution to indigenous recruitment. We discussed about supplementation programs for this river from the perspective of three units of conservation and the risks associated with using domesticated fish.

The aim of this study was to evaluate the effect of the addition of Chaetoceros calcitrans, Navicula sp. and Phaeodactylum tricornutum (diatoms) on phytoplankton composition and the growth of Litopenaeus vannamei postlarvae reared in a biofloc system. Four treatments were used: BFT (biofloc system without feed and no addition of diatoms); BFT-F (biofloc system with feed and no addition of diatoms); BFT-D (biofloc system with the addition of diatoms and no feed); and BFT-FD (biofloc system with the addition of feed and diatoms), all in triplicate. The shrimp (16 ± 0.02 mg) were stocked at 2500 postlarvae m−3 and fed a commercial feed. Diatoms were added on the 1st, 5th, 10th and 15th day at a density of 5 × 104 cells mL−1 for each species. No significant differences (P > 0.05) between treatments were observed for gross primary production, net ecosystem production and water column respiration rate. However, significant differences (P

The aim of this study was to evaluate the effect of supplementation with Chlorella vulgaris and molasses application rates on water quality, zootechnical performance, proximate composition and health status of Nile tilapia (Oreochromis niloticus) fingerlings cultivated in low-salinity (10 g L-1) biofloc systems. Four treatments were tested in a factorial design (supplemented with microalgae and molasses application rates): BFT-C30 (Biofloc supplemented with C. vulgaris and molasses application rates of 30% of the total daily feed); BFT-30 (Biofloc with molasses application rates of 30% of the total daily feed); BFT-C50 (Biofloc supplemented with C. vulgaris and molasses application rates of 50% of the total daily feed) and BFT-50 (Biofloc with molasses application rates of 50% of the total daily feed), for 70 days. Fingerlings of O. niloticus (initial mean weight of 3.15 ± 0.5 g) were stocked at a density of 680 fish m-3 in experimental units (50L), where 50% of this volume was biofloc previously matured. Throughout the experiment, they were supplemented with C. vulgaris every five days at the concentration of 5x104 cells mL-1. A significant interaction between supplementation with C. vulgaris and molasses application rates for final weight and length, survival, feed conversion ratio, specific growth rate, water consumption, protein efficiency ratio, sedimentation time, planktonic community and hematological indices were observed. The results indicated that the high molasses application rates (50%) in the biofloc system affects the zootechnical performance, water consumption, sedimentation time and the hematological indices of the Nile Tilapia fingerlings, hampering their development. Therefore, molasses application rates of 30% of the total daily feed for the tilapia fingerlings culture in low-salinity biofloc system is recommended.

The aim of this study was to evaluate the effect of supplementation with Chlorella vulgaris and molasses application rates on water quality, zootechnical performance, proximate composition and health status of Nile tilapia (Oreochromis niloticus) fingerlings cultivated in low-salinity (10 g L-1) biofloc systems. Four treatments were tested in a factorial design (supplemented with microalgae and molasses application rates): BFT-C30 (Biofloc supplemented with C. vulgaris and molasses application rates of 30% of the total daily feed); BFT-30 (Biofloc with molasses application rates of 30% of the total daily feed); BFT-C50 (Biofloc supplemented with C. vulgaris and molasses application rates of 50% of the total daily feed) and BFT-50 (Biofloc with molasses application rates of 50% of the total daily feed), for 70 days. Fingerlings of O. niloticus (initial mean weight of 3.15 ± 0.5 g) were stocked at a density of 680 fish m-3 in experimental units (50L), where 50% of this volume was biofloc previously matured. Throughout the experiment, they were supplemented with C. vulgaris every five days at the concentration of 5x104 cells mL-1. A significant interaction between supplementation with C. vulgaris and molasses application rates for final weight and length, survival, feed conversion ratio, specific growth rate, water consumption, protein efficiency ratio, sedimentation time, planktonic community and hematological indices were observed. The results indicated that the high molasses application rates (50%) in the biofloc system affects the zootechnical performance, water consumption, sedimentation time and the hematological indices of the Nile Tilapia fingerlings, hampering their development. Therefore, molasses application rates of 30% of the total daily feed for the tilapia fingerlings culture in low-salinity biofloc system is recommended.

