Banca de QUALIFICAÇÃO: JULIANA SILVA SOUZA LUZ

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JULIANA SILVA SOUZA LUZ
DATE: 07/11/2025
TIME: 10:00
LOCAL: Google Meet (https://meet.google.com/jek-yxbz-ins)
TITLE:

TROPHIC RELATIONSHIPS ON THE BEACHES OF FERNANDO DE NRONHA: PATTERNS OF OCCURRENCE OF NEGAPRION BREVIROSTRIS IN RELATION TO THE PRESENCE OF SARDINES (HARENGULA SP.) AND LOCAL PERCEPTIONS OF PREDATION

KEY WORDS:

trophic ecology; coastal interactions; participatory monitoring; ethnoecology; oceanic islands

PAGES: 76
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Sardines play a crucial role in sustaining marine ecosystems, acting as an intermediate link in the flow of energy between lower and higher trophic levels. In the Fernando de Noronha Archipelago, in addition to their ecological importance, sardines (Harengula sp.) have a relevant socioeconomic role, being used as premium bait for catching larger fish. They are commonly found in surf zones, and their abundance attracts predators such as the lemon shark (Negaprion brevirostris), a coastal and threatened species that occurs in Fernando de Noronha and completes all life stages within the archipelago. The formation of large sardine schools near the shore creates a complex environment of predation interactions, which overlap with human activities such as fishing and surfing. This study aimed to identify the main areas and periods of lemon shark occurrence in relation to the presence of Harengula schools, as well as to investigate local community perceptions of sardine predation dynamics along the beaches. The research was divided into two complementary chapters. In the first, a citizen science program based on the Instagram platform gathered 6,798 elasmobranch records, of which 632 corresponded to lemon sharks. Sardine occurrence data were obtained from a complementary citizen science survey conducted by Agostinho (2025). In the second chapter, ethnoecological interviews were carried out with fishers, surfers, and tour guides, structured into three thematic dimensions: (1) sardine concentration and related environmental factors; (2) “arrufo” and collective predation events; and (3) influence of large predators on human activities. Results indicated occurrence of hotspots on the “inner sea” (leeward side), especially in sandy beaches, with a marked spatial effect: beaches in Clusters 2 and 3 showed approximately 58% and 88% lower rates than those in Cluster 1. A positive effect of the dry season and of Harengula frequency was observed, while swell conditions were not significant within the sampled period. In the second chapter, results revealed predation strategies such as herding/encirclement and wave use, along with multispecific participation of jacks, scads, seabirds, and sharks. There was consensus regarding “arrufo” as a joint predation event and only minor perceptual differences among groups concerning predator influence. The study highlights the potential of participatory monitoring and local ecological knowledge (LEK) to improve understanding of coastal ecological interactions and to inform participatory management and marine conservation in protected insular environments.

COMMITTEE MEMBERS:
Presidente - 1378974 - LIANA DE FIGUEIREDO MENDES
Externa ao Programa - ***.618.874-** - MARIE-CHRISTINE RUFENER - UFRN
Externo à Instituição - RENATO AZEVEDO MATIAS SILVANO - UFRGS