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Fish viscera can be an important source of protein and energy for aquafeed, and its use contributes to circular aquaculture. The aim of this study was to produce acid and fermented silage from fish viscera to determine their nutritional value and the apparent digestibility coefficient of nutrients and energy for juvenile tambaqui (Colossoma macropomum). An acid silage and three fermented silages with different sources of carbohydrates (molasses, wheat bran, and cassava waste) were produced with 0.25% sorbic acid as an antifungal in the formulation. Silages presented an average of 55% dry matter, 62.9% lipids, and 12% crude protein. Leucine and lysine predominated as essential amino acids in the acid silage and fermented silages. Fish viscera silages presented EPA and DHA content from 5.4 to 17.8 and 1.7 to 8.9 mg.g−1 of lipids, respectively. The apparent digestibility coefficient (ADC) (indirect method) was above 82% for gross energy for all the formulations. The ADCs for protein were similar for the fermented silages, with a maximum 92% level for the fermented wheat bran silage. The bioconversion of fish viscera into silage makes it an energy ingredient for aquafeed that is well digested by tambaqui juveniles.

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

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...

Large dams disrupt river ecosystems, causing negative effects on fish assemblages. Few studies, however, have investigated how Neotropical fish diversity responds to river regulation in longer temporal scales. In this study, we used a multi-metric approach to investigated temporal changes in taxonomic and functional fish diversity over 15 years-period following the construction of a large dam in the Upper Tocantins River, Amazon. We analyzed biological and environmental data collected in the impounded area before (2000–2002) and after (2003–2014) river regulation. Diversity metrics responded differently to the impoundment. Some metrics were not affected, as they showed little variation over years, such as fish abundance, species, and trait richness. Other metrics changed significantly between periods, such as taxonomic composition, temporal beta diversity, and trait abundance. Species with traits that are sensitive to hydrological alterations declined in the impoundment, while sedentary species were favored. Assemblage trajectories were variable, but community structure developed into a different state in the impoundment. Landscape variables explained changes in fish dissimilarity over time. In general, our study supports the notion that fish diversity in Amazonian rivers is vulnerable to river damming, but also indicates that different metrics show particular responses to this disturbance.

Made available in DSpace on 2022-04-29T08:38:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-15 The present study evaluated the effect of luteinizing hormone-releasing hormone analogue (LHRHa) with and without dopamine antagonist (i.e., domperidone (D)) on the reproductive performance of lambari females (Astyanax altiparanae) as well as on secretion of 17α-20β-dihydroxy-4-pregnen-3-one (17,20β-P) and prostaglandin F2α (PGF2α)) and on the histological evaluation of ovarian structures in two independent and consecutive experiments. In the first experiment (Exp. 1), five LHRHa doses (20, 60, 180, 540, and 1620 μg/kg BW) were tested with three replicates each, while in the second experiment (Exp. 2) the dose of 180 μg/kg was tested in combination with D at a dose of 20 mg/kg with four replicates. The replicates in both experiments consisted of an experimental unit in which five females and 10 males were placed. In both experiments, two control groups were formed, 0.9% saline (negative control) and 6 mg/kg of carp pituitary homogenate (CPH), and females from all groups received the total dose in two injections (i.e., one comprising 10% of the total dose and a second one 12 h later comprising the resolving dose). There was a decrease in fertilization and hatching rates that coincided with the two highest doses of LHRHa (540 and 1620 μg/kg), suggesting that these doses may have caused hormonal overstimulation affecting egg quality. Taken together, these results were not in favor of an obvious dopaminergic control of final oocyte maturation (FOM) in lambari, since the use of LHRHa associated with D did not improve reproductive performance of lambari compared to LHRHa alone, CPH, and negative control. Plasma levels of 17,20β-P were related to FOM and/or ovulation in most cases. There was not a clear association between ovulation and PGF2α plasma levels. The CPH-treated group was the only one performing better than the negative control, increasing the spawning rate and spawning volume per female body mass as well as triggered FOM in almost all females submitted to hormonal induction, indicating that CPH is the most suitable hormonal therapy to induce FOM and ovulation in lambari (among the treatments tested here). Universidade Estadual Paulista (Unesp) Centro de Aquicultura da Unesp (Caunesp) Universidade Estadual Paulista (Unesp) Centro de Aquicultura da Unesp (Caunesp)

Epactionotus species are known for inhabiting the rocky-bottom stretches of fast-flowing rivers in a limited geographic area along the Atlantic coast of southern Brazil. These species are endemic to single coastal river drainages (two neighbouring drainages for Epactionotus bilineatus) isolated from each other by the coastal lacustrine environments or the Atlantic Ocean. E. bilineatus is from the Maquiné and Três Forquilhas River basins, both tributaries of the Tramandaí River system, whereas E. itaimbezinho is endemic to the Mampituba River drainage and Epactionotus gracilis to the Araranguá River drainage. Recent fieldwork in the Atlantic coastal drainages of southern Brazil revealed new populations in the Urussanga, Tubarão, d'Una and Biguaçu River drainages. Iterative species delimitation using molecular data (cytochrome c oxidase subunit I) and morphology (morphometrics and meristics) was applied to evaluate species recognition of isolated populations. With regard to new data, the genus was re-diagnosed, the status of Epactionotus species/populations was re-evaluated, formerly described species were supported and population structure was recognized. As for the newly discovered populations, both morphological and molecular data strongly support the population from the Biguaçu River drainage, in Santa Catarina State, as a new species. Molecular data revealed strong per-basin population structure, which may be related to species habitat specificity and low or no dispersal among drainages.

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 2020-12-12T02:21:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 In view of the established climate change scenario and the consequent changes in global temperature, it is essential to study its effects on animal spermatogenesis. Therefore, the aim of this study was to verify the duration of spermatogenesis at different temperatures. For this purpose, 96 male and adult specimens of Astyanax altiparanae were kept in a closed circulation system with water temperature stabilized at 27 °C and 32 °C. Subsequently, the specimens received pulses of BrdU (bromodeoxyuridine) at a concentration of 100 mg/kg/day for 2 consecutive days, and the samples were collected daily for a period of 15 days. Their testes were removed, fixed, processed in historesin, and sectioned in 3 μm, submitted to hematoxylin/eosin staining and to bromodeoxyuridine immunodetection. Partial results of the optimum temperature experiments allowed the classification of A. altiparanae spermatogenic cells in Aund, Adiff, and type B spermatogonia, spermatocytes, spermatids, and spermatozoa. The duration of spermatogenesis was determined as approximately 6 days for animals at a temperature of 27 °C and 1 day for animals at 32 °C. The elevated temperature was also responsible for increasing cell proliferation, resulting in an increase in the number of spermatocytes, spermatids, spermatozoa, and cell death (cell pyknotic). The duration of spermatogenesis in A. altiparanae was directly affected by the elevated water temperature, causing a reduction in the estimated time of spermatogenesis. Departamento de Biologia e Zootecnia. L.I.NEO - Laboratory of Neotropical Ichthyology UNESP - Universidade Estadual Paulista “Júlio de Mesquita Filho” Câmpus de Ilha Solteira, Rua Monção, n 226, 15385-000 Programa de Pós-Graduação em Ciências Biológicas (Zoologia) Instituto de Biociências de Botucatu (UNESP - IBB), R. Prof. Dr. Antonio Celso Wagner Zanin, 250, 18618-689 Instituto de Estudo em Saúde e Biologicas (IESB) Research Group of Reproduction on Amazon Fish (GERPA/LaNec) UNIFESSPA - Universidade Federal do Sul e Sudeste do Para, Folha 31, Quadra 07, Lote especial s/n, 68.507-590 Departamento de Morfologia Reproductive and Molecular Biology Group UNESP - Universidade Estadual Paulista “Júlio de Mesquita Filho” Câmpus de Botucatu Instituto de Biociências de Botucatu, R. Prof.Dr. Antonio Celso Wagner Zanin, 250, 18618-689 Departamento de Biologia e Zootecnia. L.I.NEO - Laboratory of Neotropical Ichthyology UNESP - Universidade Estadual Paulista “Júlio de Mesquita Filho” Câmpus de Ilha Solteira, Rua Monção, n 226, 15385-000 Programa de Pós-Graduação em Ciências Biológicas (Zoologia) Instituto de Biociências de Botucatu (UNESP - IBB), R. Prof. Dr. Antonio Celso Wagner Zanin, 250, 18618-689 Departamento de Morfologia Reproductive and Molecular Biology Group UNESP - Universidade Estadual Paulista “Júlio de Mesquita Filho” Câmpus de Botucatu Instituto de Biociências de Botucatu, R. Prof.Dr. Antonio Celso Wagner Zanin, 250, 18618-689

