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Caffeine is a contaminant frequently detected in water bodies. Growth trends in both human population and caffeine consumption per capita are expected to exacerbate the occurrence of caffeine in freshwaters. Yet the effects of caffeine on native fish fauna are poorly understood. We exposed larvae of an endemic Neotropical catfish (Rhamdia quelen) to a range of caffeine concentrations for 30 days. We found that larvae exposed to the highest concentration (16 mg L−1) showed skeletal deformations and reduced growth. We further compiled measured environmental concentrations of caffeine in surface freshwater globally and performed a risk assessment. Our analysis points to a low risk to R. quelen and equally sensitive fish species in ~90% of the freshwater ecosystems considered in our analysis. The risk quotient is higher in freshwater ecosystems of South and Central America, where R. quelen is endemic. Although the ecotoxicological risk is currently low in most places, increased caffeine consumption, exacerbated by the lack of sanitation, is expected to increase caffeine concentrations in many parts of the world, posing a threat of sublethal morphological effects to local fish species.

Made available in DSpace on 2022-04-29T08:36:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) To promote the maximum fertilization rates (FRs) and normal embryonic development, the appropriate ratio of motile sperm to oocytes and adequate water volume should be applied in fish. Therefore, the aim of this study was to determine the proportion of “sperm: egg: water” for maximum use in artificial fertilization in Brycon insignis. A completely randomized experimental design in a factorial scheme (4 × 4) was applied that consisted of four inseminating doses (50,000, 350,000, 650,000 and 950,000 mobile sperm per oocyte), and they were activated with four different volumes of water (1, 5, 10 and 15 ml g−1 of oocytes), performed in triplicate. There was a significant effect on the FR (p

A fauna de peixes de riachos brasileiros compreende 40 familias de peixes teleosteos de agua doce. O conhecimento sobre a sistematica e filogenia deste conjunto de especies ampliou-se consideravelmente nas ultimas duas decadas, porem ainda e muito heterogeneo, havendo grupos sobre os quais pouco se conhece, assim como grupos para os quais ha chaves de identificacao e hipoteses filogeneticas recentes e bem documentadas. O numero de familias de peixes de agua com presenca frequente em riachos brasileiros ampliou-se de 31 para 40. Este crescimento no conhecimento da diversidade dos peixes neotropicais refletiu-se no grande desenvolvimento das hipoteses sobre sua evolucao e contribuiu para o entendimento da historia filogenetica e estruturacao das comunidades de peixes de riachos. TAXONOMY AND PHYLOGENY OF FISHES FROM BRAZILIAN SMALL STREAMS: The fish fauna occurring in Brazilian small streams comprises 36 families of teleost freshwater fishes. The systematics and phylogenetic knowledge about this fauna greatly expanded during the last two decades, but is still very heterogeneous. For some taxonomic groups there are taxonomic identification keys and well-documented phylogenetic hypotheses, while other groups are mostly comprised by poorly known species. The increase in the knowledge of Neotropical fish diversity was associated with the significant growth of hypotheses about their evolution and contributed to the understanding of the phylogenetic history of fish comunities and their structure in small streams.

Systematic review and meta-analysis (MA) were performed to summarize scientific evidence of the effects of cryopreservation of sperm from South American species of freshwater fish using the motilit...

This study undertook the first investigation of malacosporean infections in Neotropical fish. We used polymerase chain reaction detection with a primer set generally targeting known malacosporeans to assay for infection in the kidney of 146 fish in 21 species belonging to 12 families collected from two areas in the Amazon Basin. Infections were found in 13 fish variously belonging to seven species in six families and included the first identification of a malacosporean infection in cartilaginous fish (a freshwater stingray). Based on ssrDNA, all infections represented a singleBuddenbrockiaspecies (Buddenbrockiasp. E) that demonstrates an exceptionally broad range of fish species infected, and countered our expectations of high Neotropical malacosporean diversity. Infections were characterized at varying and often high prevalences in fish species but sample sizes were small. Ascertaining whether highly divergent malacosporeans have not been detected by current primers, and more comprehensive sampling may reveal whether malacosporeans are truly as species poor in the Amazon Basin as present data suggest. Our results prompt speculations about evolutionary scenarios including introductionviamarine incursions and patterns of host use over time.

The present study aimed to evaluate the morphometric and yield characteristics and the chemical composition of Pimelodus britskii in two seasons (winter or summer) to provide information for its in...

