O impacto da degradação costeira sobre a dieta da tartaruga-verde, Chelonia mydas

Abstract

Coastal regions are home to a wide variety of ecosystems and an abundance of marine life, which collectively, offer numerous benefits and services to society. Recognizing the importance of these regions, human settlements have grown in these areas, leading to increased population density and a subsequent rise in human activities that have had significant impacts on the environment. One of the primary consequences of these activities is pollution, which has emerged as a key factor contributing to the disruption of marine communities. This, in turn, has had a profound effect on animals with coastal habits, including the green turtle, Chelonia mydas. Therefore, the aim of this study was to investigate how coastal degradation has affected the feeding ecology of green turtles by comparing their diets in two regions with different degrees of urbanization. To achieve this, samples from twenty-three individuals from two locations were used, ten from the capital of Alagoas, Maceió (urbanized area), and thirteen from the Costa dos Corais Environmental Protection Area (APACC). We examined and compared the contents of their stomachs, sorting, weighing, identifying and assessing their representativeness. To evaluate the overall health of the turtles, we also looked into the prevalence of fibropapillomatosis (FP), a debilitating disease that affects green turtles. Our results revealed that the diet of turtles in both locations primarily consisted of macroalgae, with 62,3% in APACC and 67,9% in Maceió. In APACC, red algae were the dominant component, making up 44,4% of their diet. This region displayed a higher species richness, with turtles consuming macrophytes from 21 different genera, with Gelidium having the higher intake (20,7%). In Maceió, seagrass and green macroalgae (Chlorophyta) were the most consumed groups, accounting for 27,3% and 28,1% of the diet, respectively. However, the variety of genera consumed was lower in comparison to APACC. Our research also showed that the prevalence of FP was higher in Maceió, affecting 40% of the turtles, while the prevalence in the APACC region was considerably lower at 7,7%. These results indicate that turtles in the urbanized region may be facing a reduced diversity of genera in their diet, further supporting the hypothesis that coastal degradation is impacting the feeding ecology of green turtles. The increased prevalence of FP in the more degraded region may be linked to this nutritional deficiency. As a consequence, the health and ability to perform their ecological role could be compromised. Therefore, it is vital to implement conservation efforts to protect green turtles and the entire ecosystem they inhabit.