Unravelling the effect of climate variability on species biology has been one of the main goals of ecological studies. Environmental factors such as river discharge and temperature have being proposed as triggers of reproductive cycle in fish. In temperate climates, fish reproduction is affected mainly by temperature, while is influenced by flood pulses in large tropical rivers. We evaluated the influence of temperature and river discharge as triggers of Iheringichthys labrosus’ reproduction. We studied the following reproductive variables: gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (K). Females of I. labrosus were examined in a time series of ten years along three sites located in Lower Uruguay River at the beginning (last week of November‐first week of December, spring) and by the end of the reproductive period (middle‐end of April, autumn). Generalised linear models detected a positive effect of mean winter temperature and site on the spring mature female GSI. Site was significant in addition to the interaction between temperature and site. Moreover, the effect of winter temperature was stronger than water discharge in triggering reproductive timing of I. labrosus, contrary to the model proposed for other species in tropical systems. Additionally, a literature review suggested a latitudinal gradient on reproduction, occurring earlier and prolonged with decreasing latitude (and increasing temperature). In this study, we stated the effect of temperature on the life history in a Neotropical fish using a multifaceted approach, particularly important in the current context of global climate warming.

Aim We characterize the diet and trophic guild to the fish community in a protected area to contribute information about the trophic ecology. Methods The collection was carried out at three sampling points, in 2017 and 2018, with the help of gill nets. The collected specimens were euthanized in a 0.5% benzocaine solution. In the laboratory, all specimens' stomachs were removed, fixed in a 4% formalin solution, and preserved in 70% alcohol. Stomach contents were examined, and the food items were identified to the lowest possible taxonomic level. Food items were quantified according to the volumetric method. The characterization of the diet was presented through the percentage volume of each food item consumed. To determination of the trophic guild of each species, the predominance of a type of food resource (> 51% of the total volume) in the population's diet was considered. Results The species' diets were distributed in 16 food items (predominance of decapods, fish fragments, terrestrial insects, and aquatic plants), and four trophic guilds were observed (carcinophage, piscivore, terrestrial insectivore, and herbivore). Furthermore, there was the occurrence of microplastic in the diet of three species. Conclusions the fish community evaluated here demonstrates the wide range of resources that can make up the fish diet and demonstrates the different trophic guilds that can be observed in a protected area. As it is a conservation unit, knowing the diet and trophic guilds that make up the fish community can contribute to understanding the dynamics of food chains, the structure of the community, and the functioning of the ecosystem. Thus, this work can contribute information about the biology of the species evaluated for future work and conservation programs. Resumo: Objetivo Caracterizamos a dieta e a guilda trófica da comunidade de peixes em uma unidade de conservação para contribuir com informações sobre a ecologia trófica. Métodos As coletas foram realizadas em três pontos de amostragem, em 2017 e 2018, com o auxílio de redes de espera. Os espécimes foram eutanasiados em solução de benzocaína a 0,5%. Em laboratório, os estômagos foram retirados, fixados em formol 4% e preservados em álcool 70%. O conteúdo estomacal foi examinado e os itens alimentares foram identificados até o menor nível taxonômico possível e quantificados de acordo com o método volumétrico. A caracterização da dieta foi apresentada por meio do volume percentual de cada alimento consumido. Para a determinação da guilda trófica de cada espécie, foi considerada a predominância de um determinado tipo de recurso alimentar (> 51% do volume total) na dieta da população. Resultados A dieta das espécies foi distribuída em 16 itens alimentares (predominância de decapoda, fragmento de peixe, inseto terrestre e vegetal aquático), e quatro guildas tróficas foram observadas (carcinófago, piscívoro, insetívoro terrestre e herbívoro). Além disso, houve a ocorrência de microplástico na dieta de três espécies. Conclusões A comunidade de peixes aqui avaliada demonstra uma ampla gama de recursos que podem compor a dieta dos peixes e demonstra as diferentes guildas tróficas que podem ser observadas em uma área protegida. Por se tratar de uma unidade de conservação, conhecer a dieta e as guildas tróficas que compõem a comunidade de peixes pode contribuir para o entendimento da dinâmica das cadeias alimentares, da estrutura da comunidade e do funcionamento do ecossistema. Assim, este trabalho pode contribuir com informações sobre a biologia das espécies avaliadas para futuros trabalhos e programas de conservação.

We employed the trophic upsurge hypothesis as an analytical framework to describe the response of Neotropical fish communities to terrestrial inundation associated with river damming. Data were collected for the impact assessment of the Peixe Angical Dam, Tocantins River, Brazil. Monthly surveys were conducted at nine sites (seven upstream, two downstream) from 15 months before to 20 months after dam closure and a follow‐up survey 60–83 months after closure. Fish responses differed in timing and magnitude across sites. In the new reservoir, populations peaked 8–13 months after flooding, demonstrating increases in richness (84 ± 52%), biomass (329 ± 266%) and abundance (681 ± 348%) with the maxima for richness and abundance tending to precede biomass maxima. Populations of all families increased but were greatest for Engraulidae, Hemiodontidae, Serrasalmidae and Characidae, and lower for the benthic catfish: Sciaenidae, Dorididae, Pimelodidae. Downstream populations peaked 5–12 months after closure or showed consistent decline. Five years after dam‐closure richness and abundance were lower compared to predam levels, with populations at all sites demonstrating an ongoing decline. Reservoir creation triggers reproductive recruitment and otherwise pools spatially disparate populations from across the flooded valley. If the rise in richness is largely explained by the increased catchability of species otherwise present prior to flooding, it may be more appropriate to estimate species loss with reference to upsurge data. As peak biomass coincides with declining richness, modelling fisheries production from annually aggregated data may risk overestimating the potential for sustainable harvests. Upsurge–response curves can help identify the timing of critical ecological thresholds for flood‐managed fisheries.

