We investigated the intraspecific partitioning of food resources of the Brazilian silverside Atherinella brasiliensis in a tropical estuary. A total of 1,099 stomachs were analyzed, and the diet consisted mainly of Gastropoda, Ceratopogonidae larvae, Decapoda larvae, Calanoida, Cyclopoida, Hymenoptera and Brachyura. Ordination of the mean volumetric percentage contribution of preys indicated differences in the dietary compositions between sites and size classes. By SIMPER analysis, we detected high dissimilarity between size classes, suggesting ontogenetic niche shifts: the diet of the early juveniles was based in zooplankton, whereas adults consumed mainly benthic macroinvertebrates. These shifts were related to changes in feeding structures and foraging abilities that show a strong relationship with body size, and showed functional trade-offs in swimming capacity, and feeding strategies used to capture prey. Differences in the diet between size classes and habitat selection by Brazilian silverside are likely strategies to avoid intraspecific competition, clearly related to the abundance and accessibility of resources along the estuarine habitats.Nós investigamos a partição intraespecífica de recursos alimentares do peixe-rei Atherinella brasiliensis em um estuário tropical. Um total de 1.099 estômagos foi analisado, e a dieta foi constituída principalmente de Gastropoda, Larva de Ceratopogonidae, Larva de Decapoda, Calanoida, Cyclopoida, Hymenoptera e Brachyura. A análise de ordenação da contribuição do volume das presas indicou diferenças na composição da dieta entre locais e classes de tamanho. Pela análise do SIMPER, nós detectamos alta dissimilaridade entre as classes de tamanho, sugerindo mudanças ontogenéticas: a dieta dos indivíduos menores foi baseada em zooplâncton, enquanto os maiores indivíduos consumiram principalmente macroinvertebrados bentônicos. Essas variações foram relacionadas com mudanças nas estruturas para captura do alimento e na habilidade de forrageamento que evidenciaram uma forte relação com o tamanho do corpo, e mostraram trade-offs funcionais na capacidade de natação e no modo de captura das presas. Diferenças na dieta entre as classes e a seleção de habitat pelo peixe-rei são estratégias para evitar a competição intraespecífica, claramente relacionada com a abundância e a acessibilidade dos recursos alimentares ao longo dos habitats estuarinos. Palavras-chave:Áreas costeiras, Estratégia Trófica, Heterogeneidade de habitat.
ResumoA Reserva Particular do Patrimônio Natural Fazenda Pacatuba está localizada na porção baixa da bacia do rio Paraíba do Norte, um dos últimos remanescentes de Mata Atlântica no norte do rio São Francisco. Juntamente com a floresta de Jacuípe e a Reserva Biológica de Guaribas, é considerada uma área de importância biológica ainda desconhecida e prioritária para a conservação da biodiversidade no Nordeste. Assim, o presente estudo teve como objetivo analisar a ictiofauna da reserva e seu entorno, a fim de contribuir para os dados sobre a distribuição das espécies de peixes da Mata Atlântica do Nordeste e para o conhecimento de sua biodiversidade. Foram coletados 1.005 exemplares em cinco pontos amostrais, distribuídos em 6 ordens, 11 famílias, 16 gêneros e 21 espécies de peixes de água doce.Palavras-chave: Peixes, Mata Atlantica, Riachos, Conservação. AbstractThe Private Natural Heritage Reserve Pacatuba Farm is located in the Paraíba do Norte river low basin, one of the last remnants of Atlantic Forest in the north of the São Francisco river. Together with Jacuípe forest and Guaribas Biological Reserve, it is considered an area of biological importance still unknown and priority for the biodiversity conservation in the Northeast. Thus, the present study aimed to analyze the icthyofauna from the reserve and its surroundings in order to contribute to the data on the fish species distribution in the Northeastern Atlantic Forest and to the knowledge of its biodiversity. It was collected a total of 1.005 specimens at five sampling sites, which are distributed over 6 orders, 11 families, 16 genera and 21 species of freshwater fish.Keywords: Fish, Atlantic Forest, Streams, Conservation. ResumoLa Reserva Particular del Patrimonio Natural Fazenda Pacatuba está ubicada en la Cuenca Baja del río Paraíba do Norte, uno de los últimos remanentes de Mata Atlántica al norte del río São Francisco. Junto con el bosque de Jacuípe y la Reserva Biológica de Guaribas, esta reserva se considera un área de importancia biológica aún desconocida y prioritaria para la conservación de la biodiversidad en el Nordeste del Brasil. Así, el presente estudio tuvo como objetivo investigar la ictiofauna de la reserva y su entorno, a fin de contribuir con datos sobre la distribución de las especies de peces de la Mata Atlántica del Nordeste y para el conocimiento de su biodiversidad. Fueran recolectados 1.005 ejemplares en cinco puntos de muestreo, agrupados en 6 órdenes, 11 familias, 16 géneros y 21 especies de peces de agua dulce.Palabras claves: peces, Mata Atlántica, arroyos, conservación
Pneumatophore fringes and mudflats are extremely valuable habitats and provide structures on which many fish species benefit in terms of food and reduced predation risk. We analysed the spatiotemporal patterns in feeding habits, reproductive aspects and effects of predatory fish presence to assess the ecological drivers of the common halfbeak, Hyporhamphus unifasciatus, in a Brazilian estuary. Sampling was conducted in the rainy (January to July 2016) and dry (August to December 2016) periods. Fish were collected in the two estuarine habitats using a beach seine. In summary, the results demonstrated that the number of predatory fishes was a strong predictor of population abundance and biomass, followed by pneumatophore complexity. The abundance and biomass values tended to increase with increasing habitat structural complexity towards the upper estuary. There was evidence that fish exhibited movement during the rainy season related to spawning events and subsequent juvenile recruitment in this area. Hymnoptera was the item most frequently ingested and made the greatest contributions to the volume of diet in habitat types throughout the year. There was an increase in the condition factor in the rainy season and thus was associated with energy reserves, reproduction and growth (fitness). We concluded that predation is an important ecological process that operates at local spatial scales and that together with the density of pneumatophores, predation is considered an important attractiveness that could affect the abundance of common halfbeak populations associated with estuarine habitats.
Estuarine ecosystem conditions actively influence the early life stage of fishes. This study reports how environmental factors influenced the ichthyoplankton in a tropical estuary within an Environmental Protection Area by comparing the structure and composition of fish eggs and larval assemblages. A total of 1672 fish larvae and 486 fish eggs were collected. Higher densities of larvae were recorded for Engraulidae, Characidae, Clupeidae, Gerreidae, Mugilidae and Atherinopsidae, and higher egg densities of the families Mugilidae, Clupeidae and Engraulidae were found. The spatio-temporal variations were determined by the environmental predictors salinity, pH, dissolved oxygen and temperature, with salinity influenced by precipitation as one of the main predictors of the distribution of ichthyoplankton. During the rainy season, greater densities of eggs were recorded in the upper and intermediate zones, mainly Characidae and Engraulidae; in the dry season, in the lower zone, there was a greater density of larvae, particularly Atherinopsidae and Mugilidae. The information provided in the present study contributes to our knowledge of nursery habitat requirements for the initial development of marine migrant and resident species in tropical estuaries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.