Sexual, ontogenetic, temporal and spatial effects on the diet of Urotrygon rogersi (Elasmobranchii:Myliobatiformes)
The food habits and trophic ecology of Urotrygon rogersi were analysed to ascertain sexual, ontogenetic, temporal and spatial effects on the diet. These effects were examined with contingency tables, simple correspondence analysis and MANOVA. The trophic relationships of the species were determined with Levin's niche amplitude index and Pianka's diet overlap index. Urotrygon rogersi is a predator of benthic organisms, especially shrimp and polychaetes. Analysis of sex and time showed no significant differences, but differences among class sizes were found. A strong trend towards diet specialization and a strong overlap between sexes and between class sizes were found. Finally, fishing activity on shrimps in the study area could force U. rogersi to change its trophic spectrum over time as an adaptation to the considerable reduction in its principal prey.
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Rogers round ray;
Document Type: Regular Paper
Griffith University, 170 Kessels Road, Nathan, Qld 4111, Australia
Grupo de investigación en Ecología Animal, Sección de Zoología, Departamento de Biología, Universidad del Valle. A.A. 25360, Cali, Colombia
Publication date: 2011-04-01