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Spatial and temporal distribution of larvae and juveniles of trahira, Hoplias aff. malabaricus (Erythrinidae), and their relationship with environmental parameters in the Upper Paraná River floodplain were analyzed. Sampling of larvae and juveniles of H. aff. malabaricus has been conducted during the period from November 1991 through February 1995, with 42 sampling stations distributed in four sub-areas: Ivinhema I, Ivinhema II, Baía, and Paraná. During the same period, data were obtained for water temperature, dissolved oxygen, pH, electrical conductivity, river level, precipitation index, and photoperiod. The largest catches of larvae were in the Ivinhema I sub-area (47.06%), and of juveniles in the Paraná sub-area (54.55%). Larvae and juveniles were caught from October to February. Larvae were mainly collected at night and in all types of environments sampled (lotic, semi-lotic, and lentic). Principal Component Analysis of the environmental parameters and larval density showed that the largest catches were obtained in dry season months, with low values for temperature, electrical conductivity, river level, and photoperiod, and with high concentrations of dissolved oxygen and pH. This reproductive strategy may minimizes predation and maximizes food utilization, as it enables the fish to reach advanced developmental stages, while most other species are spawning.

Diets of fish larvae may vary within populations and among species and are affected by larval prey availability and foraging capacity. We aimed to describe the diet of fish larvae based on empirical field observations, emphasizing the interaction and organization of the predator–prey network using Auchenipterus osteomystax as a species model. The network showed few interactions (low connectance and modularity) but a nested structure (some items that had fewer records tended to occur together with the most frequent ones), low complementary specialization (the proportions of ingested items tended to be equivalent) and a pattern of segregation (some items tended not to be consumed together) in the use of resources among individuals. Robustness was low when the removal of prey with a higher consumption frequency occurred. The correlation between morphological variables and network attributes was significant and positive for abundance and strength, while the correlation with nested rank was negative. The availability of suitable dietary resources is likely to be the key factor for success and survival in the early stages of development. With changes in morphology during larval development, A. osteomystax showed a generalist position in the network as its predation capacity increased. A new approach to trophic ecology studies of fish larvae incorporating network analysis may help explain the individual characteristics of larvae and assess the pattern of interactions in the population. [ABSTRACT FROM AUTHOR]

In order to investigate the reproductive dynamics of the ichthyofauna in the Brazilian Pantanal, this study examines the spatial and temporal distribution of ichthyoplankton, taxonomic composition, and its correlation with environmental factors within one of the most important sub‐basins, the Taquari River. Egg and larvae collections were conducted at 11 sampling points between October and March of 2017/2018 and 2018/2019. Significant differences were observed between collection points, months, and years, with higher ichthyoplankton densities in the Coxim and Taquari rivers, particularly between November and January. Twenty‐eight genera and/or species of fish were identified, including 10 long‐distance migratory species. Egg density showed a negative correlation with water temperature and rainfall. For larvae, water transparency and rainfall were both significant, negatively influencing larval abundance. However, different species tend to occur in environments with distinct abiotic qualities. Yolk‐sac, preflexion, and flexion larval development stages were distributed throughout the sub‐basin, especially near the Pantanal. Considering the data and analyses presented in this study, the importance of connectivity between these environments, specifically between the plateau and Pantanal, is evident, highlighting the significance of the entire sub‐basin for fish reproductive processes. Therefore, research focusing on the ecological processes influencing the distribution of ichthyoplankton offers valuable insights for ecosystem conservation and aids in effective environmental management. [ABSTRACT FROM AUTHOR]

ABSTRACT The Characidium orientale Buckup & Reis, 1997 larvae development is described using specimens collected in the natural environment of Antas River, in the Taquari-Antas river basin, Rio Grande do Sul, Brazil. Were considerate ontogenetic changes in morphology, pigmentation, fin morphology, and meristic characters. Thirty-six larvae (33 in the preflexion stage, two in flexion, and one in the postflexion stage), with a standard length between 4.24 and 11.26 mm were analyzed. The larvae of C. orientale are altricial and present fusiform body, subterminal mouth, long intestine with anal opening posterior to the vertical line over the median region of the body. Two chromatophores are evident in the interorbital region, as well pigments concentrated on the side of the body, forming a longitudinal stripe, and between the rays of the caudal fin, which intensify during the development. Also, a conspicuous remnant of the embryonic membrane (finfold) in front of the dorsal fin appears to be characteristic of species of the genus during larval development. The total number of myomeres varies from 32 to 35 (18-23 pre; 11-16 postanal). The main changes in morphometry occur during the preflexion stage and suggest physiological and behavioral changes.