Made available in DSpace on 2020-12-12T02:20:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Seven new species of Urocleidoides from the gills and skin of nine Neotropical fish hosts (Anostomidae, Parodontidae, and Gymnotidae) are described: Urocleidoides digitabulum n. sp. on Leporinus friderici, Leporinus octofasciatus, and Megaleporinus elongatus (Anostomidae); Urocleidoides solarivaginatus n. sp. on L. friderici, L. octofasciatus, and Leporinus striatus (Anostomidae); Urocleidoides falxus n. sp. and Urocleidoides sapucaiensis n. sp. on M. elongatus; Urocleidoides tenuis n. sp. on Apareiodon piracicabae and Apareiodon affinis (Parodontidae); Urocleidoides sinus n. sp. on L. striatus, Schizodon nasutus, and Schizodon intermedius (Anostomidae); and Urocleidoides uncinus n. sp. on Gymnotus sylvius (Gymnotidae). Urocleidoides paradoxus was also found in this study on L. friderici and included in the phylogenetic analysis. Molecular data (partial 28S rDNA and mitochondrial cytochrome oxidase subunit I) were obtained for U. digitabulum n. sp., U. tenuis n. sp., U. sinus n. sp., and U. uncinus n. sp. The identification of Urocleidoides is amended herein to include all taxonomic modifications observed in this genus over time and add new characteristics observed in the species in the present study. Phylogenetic analysis revealed Urocleidoides digitabulum n. sp. and Urocleidoides sinus n. sp. (parasites of anostomids) closely related in the tree topologies. Furthermore, the new species described herein parasitized phylogenetically distant host species (Characiformes and Gymnotiformes), suggesting the effect of the dynamic process of ecological fitting. Department of Parasitology Institute of Biosciences São Paulo State University (UNESP), Rua Professor Doutor Antônio Celso Wagner Zanin, n° 250, Botucatu Department of Biological Sciences Regional University of Cariri (URCA), Rua Coronel Antônio Luiz, n° 1,161 Department of Parasitology Institute of Biosciences São Paulo State University (UNESP), Rua Professor Doutor Antônio Celso Wagner Zanin, n° 250, Botucatu

Intensive agricultural and livestock activities demand high pesticide use and, consequently, contaminants reach aquatic ecosystems. In the lower Jacuí River, southern Brazil, there is a lack of knowledge about pesticide residues in water samples and the biochemical responses in native fish species. Thus, this study aimed to estimate the influence of pesticide residues and water parameters to biomarker responses in the native fish Astyanax spp. We performed seasonal biomonitoring in 2017 with water samples and fish collections. Biomarkers of oxidative stress, antioxidants, biotransformation, and neurotoxicity were analyzed in fish tissues. Fourteen pesticide residues were detected; they presented correlations with detoxification enzyme and oxidative stress biomarkers. These data indicate that most of variations can be related to the pesticide presence in water indicating high aquatic pollution in this place.

Fish populations that reside in completely isolated freshwater ecosystems are rare worldwide. The Vila Velha State Park (VVSP), located in southern Brazil, is recognized for its arenitic formations called sinkholes (furnas), which are completely isolated. Fish populations within, such as those of Psalidodon aff. fasciatus, often develop vertebral malformations due to this isolation from other conspecifics and other species. In this study, we analyzed geometric morphology in digital radiographs to identify congenital deformations of Psalidodon aff. fasciatus in Furna 2 of VVSP. We found many fish with spinal deformities, including wide variation in the number of caudal vertebrae and corporal deformations related to a flattened body and spinal curvature. Females were more affected than males. We also demonstrated that these deformations reflect inbreeding and an absence of gene flow in the population. In conclusion, isolated populations such as fish species in furnas are potential models for evo-devo research.

This study aimed to know the daily variation of Astyanax lacustris (Lütken 1875) feeding in a lotic environment. Fish were caught with a net for three days every three hours in the summer to capture ten individuals per hour in a stretch of the Ijuí River, Middle Uruguay River, Brazil. The captured specimens had their stomachs removed and the content analyzed and separated into seven food categories with the aid of stereomicroscope. For the analysis of food items were used the frequency of occurrence methods, volumetric method and applied the Alimentary Index (IAi). Two hundred stomachs were analyzed, of which 95% had food content. The most abundant items were algae and autochthonous insects. Astyanax lacustris feeds throughout the day especially early in the morning (9 hours) and reduces its feeding at night (24 hours and 3 hours). It was also verified variation of AI of different food items throughout the day. It is concluded that A. lacustris feeds throughout the day, especially in the daytime and that throughout the 24 hours it varies its diet due to photoperiod and food availability. This study aimed to know the daily variation of Astyanax lacustris (Lütken 1875) feeding in a lotic environment. Fish were caught with a net for three days every three hours in the summer to capture ten individuals per hour in a stretch of the Ijuí River, Middle Uruguay River, Brazil. The captured specimens had their stomachs removed and the content analyzed and separated into seven food categories with the aid of stereomicroscope. For the analysis of food items were used the frequency of occurrence methods, volumetric method and applied the Alimentary Index (IAi). Two hundred stomachs were analyzed, of which 95% had food content. The most abundant items were algae and autochthonous insects. Astyanax lacustris feeds throughout the day especially early in the morning (9 hours) and reduces its feeding at night (24 hours and 3 hours). It was also verified variation of AI of different food items throughout the day. It is concluded that A. lacustris feeds throughout the day, especially in the daytime and that throughout the 24 hours it varies its diet due to photoperiod and food availability.

