O aquarismo é um hobby praticado mundialmente com aumento de popularidade no Brasil nas últimas décadas. A soltura de peixes ornamentais em ambientes naturais é equivocada, sendo considerada introdução de espécies e crime ambiental. Dessa maneira, objetivou-se verificar a existência de registros de solturas disponíveis na web, na mídia social Youtube™ no Brasil. A busca por vídeos com situações de soltura ou descarte foi realizada entre julho e dezembro do ano de 2018, totalizando-se 616 horas de busca. Como resultado, obteve-se 48 registros de solturas, sendo as mais incidentes as regiões do Sudeste, Nordeste e Sul. São Paulo, Minas Gerais, Espírito Santo e Rio de Janeiro foram os Estados com maior número de registros. Registrou-se 33 táxons de peixes (18 gêneros e 15 espécies) e dois híbridos, sendo muitas delas espécies invasoras. A maioria dos praticantes não tem conhecimento sobre a ilegalidade do ato ou a possibilidade de impacto ambiental. O perigo das solturas ornamentais quanto à oportunidade de invasão biológica, a pressão de propágulo empregada e os conceitos equivocados sobre ecologia abordados nos vídeos são discutidos. Sugere-se a conscientização dos aquaristas e maior controle sobre o hobby, sendo as redes e mídias sociais uma nova ferramenta para os órgãos fiscalizadores detectarem distúrbios que possam prejudicar os ambientes naturais.
Abstract. Garcia DAZ, Vidotto-Magnoni AP, Costa ADA, Casimiro ACR, Jarduli LR, Ferraz JD, De Almeida FS, Orsi ML. 2019. Importance of the Congonhas River for the conservation of the fish fauna of the Upper Paraná basin, Brazil. Biodiversitas 20: 474-481. The Upper Paraná River basin is among the most fragmented watersheds in the world. The Congonhas River belongs to this drainage system, which has its mouth in the Capivara Reservoir and can be considered the largest tributary free-from-dam, becoming important for the maintenance of fish species richness. In order to know more about the species present in this tributary, we aimed to provide an inventory of fish fauna of the Congonhas River and reproductive strategies to determine whether the river is used by migratory species and whether there is a longitudinal variation in the fish assembly. These findings will provide subsidies to contribute to the implementation of policies to protect biodiversity. Samplings occurred in the upper, middle and lower stretches of the Congonhas River during four periods between 1991 and 2011. Fishes were captured using gill nets from 2 to 14 cm mesh sizes between opposite knots and cast nets, identified and categorized according to their reproductive strategies. A total of 4,640 individuals belonging to 63 species, of which 79.4% consisted of Characiformes and Siluriformes were captured. Furthermore, 14% of fish were long-distance migratory species (e.g., Piaractus mesopotamicus, Megaleporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis, Pinirampus pirinampu, and Pseudoplatystoma corruscans). In addition, there was an increase in the fish species richness from upstream to downstream. Management actions such as prohibition of fishing, rehabilitation of riparian vegetation, and protection of the basin against dam construction will reduce anthropogenic impacts on the ecosystem. The Congonhas River highlights the importance of preserving lotic environmental for the conservation of migratory and non-migratory Neotropical fish diversity into a heavily modified watershed.
O aquarismo é um hobby difundido mundialmente, com registros desde as civilizações antigas. No Brasil, a prática tem aumentado seu prestígio e representatividade. Dentre as modalidades do aquarismo de água doce, o "jumbo" tem se tornado popular, e sua prática tem gerado ampla divulgação via Internet. A modalidade se caracteriza pela escolha de espécies de peixes de médio a grande porte com comportamento agressivo e predatório, o que representa ameaça aos ambientes naturais principalmente como consequência do descarte inadequado das espécies. O objetivo do presente estudo foi investigar, com base no conteúdo disponível na Internet, se houve aumento da divulgação da modalidade ao longo dos anos, quais regiões do país mais disseminam a mesma e quais os gêneros mais presentes nesta modalidade. Vídeos da plataforma online Youtube ® foram acessados e quantificados quanto ao ano de postagem, Estado brasileiro de origem, gêneros de peixes presentes e a abundância destes nos aquários. Como resultado, observou-se aumento significativo da quantidade de vídeos disponíveis no intervalo de 2007 a 2017. Rio de Janeiro, São Paulo e Minas Gerais foram os Estados com maior número de vídeos postados. O apaiari Astronotus, o tucunaré Cichla e o híbrido peixe papagaio (Vieja melanurus x Amphilophus citrinellus) foram os gêneros mais abundantes. A maioria dos vídeos presentes nesta plataforma estimula a prática desta modalidade por outras pessoas. Assim, devido à falta de informação a respeito do risco que essas espécies representam aos ambientes naturais, recomendamos maior atenção à prática do aquarismo jumbo no Brasil. Comunicação adequada entre pesquisadores, lojas do ramo e agências fiscalizadoras é necessária e urgente, visando à conscientização dos aquaristas quanto aos problemas relacionados à soltura inadequada de peixes na natureza e a invasão biológica, tendo como objetivo promover um hobby mais saudável.Palavras-chave: descarte de aquarismo; invasão biológica; peixes grandes; pressão de propágulo; rede social.