The assemblage and functional structure of the fish fauna of the Maracaí­­pe River, municipality of Ipojuca - PE, was characterized by monthly beach trawls carried out from March of 2012 to February of 2013. A beach trawl net (picaré) was used at three different points of the estuary (EST 1, EST 2 and EST 3) during day and night trawls. The captured specimens were measured and weighed in the laboratory, identified and separated into use and trophic guilds using appropriate literature. Abiotic variables (temperature, salinity, dissolved oxygen, pH, turbidity and chlorophyll-a) were analyzed as for differences between day periods (night and day) and seasons (dry and rainy), and correlated to fish abundance. No difference was detected between day periods (p>0.07 for all variables), but they differed between seasons for most variables (pâ"°¤0.02), and between sampling points only for dissolved oxygen (p=0.03). In one year of collection, 11,513 specimens were captured, belonging to 92 species, 38 families and 15 orders. Gerreidae, Atherinopsidae, Clupeidae, Gobiidae and Hemiramphidae were responsible for 82.9% of the total abundance. The estuary of the Maracaí­­pe River presents a rich ichthyofauna, but with the quantitative predominance of seven species (Atherinella brasiliensis, Eucinostomus argenteus, E. melanopterus, Ulaema lefroyi, Lile piquitinga, Ctenogobius boleosoma and Hyporhamphus unifasciatus). In the estuary, six species classified as vulnerable on the IUCN Endangered Species List were reported. The estuary presents a high diversity of species, most of them marine, carnivorous, and opportunistic, showing the high resilience of this environment. The predominance of juvenile fish underscores the importance of the Maracaí­­pe River estuary for the maintenance of population stocks of coastal species, demonstrating the urgent demand of management of this environment.

O hábito alimentar do beijupirá, Rachycentron canadum, foi descrito ao longo da costa do Estado de Pernambuco, Nordeste do Brasil. Foram capturados 110 exemplares entre fevereiro/2004 e agosto/2006, com comprimento furcal ou zoológico variando entre 40,0 e 137,0 cm (média e desvio padrão: 85,8±18,0 cm) e peso total entre 0,4 e 29,8 kg (7,5±4,4 kg). Foi avaliada a importí­¢ncia de cada item alimentar na dieta utilizando o í­­ndice de importí­¢ncia relativa (IIR). Dentre os 110 estômagos analisados (52 fêmeas e 58 machos), 92 (83,6%) com algum item alimentar e 18 (16,4%) vazios. Os peixes ósseos foram os principais itens consumidos na dieta alimentar (IIR = 98,7%), entre os quais a mariquita (Holocentrus adscensionis) e o baiacu (Diodon sp.) foram as presas mais consumidas (IIR = 30,7% e 8,2%, respectivamente). A dieta foi composta, ainda, por elasmobrí­¢nquios, crustáceos e cefalópodes (IIR

A 42-day trial was conducted to evaluate the effects of a low-salinity biofloc system with different stocking densities on water quality and zootechnical performance of Nile tilapia fingerlings (10 g/L). Four treatments were tested at different densities: 500 fish/m³, 750 fish/m³, 1,000 fish/m³ and 1,250 fish/m³, all in triplicate. Fingerlings of Oreochromis niloticus (initial mean weight of 1.17 ± 0.05 g) were stocked in twelve experimental black-plastic tanks (40 L) with no water exchange during the experimental period. Molasses was added daily to the system at 30% of the amount of feed, and fish were given four daily rations of a formulated feed composed of 36% crude protein and 9% lipids. Water quality variables (dissolved oxygen, pH, salinity, TAN, NO 2 , NO 3 and PO 4 3 ) did not demonstrate significant differences between the treatments. However, significant influences (α ≤ 0.05) of the stocking densities were observed for total suspended solids, settleable solids, final weight, yield, and protein efficiency ratio. The results showed survival over 96%, final weight values between 12 and 18 g, yield between 9.49 and 15.27 kg/m 3 , water consumption of 52 to 101 L/kg fish, and total time of settling chambers between 238 and 305 h/kg fish. These results indicate a negative effect of stocking density on final weight, survival, alkalinity, NO 2 , PO 4 3 and water consumption, and a positive effect on yield in Nile tilapia fingerling culture (1-20 g) in a low-salinity biofloc system with densities up to 1000 fish/m³.