Intra and interspecific competition may influence the strength of individual specialization in resource use. We evaluated how intra and interspecific competition affects the degree of individual specialization in food resource use within sub-populations of Hoplerythrinus unitaeniatus. To do so, we identified food items from fishes collected in the Pantanal wetland. We tested whether individual specialization was related to H. unitaeniatus density (a proxy of intraspecific competition) or to the density of a potential interspecific competitor (Hoplias malabaricus) using a multiple regression. Dietary variation was related to ontogeny. Hoplerythrinus unitaeniatus density, instead of Hoplias malabaricus density, had an effect on the specialization of H. unitaeniatus individuals. A greater the density of H. unitaeniatus leads to a greater individual specialization. Our results point to a lack of specialization in H. unitaeniatus individuals. In addition, intra and not interspecific competition affected the use of food resources. Individuals of denser populations may consume secondary resources, reducing the effects of intraspecific competition and becoming more specialists.

Brazilian laws allow the catch of some species as ornamental fish; however, in the absence of biological information, such catch can threaten species conservation. Therefore, this study aimed to offer population and reproductive information about Farlowella hahni in streams of the Ivinhema River Basin, Upper Paraná Basin. To accomplish this, a total of 165 F. hahni individuals were analyzed, including 109 females and 48 males, resulting in an important sex ratio difference from 1:1 (χ 2=19.97; p

The recent increase of freshwater eutrophication has favored cyanobacteria blooms and consequently the increase of toxins such as microcystin-LR in aquatic environments, but few is know about the associated effect of toxin and other compounds. Pyriproxyfen is an insecticide indicated by WHO (World Health Organization) to control Aedes aegypti mosquito (vector of Dengue, Chikungunya and Zika diseases), however, the effects are not well described to non-target species, such as fish. The early life stages (ELS) of fish are more sensitive to chemical stress due to higher metabolic rate, immature immune system and high superficial area/volume ratio. In the current study, ELS of R. quelen a Neotropical fish were exposed to environmentally realistic concentrations of microcystin (1, 10 and 100 µg L−1; M1, M2 and M3 groups, respectively) from an algal extract, pyriproxyfen (1 and 10 µg L−1, P1 and P2) and their association (co-exposure). The hatching, survival and larvae deformities were analyzed, and applied a mathematical model to evaluate the effects on the population size along further generations. Both compounds were toxic to embryos/larvae of fish, but the effects were more pronounced in M2, P1M2 and P2M1 for hatching and M2, P1M2, P2M1 and P1 for survival. Deformities prevailed in groups exposed to the chemicals at 48 hpf (hours post-fertilization) were suggestions of toxicological interaction in P1M2, P2M1 and P2M2 at 48 and 72 hpf. In 96 hpf, the levels of deformities were lower than in previous times. Model predicted population density over 100 years decreased to lower than 0.5 (50%) in all groups, except for P1M1, indicating risk of extinction. P1M2 had the worse results, followed by M2, P1M3 and P2M1. Cyanobacterial blooms can lead to microcystin-LR levels higher than M2 (10 µg L−1), and the suggestion of toxicological interaction with pyriproxyfen is relevant because both compounds may potentially coexist in aquatic environments. Finally, mathematical models may provide an ecological interpretation of the risk of exposure of fish.