We evaluated the fish composition and ecological attributes of the ichthyofauna collected in a limnological zone of the Taquaruçu Reservoir, lower Paranapanema River. Information about the fish community was updated when compared to the previous study (2006). Non-metric multidimensional scaling (NMDS) showed differences in species composition between periods and community weighted means (CWMs) exhibited changes in functional composition over time. Four functional indices were used in the principal coordinate analysis (PcoA) to measure changes in the functional space of species, whereas functional β-diversity inspected differences in the traits composition between the periods. 1,203 individuals were sampled of 43 species, being 16 non-native and 14 new records. Compared to 2006, 27 species were absent, most of them native to Loricariidae and Anostomidae, while Curimatidae and Pimelodidae decreased in abundance. Functional indexes showed a reduction in functional diversity, whereas new species records exhibited functional redundancy. It might have occurred a simplification of the fish community over time, excluding the migratory and specialists species such as the herbivores and detritivores. Accordingly, we concluded that the ichthyofauna of the Taquaruçu Reservoir might have been undergoing a process towards biotic homogenization.
Studies on length-weight relationships are of great importance in fishery assessments. These studies are substantial to evaluate fish population dynamics, and in communion with the relative condition factor, could provide an estimation of potential acting environmental conditions. In this paper, we evaluated the length weight relationship and relative condition factor of small sized fish species. Fish were sampled quarterly between the years 2012-2013 and 2018-2020 in lagoons and tributaries of Rosana and Taquaruçu reservoirs, located at the lower Paranapanema River basin, Brazil. The standard length (SL) in millimeters and weight (W) in grams were measured, and the length-weight relationship was calculated using linear regression analysis (W = log (a) + b log (SL)). After, the relative condition factor (Kn) was calculated from the expression We = a.SLb. Thus, the length-weight relationships of 31 species were calculated in each environment considered, giving rise to 74 population allometric coefficients (b) and relative condition factors (Kn). As result, 24 b coefficients were concentrated between 2.5 and 3.5 and seven were out of the confidence interval, while the 74 Kn values demonstrated close to the central mean and not statistical different. Our results are relevant to the conservation of fish fauna, improving knowledge regarding small-sized fish and those living environment.
Understanding the potential distribution of non-native species can be an important tool in preventing biological invasions. We recorded for the first time Psellogrammus kennedyi, a small non-native characiform, in the Lower Paranapanema River, Brazil. According to environmental variables and prediction modeling, the species presents high potential distribution in the Upper Paraná river basin. The model used herein is an efficient tool to determine where non-native species may be able to establish. This approach can be used as a preventive measure, once the control and eradication measures are often ineffective and uneconomical.
Objetivo: quantificar a abundância e a biomassa de moluscos bentônicos no Lago Igapó I, Londrina, Paraná, Brasil. Material e Métodos: foram realizadas duas coletas no Lago Igapó I, a primeira em junho de 2015 e a segunda em fevereiro de 2016. O substrato (incluindo os moluscos incrustados) foi amostrado utilizando um quadrante com área de 1 m2, onde 10 amostragens foram realizadas entre três pontos distintos do lago. Os moluscos capturados foram anestesiados e eutanasiados por superexposição ao gelo. Posteriormente, o material foi quantificado em abundância (n) e biomassa total (kg), e armazenado em tambores contendo formol 4% tamponado com carbonato de cálcio. Resultados: foram identificadas cinco espécies de moluscos, sendo três não nativas (Limnoperna fortunei, Corbicula fluminea e Melanoides tuberculata), uma nativa (Aylacostoma cf. tenuilabris) e um indivíduo do gênero Pomacea. Em ambas as coletas, L. fortunei compreendeu aproximadamente 90% da abundância e biomassa total. A partir da densidade média de L. fortunei e a área total do Lago Igapó I, estimou-se que a população total de mexilhões-dourados pode chegar a 633 milhões de indivíduos, correspondendo a 638 toneladas de biomassa. Conclusão: é evidente a dominância da espécie invasora L. fortunei no Lago Igapó I, onde esta pode causar diversos efeitos negativos, como alterações no ciclo de nutrientes, redução de espécies nativas, introdução de parasitos, bioacumulação de metais pesados na cadeia trófica, diminuição da qualidade da água para uso humano e obstrução de encanamentos com risco de alagamentos. Desta forma, recomenda-se uma imediata ação de manejo neste ambiente para retirada de indivíduos da espécie, com consequente redução de sua abundância.
Aim: To verify variations of early fish stages through density, species composition and ecological attributes in the lower Paranapanema River. Methods: The Canoas I and Canoas II reservoirs were sampled during three reproductive periods (RP´s) between 2012 and 2015. Eggs and larvae were collected using conical-cylindrical plankton nets and juveniles by seines and sieves. After euthanasia and fixation, the samples were identified at the lowest taxonomic level and grouped according to their reproductive strategy and life history. Variations in the eggs, larvae, and juvenile’s densities were tested by Kruskal-Wallis with post-hoc Dunn's test from RP´s, while Student T-test detected differences between reservoirs. Non-metric multidimensional scaling ordination (NMDS) with post-hoc analysis of similarities (ANOSIM) were employed to elucidate differences in species composition. Major results: We sampled 5,513 eggs, 3,137 larvae, and 187 juveniles in Canoas I Reservoir, and 2,709 eggs, 237 larvae, and 13 juveniles in Canoas II Reservoir. Fishes were identified in seven orders, 15 families, and 31 species, with Pimelodus maculatus, Anostomidae, and small-sized characids being the most abundant. There was a predominance of non-migratory reproductive strategy (46%) and periodic life history (60%), most of them opportunistic species. Differences in densities were observed between RP´s and reservoirs. A clustering of three groups were performed to larvae and juveniles, where the divergences were statistically confirmed (p < 0.05). Conclusions: Our findings demonstrated the decrease of early fish stages density overtime and the dominance of opportunistic species, suggesting that these species complete their life cycle in the reservoirs. Thus, P. maculatus can be an important species for the health of ecosystems, in addition to serving as a fishing resource in reservoirs. However, the absence of critical sites for reproduction and the climatic events, along with human responses to this, may have impaired the conclusion of life cycle from many species.
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