This study investigated the in vitro and in vivo efficacy of trichlorfon against Dawestrema cycloancistrium, as well as its physiological effects on arapaima. Naturally parasitized arapaima gill arches were exposed in vitro to 100, 250, 500 and 750 mg/L of trichlorfon and a control group (only distilled water), in triplicate. Parasites were monitored, and mortality was used to determine the median effective concentration (EC50 ). The 750 mg/L concentration demonstrated 100% in vitro efficacy against D. cycloancistrium after 60 min, while the intermediate (500 mg/L) and the lowest (100 and 250 mg/L) tested concentrations were completely efficient after 90 and 130 min, respectively. The EC50-1h of trichlorfon for D. cycloancistrium was determined at 171.73 mg/L. Parasitized arapaima juveniles were exposed to a control group and 150 mg/L of trichlorfon in triplicate. Fish were exposed to two therapeutic baths for 60 min with 24-h intervals between treatments. Therapeutic baths with 150 mg/L of trichlorfon were 92.99% effective against D. cycloancistrium and did not bring about haematological alterations (erythrogram, white blood cell count, thrombogram, plasma glucose and total proteins). Therefore, 150 mg/L of trichlorfon can be used in therapeutic baths to control and treat D. cycloancistrium infestations with no physiological impairments for arapaima.

Anesthetics have been used frequently in aquaculture to minimize stress during handling. However, several factors can affect the efficiency of anesthetics. For example, temperature is one of the abiotic factors that control animal metabolism and consequently, the effect of anesthetics. This study aimed to evaluate the effectiveness of benzocaine as an anesthetic for early juveniles of curimba Prochilodus lineatus at different water temperatures. Juveniles (4.7 ± 1.6 g and total length of 7.4 ± 0.7 cm) were submitted to anesthesia at concentrations of 30, 40, 50, 60, 70, and 80 mg L-1 of benzocaine and temperatures of 22, 25, 28, and 31 °C. The effects were evaluated by measuring the induction time to deep and surgical anesthesia, recovery time, time to appetite return, and 96-h mortality rate. The higher temperatures (25, 28 and 31°C) provided shorter induction times to reach deep anesthesia and at 50 mg L-1 of benzocaine, the induction time was between 2 and 3 min. Juveniles at temperatures of 28 and 31 °C showed lower surgical anesthesia induction time at concentrations ranging from 60 to 80 mg L-1. Recovery time was longer at 22 °C at all concentrations. The time to appetite return occurred in the first 24 h after anesthesia and the 96-h mortality rate was lower than 10%. Under these conditions, for deep anesthesia, benzocaine concentration of 50 mg L-1 for water temperatures of 25, 28, and 31 °C and 60 mg L-1 for 22 °C are recommended. Surgical anesthesia can be performed with 50 mg L-1 of benzocaine at all four water temperatures. The differences documented in the present study underline the need for adequate concentrations of anesthetics depending on the prevalent water temperature for Neotropical fish species. This should be considered in recommendations for large-scale use.

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.

Aim We evaluated the longitudinal patterns in distribution of native and non-native fish species in a hydrologically fragmented and environmentally variable lowland temperate river. Methods Four sites representing contrasting habitat and environmental conditions were sampled: a clear water reservoir, a turbid water lagoon and two river reaches with clear and turbid waters each. Environmental variables were measured in situ and in the laboratory. Fishes were sampled using trammel and beach seine nets. Results Two main environmental scenarios were identified: the upstream reaches, with colder, clearer and nutrient-oxygen poor waters (reservoir and its downstream river) and the downstream reaches, where turbidity, dissolved oxygen, water temperature, conductivity and nutrients largely increased (lagoon and its downstream river). Fourteen species with a high non-native/native (4:10) ratio were collected. Non-native species (NNS) were confined to lentic conditions, where the silverside Odontesthes bonariensis dominated. Native species (NS) better thrive in lotic conditions where the turbid scenario further favored tolerant species. Environmental conditions also seemed to influence the distribution of NNS. Fish assemblage structure considering either, all species, NNS or NS significantly differed among sampled reaches and habitat (lentic-lotic) conditions. Total fish abundance was higher in lentic reaches. Species richness and diversity were favored by the turbid scenario. Beta diversity was mostly explained by the replacement component revealing the substitution of species as the main pattern of variation. Water conductivity, nitrates and dissolved oxygen were the most important predictor variables in the best and most frequent explanatory models of fish assemblage structures. Conclusions Our results revealed that a low diversified Neotropical fish fauna is disrupted by habitat fragmentation due to the creation of artificial impoundments and the introduction of NNS. Environmental conditions further modulate the fish assemblage structure by affecting the distribution of species where tolerant species were favored by turbid, nutrient-rich waters with higher conductivity and pH. Resumo: Objetivo Neste trabalho avaliamos os padrões longitudinais de distribuição de espécies nativas e não-nativas de peixes em um rio de planície fragmentado hidrologicamente e variável limnologicamente. Métodos Quatro locais representando condições ambientais e de habitat contrastantes foram amostrados: um reservatório de águas claras, uma lagoa de águas turvas e dois trechos do rio, um de águas claras e outro de águas turvas. As variáveis ambientais foram medidas in situ e no laboratório. Os peixes foram amostrados com redes de arrasto e de espera. Resultados Dois cenários ambientais foram identificados. Um à montante, com águas mais frias, claras e pobres em nutrientes e oxigênio dissolvido (o reservatório e o trecho do rio abaixo do mesmo) e outro, à jusante, onde a turbidez, oxigênio dissolvido, temperatura da água, condutividade e os nutrientes aumentaram consideravelmente (a lagoa e o trecho do rio abaixo da mesma). Quatorze espécies com uma alta proporção entre espécies não-nativas e nativas (4/10) foram coletadas. As espécies não-nativas (NNS) estiveram confinadas a condições lênticas, onde o peixe-rei Odontesthes bonariensis dominou as assembleias de peixes. As espécies nativas (NS) proliferaram melhor em condições lóticas onde o cenário de águas turvas favoreceu as espécies tolerantes. As condições ambientais também parecem ter influenciado a distribuição das NNS. A estrutura da assembleia de peixes considerando todas as espécies em conjunto ou NS e NNS em separado, foram significativamente diferentes entre os trechos amostrados e condições de habitat (lêntico-lótico). A abundância total de peixes foi maior em trechos lênticos. A riqueza de espécies e a diversidade foram favorecidas pelo cenário de turbidez. A análise da diversidade beta foi explicada em maior parte pelo turnover revelando a substituição de espécies como o principal padrão de variação. A condutividade elétrica da água, os nitratos e oxigênio dissolvido foram as variáveis preditivas mais importantes nos melhores e mais frequentes modelos explicativos das estruturas da assembleia de peixes. Conclusões Nossos resultados revelaram que uma fauna de peixes Neotropicais pouco diversificada é alterada pela fragmentação do habitat devido à construção de barragens e pela introdução de NNS. As condições ambientais modularam ainda mais a estrutura da assembleia de peixes afetando a distribuição de suas espécies onde as espécies tolerantes foram favorecidas por aguas turvas, ricas em nutrientes, com maior condutividade e pH.