Made available in DSpace on 2021-06-25T11:09:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01. Added 1 bitstream(s) on 2021-07-15T15:05:37Z : No. of bitstreams: 1 S0103-84782021000100403.pdf: 820089 bytes, checksum: f46eadd0b745e0e457b3cab89f2b0204 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) China Three Gorges Corporation Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Leporinus friderici is a migratory neotropical fish with elevated ecological and economic importance in Brazil. Microsatellite markers are highly important in population genetic studies, management, and conservation programs; however, no markers are available for this species. In this study, seven microsatellite loci, previously developed for Megaleporinus obtusidens, were successfully cross-amplified in L. friderici. Among these loci, five presented moderate to high genetic variability levels, with four to seven alleles per loci and expected heterozygosities varying from ≥ 0.574 to 1.000. These markers represent a valuable tool for the future management and ecological studies involving this species and group of neotropical fishes. Faculdade de Ciências Universidade Estadual Paulista (UNESP) Instituto de Biociências Universidade Estadual Paulista (UNESP) Departamento de Genética Instituto de Ciências Biológicas e Saúde (ICBS) Universidade Federal Rural do Rio de Janeiro (UFRRJ) Faculdade de Ciências Universidade Estadual Paulista (UNESP) Instituto de Biociências Universidade Estadual Paulista (UNESP)

Cnesterodon decemmaculatus is a Neotropical teleost fish frequently used in ecotoxicological evaluations, whose biology has been thoroughly studied. Although there is considerable information on its response to different toxicants, no range of reference values has been so far established for the different biological parameters proposed as biomarkers of effect or exposure. Moreover, no study has yet examined the possible influence of the metabolic status of the exposed animals on their response to toxic stress. Therefore, the aim of this work was to provide a first baseline for a set of bioenergetic biomarkers in C. decemmaculatus adults exposed to a control medium under previously standardized conditions, and to assess their possible intrinsic seasonal variability. The responses of the biomarkers obtained from the controls were contrasted with those from the reference toxicant (Cadmio-Cd) and receiving waters (surface waters of the Reconquista River RR, Buenos Aires Province, Argentina). We conducted four 12-day assays (one in each season) of exposure to control media, (reconstituted moderate hard water, MHW) and two assays of exposure to Cd in MHW and surface river water (RR) in both summer and autumn. The variables recorded were: Food intake (In), fecal production (F), specific assimilation (A) and cumulative mortality, oxygen extraction efficiency (OEE), specific metabolic rate (SMR), ammonia excretion (N), ammonia quotient (AQ) and scope for growth (SFG). The seasonal variation shown by some physiological parameters, points to the need for establishing a baseline obtained from standardized media, preferably on a seasonal basis. Moreover, SFG and A appeared as the most sensitive biomarkers, emphasizing the importance to consider the metabolic status of the test organisms for the appropriate interpretation of results from ecotoxicological studies performed under controlled experimental conditions. The obtained results provide useful information on C. decemmaculatus as model species in ecotoxicological bioassays involving biomarkers of early effect.

Made available in DSpace on 2022-04-29T08:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 We evaluated the effect of gonadotropin in controlled-release implant together with temperature manipulation in the reproduction of Astyanax altiparanae (lambari) during the non-breeding season. Three groups of adult females were maintained at 20°C and three at 28°C. For each temperature, one group was treated with 4 μg GnRHa g−1, other with 8 μg GnRHa g−1 and other was sham implanted as a control during 4 weeks. Afterwards, 4 females/experimental group were induced to spawn with human chorionic gonadotropin, while 4 females/group were injected with saline. GnRHa implants increased fshβ and lhβ gene expression in females maintained at 28°C. The vtgA gene expression increased in the high GnRHa dose at 20°C, while this higher GnRHa dose associated with the higher temperature increased Gonadosomatic Index. The hCG injection increased the plasma Mature Induction Steroid levels and trigger ovulation, except in control at 28°C. The control females at 20°C spawned but with low reproductive performance, confirming that this is not a limiting temperature for reproduction. The administration of GnRHa as implant increased gonadotropin gene expression at 28°C, temperature at which GSI also increased. Qualitatively, the implants improved reproduction at 20°C, providing offspring out of the reproductive season, improving lambari production throughout the year. UNESP- Universidade Estadual Paulista - Centro de Aquicultura (CAUNESP) Institute of Marine Biology Biotechnology and Aquaculture Hellenic Center for Marine Research Universidade Federal do Amazonas Universidade Anhembi Morumbi Instituto de Biociências –Universidade de São Paulo (USP) UNESP- Universidade Estadual Paulista - Centro de Aquicultura (CAUNESP)

