Diet of two insectivorous fish species in a Brazilian semiarid reservoir

Long periods of aridity can cause changes in the diet of fish since hydrological variations affect the availability of food resources. The objective of this study was to investigate the diet of two species of fish (Astyanax aff. bimaculatus and Triportheus signatus), present in the Umari reservoir in Upanema, Rio Grande do Norte, Brazil, to evaluate the influence of seasonality on their diets. The samples were collected quarterly during the months of February to November 2013, with four days in the field, and at five different sites of the reservoir with nets with meshes ranging from 12 to 70 mm (between adjacent nodes). For the identified items in the diet, the frequencies of occurrence and volume, combined in the calculation of the Alimentary Index (IAi), were obtained. Significant alterations in the diet of the species were observed, predominantly in insects. The changes found in the diet indicate an influence of seasonality on the feeding habits of these species, with a predominance of autochthonous items in the dry period and allochthonous items in the rainy period.

Diet of two insectivorous fish species in a Brazilian semiarid reservoir

Long periods of aridity can cause changes in the diet of fish since hydrological variations affect the availability of food resources. The objective of this study was to investigate the diet of two species of fish (Astyanax aff. bimaculatus and Triportheus signatus), present in the Umari reservoir in Upanema, Rio Grande do Norte, Brazil, to evaluate the influence of seasonality on their diets. The samples were collected quarterly during the months of February to November 2013, with four days in the field, and at five different sites of the reservoir with nets with meshes ranging from 12 to 70 mm (between adjacent nodes). For the identified items in the diet, the frequencies of occurrence and volume, combined in the calculation of the Alimentary Index (IAi), were obtained. Significant alterations in the diet of the species were observed, predominantly in insects. The changes found in the diet indicate an influence of seasonality on the feeding habits of these species, with a predominance of autochthonous items in the dry period and allochthonous items in the rainy period.(AU)

Feeding patterns, trophic structure and damming rivers effect: studies applied in freshwater environments in the Brazilian semi-arid region

The knowledge of the fish trophic structure has been outstanding for providing relevant information on the functioning of the ecosystem in which they are inserted, mainly in dammed environments of semiarid regions that suffer constant changes in the level of water, resulting in alterations, especially in the feeding of the fish due to the variation of the food resources throughout the year, causing changes in the diet of the local ichthyofauna. Within this context, the objective was to describe the trophic categories of fish species in freshwater environments of the Rio Grande do Norte state. Seven trophic guilds were recorded: Detritivore/iliophagous, Insectivorous, Carcinophagous, Piscivorous, Herbivorous and Omnivorous. Through the results, it is observed that the fish species inserted in different environments of the state present the same food pattern, demonstrating flexibility on the diet, prevailing a generalist alimentary habit.(AU)

Feeding patterns, trophic structure and damming rivers effect: studies applied in freshwater environments in the Brazilian semi-arid region

The knowledge of the fish trophic structure has been outstanding for providing relevant information on the functioning of the ecosystem in which they are inserted, mainly in dammed environments of semiarid regions that suffer constant changes in the level of water, resulting in alterations, especially in the feeding of the fish due to the variation of the food resources throughout the year, causing changes in the diet of the local ichthyofauna. Within this context, the objective was to describe the trophic categories of fish species in freshwater environments of the Rio Grande do Norte state. Seven trophic guilds were recorded: Detritivore/iliophagous, Insectivorous, Carcinophagous, Piscivorous, Herbivorous and Omnivorous. Through the results, it is observed that the fish species inserted in different environments of the state present the same food pattern, demonstrating flexibility on the diet, prevailing a generalist alimentary habit.