Banca de QUALIFICAÇÃO: IGOR PERES PUERTAS DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : IGOR PERES PUERTAS DOS SANTOS
DATE: 27/11/2024
TIME: 08:00
LOCAL: Google Meet (https://meet.google.com/xft-ztao-yvu )
TITLE:

Natal origins and habitat uses of male olive ridley turtles (Lepidochelys olivacea) from Sergipe coast, Brazil.

KEY WORDS:

Stable isotopes; Conservation genetics; Southwest Atlantic; Sea turtles; Marine ecology

PAGES: 51
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Understanding migratory patterns, natal origins, and habitat use by sea turtles is crucial to refining and delineating conservation strategies, particularly during non-reproductive phases. Moreover, knowledge about these characteristics in male sea turtles is scarce due to the difficulty of accessing these animals, which, unlike females, spend their entire lives at sea. The olive ridley sea turtle (Lepidochelys olivacea), classified as “vulnerable” both nationally and internationally, is the most abundant sea turtle species in the world yet one of the least studied. Sergipe, in northeastern, hosts the main nesting area for this species along the Brazilian coast. Although nesting numbers have increased in recent years, the high number of stranded turtles is concerning for population stability, especially due to high male mortality. This high number of male strandings is believed to be due to their presence along the Sergipe coast during the whole year. Additionally, there is a tendency toward female-biased hatchling sex ratios in the region due to high temperatures, suggesting that the male population feeding and reproducing along the Sergipe coast may represent a mixed stock. Based on this, the study aimed to assess the genetic diversity and natal origins of male olive ridleys stranded along the Sergipe coast using the mtDNA control region and to identify preferred habitat use areas for males by analyzing stable carbon and nitrogen isotopes in epidermal tissue. To date, the control region of 15 individuals has been amplified, and isotopic analysis was performed on 32 specimens. Individuals were grouped by reproductive period, stranding season, and the season that the isotopic signature represents. No significant difference was found between δ13C and δ15N isotopic signatures among any groups, and habitat-use ellipses indicated little variation with significant overlap among them. Isotopic mixing models showed a contribution of neritic prey (crabs) for the evaluated individuals, with little input from oceanic prey (hydrozoans; Velella velella). Preliminary results suggest that male olive ridleys feeding and reproducing along the Sergipe coast exhibit foraging habits similar to those of females during the reproductive period but show differences in the post-reproductive period, in which females migrate to feeding areas while males remain in the region.

COMMITTEE MEMBERS:
Presidente - 1678338 - ADRIAN ANTONIO GARDA
Interna - 3058386 - VANESSA GRAZIELE STAGGEMEIER
Externo à Instituição - GUSTAVO DAVID STAHELIN
Externa à Instituição - DANIELLE DA SILVEIRA MONTEIRO - FURG