Made available in DSpace on 2021-06-25T10:34:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Pacu (Piaractus mesopotamicus) belongs to the main native fish group of the continental aquaculture in South America. However, breeding programs are not available for this species. The estimation of parameters for different traits and in different environments are needed to set up optimized breeding programs Therefore, the objectives of this study were to estimate genetic parameters, to evaluate genotype by environment (GxE) interaction, and to identify morphotypes for growth traits in pacu, using an experimental data of a pedigreed population in Brazil. Data from 1380 individuals corresponding to 48 full-sib families for ten growth traits (initial weight, final weight, average daily gain, total length, standard length, head length, pelvis length, total height, head height, height at the posterior region) were evaluated in two distinct environments (breeding nucleus: env1; commercial fish farm: env2) at 15 months old. The average of final weight was 591.90 ± 274.60 g in env1 and 1035.80 ± 270.00 g in env2. The heritability estimates were registered as moderate/high, which ranged from h2 = 0.27 ± 0.12 to 0.74 ± 0.19. Correlation values between the growth traits were positive and low-high, ranging between 0.32 ± 0.04 to 0.96 ± 0.10 (phenotypic) and 0.33 ± 0.10 to 0.98 ± 0.01 (genetic). The genetic correlations between final weight and morphometric traits were significant and high (ranging from 0.70 ± 0.10 to 0.88 ± 0.05). Our results also revealed different morphotypes patterns for pacu (elliptical and rounded). GxE interaction was considered low for all traits between the two environments (correlation values of 0.80 ± 0.34 to 0.98 ± 0.23). In conclusion, our results suggest that growth traits can be incorporated into the breeding objective in pacu and superior animals evaluated at the breeding nucleus are predicted to be superior at the commercial environment. Moreover, selection can be driven according to the desired morphotype in pacu. São Paulo State University (Unesp) Aquaculture Center of Unesp São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences National Council for Scientific and Technological Development (CNPq) São Paulo State University (Unesp) Aquaculture Center of Unesp São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences FAPESP: 2016/21011-9 CNPq: 311559/2018-2

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)

Freshwater fish communities in Ecuador exhibit some of the highest levels of diversity and endemism in the Neotropics. Unfortunately, aquatic ecosystems in the country are under serious threat and conditions are deteriorating. In 2018–19, the government of Ecuador sponsored a series of workshops to examine the conservation status of Ecuador''s freshwater fishes. Concerns were identified for 35 species, most of which are native to the Amazon region, and overfishing of Amazonian pimelodid catfishes emerged as a major issue. However, much of the information needed to make decisions across fish groups and regions was not available, hindering the process and highlighting the need for a review of the conservation threats to Ecuador''s freshwater fishes. Here, we review how the physical alteration of rivers, deforestation, wetland and floodplain degradation, agricultural and urban water pollution, mining, oil extraction, dams, overfishing, introduced species and climate change are affecting freshwater fishes in Ecuador. Although many of these factors affect fishes throughout the Neotropics, the lack of data on Ecuadorian fish communities is staggering and highlights the urgent need for more research. We also make recommendations, including the need for proper enforcement of existing environmental laws, restoration of degraded aquatic ecosystems, establishment of a national monitoring system for freshwater ecosystems, investment in research to fill gaps in knowledge, and encouragement of public engagement in citizen science and conservation efforts. Freshwater fishes are an important component of the cultural and biological legacy of the Ecuadorian people. Conserving them for future generations is critical. © 2021 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.

This study focused on the distribution of fish with high reproductive activity along a basin, using a 430 km stretch of the Cuiaba River in Brazil as a model. The main objective of this study was to identify those fish that migrate long distances for reproduction, among all the basin species. Thus, a set of working criteria are proposed to classify species according to their reproductive behaviour (i.e., reproductive activity and distribution). Samplings were performed in the Cuiaba River basin, encompassing several environments (river, channels and lakes) during the reproductive periods (between October and February), from 2000 to 2004. Species occurrence (presence and absence - proxy of distribution) across the basin and index of reproductive activity values were used as criteria to identify the species that perform long-distance longitudinal migrations for reproduction. The study confirmed the classification of long-distance longitudinal migration species; nonetheless, some species were not classified as described in the literature. The proposed sequential criteria have proven to be effective in the classification of long-distance longitudinal migrations species and certainly contribute to filling some existing knowledge gaps of reproductive traits. This classification is of fundamental importance in planning new dam projects, in decision making and in the development of management and conservation actions for the ichthyofauna.

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.

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

Globally, ornamental aquaculture is a multi-million-dollar industry and popular hobby. There are circa 6700 fish taxa being exploited and traded. Various species are traded under commercial names or codes such as certain armoured catfish of families Callichthyidae (C and CW codes or numbers) and Loricariidae (L and LDA codes). Many of these species are imported, reared and multiplied in captivity without their species identification. Here we present a detailed survey of this group of armoured catfish with a special focus on pairing of commercial codes with scientific names. In this context, both species with valid names and scientifically undescribed taxa contributed significantly to the total number of ornamental fish species by circa 25%. In total, 176 species of loricariids and 47 species of small callichthyids were paired with codes used in ornamental aquaculture. The total number of loricariids introduced as ornamentals was estimated to be more than 1000 taxa while more than 500 in small callichthyids. We recommend present findings to all stakeholders and especially taxonomists, conservationists and wildlife managers who are focused on this group of Neotropical fishes. Moreover, formal descriptions of unidentified taxa are required for feasible future monitoring and appropriate management measures of wild populations.

Biotelemetry, ichthyoplankton and genetic data can provide detailed information about the migratory dynamics and reproductive cycle of freshwater fishes. However, few studies have combined these techniques in Neotropical systems. The objective of this study was to examine the migratory and reproductive dynamics of Prochilodus costatus in the Sao Francisco River watershed, south‐east Brazil, by comparing the ecological importance of two rivers to the species, an undammed segment of the Sao Francisco River and a dammed segment of one of its main tributaries, the Para River. In total, 215 fish were radio‐tagged over three years (2014–16). Eggs and larvae were sampled at seven locations and analysed by PCR to identify Prochilodus spp. ichthyoplankton. Most radio‐tagged individuals (97%) used the undammed segment of the Sao Francisco River as spawning migration route, even those captured and released in the Para River. Fish migrated to spawn from late September to late November with the arrival of the rains and returned to feeding sites from December to May after spawning. The highest densities of fish eggs and larvae were recorded in the upper reaches of the Sao Francisco River during months of peak river discharge. Returning fish showed high fidelity to sites occupied before spawning migration. Fish spent roughly 71% of the year at feeding sites, 25% at spawning sites and 4% moving between them. This study provides novel information about the migratory dynamics of Neotropical fishes and underscores the key role of undammed river segments for the conservation of Neotropical migratory fish species.

Digestive flexibility is considered an adaptive response that allows individuals to minimise maintenance costs during periods of food scarcity. Here, we evaluated changes in body condition and digestive (and energy storage) organs size during short-term (7 days) fasting in Jenynsia multidentata. Also, we analysed changes in the isotopic composition and C:N ratio (a proxy of lipids content) in the intestine, liver and muscle. Fasted animals were compared against two feeding groups: field animals and animals fed ad libitum in the laboratory. We found that intestinal length was larger in feeding and field animals than in fasting fish, while intestine and liver masses were heavier in feeding animals, followed by field animals and then by fasting individuals. Liver and intestine δ15N was higher in fasting fish than in field animals, but δ13C did not differ between both groups. Finally, body condition, C:N ratios and perivisceral fat mass, were greater in feeding and field individuals than in fasting animals. This way, our results indicate that (i) changes in digestive and energy storage organs size during fasting in fish are ubiquitous and noticeable, and (ii) nutritional status of animals should be taken in account for a proper interpretation of stable isotope results, particularly for splanchnic tissues (such as intestine and liver).