Sphincterodiplostomum is a monotypic genus of diplostomid digeneans that parasitize fish-eating birds in the neotropics. The type species Sphincterodiplostomum musculosum has a unique, dorsal, tubular invagination in the opisthosoma with a muscular sphincter. Whereas larvae of S. musculosum are relatively commonly reported in Neotropical fish helminth surveys, adult specimens from birds are rarely collected. Prior to our study, no DNA sequence data for S. musculosum were available. Our molecular and morphological study of mature and immature adult Sphincterodiplostomum specimens from three species of birds and one species of crocodilian revealed the presence of at least two species of Sphincterodiplostomum in the neotropics. We provide the first molecular phylogeny of the Diplostomoidea that includes Sphincterodiplostomum. In addition, this is the first record of S. musculosum from caimans, along with the first record of fully mature adult S. musculosum from green kingfisher Chloroceryle americana. The new species of Sphincterodiplostomum (Sphincterodiplostomum joaopinhoi n. sp.) can be morphologically distinguished from S. musculosum based on the anterior extent of vitelline follicles, narrower prosoma, substantially smaller holdfast organ and structure of tegumental spines. Our data revealed 0.7% interspecific divergence in 28S and 10.6–11.7% divergence in cox1 sequences between the two Sphincterodiplostomum species.

Introduction: Understanding the various aspects of the reproductive biology of fish is a key step towards applying effective strategies for sustainable management of fishery resources. Objective: We aimed to evaluate the sex ratio, reproductive period and lengths at first maturity for 30 fish species caught in the Verde River, upper Paraná River Basin, Brazil. Methods: Fish were sampled monthly from November 2010 to March 2011 and from October 2011 to February 2012, and sampled quarterly from May to August in 2011 and 2012; totaling 14 samples. Fish were measured and weighed in the laboratory. In addition, gender and gonadal developmental stage were identified macroscopically. Subsequently, the sex ratio was determined and significant differences were tested using the chi-square (χ²) method. The reproductive period was determined with the use of gonadal developmental stages and the gonadosomatic index. Lastly, length at first maturity was estimated only for the species that presented individuals with sufficient immature and mature gonads to adjust the model. Results: Of the captured individuals, 51.5 % were male, and 48.5 % were female. Fifteen species showed significant differences in their sex ratios. The reproductive period for most species occurred from October to February, with reproductive peaks in November, December and January. The length at first maturity was estimated for only five species, including Salminus brasiliensis, a keystone species. Conclusions: The sex ratios revealed that for many species, there is a predominance of males over females, which was not expected for this parameter. The reproductive period follows the same pattern observed in Neotropical fish. However, it is noteworthy that some species are starting their reproduction in August. Lastly, estimating length at first maturity for most Neotropical fish remains a challenge, which may lead to difficulties in the use of protective measures to maintain fisheries and conserve fish species. Resumen Introducción: Comprender los aspectos de la biología reproductiva de los peces es un paso fundamental para la aplicación de estrategias efectivas para la administración sostenible de los recursos pesqueros. Objetivo: Este estudio tuvo como objetivo evaluar la proporción sexual, el período reproductivo y la longitud en la primera madurez para 30 especies de peces capturados en el río Verde, cuenca alta del río Paraná, Brasil. Métodos: Se tomaron muestras de peces mensualmente de noviembre 2010 a marzo 2011 y de octubre 2011 a febrero 2012, y trimestralmente de mayo hasta agosto de 2011 y 2012; totalizando 14 muestras. En el laboratorio, los peces capturados fueron medidos y pesados. Además, el sexo y la etapa de desarrollo gonadal se identificaron macroscópicamente. Posteriormente, se determinó la proporción sexual y se analizó si había diferencias significativas utilizando el método de chi-cuadrado (χ²). El período reproductivo fue determinado con el uso de las etapas de desarrollo gonadal y el índice gonadosomático. Finalmente, la longitud en la primera madurez fue estimada solamente para las especies que presentaron individuos con suficientes gónadas inmaduras y maduras para ajustar el modelo. Resultados: De los individuos capturados, el 51.5 % fueron machos y el 48.5 % hembras. Quince especies presentaron diferencias significativas en la proporción sexual. El período reproductivo para la mayoría de las especies ocurrió de octubre a febrero, con picos reproductivos en noviembre, diciembre y enero. La longitud en la primera madurez fue estimada solamente para cinco especies, incluyendo Salminus brasiliensis, una especie clave. Conclusiones: La proporción sexual reveló que para muchas especies hay predominio de machos sobre hembras, lo cual no se esperaba para este parámetro. El período reproductivo sigue el mismo patrón observado en peces neotropicales. Sin embargo, vale la pena señalar que algunas especies están comenzando su reproducción en el mes de agosto. Por último, estimar la longitud en la primera madurez para la mayoría de los peces neotropicales sigue siendo un reto, lo que puede llevar a dificultades en el uso de medidas de protección para mantener la pesca y conservar las especies de peces.