The number of dams has had a significant increase in the last six decades, altering the physiography of rivers and creating systems of reservoirs in series. Therefore, it is expected that in a cascade of reservoirs, detritivorous fish will be especially affected due to the loss of nutritional quality in these regions, resulted from the high sedimentation of nutrients and organic matter. The objective of this study was to evaluate whether changes in the abundance of detritivorous fish, throughout a reservoir cascade in Brazil, resulted from trophic and limnological variations associated with sediment and nutrient retention. We used the Structural Equation Models approach (SEM) to test hypotheses. The six reservoirs studied are located in the Sao Francisco River, in the Northeast Brazil. The variables used to index latent variable oligotrophication were divided into trophic (total phosphate, nitrate and chlorophyll-a) and limnological variables (turbidity and water residence time accumulated), and the abundance of the detritivore guild was indexed by the catch per unit effort (CPUE). Our results indicate a significant negative impact of the both trophic (total phosphate, chlorophyll-a and nitrate) and limnological indicators (turbidity) on the oligotrophication process. The longer residence times of the water accumulated along the reservoir cascade augment the oligotrophication process, consequently affecting negatively all the trophic and limnological indicators analysed. Finally, the latent variable oligotrophication had a significant negative effect on the latent variable detritivorous fish abundance throughout the cascade. The Curimatidae family was the most affected by oligotrophication along the cascade, followed by Prochilodontidae. These different responses to the detritivorous fish families reflect different patterns in the morphology of the oral apparatus and forms of food apprehension. Our findings are of particular importance for the management of fish species in highly fragmented rivers.

The aim of this study was to evaluate the effect of the addition of Navicula spp. and Brachionus plicatilis on water quality and growth of postlarvae shrimp Litopenaeus vannamei reared in a biofloc system. Four treatments were considered: a control (biofloc system – BFT); BFT with the addition of Navicula spp. (BFT-N); BFT with the addition of Brachionus plicatilis (BFT-B) and BFT with the addition of Navicula spp. and Brachionus plicatilis (BFT-NB), each in triplicate. Shrimp (16.2 ± 0.03 mg) were stocked at a density of 2500 shrimp m−3 and plankton were added on days 1, 5, 10, 15, 20, 25 and 30 at a density of 5 × 104 cells mL−1 (Navicula spp.) and 30 organisms L−1 (Brachionus plicatilis). The shrimp were fed a formulated feed in four daily rations composed of 40% crude protein and 8% lipids. Significant differences between treatments were observed for final weight, yield, feed conversion ratio, specific growth rate, protein efficiency ratio and protein content of the shrimp. The combined plankton addition of Navicula spp. and B. plicatilis had better performance parameters, indicating their benefit as natural food sources for postlarvae L. vannamei in biofloc systems.

This study aimed to compare the structure of the ichthyoplanktonic assemblage in two estuarine complexes of Pernambuco (Rio Formoso and Suape), and relate i...

We evaluated the response of the biomass of aquatic macrophytes under limnological changes after water level fluctuation (WLF) of two tropical reservoirs (R1 and R2), located in northeastern Brazil. Initially we tested the hypothesis that post-WLF limnological conditions and biomass of macrophytes increase or decrease, depending on the variable or species. We monitored a 4 × 50 m permanent plot, in four expeditions per period (pre- or post-WLF), assessing species biomass and 10 limnological variables. We utilized 0.25 × 0.25 m quadrats for biomass. Once the effect of WLF in limnological variables and species biomass was confirmed, we utilized Canonical Correspondence Analysis to understand the relationship between limnological variables and species biomass. The abundant and/or dominant species in pre-WLF of R1 ( Pistia stratiotes, Eichhornia crassipes and Salvinia auriculata) and R2 (Paspalidium geminatum and S. auriculata) reduced their biomass post-WLF and were correlated with temperature, total phosphorous and nitrate. The reduced biomass of P. stratiotes, E. crassipes and S. auriculata in post-WLF widened resource availability, allowing coexistence of species. Therefore, we suggest that the change of limnological conditions in post-WLF in artificial lakes acts only as a moderator factor of the interspecific interaction (especially coexistence), without direct relation between these conditions and species biomass. Resumo Avaliamos a resposta da biomassa de macrófitas aquáticas às alterações ambientais após flutuação do nível de água (WLF) de dois reservatórios tropicais (R1 e R2), localizados no Nordeste do Brasil. Inicialmente, testamos a hipótese de que após uma WLF as condições limnológicas e a biomassa das macrófitas aumentam ou diminuem, dependendo da variável ou espécie. Por isso, monitoramos uma parcela permanente de 4 × 50 m, em quatro amostragens por período (pré ou pós-WLF), avaliando a biomassa de espécies e 10 variáveis limnológicas. Utilizamos quadrados de 0,25 × 0,25 m na amostragem da biomassa. Uma vez que o efeito do WLF em variáveis limnológicas e biomassa das espécies foi confirmado, utilizamos a Análise de Correspondência Canônica para compreender a relação das variáveis limnológicas com a biomassa de espécies. As espécies abundantes e/ou dominantes no pré-WLF de R1 (Pistia stratiotes, Eichhornia crassipes e Salvinia auriculata ) e R2 (Paspalidium geminatum e S. auriculata ) reduziram sua biomassa pós-WLF, correlacionando-se diretamente com temperatura, fósforo total e nitrato. A redução da biomassa de P. stratiotes , E. crassipes e S. auriculata em pós-WLF ampliou a disponibilidade de recursos, permitindo a coexistência de espécies. Portanto, sugerimos que a mudança das condições limnológicas no pós-WLF em lagos artificiais atua apenas como um fator moderador da interação interespecífica (em especial a coexistência), sem relação direta entre essas condições e a biomassa das espécies.