The formation of pharmacobezoars from suspensions of spray-dried amorphous solid dispersions (SD-ASDs) of new chemical entities (NCEs) and hydroxypropyl methylcellulose acetate succinate (HPMC-AS) represents a non-compound related adverse effect in preclinical oral toxicity studies in rodents. Whereas the contribution of the insolubility of the carrier polymer to this process taking place in the acidic environment of the rodent stomach is conclusive, unawareness of the extent of in vivo pharmacobezoar formation is adverse. In order to evaluate the risk of pharmacobezoar formation before in vivo administration, we subsequently introduce an in vitro model to assess the agglomeration potential of solid dispersions. To verify that the pharmacobezoar formation potential can be assessed based on the observed agglomeration potential, we conducted a sequence of experiments with two HPMC-AS-based SD-ASD formulations. In vitro, we found their different in vivo pharmacobezoar formation potential reflected by a significantly increased agglomerated mass of formulation 1 per day compared to formulation 2. In order to find an approach to reduce the agglomeration potential of solid dispersion from suspensions, we further applied the model to investigate the impact of the viscosity of the vehicle used to prepare suspensions on agglomerate formation.

Abstract Neotropical Ichthyology promotes the Special Issue (SI) “Human impacts and the loss of Neotropical freshwater fish diversity” with the purpose of publishing relevant scientific articles on the current biodiversity crisis and the loss of Neotropical freshwater fishes in the Anthropocene. The SI is composed of 22 publications, being two review articles and 20 original articles. A total of 107 researchers contributed to these papers, involving 44 institutions based in Brazil and six other countries. Published articles investigated main anthropic activities and their impacts on fish diversity, with special focus on river regulation, mining, land use changes, aquaculture, and fisheries. Studies provided evidence about the loss of fish diversity in the Neotropics, including fish kill events, demographic changes, contamination, changes in assemblage structure, loss of taxonomic and functional diversity, besides the degradation of ecosystem functions and services, and the lack of effective protection and conservation. Studies were conducted in rivers, streams, lakes, and reservoirs from different Neotropical systems. The studies published in this SI represent a relevant sample of the current worrisome situation of freshwater fishes in the Neotropical region and call for urgent revision in environmental policies, management and conservation initiatives, and socioeconomic priorities.

Abstract Diet and morphology of Serrapinnus notomelas and Serrapinnus sp.1 were investigated across ontogeny, as a way to elucidate the key elements linked to the resource partitioning (a main driver for species coexistence). Fish sampling was conducted monthly between October 2010 and March 2012. Individuals were captured, identified, and classified into juvenile or adult. Our results show ontogenetic and interspecific differences in feeding abilities and morphological traits. Differences in body shape (relative area of the dorsal fin, length of head, height of the caudal peduncle, the aspect ratio of the pectoral and pelvic fin) favored divergent swimming performances (more maneuverability in S. notomelas and continuous swimming to Serrapinnus sp.1). We also observed divergences in trophic apparatus traits and correlations with different diets. In this context, it is highlighted that understanding the relationship between morphology and diet can assist in elucidating the processes that permeate the coexistence between sympatric species, and between ontogenetic periods. Besides, the relevant contribution of the measures of the trophic apparatus (gill raker length, the number of teeth cuspids, and intestinal coefficient) in trophic segregation seems to be a strong evidence in favor of the proposed discriminatory and predictive capacities of these traits.