The release of water from the reservoir hypolimnion, lower concentration of oxygen and the anthropogenic regulation of the river flow, could affect the reproduction of fish, especially migratory species. However, little is known about the effects of these changes in water on non-migratory species. In this sense, the reproduction of Acestrohynchus lacustris was evaluated in two sections of São Francisco River, Minas Gerais, Brazil. Section 1, located immediately downstream from Três Marias Dam (18°09’31.65”S and 45°13’36.00”W) and section 2, located at the confluence of the São Francisco and the Abaeté Rivers (18°02’47.78”S and 45°10’57.95”W). For this, we obtained the physico-chemical parameters of water of each study section. Additionally, biometric data and biological indices of all specimens were measured. Fecundity and follicles diameters were measured in females. Temperature, dissolved oxygen and flow showed lower values in section 1. Fish captured in this section, had lower values of GSI in both sexes, and females presented decreased values of fecundity and follicles diameter. This species showed reproductive activity in the two sections analyzed, however, in section 1 where the temperature and dissolved oxygen presented significant lower values, the reproductive capacity of A. lacustris, was negatively affected.

Made available in DSpace on 2020-12-12T02:03:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Tambaqui (Colossoma macropomum) is the main native fish produced in continental aquaculture from South America. However, its production has been negatively affected by significant economic losses due to frequent outbreaks caused by the parasite Ichthyophthirius multifiliis. Genetic selection for I. multifiliis resistance may represent a sustainable and effective alternative to reduce mortality and, therefore, improve production of tambaqui. The estimation of genetic parameters is needed to validate whether I. multifiliis resistance can be included in genetic improvement programs. The aim of this study was to estimate variance components and heritability for I. multifiliis resistance in tambaqui, through experimental challenge of 218 individuals from eight full-sib families. Survival status (SS), time of death (TD) and parasite load (PL) of fish presenting clinical signs of I. multifiliis infestation were recorded in the cohabitation experimental challenge. The total cumulative survival rate varied significantly among families (16 to 100%) and TD ranged from 217 to 254 hours post cohabitation, which indicates the presence of significant phenotypic variation related to resistance to I. multifiliis infestation. High values for heritability were estimated for SS and TD (0.46 ± 0.09 and 0.60 ± 0.18, respectively). However, differences among families and heritability value were not significant for PL. This study represents the first report on genetic parameters for disease resistance against the parasite I. multifiliis in a Neotropical fish species. The results presented here suggest that resistance to I. multifiliis in tambaqui can be improved through selective breeding. São Paulo State University (Unesp) Aquaculture Center of Unesp Facultad de Ciencias Veterinarias y Pecuarias Universidad de Chile São Paulo State University (Unesp) Aquaculture Center of Unesp CNPq: 311559/2018-2 CNPq: 422670/2018-9

A new species of the characid genus Knodus is described from the rio Aripuanã (rio Madeira basin). It can be distinguished from its congeners by its very low body depth, the presence of tri- to pentacuspid teeth on the outer premaxillary series, with the median cuspid larger than the lateral ones, the teeth of the inner premaxillary series pentacuspid, distinctly larger than those of the outer series, the maxillary teeth tri- to pentacuspid, with the median cusp slightly larger than the lateral ones, the four anteriormost dentary teeth pentacuspid, the smaller posterior teeth tri- to pentacuspid, a complete lateral line with 36-38 scales, 3 longitudinal scale series from pelvic fin origin to lateral line, and 11-12 circumpeduncular scales. The new species is also compared to incertae sedis species of ‘Bryconamericus’ from northern South America since phylogenetic studies suggest a closer relationship of those species with Knodus. RESUMO Uma nova espécie de um caracídeo do gênero Knodus é descrita do rio Aripuanã (bacia do rio Madeira). Esta espécie se distingue de suas congeneres por possuir o corpo muito estreito, a presença de dentes tri- a pentacúspides na série externa do pré-maxilar, com a cúspide mediana ligeiramente maior que as cúspides laterais, dentes da série interna pentacúspide, distintamente maiores que os da série externa, dentes do maxilar tri- a pentacúspides com a cúspode central discretamente maior que as laterais, os quatro dentes mais anteriores do dentário pentacuspidados, os dentes mais posteriores tricuspidados a pentacuspidados, a linha lateral complete com 36-38 escamas, 3 séries longitudinais de escamas entre a origem da nadadeira pélvica e a linha lateral, e 11-12 séries longitudinais de escamas circumpedunculares. A nova espécie é comparada com espécies incertae sedis de ‘Bryconamericus’ do norte da América do Sul uma vez que estudos filogenéticos sugerem a próxima relação daquelas espécies com Knodus.

