Ontogenia e seletividade alimentar de larvas e juvenis de três espécies de peixes Neotropicais de diferentes categorias tróficas.

• Autor(a) principal: Santin, Miriam
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/5073
• topic: Ictioplâncton; Peixes neotropicais; Larvas e juvenis; Metamorfose; Dieta; Alimentação (Zooplâncton); Seletividade; Paraná, Rio, Bacia; Brasil.; Ichthyoplankton; Diet; Zooplankton; Selectivity; Larvae and juvenile fish; Brazil.; Ciências Biológicas; Ecologia

This work aimed to study the ontogeny and feeding selectivity of larval and juvenile fishes of different trophic guilds (Catathyridium jenynsii, Pyrrhulina australis and Hoplosternum littorale). For the analysis of ontogeny were considered individuals sampled in the main river channel Ivinhema, in Patos and Finado Raimundo lagoons, Mato Grosso do Sul, and selectivity were considered only samples taken in the lagoons. Samples were taken between the months October to March the years 2005 to 2009. Simultaneously to the ichthyoplankton samples were collected zooplankton. After collection the samples were screened and larvae and juveniles identified, measured for length standard, head length, upper jaw, and grouped into stages of development. Zooplankton was identified and quantified. Changes in the development of digestive tract have been described in relation to the position of the mouth and the morphology of the tube. The diet analysis was performed using the methods Occurrence and Numerical of Frequency. It was also analyzed feeding strategy, the amplitude changes of diet and intra and interespecific diet by Discriminant Analysis. To test the relationship between the size of the mouth and head length between species, we used Analysis of Covariance (ANCOVA) and each species, we applied the Linear Regression test. The differences in diet and these variations in the size of intra and interspecific mouth was assessed using the Multi-response Permutation Procedure. The existence of items that serve as diet of indicators among species was assessed by Indicator Species of Analysis and to assess the choice of prey on zooplankton community values were obtained selectivity. C. jenynsii was zooplanktivore during larval and juvenile fish in insectivore, P. australis ranged from insects and zooplankton during the larval and juvenile was insectivorous, while H. littorale was zooplanktivore during the early development. Only C. jenynsii presented food strategy specialist, while the others were intraspecific differences in diet. During the larval development of C. jenynsii niche amplitude remained the same and decreased in juveniles. For the other species increased values of niche breadth. To C. jenynsii increasing the size of the items consumed relates to increase the mouth during development, for P. australis and H. littorale was no variation of the sizes of the items taken. The composition of the diet varied intra and interespecific. The indicators of dietary items found in C. jenynsii were Cladocera and Calanoida and H. littorale were Alona sp., Chydoridae, Chydorus nitidulus, Daphnia gessneri, Diaphanosoma birgei and Calanoid, for P. australis was not registered any indicator species. Items Rotifera were abundant in the middle, followed by Cladocera and Copepoda. The C. jenynsii and P. australis larvae selected while the juveniles mainly Cladocera, Copepoda. For H. littorale was selection of Moina minuta and Plationus sp. in the stages of flexion and post-flexion. Thus we can conclude that the position of the mouth and digestive tract morphology and diet influence eating habits and this is yet acquired in the larval stages. Zooplankton has the largest contribution to the diet of fish larvae, however, other food items may be used. The species differ in intra and interspecific relation to diet. The choice of food is influenced by the size of the mouth, while the abundance of food influence individually the species and stage of development. Some items serve as indicators of the diet of the species, where morphological differences of the mouth determine the variation of types and sizes of prey. Individuals can select the food or enjoy the abundance in the middle. For this also depends on the swimming ability and visual acuity, which influences the capture and ingestion of food.