In Brazil, more than 150 non-native fish species have been introduced either intentionally or unintentionally, mainly due to aquaculture, fishery improvement and ornamental trade. The non-native jaguar guapote Parachromis managuensis was recorded in two artificial ponds, four rivers, one stream and two reservoirs, ecosystems belonging to the Una, Ipojuca, Capibaribe and Pajeu River basins, Pernambuco, northeastern Brazil. The sampling period was between October 2006 and July 2015. A total of 376 individuals of P. managuensis was captured by seines, casting nets and gillnets. This species may have been introduced in the study sites by accidental release during pond drainage in fish farms, stocking for the purpose of animal protein production or by aquarium dumping. The presence of various ontogenetic life stages in all studied environments is a strong evidence that the species is established. Seven management actions are proposed to prevent further introductions of P. managuensis in other environments of the region.Keywords: exotic, bioinvasion, introduction, aquarism, freshwater fish.

The use of probiotics within shrimp farms has increased as an alternative to antibiotic use because of an increasing demand for more environment-friendly aquaculture. This has improved growth performance and health of shrimp, and improved pathogen control as well as water and soil quality in culture systems. However, efficacy of probiotics in intensive systems using biofloc remains uncertain. Here, bioremediation and biocontrol of a commercial probiotic was investigated through analysis of water quality and main bacterial groups that influence a Litopenaeus vannamei culture using biofloc. Furthermore, additional knowledge was gained on phytoplankton and shrimp performance. Treatments consisted of four different probiotic concentrations ( Bacillus subtilis and B. licheniformis ): 0.5 g -3 (P0.5), 1 g m -3 (P1.0), 2 g m -3 (P2.0), 3 g m -3 (P3.0), and a control without probiotic (CTL). All variables were shown to be balanced and within the recommended limits for shrimp farming. Under the culture conditions adopted in this study, the commercial probiotic did not result in a significant effect ( P ≥ 0.05) on water quality, bacteria, phytoplankton, or shrimp performance. Bacteria naturally present in biofloc were sufficient for maintaining the balance of culture and continued to exert excellent bioremediation and biocontrol when management was conducted properly.

Prochilodus argenteus is an endemic fish species from the São Francisco River basin that is of high economic and environmental importance. The present study aimed to contribute with information to the taxonomic identification of larvae and juveniles of this species. Larvae , obtained from induced spawning of wild animals, were reared in ponds. Individuals were collected daily and classified into larval stages or juvenile phase. Morphological descriptions and morphometric measurements were performed, together with a piece wise linear regression analysis of the body proportions throughout the development process. Individuals in the preflexion stage had a standard length (SL) of 4.48 to 6.64mm, long to moderate body (BH/SL), small to moderate head (HL/SL), and a small to moderate eye (ED/HL). In the flexion stage, the SL varied from 6.60 to 11.00mm, long to moderate body, moderate head, and small to moderate eye. Larvae in the postflexion stage presented SL of 10.54-19.93mm, moderate body, moderate to big head and small eye. The juvenile phase included specimens with a SL of 18.27 to 42.21mm which presented a moderate to high body, big head and small to moderate eye. Regression analysis showed significant moments of change in rate of increase of the body proportions, presenting a change in the growth pattern from allometry to isometry during the early development.