Resumo Objetivo Comparar a percepção de estudantes de enfermagem e as contribuições do ensino com simulação clínica ou aula prática convencional em laboratório de habilidades, na primeira experiência clínica hospitalar. Método Pesquisa descritiva, qualitativa, envolvendo estudantes de graduação em enfermagem de uma universidade pública do Brasil, submetidos à simulação clínica de alta fidelidade ou aula prática convencional, ocorrida entre 2015 e 2016. Para avaliação dos dados, utilizaram-se a nuvem de palavras e a análise de similitude do software IRAMUTEQ®. Resultados Participaram 54 estudantes, sendo 27 em cada grupo. As palavras mais evocadas pelo grupo simulação foram: “paciente real, não, mais e simulador”, relacionadas à capacidade de reflexão quanto ao seu conhecimento e preparo. As mais evocadas no grupo prática convencional foram: “mais, não, muito e sentir”, relacionadas com a percepção de que a aula convencional ajuda na aquisição de habilidades, contudo, é necessária maior frequência. Conclusão As duas estratégias contribuíram positivamente para a primeira experiência clínica hospitalar. Porém, a simulação proporcionou uma visão crítico-reflexiva sobre as competências, deficiências e maior autoconfiança em relação à prática convencional. Este estudo fortalece as evidências dos benefícios proporcionados pelo ensino baseado em simulação, e a importância de instituições de ensino fazerem uso adequado dessa estratégia.

Abstract: Aim This study aimed to assist in guiding research with eggs and larvae of continental fish in Brazil, mainly in the knowledge of the early development, as well as to present the state of the art and to point out the gaps and future directions for the development of researches in the area. Methods The literature review was carried out in the electronic platforms and studies were examined to investigate whether any addressed morphological description of fish eggs and/or larvae. Results We found 121 studies, including scientific articles, theses, dissertations, chapters of books and books. This bibliographic production characterized 140 species, representing only 4.1% of the total species present in the Brazilian basins. Most of the species studied belong to the orders Characiformes and Siluriformes, which are of commercial interest and native to the Paraná, Amazon, Paraguay and Uruguay basins. For some very species-rich families in the Brazilian rivers, such as Characidae and Loricariidade, only a fraction of their species was characterized for the early development (2.6% and 0.7% of the total, respectively) and 56% of the families did not present any study addressing the early ontogeny. Regarding the content of the descriptions, for 73 species, there is characterization of the embryonic period and for 62, there is description of the whole larval period. For only 41 species there were complete descriptions (embryonic and larval) of the early development. All of these studies were conducted mainly with material derived from induced spawning and material obtained in the field (regressive series). Conclusions The characterization of eggs and larvae, still presents few studies, limited mainly to species from the rivers of the Plata and Amazon basins, to studies of fish of commercial importance and the incompleteness of most of these studies is still outstanding.

ABSTRACT The Paraíba do Sul River is affected by extensive water collection for supply, organic and industrial pollution, and dams. Nonetheless, the ichthyofauna maintains biodiversity and sustains artisanal fisheries. This study analyzes the composition, abundance and distribution of fish larvae, an important approach to determine the reproductive period and spawning sites. The sampling occurred from August 2011 through February 2013 in five sites at a transect between the banks on the lower reach of the Paraíba do Sul River. A total of 5,412 larvae belonging to 20 taxa was captured. The predominant order was Characiformes. Larvae of Prochilodus spp. and Leporinus spp. were the most abundant; larvae of Brycon insignis, an endangered species, were present. Fewer larvae were collected in the second reproductive cycle during a severe drought. The absence of eggs indicates that the study area is not used for spawning, and highlights the need for studies in the main channel and in the tributaries of the Paraíba do Sul River. Fish larvae need to have access to the marginal lagoons along the lower stretch of the river, an area which is the object of disputes between fishermen and farmers.

