Impactos do turismo na dieta de Haemulon aurolineatum (Cuvier, 1830) em recifes coralíneos do Rio Grande do Norte

Abstract

Tourism in marine environments is growing every year, especially in attractive coastal regions. One of the regular practices of tourists refers to supplementary food provisioning for fish, such as bread, biscuits and other artificial foods in the diet of these individuals. On the one hand, this activity can assist in fish conservation and environmental awareness, but on the other hand it results in negative impacts little understood so far. Thus, the objective of this study was to analyze the effects of food offer by tourists in the diet of the fish Haemulon aurolineatum in coral reefs of Rio Grande do Norte. Two areas were chosen for collection: one with supplementary feeding offered by tourists - Parrachos de Maracajau, and another with natural food - Parrachos do Rio do Fogo. Measures of length, weight, hepatosomatic index (HSI) and condition factor (K) of the two sampling areas were taken. To confirm the age class of individuals, the growth rings present in the otolith Sagitta were counted. The consumed items were identified to the smallest taxonomic category possible and the results were compared through NMDS and ANOSIM. The starch content of the stomach contents has also been analyzed. The t test pointed out differences in individuals’ length, possibly due to high food intake. However, the t tests pointed equivalent weight, HSI and K for both areas. The NMDS differentiated the items consumed for the two sampled regions and the analysis of similarity confirmed that tourism reflects on modifications in diet composition. The stomach contents of supplementary fed individuals presented 48.73% starch in its composition. Considering the natural diet of this species, carbohydrate intake can interfere with individual energy accumulation. Additionally, H. aurolineatum habitual preys are not being captured, which may lead to imbalance among the populations. Our results try to contribute to the management of reef areas, with a reduction in the volume and control of the food type being offered, so that tourism can become in fact a sustainable activity.