Cascudinhos are a group of small benthic fishes included in the Hypoptopomatinae subfamily, inhabiting small to moderate streams and rivers within the Neotropical region, from Venezuela to Northern Argentina. Until now, Otothyropsis piribebuy originally described from the rio Paraguay basin, in Paraguay, is the only species of the genus not recorded in Brazil. Recent samples in the rio Tererê, rio Paraguay basin, Brazil, revealed a population of Otothyropsis with uncertain taxonomic identity. Therefore, the study aimed to unveil the distribution of Otothyropsis within Brazilian territory. External morphology, osteology, measurements, and counts (plates, teeth, and rays) of these specimens from rio Tererê were compared to data from the original description of O. piribebuy, and also with specimens of O. piribebuy sampled in Paraguayan territory. Observations indicated no differences among the analyzed specimens. Furthermore, a Principal Component Analysis (PCA), carried out using log-transformed measures from Brazilian and Paraguayan specimens, showed no separation of these populations, also indicating that all analyzed specimens pertain to the same species. Based on this, a prediction map of distribution, using Maximum Entropy, was produced. The correct identification of spatial range of occurrence is an essential step to ensure the conservation of species, and the extended distribution of Otothyropsis piribebuy was confirmed, enhancing the list of neotropical fish from Brazil.

A broad panel of tens of thousands of microsatellite loci is unveiled for an endangered piracema (i.e. migratory) South American fish, Brycon orbignyanus. Once one of the main fisheries resources in the Platine Basin, it is now almost extinct in nature and focus of intense aquaculture activity. A total of 178.2 million paired-end reads (90 bases long) were obtained through the use of sequencing-by-synthesis (from a primary genomic library of 500 bp DNA fragments) and is made available through NCBI's Sequence Read Archive, SRA accession SRX3350440. Short reads were assembled de novo and screening for perfect microsatellite motifs revealed more than 81 thousands unique microsatellite loci, for which primer pairs were proposed. A total of 29 polymorphic microsatellite markers were already previously validated for this panel. A partial genomic assembly is hereby presented and these genomic resources are publicly made available. These data will foster the rapid development of hundreds of new DNA markers for genetic diversity studies, conservation initiatives and management practices for this important and depleted species. The availability of such preliminary genomic data will also be of use in the areas of bioinformatics, ecology, genetics and evolution.

Fish require O2 to maintain energy for their metabolism. Most of them obtain the necessary O2 directly from their aquatic environment. While gills are the main organs of gas exchange in these animals, some species can or need to breathe air; those species require accessory respiratory organs to take up O2 from atmospheric air. The availability of O2 (i.e., hyperoxia, normoxia, or hypoxia) in the aquatic environment determines the behavioral and physiological respiratory responses required to meet the O2 demand of a given species. Such adjustments in respiratory variables are associated with adjustments in the cardiovascular system. Gill innervation consists of branches of the glossopharyngeal and vague nerves as well as the distribution of chemoreceptors, baroreceptors, and nociceptors related to breathe control vary in Neotropical fish.

Made available in DSpace on 2020-12-10T19:40:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Gynogenesis is a chromosome manipulation technique applicable on the production of all-female populations, generation of inbred or clonal lines and identification of genetic sex determination mechanisms in fish. Therefore, the aim of this study was induce meiotic gynogenesis in Astyanax altiparanae and determine the genetic basis of sex determination. Firstly, we evaluated the best UV-irradiation dosage in order to inactivate sperm genome, preserving the capacity of egg activation without the genetic material contribution to the offspring. After the fertilization using the inactivated sperm, diplodization was achieved by heat-shock (40 degrees C; 2 min) by suppression of the 2nd polar body extrusion. Diploid control and gynogenetic individuals were raised until 240 days. The gynogenetic offspring were confirmed by genotyping using microsatellite markers and the sex ratio of gynogenetic progenies suggests that most data fit to a XX/XY model of sex determination. However, unexpected sex ratios were also observed and possible reasons are discussed. This was the first protocol of induced gynogenesis in a Neotropical fish and such a procedure may be used to produce clonal linage of fish and for future mass production of monosex populations in A. altiparanae and other related species. Sao Paulo State Univ, Aquaculture Ctr, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, SP, Brazil Chico Mendes Inst Biodivers Conservat, Natl Ctr Res & Conservat Continental Fish, Lab Fish Biotechnol, Rodovia Pref Euberto Nemesio Pereira de Godoy, BR-13630970 Pirassununga, SP, Brazil Univ Fed Rural Rio de Janeiro, BR 465 Km 7, BR-23897000 Seropedica, RJ, Brazil Univ Sao Paulo, Dept Vet Med FZEA, Lab Theriogenol Dr OJ Ginther, Ave Duque de Caxias Norte 225, BR-13630080 Pirassununga, SP, Brazil Sao Paulo State Univ, Aquaculture Ctr, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 2010/17429-1 FAPESP: 2011/11664-1 FAPESP: 2016/12383-0 CNPq: 471140/2012-0