The Neotropical region exhibits the largest diversity of fish worldwide; however, little is known about the early development of fish species from this region. Therefore, to contribute to this knowledge, this study aimed to morphologically describe the early stages of development (eggs, larvae and juveniles) of S. pappaterra using morphometric and meristic traits, and to assess changes in growth rates throughout larval and juvenile development by analyzing the relationships between various morphometric traits using analytical regression models. Both juvenile and adult individuals with mouth-brooded offspring were collected along the basins of the Cuiabá and Manso Rivers in the state of Mato Grosso, Brazil between March 2000 and March 2004. After the adults were identified, the offspring were classified according to its stage (embryonic, larval or juvenile period), and various morphometric and meristic variables were individually measured (when possible). The eggs of this species are yellow in color, oval shaped, show dendritic pigmentation within their yolk, have small to moderately sized perivitelline spaces and lack a mucous membrane and oil droplets. The horizontal and vertical diameters of the sample yolks ranged from 1.43mm to 2.70mm and 1.05mm to 1.68mm, respectively. The standard length of the larval period varied from 4.30mm to 7.16mm, and the standard length of the juvenile period varied from 10.29mm to 24.57mm. Larvae exhibit yolk sacs with internal dendritic pigmentation and dark punctate pigmentation in the dorsal and ventral body regions, whereas irregular transverse spots along the flanks are observed during the juvenile period. Adhesive organs are only present during the yolk-sac stage and at the beginning of the flexion stage. The mouth is terminal during all stages of development. The myomere number varied from 22 to 29 (9 to 16 pre-anal and 10 to 16 post-anal), and the maximal numbers of fin rays and spines were as follows: dorsal, XVI+10; anal, IV+8; pectoral, 16; and pelvic, I+8. Growth analyses identified periods of important change in larval morphology (i.e., metamorphosis), particularly during the flexion and post-flexion stages and in juveniles. Therefore, the morphological development of S. pappaterra is consistent with the ecological requirements of this species, which primarily occurs in structured lentic environments with aquatic macrophytes. Rev. Biol. Trop. 63 (1): 139-153. Epub 2015 March 01.

Abstract Aim: This study uses the abundance of fish eggs and larvae to evaluate the importance of the main channel of the Paraná River and the adjacent areas of the floodplain, in the last dam-free stretch in the Brazilian territory, for the spawning and development of fish of different reproductive guilds, in order to obtain subsidies to assist in the management and conservation policies of this area, focusing on the maintenance of dam-free areas. Methods Data were taken quarterly from August 2013 to May 2015, in 25 sites, grouped into three biotopes: main channel, tributaries and lagoons. Possible spatial variations in fish spawning and development as well as composition and structure of larvae were evaluated. Results Higher densities of eggs were found in tributaries (Paracaí and Amambai rivers) and greater densities of larvae were observed in lagoons (Saraiva). Significant differences in composition and structure of larvae were detected only between sampling stations. As for taxonomic composition, 29 taxa were recorded, mostly non-migratory. However, long-distance migratory were also widely distributed, such as Brycon orbignyanus, Pseudoplatystoma corruscans, Prochilodus lineatus, Piaractus mesopotamicus and Rhaphiodon vulpinus, as well as invasive species Platanichthys platana and Hemiodus orthonops. In turn, Salminus brasiliensis presented low occurrence. Conclusions This study evidenced that different species spawn in the region, mainly in tributaries, and their eggs and larvae are transported to the main channel of the Paraná River and adjacent lagoons, to complete their early development. The capture of larvae of important migratory species suggests that this environment still exhibits suitable conditions for their reproduction, mainly due to the presence of dam-free tributaries. Also, they emphasize the importance of the integrity of these environments for the maintenance of the regional fish fauna, and it is extremely important the monitoring of reproduction of the most endangered species, as well as of invasive species.

O presente estudo caracterizou o desenvolvimento inicial de Brycon hilarii (Valenciennes, 1850) através de caracteres morfométricos e merísticos e analisou as relações entre as características morfométricas das larvas ao longo do desenvolvimento usando modelos de regressão linear, quadrática e linear por partes. O material foi obtido nas bacias dos rios Cuiabá e Manso, Mato Grosso, Brasil, entre março de 2000 e março de 2004. Os indivíduos foram identificados e separados de acordo com o grau de desenvolvimento da notocorda e, posteriormente, medidos e contados os caracteres morfométricos e merísticos, respectivamente. O comprimento padrão variou entre 3,25 e 26,00 mm. Inicialmente, as larvas apresentaram maior concentração de pigmentos dendríticos ao longo do intestino e, em flexão e pós-flexão, intensificaram-se no dorso do corpo. Uma mancha umeral e outra no pedúnculo caudal foram observadas no final do estágio de pós-flexão. O intestino apresentou-se longo, o focinho curto, o órgão adesivo presente em larval vitelino e pré-flexão e a boca terminal por todo o desenvolvimento. O número total de miômeros variou de 41 a 50 (23 a 30 pré e 16 a 24 pós-anal). O número de raios das nadadeiras foi: dorsal 11; anal 30; peitoral 15 e ventral oito. A análise do crescimento indicou maior metamorfose no estágio de flexão.