The Gymnotus inaequilabiatus is a Neotropical fish widely distributed in marginal areas of bays. The aim of this study was to describe the main histological and histopathological traits in the head and exocrine kidney. Here, histometric and structural density techniques were associated with renosomatic index (RSI). The kidney was processed for light microscopy. Lipofuscin and hemosiderin content were visually estimated in the melonomacrophages centers (MMCs). All the biometric body variables were correlated with RSI, especially the kidney weight and gross lesions count. The general architecture of head and exocrine kidney was similar to that described for other teleost species. MMCs were prevalent in both portions and correlated with RSI in the head and exocrine kidney. Granulomatous structures were often observed in both portions; however, they were associated only in the exocrine kidney with RSI. Of all the structures hystometrically estimated, only proximal tubular diameter and thickness, and distal tubular thickness were correlated to renosomatic index. The RSI is an useful biometric variable that represent some physiological and morphological characteristics of kidney in G. inaequilabiatus. These findings may be used in future studies to evaluate the effects of environmental stressors on the renal adaptative physiological process. RESUMO Gymnotus inaequilabiatus é um peixe neotropical amplamente distribuído em áreas marginais de baías. O objetivo deste estudo foi descrever características anatômicas, histológicas e histopatológicas no rim cefálico e exócrino. Análises histométricas e a densidade volumétrica estrutural foram associadas ao índice renossomático (IRS). Fragmentos de ambos tecidos foram processados para análise e microscopia de campo claro. O conteúdo de lipofuscina e hemossiderina foi estimado visualmente nos centros de melanomacrófagos (CMMs). Todas as variáveis corporais biométricas foram correlacionadas com o IRS, principalmente o peso renal e a contagem de lesões superficiais. A arquitetura geral do rim cefálico e exócrino foi semelhante à descrita para outras espécies de teleósteos. Os CMMs foram frequentes em ambas as porções e correlacionaram-se com o IRS. Estruturas granulomatosas foram frequentemente observadas em ambas porções; no entanto, foram associadas ao IRS apenas no rim exócrino. De todas as estruturas estimadas histometricamente, apenas o diâmetro e espessura dos túbulos proximais e distais correlacionaram-se ao IRS. Este índice mostrou-se uma variável útil associada a características fisiológicas e morfológicas do rim de G. inaequilabiatus. Esses achados podem ser empregados em futuros estudos a fim de avaliar efeitos ambientais bem como processos adaptativos fisiológicos.

The arrival of the rains and the hydrological changes they cause are essential in the reproductive cycle of Neotropical migratory fishes, but their association with the onset of migration is still poorly understood. This study aimed to determine the role played by rainfall, hydrological changes, and the lunar cycle as triggers for migration of Prochilodus costatus (Prochilodontidae) in the upper Sao Francisco River, Brazil. In total, 132 individuals were fitted with radiotelemetry transmitters over three consecutive spawning seasons. Spawning migration began with the onset of the rains from late September to mid-December. Individuals exhibited a strong preference for initiating migration at the beginning of the rainy season, when river discharge is low, in days with positive changes in water level, and at times of new or waxing moon. The fraction of the population that initiates migration each year appears to be dependent on rainfall, indicating that P. costatus may be a partial migrant. The results show that P. costatus and, possibly, other migratory Neotropical fish, rely on different but interconnected environmental cues to trigger their spawning migration, ensuring that individuals migrate in time to reach their spawning grounds and find appropriate environmental conditions for spawning.

A new species of the genus Sturisoma from the Madre de Dios River, upper Madeira, Peru, is described. The new species can be differentiated from its congeners by the following characteristics: dorsolateral stripe reaching to less than half, or only half length of caudal peduncle (v. absence of dorsolateral stripe or, if present, spanning more than half caudal-peduncle length); premaxillary teeth longer than dentary teeth (v. dentary teeth longer); sexually mature adult males having well-developed odontodes on the sides of the head and a broader snout (v. adult males lacking well-developed hypertrophied odontodes or, if present, rostrum is same width as females' or immature males'); by having the ventral portion of the rostrum conspicuously darker than ventral surface of the body (v. rostrum light, with same colour as ventral portion of body, except in Sturisoma barbatum); by lacking the lateral process of the sphenotic (v. lateral process of sphenotic well-developed, except in Sturisoma tenuirostre); a dark spot on the first three branched pectoral-fin rays (v. brown spot absent, except in S. barbatum); and the frontal bone contributing less than half of dorsal border of the orbital ridge (v. extensive participation of the frontal, except in Sturisoma guentheri). Furthermore, the new species has 18-20 plates in the median series, which differentiates it from Sturisoma rostratum (21-22), and Sturisoma monopelte (21); and 14-15 coalescent plates, which differentiates it from S. tenuirostre (16-17). It is further differentiated from Sturisoma brevirostre by presence of an enlarged rostrum (v. rostrum not enlarged). A discussion regarding status of the type series and geographic distribution of Sturisoma rostratum is offered, and an identification key for all Sturisoma species is presented.

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and the insecticide fipronil have been used widely in agriculture and detected in aquatic ecosystems, where they threaten wildlife. This study evaluated the whole-body bioconcentration and the biochemical and morphological changes in the gills of the neotropical fish Prochilodus lineatus exposed for 96 h to 2,4-D or fipronil as single compounds or as a mixture (2,4-D + fipronil). Fish exposed to either compound alone bioconcentrated 2,4-D (77 ± 23 ng g − 1 fish dry mass) and fipronil (789 ± 178 ng g − 1 fish dry mass). Fish exposed to 2,4-D + fipronil bioconcentrated fipronil (683 ± 73 ng g − 1 fish dry mass) but not 2,4-D. In the gills, catalase (CAT) and glutathione-S-transferase (GST) activities and the lipid peroxidation (LPO) level increased after exposure to 2,4-D. GST activity increased after exposure to fipronil. Conversely, no changes occurred in CAT and GST activities and LPO upon exposure to 2,4-D + fipronil. Histopathological changes such as hyperplasia, cellular hypertrophy, epithelial lifting, and vascular congestion were frequent in the gills of fish exposed to 2,4-D or fipronil individually or 2,4-D + fipronil. The mitochondria-rich cell (MRC) density increased on gill surface in fish exposed to fipronil or 2,4-D + fipronil. Only exposure to 2,4-D alone induced oxidative stress in the gills. Most morphological changes showed defense responses against the pesticides; however, hypertrophy and the change in MRC indicated compensatory responses to maintain the gill osmoregulatory function. The 2,4-D + fipronil mixture showed antagonistic interaction, except for the MRC fractional area at gill surface, which showed synergistic interaction. This is the first report showing antagonistic interaction of 2,4-D and fipronil in the gills after exposing fish to the mixture of both pesticides. The biochemical and morphological changes in gills endanger the gill functions, a phenomenon that implies an energy cost for fish.

Fish farming has grown rapidly in Brazil over the last two decades, due in part to the availability of water and species with potential for cultivation, such as Colossoma macropomum. This farmed fi...

The expansion of urban centers, the increase in the use of chemicals in agriculture, and the significant expansion of industry has dumped increasing amounts of heavy metals into aquatic ecosystems, directly and indirectly affecting the entire food web in freshwater environments. In freshwater fish, many studies conducted worldwide have shown that these pollutants can cause alterations from the molecular level to behavioral, in all stages of life, including in future generations. Despite the great diversity of freshwater fish in the Neotropical region, few studies addressing the influence of metals on native species have been carried out. The last decade of studies showed that the effects of metals in neotropical species can be from the molecular to the behavioral level. Metals like Arsenic, Cadmium, Copper, Lead, Mercury, Chromium and Zinc have often been detected in environmental studies and evaluated in experimental approaches. Metabolically active organs showed higher levels of accumulation. In addition, some environmental studies have shown that ecologic and trophic conditions can be determinant in the level of exposure to metals. Oxidative stress, genotoxicity and several histopathological alterations were the most recurrent effects detected in target organs.