The chapter presents the current knowledge about the organization and mechanisms of stress response in fish, and explores the factors that modulate the immune system during this response. In addition, the chapter discusses some strategies to reduce stress and combat pathogens, mainly with emphasis on Neotropical fish, as well as advances and future perspectives. Lastly, it helps us to have a better understanding of the complex neuroimmunoendocrine system and applications for fish production.

The contents of ions and organic compounds in freshwaters vary to a great extent. In turn, the body fluids of freshwater fish are hyperosmotic in relation to their habitat, making osmoregulatory mechanisms a key feature of their general well-being and survival. This chapter discusses the structure and function of osmoregulatory organs—epithelia, gills, gastrointestinal tract, kidney, and urinary bladder—of Neotropical fish, addressing effects of hypoxia, pH, water hardness, and dissolved organic matter on osmoregulation. Even though a consistent core of knowledge on the subject is recognizable, studies regarding osmoregulatory mechanisms in Neotropical fish remain necessary, given the scarcity of reports on species dwelling in alkaline waters and hard waters, independently of pH range. Studies on the ionic dynamics of the gastrointestinal tract of feral fish can add to the knowledge on osmoregulation of freshwater fish, especially in ion-poor waters, an environment in which it is assumed that a considerable part of the ion uptake derives from ingested food.

Studies on fish reproduction and early development are important to establish measures of conservation of ichthyofauna and to develop fish farming with native species. This chapter addresses the parameters of reproductive biology and embryogenesis of fish from the Sao Francisco and Grande River basins, Brazil. The size of sexual maturation, the breeding season, gonadal maturation, spawning type, egg adhesiveness, fecundity, egg size, and the times of blastopore closure and hatching are compared in different Characiformes, Siluriformes, and Perciformes fish species. The data presented here were obtained from 1990 to 2018 by the following research groups: Fish Reproduction of the Federal University of Minas Gerais (UFMG) and Ecology and Conservation of Freshwater Resources of the Pontifical Catholic University of Minas Gerais (PUC-Minas). These data are the result of several research projects developed in collaboration with undergraduate and graduate students, which contributed greatly to improving the knowledge of neotropical fish biology.

Brycon orbignyanus is a neotropical fish found in several South American countries. This species has high ecological importance and is included in the list of fish threatened with extinction. In this study, we report the development and characterisation of 12 microsatellite primers of B. orbignyanus for future genetic studies. Screening of the 12 markers in a sample of 35 individuals identified seven polymorphic loci and 22 alleles, with one to three alleles per locus. The polymorphic information content ranged from 0.054 to 0.542, with four loci showing significant deviation from Hardy–Weinberg equilibrium. Two loci possessed null alleles. Cross-species amplification tests in two closely related species showed that 11 loci are transferrable to Brycon gouldingi (B. gouldingi) and nine are transferrable to B. falcatus. The microsatellite primers designed may be used for genetic variability and population structure studies in wild populations, fish farms and restocking programmes of B. orbignyanus and the two related species.

Few studies have assessed the impact of dams on the distribution of the genetic diversity of Neotropical fish species, and some of them suggest that the genetic structure of fish metapopulations is not affected by damming. However, the effects of dams on the genetic structure of populations may hinge on the biological characteristics of the species, such as homing behavior. Dams prevent some individuals from migrating from their feeding area to their natal spawning area, constraining them to reproduce in the tributaries that are closest to the barrier, and which are already being used as breeding grounds by other subpopulations. In these places, subpopulations may interbreed, thus disrupting the overall genetic structure of the metapopulation. To test this hypothesis, we developed a demogenetic Individual-Based Model that simulates the impact of permeable and impermeable dams on the genetic structure of homing populations, in both the long-term and the short-term. Our results support that genetic homogenization occurs among the subpopulations in the short-term, especially near the dam. The impact of a dam on the genetic structure is also detectable in the long-term (100 generations after the addition of the dam) when the dam is permeable (symmetrical or asymmetrical). However, when the barrier is not permeable, the genetic differentiation among the subpopulations is reestablished in the long-term. Our results suggest that conservation programs should be developed to avoid/mitigate genetic homogenization of populations of fish that display homing behavior in the short-term, and to reestablish the pre-dam genetic structure of these populations in the long-term.