Relation Between the Temporal Pattern and Alimentary Activity of Two Species of Fish

*Corresponding author e-mail; simone@cb.ufrn.br Introduction: The circadian rhythms in fish has an endogenous control being able to be synchronized by diverse factors, as lightdark cycle, change of temperature, presence of predator, availability and competition for food, and others. This work aims to verify the existence of temporal pattern in alimentary activity and the relation between this index and the frequency of capture for fishes Plagioscium squamosissismus and Astyanax cf. lacustris , in Piató Lagoon (5°32’04.9”S/36°56’4l.8”W), municipality of Assu, Rio Grande do Norte, Brazil. Methods: The capture of animals has occurred monthly for 24 hours, with catching to each four hours (00:00, 04:00, 06:00, 08:00, 12:00, 18:00 e 20:00 hours), using seine nets located in three different points. The alimentary activity was analyzed using the Index of Stomach Repletion, that is calculated as the ration of the weight of the stomach and the weight of the fish. Results and conclusion: The results for alimentary activity showed to similar pattern Astyanax cf. lacustris and Plagioscium squamosissismus an increase around 04:00 e 20:00 hours of significantly (ANOVA p <0,05), featuring such twilight-nocturnal about to the breeds studied. The association with frequency of capture time showed a strong relation with the pattern of alimentary activity, what it indicates that both the species use the phase of lesser luminosity leave of it to exert its activities locomotive in food search. Publication History Article published online: 16 June 2026 © 2009. Brazilian Sleep Academy. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/) Thieme Revinter Publicações Ltda. Rua Rego Freitas, 175, loja 1, República, São Paulo, SP, CEP 01220-010, Brazil