Banca de DEFESA: CLARA DE SOUZA MELO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CLARA DE SOUZA MELO
DATE: 26/02/2026
TIME: 09:30
LOCAL: Sala da Pós graduação do PPGBIOEF
TITLE:

Reproductive patterns and congenital malformations in sea turtles: an ecomorphological assessment in an emerging nesting area.

KEY WORDS:

sex ratio; embryonic development; coastal urbanization; Eretmochelys imbricata.

PAGES: 89
BIG AREA: Ciências Biológicas
AREA: Morfologia
SUMMARY:

 

Sea turtles play a fundamental ecological role in marine and coastal ecosystems, and the monitoring of nesting areas is essential for understanding reproductive patterns, population trends, environmental impacts, and ecomorphological variations associated with embryonic development. The region of São Miguel do Gostoso (Rio Grande do Norte, Brazil) has shown a marked increase in the number of nesting events in recent seasons, suggesting that it may be emerging as a new reproductive area in the South Atlantic. In this context, the present study aimed to characterize sea turtle reproductive activity along the northern coast of Rio Grande do Norte by integrating analyses of the spatiotemporal distribution of nests, environmental incubation factors, and morphological aspects of hatchlings, with emphasis on sex ratio and the occurrence of congenital malformations.Between September 2024 and August 2025, a total of 579 reproductive events were recorded along 57 km of beaches monitored daily in the municipalities of São Miguel do Gostoso, Pedra Grande, São Bento do Norte, and Touros by the Center for Environmental Studies and Monitoring (CEMAM), resulting in 434 confirmed nests. Eretmochelys imbricata accounted for the majority of records (≈70%), followed by Chelonia mydas and Lepidochelys olivacea. Spatial analysis revealed a strong concentration of nests in São Miguel do Gostoso (84%), with significant differences among the monitored beaches, while temporal distribution indicated an increase in nesting activity between January and March, characterizing the reproductive seasonality of the region. Climatic parameters like air temperature, relative humidity, and precipitation, obtained from the NASA/POWER platform were used to characterize the environmental context during nest incubation, which reached a reproductive success rate of 77%. Despite these satisfactory rates, thermal variation showed a correlation with increased numbers of unhatched eggs and stillborn hatchlings, highlighting the sensitivity of embryonic development to environmental conditions. Histological analysis of the gonads of 104 stillborn E. imbricata hatchlings revealed a female-biased sex ratio in the study area, with 75.96% of individuals identified as females and 24.04% as males, resulting in an approximate sex ratio of 3:1. Regarding congenital malformations, 152 hatchlings showing evidence of anomalies were recorded in the field, of which 42 presented adequate conditions for detailed morphological analysis in the laboratory. Malformations were grouped into five main categories, with carapace and plastron abnormalities being the most frequent, followed by craniofacial and ocular anomalies, polymalformative syndromes, pigmentary alterations such as leucism, and, rarely, limb malformations. The results demonstrate that even under conditions of high reproductive productivity, environmental and anthropogenic factors can influence the quality of embryonic development, reflected in both sex ratio bias and the occurrence of congenital malformations. Thus, this study provides an unprecedented ecomorphological overview of the reproductive activity of sea turtles along the northern coast of Rio Grande do Norte, contributing to the recognition of São Miguel do Gostoso as a priority area for conservation, especially in light of the increasing tourism and real estate pressures on the coastal environment.

COMMITTEE MEMBERS:
Presidente - 1672446 - SIMONE ALMEIDA GAVILAN
Externa à Instituição - ALINE DA COSTA BOMFIM VENTURA - CEMAM
Externo à Instituição - GERALDO JORGE BARBOSA DE MOURA - UFRPE