Ontogenetic variations and feeding habits of a Neotropical annual fish from southern Brazil

Feeding Habits of Dentex maroccanus and the Effect of Body Size

The feeding habits of organisms are important elements in their ecological role and are affected by several factors. The present study provides for the first time information on the diet and feeding strategy of Dentex maroccanus (Valenciennes, 1830) and examines the effects of various factors on the species' feeding activity. Various indices (vacuity index, numerical and weight proportion, frequency of occurrence, alimentary coefficient, index of relative importance, diet breadth and overlap, Shannon-Wiener index, and trophic level) were estimated. The diet of the species consisted of 18 different prey taxa. The most important prey taxon was Decapoda. The study of the feeding strategy showed the narrow width of the species. Body size was found to significantly affect the species' feeding habits. Polychaeta and Stomatopoda were found only in individuals with size ≥165 mm, Bivalvia mainly in sizes ≤120 mm, and Decapoda in the intermediate sizes. The largest individuals showed the lowest overlap with all other size groups. The trophic level increased from 3.7 in young individuals to 4.0 in larger sizes, indicating the carnivorous character of the species. The results of the present work contribute to a better knowledge of the species' feeding ecology.