Bryconamericus is a highly diverse group of characid fishes, being cytogenetic a valuable tool for the delimitation of species. Bryconamericus aff. iheringii (Upper Uruguay/Lower Paraná), B. coeruleus (Upper Paraná), B. cf. ecai e B. cf. eigenmanni (Upper Uruguay) were studied cytogenetically, and presented 2n=52 chromosomes, with interpopulational/interspecific variation of karyotype and fundamental number. Heterochromatin was evidenced in pericentromeric, telomeric and interstitial regions, and it was shown to be an important cytogenetic marker. Single nucleolar organizing regions (NORs) were found in B. cf. eigenmanni, B. cf. ecai and B. aff. iheringii (Lower Paraná), and multiple in B. aff. iheringii (Upper Uruguay) and B. coeruleus, with occurrence of two patterns for the first species, and three for the second. The 5S/18S rDNA-FISH confirmed the location of the NORs and showed single 5S rDNA cistrons only in B. aff. iheringii (Lower Paraná), evidencing the dispersion of both genes, often co-located, in the karyotype of the others species. The data of this work contribute for the delimitation of the species of the genus. Co-localization of ribosomal genes may represent a plesiomorphic condition for the group, and their dispersion suggest the occurrence of duplication, pseudogeneization and transposition events mediated by mobile genetic elements. RESUMO Bryconamericus é um grupo altamente diverso de caracídeos, sendo a citogenética uma valiosa ferramenta para a delimitação de espécies. Bryconamericus aff. iheringii (Alto Uruguai/Baixo Paraná), B. coeruleus (Alto Paraná), B. cf. ecai e B. cf. eigenmanni (Alto Uruguai) foram estudados citogeneticamente, e apresentaram 2n=52 cromossomos, com variação interpopulacional/interespecífica de cariótipo e número fundamental (NF). Heterocromatinas foram evidenciadas nas regiões pericentromérica, telomérica e intersticial, e mostrou-se um importante marcador citogenético. Regiões organizadores de nuclcéolos (RONs) simples foram encontradas em B. cf. eigenmanni, B. cf. ecai e B. aff. iheringii (Baixo Paraná), e múltiplas em B. aff. iheringii (Alto Uruguai) e em B. coeruleus, com a ocorrência de dois padrões de localização para a primeira espécie, e três para a segunda. A FISH-DNAr 5S/18S confirmou a localização das RONs e mostrou cístrons simples de DNAr 5S apenas em B. aff. iheringii (Baixo Paraná), evidenciando a dispersão de ambos os genes, muitas vezes co-localizados, no cariótipo das demais espécies. Os dados deste trabalho contribuem para a delimitação das espécies do gênero. A co-localização dos genes ribossomais pode representar uma condição plesiomórfica para o grupo, e sua dispersão sugere a ocorrência de eventos de duplicação, pseudogenização e transposição mediada por elementos genéticos móveis.

Brycon nattereri is an endangered Neotropical fish reported along conserved stretches of the upper Paraná, Tocantins and São Francisco rivers. Populations of this species have been very rare in some Paraná River sub basins. This study analyzes the genetic diversity and population structure of B. nattereri in a restricted area of occurrence recently identified in upper Paraná River basin. Seven microsatellite loci and 497 bp of D-Loop mitochondrial region were examined in 92 individuals from four points along the area of occurrence. Both molecular markers indicated a single population distributed along a stretch of the river approximately 80 km long. Although some of the data suggest an ancient bottleneck, current levels of genetic diversity (H E = 0.574 and h = 0.616) were similar to those of other species of the genus Brycon. The results suggest that the population of B. nattereri has been able to maintain satisfactory levels of genetic diversity, in spite of the small area of occurrence. These data have highlighted an important conservation area and action may prove essential to improve the quality of the environment, and especially the water and riparian plant life, if the area is to be managed and conserved efficiently.

A new species of Phenacogaster is described from the rio Salitre, a tributary of the lower middle rio São Francisco drainage. The new species can be clearly distinguished from all its congeners in having a conspicuous, broad caudal peduncle spot reaching the upper and lower margins of the peduncle with a short extension onto the middle caudal fin rays and another weaker extension over the lower lobe of the caudal fin. RESUMO Uma nova espécie de Phenacogaster é descrita do rio Salitre, afluente da drenagem do submédio rio São Francisco. A nova espécie é facilmente distinguida de todas as congêneres por apresentar uma conspícua e larga mancha no pedúnculo caudal que alcança as margens superior e inferior do pedúnculo com uma curta extensão sobre os raios medianos e outra mais fraca sobre o lobo inferior da nadadeira caudal.

Colostrum is a source of molecules with nutraceutical features that can attenuate the consequences of adverse conditions, such as densification. Thus, the redox balance and tissue development of juvenile Piaractus mesopotamicus subjected to high stocking density and fed diets containing lyophilized bovine colostrum (LBC) were evaluated. Juveniles were distributed into 16 cages making 50 kg fish m -3 and fed diets containing 0, 10, 20 and 30% inclusion of LBC (n = 4). After 30 days, enteric, hepatic, muscular, renal and branchial tissue were sampled for the determination of glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase activity, oxygen radical absorbance capacity (ORAC), lipid peroxidation and protein and nucleotides content. SOD activity and DNA content were higher in 20% LBC compared to the others in the enteric tissue ( P < 0.10). ORAC value in erythrocytes was higher in 30% LBC than 0 and 10% LBC ( P < 0.10). Juveniles fed 10% LBC showed higher lipid peroxidation in liver than 0 and 20% LBC ( P < 0.10) and those fed 20% LBC showed lower protein/RNA ratio compared to the others ( P < 0.10). Bovine colostrum determined a decrease in liver protein synthesis and increased in intestinal DNA content with an intake of 20% of this milk secretion. Additionally, LBC increased the protection of the enteric tissue of juveniles from superoxide radicals and blood antioxidant capacity. We conclude that bovine colostrum can be used as a nutraceutical food for fish, with positive effect in redox balance and tissue development in high concentrations of inclusion in the diet, 20 and 30%.

Astyanax fasciatus is a group of neotropical fish with two different diploid chromosome numbers, and in the wild, these individuals are found in sympatry. The annual reproductive cycles of adult females of species with different numbers of chromosomes (G1: 46 chromosomes, low responsiveness to induced spawning; G2: 48 chromosomes, responsive to induced spawning) were investigated in the wild and in captivity. Plasma estradiol (E2) levels, relative fecundity (RF), oocyte diameter, gonadosomatic index, and ovarian morpho-histology were evaluated to identify the ovarian maturation stage. The G1 females in both environments began the vitellogenic phase during winter, concurrent with increased plasma E2 levels. In wild G1 females, large numbers of vitellogenic oocytes were observed during spring and summer, when plasma E2 levels remained high. In contrast, captive G1 females showed higher E2 levels during the winter. They also retained significantly higher RF and vitellogenic oocyte numbers than wild females, but showed no spawning and slow yolk reabsorption. Wild G2 females began the vitellogenic phase in autumn and had progressively increasing E2 levels that peaked in the spring, with spawning occurring during the summer. In captive G2 females, the E2 levels and RF remained high throughout the year. These data suggest that A. aff. fasciatus with different numbers of chromosomes differ in their reproductive performance in the wild and show altered sensitivity to environmental cues in captivity. Our results indicate that G1 females likely respond best to artificial spawning just after winter, whereas G2 females should respond year-round.