A Região Neotropical possui um elevado número de espécies de peixes de água doce, cujas adaptações para explorar diferentes tipos de alimento é particularmente evidente em reservatórios, refletindo numa considerável plasticidade alimentar. Characiformes é a mais diversificada ordem de peixes da região, tendo Anostomidae como uma das famílias mais especiosas, com destaque para Leporinus, com cerca de 80 espécies válidas. Embora suas espécies sejam consideradas primordialmente onívoras, algumas apresentam dieta herbívora, e a plasticidade alimentar do gênero é uma característica comum em ambientes sujeitos a variação sazonal de nível da água. No presente trabalho, são analisadas a composição da dieta de Leporinus reinhardtii Lütken, 1875 no reservatório de Sobradinho e a influência da variação sazonal de seu nível sobre a mesma ao longo de três ciclos anuais (2006-2009). Dentre os 876 indivíduos analisados, 302 foram coletados no período de seca e 574 no de cheia. A dieta foi composta por 47 itens, agrupados em nove categorias: Moluscos, Microcrustáceos, Insetos, Insetos (partes), Chironomidae, Vegetais, Sementes, Sedimento e Outros. Chironomidae representou em média 60% do peso total das categorias alimentares, seguido de Sementes com 25% e as demais categorias com menos de 10%. No período de cheia, nos trechos lêntico e de transição, predominaram Sementes na dieta, tendo Chironomidae sido mais representativa no trecho lótico, e as demais categorias não ultrapassando 20% de participação nos três trechos neste período. No período de seca, houve diferença nos itens predominantes, com predominância de Insetos no trecho lêntico, principalmente Coleoptera, e de Vegetais no lótico, com maior participação de macrófitas aquáticas, algas filamentosas, clorofíceas e da diatomácea Oscillatoria. Já no trecho de transição, Microcrustáceos dominaram na dieta, diferindo dos demais trechos. A dieta de L. reinhardtii se caracterizou por baixos valores de frequência de ocorrência de todas as categorias alimentares (predominantemente inferiores a 50%) e elevada abundância relativa (>80%) de diferentes categorias. A amplitude de nicho foi restrita nos diferentes trechos nos dois períodos, sendo ligeiramente mais elevada na cheia, devido à maior diversidade de itens, em particular no trecho lêntico. Leporinus reinhardtii possui hábito onívoro com comportamento especialista no reservatório de Sobradinho, cujas categorias predominantes da dieta dependem do regime hidrológico do reservatório e das características ambientais de cada trecho, refletindo numa amplitude restrita de nicho trófico para a espécie. The Neotropical region presents a high number of freshwater fish species, whose capability to explore different kinds of food is particularly evident in reservoirs, and reflects a considerable feeding plasticity. Characiformes is the most diversified fish order in the region, and Anostomidae one of its most speciose families, evidencing Leporinus and its 80 valid species. Although its species are mainly considered omnivorous, some present herbivorous diet, and the food plasticity of the genus is a common feature in environments subject to a seasonal variation of water level. In the present work, the diet composition of Leporinus reinhardtii Lütken, 1875 in the Sobradinho reservoir and the influence of its seasonal water level variation is analyzed along a three-year period (2006-2009). Among the 876 individuals analyzed, 302 were collected in the dry phase, and 574 in the flooding phase. The diet was composed of 47 items, grouped into nine categories: Mollusks, Microcrustaceans, Insects, Insect (parts), Chironomidae, Plants, Seeds, Sediment and Others. Chironomidae represented a mean of 60% of total weight of all food categories, followed by Seeds with 25% and the remaining categories with less than 10%. In the flooding phase, Seeds prevailed in the diet in the lentic and transition stretches, Chironomidae was most represented in the lotic one, and the remaining categories represented less than 20% in all stretches at this phase. In the dry phase, the prevailing items differed, with a higher dominance of Insetcs in the lentic stretch, mainly Coleoptera, and Plants in the lotic one, with greater participation of aquatic macrophytes, filamentous algae, Chlorophyceae and the diatom Oscillatoria. In the transition stretch, Microcrustaceans dominated in the diet, differing from the other stretches. The diet of L. reinhardtii was characterized by low values of frequence of occurrence for all food categories (mostly inferior to 50%), and high relative abundance (>80%) of all categories. Niche breadth was restricted in the different stretches in both periods, somewhat higher during flooding, due to a greater item diversity, particularly in the lotic stretch. Leporinus reinhardtii presents an omnivorous habit with specialized behaviour in the Sobradinho reservoir, whose prevailing food categories in the diet depend on the reservoir level, as well as the environmental characteristics of each stretch, thus reflecting a narrow trophic niche breadth for the species.