The upper Paraná River floodplain is composed of several marginal lagoons, making it a natural breeding ground for many fish species at developmental stages. The aim of this study is to estimate the trophic positions of these fishes based on feed intake (measured via diet) and nitrogen assimilation (measured via δ15N). The monthly samplings were concentrated during the spawning season in the Ivinheima River, which is located in the upper Paraná River floodplain. The specimens were grouped into preflexion, flexion and postflexion stages. Trophic positions were estimated based on the isotope value of nitrogen and on diet. During the developmental stages of P. squamosissimus, there were significant differences in the isotope values of δ15N; for H. edentatus, however, no significant differences were found. During the developmental stages, both species were classified as either at or above the third trophic level. Once this information is obtained for other species and components of the ecosystem, it will not only provide a more precise view of the energy allocation and flow in the ecosystem, but will also make possible for management measures to promote sustainability in this environment.A planície de inundação do alto rio Paraná é formada por várias lagoas marginais, tornando-se um criadouro natural de várias espécies de peixes nos estágios de desenvolvimento. O objetivo do estudo foi estimar as posições tróficas destes peixes, com base no alimento consumido (medido através dieta) e o nitrogênio assimilado (medido através δ15N). As amostragens mensais concentraram-se no período de desova das espécies, no rio Ivinheima, na planície de inundação do alto rio Paraná. Os espécimes foram agrupados em: pré-flexão, flexão e pós-flexão. As posições tróficas foram estimadas com base no valor isotópico de nitrogênio e na dieta. Nas fases de desenvolvimento de P. squamosissimus houve diferença significativa nos valores isotópicos de δ15N, enquanto que, para H. edentatus, não foram identificadas. Ambas as espécies, durante os estágios de desenvolvimento, foram classificadas em igual ou acima do terceiro nível trófico. Estas informações, quando obtidas para outras espécies de peixes e componentes do ecossistema, fornecerão uma visão mais precisa da distribuição e fluxo de energia no ecossistema, além de tornar possível medidas de manejo, que visem promover a sustentabilidade deste ambiente.

Pseudopimelodidae are Neotropical catfishes characterized by having slightly to strongly depressed body in fully developed specimens. The largest species of the family with 500 mm SL, Lophiosilurus alexandri, experiences impressive changes in body shape during development, becoming extremely depressed when fully developed. Accordingly, Lophiosilurus alexandri is an ideal species to observe the morphological changes during ontogeny, and to seek solid interpretations on the polarity of characters. Specimens of distinct larval periods (yolk sac, flexion and postflexion; n = 186 specimens) and juvenile stages (n = 20) were analyzed. Changes in body shape, position of mouth and eye, morphology of fins and pigmentation were observed during the development of Lophiosilurus. Larvae (5.7-11.2 mm standard length) had pigmentation concentrated on the head and parts of body, eyes small and pigmented, short barbels, and well-developed finfold. Juveniles (15.9-28.1 mm standard length) had body shape similar to adult, with head depressed and bearing bony ridges, large mouth, dorsally-oriented eyes, small barbels and well-developed shoulder bulges (cleithral width). The greatest morphological changes in the development of L. alexandri occurred during the postflexion larval stage. Relative to standard length, measurements of snout length, head depth and body depth are smaller in juveniles than in larvae, but body width is larger. New interpretations on the phylogenetic characters related to these changes are provided in view of the two alternative hypotheses of the evolution of Pseudopimelodidae.