Photoperiod is considered an important synchronizer of biological activities and endocrine pathways, including growth. As ectotherms, fish have many physiological functions controlled by the photoperiod. However, the combined effects of photoperiod and temperature should be clarified, particularly for tropical fish living near their upper thermal limit, as is the case of Amazonian fish. The central aim of this study was to evaluate the combined effect of photoperiod and temperature on growth and physiological aspects of tambaqui (Colossoma macropomum). Juveniles of tambaqui were distributed in 70 L tank, following a factorial design that included three photoperiods (light 0 h: darkness 24 h; light 12 h: darkness 12 h; and light 18 h: darkness 6 h) associated with three temperatures (26, 29 and 32 oC). They were maintained under these conditions for two months. Fish reared in the dark at 29 and 32 oC showed better performance compared to fish reared under extended light conditions at all temperatures. Among physiological responses, it has been observed that blood parameters tend to be disturbed with increasing temperature and that extended light conditions at low temperatures caused similar effects on the analyzed fish, suggesting blood hemoconcentration. Fish under extended light conditions showed an increase in glucose, cortisol, cholesterol and total proteins, indicating additional physiological disturbances. In conclusion, our study shows that, unlike marine and temperate fish, C. macropomum, a fish species endemic to the Amazon, grows better in warmth dark, showing no significant physiological disturbances, similar to observations described for wild animals of this species. Our results support that changes in fish growth occur in response to environmental conditions. Therefore, fish species from freshwater, estuarine and marine environments, must be specifically analyzed regarding the combination effects of photoperiod and temperature.

Brazil has more than 700 large reservoirs distributed in all of the major river basins of South America. Most dams were constructed to produce electricity. Although these reservoirs favor the development of local and regional economies, they seriously impact the aquatic biota. An unavoidable consequence is the change in the composition and abundance of species, with the proliferation of some and reduction or even local extinction of others. The intensity and nature of these changes are related to peculiarities of the local biota and the location, morphometric and hydrological characteristics of the reservoir, dam operation and interactions with other uses of the basin, including other reservoirs. These impacts exhibit substantial spatiotemporal variations. The filling phase is marked by abrupt and intense changes in the key attributes of aquatic habitats, followed by predominantly heterotrophic processes, with possible thermal stratification and anoxic conditions. Fish richness increases soon after filling and decreases in subsequent years. Trophic depletion is expected, and diversity gradients are intensified toward more lentic stretches, the average length of fish decreases, and the fish fauna becomes dominated by species with sedentary strategies and/or parental care. The virtual absence of species with pre-adaptations to inhabit lentic areas of large reservoirs leads to a concentration of biomass in shallow littoral areas. Long-distance migratory species are the most affected, which include larger fish with high market value. Migratory species require different biotopes to fulfill their life cycles and strongly depend on the seasonal flood regime, which is altered due to dam operation. In this study, we discuss the details of these trends as well as the mitigation measures and management actions that are practiced in Brazil. We conclude that these actions have not promoted the conservation of fish; on the contrary, some of them have generated additional impacts. As a consequence, the conservation of Neotropical fish and aquatic resources is severely threatened.

Several studies have shown that fish assemblages are structured by habitat features, most of them have proposed that there is a positive relationship between habitat structural complexity and species diversity. In this study, we aimed to test this positive-relationship idea in three habitats types (creeks, oxbow lakes and river sandbanks) distributed along the Bita River Basin in South America. Standardized surveys were conducted during January and February of 2016 (low water period) in 30 sites distributed along the entire basin. We recorded 23,092 individuals representing 191 species. To investigate possible relationships between habitat structural complexity and species diversity, we calculated the first three Hill’s numbers, and performed a Non-metric Multidimensional Scaling (NMDS), a Principal Component Analysis (PCA) and a Canonical Correspondence Analysis (CCA). Our results showed that river sandbanks and creeks had the highest species richness. Results from the NMDS analysis (stress = 0.19) showed that fish community composition was different in the assessed habitats (ANOSIM

Made available in DSpace on 2019-10-06T16:47:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-15 Made available in DSpace on 2019-10-06T16:47:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Pacu (Piaractus mesopotamicus) is one of the main farmed freshwater fish species of South America. Disease outbreaks caused by Aeromonas hydrophila are considered one of the major bottlenecks for the development of pacu production. Genetic selection for disease resistance may represent a sustainable and effective alternative to reduce mortality and, therefore, improve productive performance of pacu. To verify whether A. hydrophila resistance can be included in genetic selection programs, the estimation of genetic parameters is needed. The aim of this study was to estimate variance components and heritability for A. hydrophila resistance in pacu, through experimental challenge performed in 36 full-sib families, resulting in the analysis of 1094 individuals. During 14 days of challenge, survival rate (TS) and time of death (TD) of fish presenting clinical signs of A. hydrophila infection were recorded. No influence of weight on TS or TD was detected. Genetic data were analyzed with two different univariate animal models using TS and TD. The total cumulative TS varied considerably among families (0 to 65.5%), which indicated a significant phenotypic variation related to resistance to A. hydrophila infection. TD ranged from 313 to 14,846 min, with an average of 1722 ± 1476 min. Low values for heritability were found for TS and TD (0.15 ± 0.05 and 0.12 ± 0.05, respectively). Our results represent the first report of genetic parameters for disease resistance in a Neotropical fish species and indicate that resistance against A. hydrophila in pacu might be improved through selection breeding. São Paulo State University (Unesp) Aquaculture Center of Unesp São Paulo State University (Unesp) Campus of Registro Facultad de Ciencias Veterinarias y Pecuarias Universidad de Chile São Paulo State University (Unesp) Aquaculture Center of Unesp São Paulo State University (Unesp) Campus of Registro CAPES: 001 CNPq: 140740/2016-3 FAPESP: 2016/18294-9 FAPESP: 2016/21011-9 CNPq: 311559/2018-2

In several genera, the otolith shape is species-specific and the use of thisstructure provides a useful tool aiding in the species identification. In manystudies regarding Neotropical fish fauna, species of the genus Astyanax arecommonly identified at the genus level, mainly due to the phenotypicplasticity of the morphological characters traditionally used for speciesdetermination. In consequence, additional tools intended to better elucidatethe taxonomic boundaries between species of Astyanax are certainly needed. In the last decade, the shape of otoliths has allowed to discriminate among closely related species. In this work, Fourier descriptors and shape indices of lapillus otolith were evaluated for the discrimination among three sympatric species of genus Astyanax inhabiting streams of the Atlantic Rain Forest (Argentina). Aspect ratio, roundness and ellipticity of otoliths were significantly different between the species (p < 0.05) while, no significant differences were found for circularity, rectangularity and form factor (p > 0.05). PERMANOVA analysis reveal significant differences between species using Fourier descriptors (F = 96.7, 0.0001 < p < 0.02) and the reclassification rates of quadratic discriminant analysis were high, averaging 86.3% (82.7 and- 88.6%). Multivariate analyses of shape indices were not effective to discriminate between species. Instead, high classification percentages suggest that the otolith outline is a potential tool for the identification of sympatric morphologically similar species of Astyanax. Our results could contribute to future taxonomic andphylogenetic studies and may be an interesting input for both paleontological and trophic studies in sympatric species. Fil: Avigliano, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina Fil: Rolón, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina Fil: Rosso, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Mabragaña, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Volpedo, Alejandra Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina

Made available in DSpace on 2018-11-26T17:48:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-10 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) The present study aimed to evaluate the effect of dietary linoleic acid to linolenic acid (LNA/ALA) ratio on growth performance, feed utilization, plasma metabolite profiles, and muscle and liver fatty acid profiles of juvenile tambaqui Colossoma macropomum. Six diets were formulated to contain incremental levels of corn oil (rich in LNA) from 0 to 7% at the expense of linseed oil (rich in ALA), resulting in dietary LNA/ALA ratios ranging from 3.1 to 26.9. A control diet including fish oil was also formulated. The trial lasted 49 days, and each diet was assigned to six groups of fish with an initial body weight of 43 g. At the end of the trial, dietary LNA/ALA ratio did not affect growth performance, feed utilization, and plasma metabolites profile, except for HDL that was lower in fish fed the 3.8 LNA/ALA diet than the 3.1 or 5.0 LNA/ALA diets. Whole-body protein content was lower in fish fed the control and 3.1 LNA/ALA diets. Composition of triglycerides, glucose and protein of liver and muscle was unaffected by dietary treatments. Eicosapentaeneoic acid (EPA, 20: 5n-3) plus docosahexaenoic acid, (DHA, 22: 6n-3) content of muscle decreased with the increase of LNA/ALA ratio. Fish fed 3.9-5.6 LNA/ALA diet showed the highest concentration of muscle ARA (arachidonic acid, 20: 4n-6) and EPA+ DHA among vegetable oil diets, though lower than that of fish fed the fish oil based diet. In conclusion, dietary LNA/ALA ratio should range between 3.9-5.6 to produce fillets with high EPA, DHA, and ARA contents, thus improving the nutritional quality of tambaqui fillets for human consumers. Univ Fed Lavras, UFLA, Dept Zootecnia, Lavras, MG, Brazil Univ Porto, Fac Ciencias, Dept Biol, Porto, Portugal Univ Estadual Paulista, Dept Zootecnia, Fac Ciencias Agr & Vet Jaboticabal, Jaboticabal, SP, Brazil Ctr Invest Marinha & Ambiental, CIIMAR, Terminal Cruzeiros, Matosinhos, Portugal Univ Estadual Paulista, Dept Zootecnia, Fac Ciencias Agr & Vet Jaboticabal, Jaboticabal, SP, Brazil CNPq: 140740/2013-9 CAPES: 99999.010687/2014-09 FAPEMIG: PPM 00227/12

Data on 15 novel microsatellite loci from the Neotropical fish Bryconamericus aff. iheringii are presented here. Analyses of 32 individuals from four different streams revealed 192 different alleles, ranging from four to 32 alleles per locus (mean of 12.8 per locus). Observed and expected heterozygosities ranged from 0.094 to 0.813 and 0.205 to 0.952, respectively. These loci showed high polymorphic information content and will be a resource for genetic studies of B. aff. iheringii. Furthermore, several loci also amplified other small Neotropical Characidae (Piabarchus stramineus and Piabina argentea) and should be useful for these species. RESUMO Um total de quinze novos locos microssatélites é aqui apresentado para o pequeno peixe Neotropical Bryconamericus aff. iheringii. A análise de 32 indivíduos provenientes de quatro ribeirões diferentes revelou 192 alelos diferentes, variando de quatro a 32 alelos por loco (média de 12,8 por loco), e heterozigozidades observada e esperada variando de 0,094 a 0,813 e 0,205 a 0,952, respectivamente. O conjunto de locos obtido mostrou alto conteúdo de informação polimórfica e bom potencial para estudos genéticos de B. aff. iheringii, além disso vários locos amplificaram para outras espécies de pequenos Characidae neotropicais (Piabarchus stramineus and Piabina argentea).

Aim β diversity was used as an indicator to test the hypothesis that a fishway can increase river connectivity, as a reduction in the value of this metric indicates greater similarity among fish assemblages. Methods Quarterly sampling was performed with gillnets upstream and downstream of the Porto Primavera dam, Upper Paraná Basin, before the opening of the fishway between February 1999 and May 2001, and between February 2003 and May 2005 with the fishway in operation (10 samples per period/site). The correlation between the fish assemblages and sites was verified by applying two Mantel tests (downstream versus upstream before and one equivalent after the fishway) using the distance matrices generated by the Bray‐Curtis index. The β diversity between downstream and upstream was calculated using the Sørensen index for each sample for the comparison of such values before and after the operation of the fishway, which were tested with Asymptotic Wilcoxon-Mann-Whitney Test. To summarize changes in the structure of the fish assemblages between the sites and periods nonmetric multidimensional scaling (NMDS) was applied based on Bray-Curtis dissimilarities, using multi-response permutation procedures (MRPP). Results The Mantel tests showed no correlation between the upstream and downstream assemblages before the operation of the fishway but greater correlation after. β diversity was lower after than before the fishway, representing an increase in similarity between downstream and upstream with the fishway. MRPP analysis indicated that the fish assemblages between the sites differed more than was expected by chance, with smaller divergence between the sampling sites after the fishway (A = 0.08) than before it opened (A = 0.09). Conclusions Although fishways remain an incipient and controversial theme for neotropical fish, the Porto Primavera fishway appears to be effective in terms of the restoration of connectivity. Resumo Objetivo Testamos a hipótese de que sistemas de transposição de peixes (STP) aumentam a conectividade fluvial usando a diversidade β como indicador, uma vez que valores mais baixos dessa métrica indicam maior similaridade entre as assembleias de peixes. Métodos Coletas trimestrais com redes de emalhar foram realizadas em uma área a jusante e outra a montante da barragem de Porto Primavera, bacia do Alto Paraná, antes (fevereiro/1999 a maio/2001) e após (fevereiro/2003 a maio/2005) o início de operação do STP. Inicialmente verificamos a correlação das assembleias de peixes entre as áreas aplicando dois testes de Mantel (jusante versus montante, antes e após a operação do STP), usando matrizes de distância geradas a partir do índice de Bray-Curtis. A seguir calculamos a diversidade β usando o índice de Sørensen entre jusante e montante, visando comparar os valores antes e após a operação do STP, com aferição pelo teste Assintótico Wilcoxon-Mann-Whitney. Para sumarizar as alterações de estrutura da assembleia entre áreas e períodos foi aplicado um escalonamento multidimensional não-métrico (NMDS) baseado nas dissimilaridades de Bray-Curtis, com uso de procedimentos de permutação multi-resposta (MRPP). Resultados Os testes de Mantel demonstraram ausência de correlação entre as assembleias de jusante e montante antes da operação do STP e existência de correlação após. A diversidade β apresentou valores inferiores antes em relação à depois, evidenciando o incremento da similaridade entre jusante e montante após a operação do STP. A análise por MRPP indicou que as alterações nas assembleias de peixes entre as áreas não foram ao acaso, ocorrendo diferenças menores após (A = 0.08) a abertura do STP que antes (A = 0.09). Conclusões Embora as passagens para peixes continuem a ser um tema incipiente e controverso para a região Neotropical, o STP de Porto Primavera provavelmente é efetivo no aspecto de restauração da conectividade.